Revealed: The secret behind Mercedes getting on top of tyre issues
Innovation
XPB.cc
Posted By: James Allen  |  13 Sep 2013   |  11:31 am GMT  |  106 comments

One of the defining stories of this 2013 F1 season has been the rise of Mercedes and the way they not only grabbed pole position in eight of the first 12 qualifying sessions (by getting the most out of the Pirelli tyres), but also got on top of heavy tyre wear issues in races to allow Rosberg to win twice and Hamilton once.

Analysis by former Williams chief engineer and JA on F1 technical adviser Mark Gillan of photos of Mercedes wheels, taken by leading F1 photographer Russell Batchelor of XPB Images, shows the complex internal design which Mercedes has evolved to master thermal management of the tyre. It is F1 innovation in action.

Mercedes’ steady improvement in tyre management in races has not happened without controversy, as they took part in a 1,000km Pirelli test in May which landed them in the FIA International Tribunal, where they were found to have breached the Sporting Regulations, but the Tribunal found that the breach had been made in “good faith” based on communications with the FIA.

Here is Mark Gillan’s analysis:

Background

Take a look at what the regulations say about wheels (at the bottom of this post).

As the wheels are easy for other teams to look at one is always very careful to ensure that their legality is crystal clear and if there are any ‘grey areas’ then one will run the idea past Charlie Whiting at the FIA to ensure that there are no problems. Whilst wheels are relatively inexpensive to manufacture (per item) the manufacturing lead times are relatively long and one typically needs 30+ sets of wheels (i.e. 120+ wheels) to remain operationally efficient at races so wheel upgrades during a season are not too common.

The Mercedes wheels in detail
In my experience conjecture about what a team is actually doing with a particular design is often wide of the mark.

What one can say is that to modify a wheel a team needs a good reason to do so because of the lead-times and quantities involved. As tyre thermal management has been a major performance differentiator this season all teams have been working on mechanisms/process to get the tyres into their operating temperature window as soon as possible and then keeping them in this window for as long as possible. The thermal window is quoted by Pirelli as typically 20C to 25C, with running temperatures of between 90C to 135C, depending on compound.


Mercedes has been evolving what it does inside the wheels. Mercedes now has a new set of front and rear wheels which were captured very clearly in Monza by photographer Russell Batchelor. On the inner surface of the wheel there is a complex dimple pattern, which is actually fully integral to the wheel itself and almost certainly there solely for thermal management purposes in order to get and keep the tyres within their optimal temperature window.

This complex dimpled and scalloped pattern (see close up of the front tyre, below) is not straightforward to manufacture and therefore indicates a lot of research and development has gone into developing this component and proving its benefit before committing to its manufacture.

This type of pattern is quite common on modern heatsink designs, where dimples have been shown to give up to 25 to 30% thermal transfer improvements over the smooth surface variant. Only Mercedes will know whether the effort was worthwhile and how good the correlation was to their simulation and rig programme, but one has to applaud their ingenuity and effort.

What the F1 regulations say
Firstly, Article 12 of the 2013 Technical Regs determines what a team can/cannot do with the design of their wheels. The regulations are pretty prescriptive, but the main points can be summarised as:

i) Wheel must be made from a magnesium alloy (AZ 70 or 80);
ii) The width and diameter of the complete wheel (wheel and tyre) is specified within a range;
iii) The wheel minimum thickness is 3mm increasing to 4mm at the bead;
iv) The wheel must not be handed i.e. the left and right wheels on a given axle must be identical;
v) Surface treatments are only allowed for appearance and protection e.g. painted/clear coated to avoid corrosion and allow for livery schemes.
vi) One can then add to the wheel a limited number of items such as spacers, balance weights, tyre pressure and temperature monitoring systems, pegs etc

Featured Innovation
FOM
INNOVATION BRIEFING
technical innovation from tata COMMUNICATIONS
Previous
Next
Share This:
Posted by:
Category:
106 Comments
  1. Haydn Lowe says:

    Wow! Another fantastic insight in an extremely fascinating area of current F1 tech. Do you think the other teams will have similar systems in place in their own wheel manufacturing processes, or is this a true one-off innovation that will leave Mercedes’ opponents desperately playing catch-up, much like double deck diffusers?

    1. Marc says:

      Merc’s idea is great innovation, fine, but what I don’t understand is if the Pirelli test was a crucial part of their improved performance. I mean, did they just test their (ready to use) new device or did the Pirelli stint spark the idea and then they rushed production?

      1. Quade says:

        I doubt the Pirelli test had anything to do with it.
        In fact, it would seem that Mercs wheels have been evolving, past shots show a slot and now we have dimples. Pirelli only knows how to make tyres, their expertise does not cover wheels; that wizardry is 100% due to Mercs back room boys and girls.

      2. gpfan says:

        Trust me, Quade; Pirelli know how to make wheels and why to make them a certain way. Your comment is akin to saying ‘Cosworth only know how to make engines, and not exhaust systems’.

        Pirelli designed tyres that most of the teams were able to make work just fine. It was only Mercedes that seemed to have an over-heat issue. I’d be willing to bet that some version or another of this wheel was used during the illegal tyre test.

      3. Nick says:

        That’s a very good question! It’s coincidental evidence, but the upturn in form immediately after the test suggests they tested it there. Sneaky

      4. Poyta says:

        No one said anything about the Pirelli test being crucial to their improved performance. Pretty sure they were not allowed to test any new parts at that test.

      5. Nick says:

        Not crucial but their performance pre and post test opens questions as to what was done. Would anyone at Pirreli have raised questions or noticed the wheels were different? I’m sure having just raced there the drivers feedback and lap times would have been sufficient data. As for not testing new parts, well that would be trusting a team that were found to have conducted the test illegally (on “good faith” mind).

  2. Joe says:

    I don’t know about you guys but the top wheel looks like it has dimbles and the lower wheel looks like it has a layer of carbon fibre for heat protection.

    1. Optimaximal says:

      That’ll likely just be the light catching the dimples at different angles.

    2. Giorgio says:

      Lower wheel is wet.

    3. Quade says:

      The rear wheel has a matt black coating for better heat absorption, the front wheel has none.

      1. Joe says:

        I agree, either heat absorption or reflection. They might be trying to achieve two different things with each picture.

    4. To me it looks like the top image shows a new wheel about to be put on the car with the tyre still in the blanket. The lower image is of a wheel following removal after doing a stint on the car. The top one shows a nice, uniform pattern and finish – which is what you would expect being new. The lower one shoes a lot of scoring and damage due wear from something trapped between the wheel rim and braking/axle components (micht even be the brake housing itself due to the tight tolerances and differential expansion of components causing some friction). That friction CREATES heat – maybe their tool for getting the tyre up to temperature quickly and stops generating heat once the thing that is causing the friction (or the wheel rim itself) has worn sufficiently.

      1. roberto marquez says:

        You know how dangerous it would be if gripping occurred between both parts ? Have you ever seen two pieces of metal being welded in a lathe just by making one turn against the other ( stationary ) to produce enough heat ? I think the bumps are there to avacuate heat rather than produce it, they are like tiny fins to maxime heat exchange.

  3. Robert N says:

    Has any other team got a similar design? Or is this only beneficial to Mercedes, who used to overheat the tyres?

    Is Mercedes going to use the same design in 2014 as well?

  4. Akshay says:

    There seems no hard rule on the surface profile of the wheel. Unless they want to put that under surface treatment.

  5. Sebee says:

    Seems like the easiest thing to copy between teams. Seems also that as importance of tire management is significant that as a team principal I would photograph all tires going in and out of Pirelli tire mounting station to see what other teams are doing. All this means, it shouldn’t have taken Mercedes this long to figure this out.

    1. Spyros says:

      Easiest thing to copy?? Not with a few months’ worth of lead time, it isn’t!

      1. Sebee says:

        How long has Mercedes had tire heat issues?

    2. Blackmamba says:

      Well, Sebee I imagine it is not as easy as copying another team’ tyre design as different chassis have different ways they deliver energy through their tyres when making contact with the tarmac. The cars have different downforce levels, different front and rear wings, different ride heights and have different entry and exit speeds when cornering I could go on. Really, your advice is to take pictures and copy? If F1 was as easy as that I Imagine every car would look like the Redbull.

      1. Sebee says:

        Of course there are many variables, but if it’s something relatively simple (by F1 standars) as a wheel, surely it’s an area every team should explore and can refine at relatively low cost and time window. I don’t disagree with you about other variables, but in this case we’re looking for a “heat sink” to move heat away from wheel or to insulate break heat from radiating toward the rim to prevent taking the tire beyond ideal range.

        Photographers like Russell can sell their quality images of each team’s solution as it rolls out of the Pirelli tire mounting area, and it would be irresponsible for a top team to not look into this area. Really, Mercedes had this problem for how long?

        Perhaps there is a case to be made for standardized wheel rim in all this?

      2. Kingszito says:

        @Blackmamba, I enjoy reading your post, not because you are a Mercedes fan (If you are), but because you call it as it is. As for Sebee, he pretends to be you, but he is bias. I recall him saying that Mercedes invaded McLaren when they signed Lewis and Paddy. I have been going through posts to hear him say that Ferrari invaded Lotus by signing three of their employees, but you can’t hear that from him.

        Back to the topic, if F1 is copy and paste like Sebee portrays, every car would be as fast as a Red Bull.

      3. Sebee says:

        I feel compelled to respond Kingszito.

        First, you must admit the sequence of events at McLaren is much different than Lotus. Mercedes clearly recognized the ability of McLaren to build a fast car around its engine and went after everyone to gain the knowledge, benefit, and gutted the ranks top down starting at the guy holding the steering wheel.

        Allison left Lotus way ahead of Kimi signing, and it was never a foregone conclusion that Kimi would end up at Ferrari. If you recall, it was in fact a darn near coinflip that Kimi was going to be drinking Red Bull ad nauseum in 2014. Only after what appears to have been Kimi’s 1st choice turned him down, did Kimi end up at Ferrari with Allison hired long before. So while indeed, the result is similar to McLaren, it’s more of a coincidence and Ferrari taking the opportunities rather than Mercedes vigorously targetting McLaren’s human assets.

        As for your copy/paste point, my comment above addresses this. The change here is a better heat sink and increased surface area to spread the break heat over larger surface and allow that larger surface to only reach a certain temperature. It’s not rocket science, and this type of innovation should have been easy to copy by any team having tire heat issues. In fact, with break heat being such a huge issue in F1 since begining of time, I’m surprised that such improvement is only now being made at Mercedes, or any other team who didn’t have this for that matter.

      4. Sebee says:

        Oh, and I recognize that there is a fine dance between many components in an F1 car to maintain certain heat in the tires and brakes. But if higher level of heat in the rubber is clearly isoleted the way we have seen at Merceds, then I would expect the engineering teams to have this option already on the short list. Hence my surprise that only now is it here, and that Schumi didn’t get the benefit of it last year. :-)

      5. Kingszito says:

        @Sebee, nothing is different from the way Mercedes hired their employees to the way Ferrari hired theirs. If any difference, Mercedes’ was even fair fight considering they were against a big team like McLaren.

        Not as if Hamilton’s contract with McLaren was still valid when he moved team. McLaren didn’t agree with Lewis during contract negotiation so he had to look elsewhere. Paddy was already on his way to Williams because of Toto, but when Mercedes hired Toto, he convinced Paddy to follow him to Mercedes instead of Williams. So using the word “Invade” and portraying it as if Mercedes committed a crime is what I don’t understand.

      6. SteveR says:

        @ Sebee. I think you have it backwards. The increased surface area from the dimpling gives a larger surface for heat to transfer from the brake tin to the wheel, increasing tire temperature, not the other way around. ScarbsF1 indicates Mercedes is having trouble heating the new spec tires, and this is a way to transfer more heat from the brake to the wheel.

      7. Sebee says:

        OK Kingszito, now with Dirk de Beer signing, Ferrari getting closer to Mercedes!
        But still, it’s Allison who probably pushed for his friend/co-worker. Not Ferrari specifically. So again, there is a difference.

      8. Sebee says:

        SteveR,

        Intersting. So there is not enough heat now?
        It makes sense what you say. I thought that larger area would require more energy to bring it up to same temperature as a smaller area, meaning wheel takes longer to bring up to temp thus keeping tire cooler. But I guess it also makes sense that larger surface captures more radiant energy. So it’s down to how much of that heat is present and needs to be retained. Also, I wondered what all these dimples do for unsprung weight, as there are minimum thickness requirements on the rim, right?

      9. Sebee says:

        Point taken Kingszito. Maybe I was a bit harsh. It just felt harsh to me. Lotus is not a partner of Ferrari. Mercedes was a long time partner of McLaren. That also plays a part for me. But I guess it was McLaren who decided to do their own car when Mercedes was reaching out for exotic car partnership. So your point on my choice of wording has merit perhaps. Business is business.

      10. Kingszito says:

        @Sebee, I may disagree with u in whole lot of things, but u have earned my respect. Fair play and straight up criticism is what I want. We must not like or support the same team, but let’s at least be unbiased as much as we could. One’s again you are the man and I would be very happy to oppose or agree with you on some topics.

      11. Sebee says:

        SteveR,

        If the Mercedes tires were getting too hot, and now the new rubber is not getting up to temperature and this dimple pattern is responsible or contributes to that, why would Mercedes continue with it?

        So if the rubber was too hot, the two areas in question would be cool the brakes to reduce transfer or introduce some type of heat removal diple heat sink. Is my thinking illogical?

    3. Karim says:

      That post has got me thinking actually, which has nothing to do with the article incidentally.

      Could it be that teams that come up with sporadic upgrades during the course of the season, do so in a strategic conscious manner and that these upgrades are all pre-planned for the season, but that these upgrades also depend on points totals etc.?

      Also, when a team has an upgrade already in place, could it be they want to limit the time allowed for rival teams to copy them by installing them later?

      I understand this wouldn’t make much sense for most teams, but for a team like Redbull now for instance, who have the title in the bag practically, if I were Team Principal I wouldn’t want the team to install any upgrades (even track related specific ones) out of fear of teams copying them for next season, so maybe most of them should be saved for the next season…… (at least those upgrades that can be photographed).

      Wouldn’t mind to hear some thoughts on that!

      1. RodgerT says:

        Top teams already do this to an extent. The car you see at the press launch isn’t the same as what is at the first test. The car at the second test isn’t the same as at the first, and so on until the first race of the season.

      2. Martin says:

        Hi Karim,

        As always in F1 it is never simple. McLaren had time to race the f-duct in 2009 but for competitive reasons chose to wait until 2010. Waiting allowed McLaren to integrate the concept into the overall aerodynamic design and it remained unchanged for most of season. It changed once other teams found there was a better way of doing it, blowing the main element rather than the flap. Introducing it in 2009 when McLaren was well behind in the points would have given the other teams a massive head start.

        In terms of designing a new car and the potential it has for further upgrades, the teams aren’t holding back ideas at the start of the season, but in designing a car the engineers are looking at the perceived performance potential that could be found be further development. For example with a side pod the teams need to consider the cooling of the engine and KERS, the crash safety, the centre of gravity and the airflow off the front wing and around the wheels, all to consider what quantity and quality of airflow it can get to the rear floor area. The teams will simulate the major limits of a side pod shape using their previous experience and quantitative data. So a particular concept will have immediate performance X and potential Y. Developments that have generally been considered for experimentation get tested in CFD and then possibly the wind tunnel.

        The first car rolled out at testing tends to be conservative in terms of airflow management – minimal risk of air flow becoming detached or wings stalling. The upgrade path initially is probably just a more aggressive approach to exploiting the airflow. It tends to involve the whole car as the front wing tends to be critical to the flow around the rest of the car. So at the Spanish GP the first major upgrade trends to arrive with a new floor and wings and turning vanes. Generally this upgrade works pretty evenly across the field. Some teams hit Melbourne with a stronger package and have a little less potential to improve in Spain. The next big whole of car upgrade tends to occur around the British or German GP. Around this point to me it seems the teams tend to have exhausted the imagined potential development of the car when it was designed the previous year. The teams are then reacting to the data from the track a lot more and the upgrades then to be incremental changes to individual elements. Big changes tend to come from new ideas that weren’t in the initial design. For example Red Bull’s DRS system last year and Lotus’ longer wheelbase this year.

        In general teams always want to win the next race, as you cannot control what other teams might come up with to deny you in the future. Big ideas are held back sometimes to get maximum benefit, and more data is often useful to ensure parts works to their potential.

        Cheers,
        Martin

    4. Grant H says:

      As a time served design engineer I can tell you the amount of development, modelling and testing that would have gone into that part will make it difficult to replicate overnight,

      Lead time will be long when you factor in development

      Excellent and insightful article, thanks for sharing James

    5. Quade says:

      Merc has a radically different suspension (FRIC) from the other teams, in my opinion that is why they have had tyre issues and that is why other teams wouldn’t be copying their wheels.

      Suspension characteristics are a major part of tyre wear and speed (ask McLaren). Quite clearly, the benefits of the FRIC system are so immense that Merc has spent two years in tyre hell as a sacrifice for its development. Perhaps without the cheese tyres, Merc would be a full second or two ahead of the field.

  6. goferet says:

    Very clever indeed by Mercedes.

    We can only sit back and wonder what could have been if the team had this technology from the very start, perhaps we would have had an entirely different season.

    Now, the only question that needs answering is whether the new components will affect the teams performance on low temperature tracks but seeing as the likes of Lewis can work their tyres harder, heat generation will never be a problem.

    Anyway, now that we have the low downforce circuits out of the way, lets see what rabbits the team will pull out at the remaining races.

  7. Elie says:

    Surely then this wheel is illegal. Because if the wheels have patterns they surely can’t conform with item V above ?

    1. KARTRACE says:

      Now this is another gray area in which Ross got PHD.
      Is it the surface or it is the rim structure that they designed and manufactured dimpled. Now other question is are they having minimum thickness and how to measure it. Furthermore, if this is a consequence of that extra ( secret ) tire testing and data gathering then clearly they gained unfair technical advantage over other competitor, which was refuted, remember ?

    2. G says:

      Its not a surface “treatment”…. that would imply some form of modification or application of a material “after” the manufacturing/painting processes. This is integral to the wheel itself

      Other commentators have suggested that there is also a special paint used that reduces wind turbulence between the wheel and the brake assembly…. how true this is, we will never know

      G

      1. KARTRACE says:

        One photo shows that this surface is sort of peeling off. It could be that it is not integral part of the alloy/ casting.

      2. Elie says:

        @G – yeah I think your right- the “dimples” are actually formed as part of te rims. After reading the article again it says

        ..”This complex dimpled and scalloped pattern (see close up of the front tyre, below) is not straightforward to manufacture “..
        Very, very interesting you would think that somewhere the rules would be very specific about a rim being perfectly flat (smooth) but kudos to them .

    3. Sebee says:

      I believe there is a wording technicality in play here. Sufrace refers to outside look/design of the wheel, as in 5 star, 4 star, spoke and the “visible” part of the wheel. The area shown here in the Mercedes is actually the rim, or the inner rim. So by definition it is not the surface of the wheel. However, you’re right to point out that everything on the wheel has a surface, and unless the definition of which surface V refers to it could be interpreted that this is illegal.

      Hey, RBR are you reading this? Mod your wheels to entire no-surface treatement wheels and file a protest against Mercedes wheels surface treatment. :-)

      1. Jonathan says:

        I think you will find it is a lot simpler than that.

        Surface treatment is what you do to the surface as the final part of manufacture. Applying paint, polishing, anodising or galvanising are all surface treatments that happen after casting and machining.

        I haven’t yet seen any point referring directly to the difference between front and rear wheels. From what I can see one has dimples or indentations meaning less material on a thicker rim whilst the other appears to have additional material like studs or spikes added to a thinner rim. I wonder if they have found that it works to improve the direction of heat transfer. Is one intended to radiate heat whilst the other is intended to absorb heat?

        Given this I assume the first are machined out of the rim whilst the other are cast as part of the rim. I also notice that the rim edge detailing is different. The upper photo shows a scalloped whilst the lower wheel has a much squarer edge.

      2. Sebee says:

        I’m still a bit mixed up if this system is intended to move heat out of the tire/rim, or if it is designed to bring in heat from the brake system? To me the instant logical purpose is to move heat out, but some above suggest it’s to bring heat into the wheel/tire from brakes. Seems like a strange purpose, because brake systems likely have a way wider operating range than tires, and why have additional unsprung weight at circuits which don’t produce sufficient brake heat to heat the wheel/tire? So I’m still stuck thinking this is to move heat out of the tire unless I get the logic of the opposite purpose.

        Also, if there is a minimum thickness of rim, then surely it’s uniform thickness not allowing for some points to be set number of mm while others are thinner like the drilled indentations. Meaning, added unsprung mass, no?

        Once you start getting into the details, this stuff is fastinating. I’d simply like to understand the solution function and purpose fully.

    4. Elie says:

      Appreciate this is only a summary but V does not suggest inner or outer rim and that modifications are only for appearance purposes. Clearly these patterns are deviations from that, but maybe it’s covered elsewhere.

      Also I would suggest that the scraped rim in the second pic happens as the patterns scrape on the brake drum when they are fitted/ removed. The patterns obviously create space between the hub and the main part of the rim allow heat to dissipate at a steady pace. Clever solution ,Red Bull and others don’t need this as they have managed this problem in other ways.

  8. Chris says:

    This is a great spot and an interesting read James cheers as always for the insight.

    Do any other teams adopt this approach to effectively increasing the internal surface area and thus improve thermal dissipation to aid tyre temp that you are aware of?

  9. aveli says:

    the key word is relative. how does that picture compare to pictures from other teams?
    surely there is a lot more to it than that. several other factors must contribute ie how the tyres are treated before mounting, how hard the driver attacks the out lap, heat shields around the breaks etc.
    the secrete is yet to be revealed.

  10. K says:

    Nice job catching it.

    If RBR had been doing this, people would be screaming ‘cheaters’ from the highest buildings, no matter if it is within the regulations.

    1. kfzmeister says:

      Ridiculous!

    2. BreezyRacer says:

      Yep, I agree ..

  11. R Y says:

    Concept can work in two directions – it could transfer heat _out_ of the tire in marginal conditions.

    1. Grant H says:

      Would have assumed the modelling done pre-manufacture would allow them to tweak the design for different typical conditions, obviously you cant cover all basis and there must be an eliment of tuning

  12. W Johnson says:

    Get to work Martin! (Whitmarsh)

    1. Andrew Carter says:

      You do realise that the only car capable of looking after it’s tyres as well as the McLaren is the Lotus?

      1. grat says:

        Well, yes, but that’s because the MP4-28 is slow in the corners, and can’t load up the tires the way the other cars can. ;)

      2. Andrew Carter says:

        You mean like the Sauber, Torro Rosso, Caterham, Marussia and Williams; all slower cars that can’t generate the loads of the top teams, or McLaren, yet still have higher tyre ware.

      3. Christos Pallis says:

        I wonder weather the stiffly sprung McLaren suspension lends its self to being kind on its tyres. Stiff suspension would mean less deforming over surfaces hence less energy going through the tyres!

        It’s not strictly related to corner speed as the comment about other teams makes clear. That would suggest that Marussia would have the least tyre wear of all teams!

      4. Quade says:

        Christos Pallis
        Its a mixture of things. Stiff springing makes the tyre take the place of the springs and buckle under load. That would help to heat the tyres up, but wouldn’t do much good for their longevity. However, the loading (and life) of the tyre greatly depends on how it is set up for cornering and braking, and these are affected by how tightly sprung the car is.

    2. kfzmeister says:

      …but not on this design. They need work in other areas!

  13. Craig says:

    Looking at the two photographs, the upper picture seems to show the dimples included in the construction as part of the rim. However the bottom picture appears to show an “insert” rather than a completely new design of wheel as suggested in the article?

    1. Tim says:

      Front and rear wheels ? I believe the front brakes work harder , hence more heat produced , different design required to dissipate the heat ?? Not sure, just a guess .

    2. Quade says:

      The upper photo is the rear wheel, while the lower is the front.

      The front and rear wheels have different heat characteristics, that’s why they are constructed slightly differently.
      Both the front and rear wheels get heated by braking and the energy of the tyres from repeated flexing.
      In addition, the rear wheels get heated by exhaust gases and sliding around corners, while the fronts are the focal points of the cornering forces.

  14. Methusalem says:

    Why were they then out-qualified?

  15. Fan says:

    Was this tested and perfected during Mercs private in season test? We will never know…

  16. Grant says:

    Well the Merc is much slower now, with this tech.

    So neither here nor there really.

    1. KARTRACE says:

      No one designs, develops, produces components or assembly with the idea to make them slower. The intent was to make them, faster, more consistent, more reliable. So when one judge those components he/she isn’t worried how successful it is, but the intention.

    2. SteveS says:

      Hamilton had the fastest lap of the race in Monza, and I think Rosberg had the second fastest. So no, they have not gotten “much slower”.

    3. Grant H says:

      Please explain this comment it does not make sense?

    4. Siddhesh says:

      Nah! Not much point going by their performance in Monza, where the track characteristics would mean the team coming with the lowest downforce setup would perform the best. I’d actually take heart from Hamilton’s race pace which was quite good. Singapore will provide a much better test. I think the Merc is still the best in generating heat and getting the most out of their Pirelli’s over one lap, so it should be interesting.

    1. j says:

      Yeah, a week ago. With pics from SomersF1 blog. It’s great to see all these fan tech blogs getting started and even getting the scoop on some of the new ideas cropping up during the season.

  17. Random 79 says:

    Some very clever boffins at Mercedes :)

  18. SteveS says:

    The reality of technical regs in F1 is that they are whatever Charlie Whiting (or in some cases, the tribunal) says they are.

    The Renault mass damper of 2006 was ruled illegal for being a “movable aerodynamic device”, for instance. Rotating dimples (or are they actually small holes?) are far more obviously a moving aerodynamic device than the mass damper was. And if they ARE holes, which they appear to be from the photos, than this could also run afoul of the “Air Ducts” section of the regs.

    If the authorities *wanted* to ban what Mercedes are doing here, they could plausibly do so. But such decisions always have as much to do with politics as with the strict letter of the law. A modicum of success for Mercedes is necessary to keep them in F1, so Charlie isn’t going to rock the boat.

    1. SteveS says:

      I meant the 11.4 air ducts section, discussing air ducts around brakes.

    2. Grant H says:

      They are not holes, device works by transferring heat therefore not aero device

      1. j says:

        True, the dimples work for creating more surface area but there has also been speculation that the dimples might have a secondary benefit of reducing airflow resistance in the small space between the brake duct and the rim.

      2. SteveS says:

        Nobody outside of Mercedes knows whether they are holes or dimples.,

        Holes increase the surface area, just as dimples do, and also allow for air flow. So it would be smart for Merc to have used holes rather than dimples.

  19. Seized Up says:

    I can’t help thinking the wheel looks like a washing machine drum… Maybe smaller holes?

    1. Tim says:

      Thank you – I knew that it reminded me of something – lol :-)

  20. Iain:R8 says:

    The profile of those ribs, seems to be far too shallow for any significant thermal effect. Unless there is an enormous airflow, or they extend in to the air space between the wheel and the tyre. Of course that could also provide a means to help with a partially deflated tyre, if the top of the ‘spikes’ was covered with a solid layer. Maybe a deflation compensating device. Remember how Lewis had a slow puncture for a few laps, and no real problems with it, as I recall. I think what we are seeing, is a surface effect for aerodynamic reasons. Similar to a golf ball.

  21. f1316 says:

    James, is this so idiosyncratic to Mercedes’ tyre issues or will other teams be likely to take a similar approach to either get the heat in or out of the tyre better?

  22. GDR says:

    It’s basically a heat sink which dissipates heat very effectively… Clever

  23. ThrowFarFarAwy says:

    People, this isn’t to decrease the tire temp, it’s to increase the temp of the tire case. By using the brake as a heater.

    Graining occurs when the surface temperature of the tire increases significantly more than the case temp does. This increases case temp, thus reducing graining.

    See also: http://scarbsf1.com/blog1/2013/09/06/mercedes-cross-cut-wheel-rims/

    1. KARTRACE says:

      It is a lot of unknown about this finish. But according to paragraph V it is not legal. The link that you are referring to contain one incorrect statement that black pain absorbs the heat. Mat black dissipates the heat and matt white is absorbing the heat. There are some other exotic finishes involving ceramic particles which are used in thermal control of various components.

      1. Quade says:

        Black absorbs heat and white reflects it.

      2. KARTRACE says:

        Right you are, but we are here not observing reflectiveness. If you have the heat that is inside some physical body radiator, exhaust system or wheel which contains gas then it’s different all together. To allow heat dissipation one would use matt black paint and in order to contain it one would use white. We are not here discussing if the black absorbs or white reflects the sunlight or any other light source fir that matter. Heat dissipation(conductivity)and reflection are two different physical phenomenons. In order to improve the gas flow in the exhaust system by reducing heat dissipation Ferrari use to finish their pipes in white. They didn’t do that just to make their cars prettier. Kindly refer to the link. http://www.tumblr.com/tagged/ferrari-312

      3. Quade says:

        Thanks for the link.
        But, lighter colours are only used where convection (or conduction) matters more than radiation (eg home radiators – which are really convectors).
        In the Ferrari case, they wanted to minimise heat transfer to the surrounding air, if they’d wanted to maximise it, then the colour would have been matt black like the inside of the Mercs rear wheel.

        @ThrowFarFarAwy
        The reason for the colour is most likely because Merc is creating a heat pump between the brakes and the inflation gases in the rear wheel. So, the heat from the brakes would actually be cooling the rear tyres.

    2. ManOnWheels says:

      Well, dimples increase the surface area to volume ratio, so when the brakes are loaded their heat will transfer faster into the wheels and when the brakes are not loaded, the heat will transfer faster from the wheels into the air. So I’d gues that the wheel heat up faster in the braking zones (after getting cold on the straight) and when during and accelleration they are not overheating so fast.

      1. ManOnWheels says:

        That was meant to be: “when cornering and durung accelleration”. My bad.

  24. Rich says:

    Brilliant stuff James. Thanks for that really interesting info. It explains why Mercedes suddenly became competitive in the races.
    Just need Lewiws to believe in himself now, and get his head right !!!

  25. dean cassady says:

    the mercedes public relations efforts has no bounds.

  26. Clarks4WheelDrift says:

    Wow, looks as if they could throw these wheels on without wheelnuts in a sub 2s stop and they’d stick on!

    Amazing that the friction heat on the outer contact patch could still be influenced by the inner heatsink, I guess every little helps.

    DC did always say it was the brakes that heated the tyres more than the weaving on warm-up laps. You’d think it could affect the drivers getting the tyres up to temp on a cool day say after a pitstop or safetycar.

    They surely also have air blowing on the heatsink area somehow through the wheel hub?

    The things Merc have to do to stop oversteering Lewis chewing up his tyres eh!
    (joke, it’s a joke, fanatical fanboys please sit back down…)
    I expect to see the Mercs back fighting for pole as we move back to the slower tracks. They just need to watch the driver tracker screens for Sutil… ;)

  27. BJ says:

    Scarbs discussed this about a week ago, maybe more.

  28. Matt says:

    Innovation is not dead in Formula One! This kind of insight is the reason your site is a must-read, James.

    Now we just need to figure out whether they have had this design all season or if it was only introduced after the tyre test.

  29. TGS says:

    Sergio Perez said that McLaren are bringing new parts to Singapore with an eye to next year’s car. Does this mean that the parts will work on both cars? I had assumed that there would be drastic changes to the chassis that would prohibit this. Any chance you could do an article on how the engine affects car design James? Cheers.

  30. Elie says:

    James is it safe to assume the dimpled pattern actually sits on the drum, this cause a space between the dimples and sustaining a constant temperature and allowing excess heat to ease out.or does the wheel sit more on the smooth inner edger of the wheel just ahead of the dimples ?? Thanks

  31. franed says:

    Slight miss-quote of the regs there James.
    12.8.1 Actually says:-
    The only parts which may be physically attached to the wheel in addition to the tyre are surface treatments for appearance and protection, valves for filling and discharging the tyre, wheel fasteners, balance weights, drive pegs, tyre pressure and temperature monitoring devices and spacers on the inboard mounting face of identical specification on all wheels for the same axle.

    The magic word there is of course “attached”, while the patterning seems to be part of the wheel casting itself.

    It is an interesting problem, moulding or casting on a concave surface, since the male part of the mould has to collapse in on itself. Of course if one machines the pattern on instead it looks like two or more cutting operations (lathe plus linear shaper) and a lot of time, still I suppose a decent sized CNC machine tool could handle it.

    One thing to consider is that not only is the surface area increased, possibly doubled but the mass is also increased.
    (It must be a surface addition since to cut into the wheel would take it below required minimum thickness of 3mm. Which is pretty dramatically thin anyway. On a CAD course (ProE) some 14 years ago one of the exercises was using a prt file of an F1 wheel and at the time we could not believe how thin it was.)

    It is all obviously to increase the heat transfer rate from the brakes into the wheel, but Lewis is still having problems with the brake characteristics.

  32. Quade says:

    I could bet my last penny that those are not dimples, but holes into a space in the wheel hub. Before this, Merc spotted wheels that had a slot in them. Some argued that the slot was an illusion and really just a piece of tape, but those that argued it was a slot seem to have been proven right.

    You can check some of the arguments (F1 technical) that raged as far back as July about Mercs wheels starting from this page: http://www.f1technical.net/forum/viewtopic.php?f=12&t=14607&start=2775

    1. franed says:

      No it’s just a conductive, or non reflective coating. (since there will be radiated heat as well as convected.)
      Enlarge the top photo in yr link as far as poss then look far left, you can just see the coating on the rim where the balance weights go. The lower pic shows a weight in place (near the red arrow) on top of the coating. I had said tape initially but I doubt you would stick a weight on top of PTFE, tape

      1. Quade says:

        There are a few more pages of interesting arguments (and pics) at that link. The holes in the current rear wheel convince that we are looking at an evolution of the slot in the previous incarnation of the cooling concept. Perhaps, holes are suitable for some circuits, while a slot is preferable at others.

    2. SteveS says:

      They do look more like holes than dimples. Holes have all the advantages of dimples (they would increase surface area and thus promote better cooling) and others as well.

    3. Quade says:

      franed
      I have argued somewhere above that:

      “The reason for the colour is most likely because Merc is creating a heat pump between the brakes and the inflation gases in the rear wheel. So, the heat from the brakes would actually be cooling the rear tyres.”

      I really think that’s whats going on. Merc have used the rear heat from brakes and exhaust to create a tuneable fridge for the rear wheels. Holes and a sophisticated set of chambers would suit such a purpose better.

  33. Hans Faynmann says:

    That’s just a great piece of insight!
    Thanks for your investigative efforts that you don’t get from other F1-related websites!

  34. Macht Exim says:

    Graining happens when the surface temperature of the wheel improves. This improves situation temperature, thus reducing graining.

LEAVE A COMMENT

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Top Tags
SEARCH Innovation
JA ON F1 In association with...
Download the chequered flag podcast today
Download the chequered flag podcast today
MTS
Industry-Leading Testing and Sensing Solutions
Multi award winning Formula One photographer
Multi award winning Formula One photographer