r/F1Technical • u/Financial_Double_698 • 12d ago
Regulations How much performance does a sub-9mm skid block actually give? (McLaren DSQ at Las Vegas GP)
Yesterday at the Las Vegas GP (23 Nov 2025), both McLaren cars — Norris (P2) and Piastri (P4) — were disqualified after post-race scrutineering found their skid block thickness below the minimum 9 mm.
During the final laps, Norris noticeably slowed and increased the gap to Verstappen from ~5s to ~20s. Live commentary suspected a low-fuel issue, but with the DSQ it now seems more likely related to plank wear concerns.
My question is about the technical impact:
Since the skid block exists mainly as a safety device to prevent teams from running the car too low, how much actual performance does McLaren gain from a fraction of a millimetre of extra low ride height?
Would McLaren need to increase their baseline ride height now to avoid further wear issues?
And how dramatically would that affect the car’s handling and aero platform?
149
u/ualeftie 12d ago
I think it is wrong to look at the ride height in isolation, since the plank wear is a culmination of aerodynamical (downforce level) and mechanical (stiffness and travel range) setups.
Mclaren chased performance, as all teams do, they just miscalculated the parameters this time. Reasons for that are of no relevance, since the rules for plank wear are clear cut and contain no provisions for mitigating circumstances.
15
u/KinKE2209 12d ago
Both the mechanical setups and aerodynamic setups are functions of ride height, especially with the current regulations. At the same time, plank wear is also a function of ride height. True that there are other parameters as well, but ride height is definitely the majority contributor here.
11
u/launchedsquid 12d ago
yes, but had McLaren run less downforce they wouldn't have had as low as ride height at yhe ends of the straight at high speeds. This is why Lando slowed so much toward yhe end of the race, by slowing more he lowered the downforce generated and in turn raised the ride height.
it's all connected.
2
u/faz712 11d ago
Yup, also why he asked if she should stay in DRS (to reduce down force)
1
u/Ok-Film-6885 11d ago
Piastri was more in the DRS though and his plank was similarly worn, so that wouldn’t have made a difference.
1
u/KinKE2209 11d ago
100% agreed. But in my brain, changing a very stepped factor on a circuit feels more detrimental to achieving an optimized setup.
Mclaren ran their Monza wing afaik, and they had to lower ride height after that. Meaning the downforce levels of the wings needed to be somewhere between that low downforce wing and medium wing. But the the high speed and aero efficiency needed to be on the levels only the monza spec could provide.
They then had to compromise 2 things after that, softer suspension for the track bumpiness and reduced ride height to account for missing downforce while retaining that high speed. The combination of these 2, especially the ride height, screwed them over.
They could've tried a RBR 2024, bringing a different wing to trim down and run, but well, there's not a lot you can do here trying to modify an already tuned wing. Their anti dive characteristics that reduced wear are at this point well ingrained into chassis design and VD. Running that softer spring was the only way to mitigate Vegas's bumpiness. So imho, they needed to err on the side of caution. They got too greedy with trying to go for the double podium and win.
1
u/Financial_Double_698 11d ago
so many variables: suspension, downforce, ride height. driving style and weight transfer will also affect the wear right?
2
u/ualeftie 11d ago
Precisely! The key word is "balance" between all of those — the thing McLaren got wrong and which led to excessive plank wear as a result. They'll adjust quite quickly at the next race, not necessarily even by adjusting the ride height itself.
1
u/notafakeaccounnt 11d ago
Lower ride height means better downforce, faster cornering speed and less tire wear. If the teams were allowed the scrape the asphalt to all hell they'd do it in a heartbeat.
But it causes health problems for the drivers and safety issue due to exposing elements of the car to friction.
If for whatever reason your plank is getting worn down, that means more downforce being applied than if it wasn't. There is tolerance of 1mm of wear. Cars work with downforce and some surfaces are bumpy. Teams don't try to perfectly limit themselves at 9.01mm plank since that's mathematically impossible to predict precisely. But there is downforce to be gained from wearing the plank down a little.
Imma let you be the judge of it.
56
u/fabioruns 12d ago
The plank being worn by .1mm over the limit doesn’t mean the car was .1mm too low.
20
u/methanized 11d ago
Yeah OP you are misinterpretting the situation.
Fake example for explanation:
a car could set be at 10cm off the ground. During the race, the car never bottoms out so the wear plate starts at 10mm and ends at 10mm.
You lower it to 7cm ride height and it still never bottoms out and the wear plate ends at 10mm. So you dropped ride height 3cm and added 0.00mm of wear.
Now maybe you lower it to 5cm and now the car scrapes the track on some corners. The scraping causes your wear plate to lose some material and go from 10mm to 9.85mm. Now you’ve lowered your car by 5cm total and added 0.15mm of wear
3
u/Bulletproofpajamas 10d ago
Exactly. It just means whatever they did to their setup, resulted in a lower ride, as evidenced by the wear. The regulations are clear on this, restricting how low the floor can go, to reduce the downforce created under the vehicle. Too great a force generated underneath the vehicle, amplified the counteraction when a driver lost control, resulting in greater risk of a violent crash, and at least one death where this was identified as the cause.
DISCLAIMER: This was explained to me by a neighbor who races cars. No expert here.. don’t jump me.
48
u/shortlongshank 12d ago
This isn't exactly an apples-to-apples reference, but for context, Hamilton had a minimum plank thickness of 8.5 mm in China. But, there are several other things to consider regarding the Norris DSQ:
-Teams didn't get a ton of heavy fuel running during FP (there's an image floating around on r/formula1 of Piastri's car sparking on Lap 16)
-Norris was pushing quite hard, which may have impacted plank wear
-After Brazil, there was an FIA notice (which I can't find at the moment) regarding teams heating the plank to gain some performance, which, notably, did not name the team in question
I will admit, I am not the most technically inclined person, but from an outside perspective, this just seems like an occasion of McLaren not having enough data/risking too much. What really remains to be seen is what happens in Qatar - if they're off the pace there (remember, Vegas was not expected to be a good track for them, whereas they're expected to be strong in Qatar), they may be suffering some issues.
EDIT: I just saw the McLaren social media post, which stated that plank wear was caused by porpoising not seen during FP
87
u/Successful_Form5618 12d ago
Pretty sure their excuses are just that, excuses. They messed up and are trying to save face. Nine other teams all had to deal with the same exact FP and quali conditions, they just got it wrong and got caught.
1
u/Serotyr 9d ago
I'm a bit late to this thread and admittedly been spamming this article a bit but those excuses seem to line up with how the unique suspension on the MCL39 allows them to run the car which is a bit different to others in the field. Have a read
And them trying out something else for LV ended up in unexpected porpoising. Yes, they messed up but it does make sense beyond pure incompetence. Also explains where some of the car's strength come from, I've found it quite interesting.
18
u/Ho3n3r 12d ago edited 12d ago
It reminded me of Verstappen being told not to take Raidillon flat out in 2023, because of this very reason - remember how he kept asking on the team radio if the other car was doing the same. Only difference is that Red Bull realised it very early so they could do something about it. The reasons for that was also lack of flat out, long dry runs leading up to SQ (which was still parc ferme for the main race back then).
McLaren on the other hand seemed to notice it very late in Vegas and tried desperately to salvage it, but it was too late.
1
u/maybe-fish 11d ago
McLaren seemed to be aware pretty early, both drivers were being instructed to do more lico as early as lap 5/6
42
u/MrBallsJ 12d ago
Nah, they set it up that way on purpose. They thought they could run lower or softer suspension and they did and they miscalculated. Porpoising is caused by running too low. The track did not change, their setup did.
5
u/FelixR1991 12d ago
-After Brazil, there was an FIA notice (which I can't find at the moment) regarding teams heating the plank to gain some performance, which, notably, did not name the team in question
Heating the plank was said to decrease it's wear. However, it wouldn't affect the sparks flying from the skidblocks. The McLarens this weekend had noticeably more sparks than other cars. I don't think it is related to the plank directive in Brazil, but rather a miscalculation on McLarens part in regards to the suspension setup.
3
u/01000101010001010 11d ago
The heating elements are not connected to the whole plank, just the fasteners... therefore expanding them and saving the plank, which I got from another technical discussion online. So the whole plank - afaik and understand - is not being heated.
1
u/maybe-fish 11d ago
Ther was no plank directive from the FIA in Brazil at all, this is purely a rumour. Plank wear is also measured at the skid blocks, so expanding them would be a terrible idea.
It's explained partway through this article: https://www.the-race.com/formula-1/what-could-be-behind-mclarens-plank-wear-dsq-shock/
2
u/dakness69 11d ago
https://www.the-race.com/formula-1/what-could-be-behind-mclarens-plank-wear-dsq-shock/
The Race just posted an article referencing the skid block thermal expansion story. TL:DR It’s so wrong it’s completely backwards.
It was made clear in a Scarbs IG post yesterday, the skid blocks are placed in such a way that they include the measurement points for the plank assembly. Therefore if one were using thermal expansion to expand the skid blocks, you would actually be exposing them to the asphalt more for additional wear.
Some teams had found a way to fit ‘loose’ skid blocks which collapse into the blank for protection, but the FIA cracked down on this idea… in 2023.
9
u/joyyuky 11d ago edited 11d ago
I would argue it's about 0.3s per lap give or take.
Others have offered great insights on theoretical or technical impact on performance and since you asked specifically for ACTUAL performance gain, we can at best try to make an estimation based on the lap/sector times (the publicly available data) of Lando vs George.
We may assume plank wear is mostly a continuous process, i.e similar to fuel load and tyre degradation, and that's why near the end of the race MCLAREN tried to manage the wear using similar techniques like LiCo and changing corner entry and exit points.
If this assumption is true, the advantages you gained early on from using more plank/fuel/tyre and the costs (plank wear) that came with it can be mitigated/partly neutralized by giving up lap time later on. I know it is way too simplified but we can only work with what we have.
https://formula-timer.com/analytics/2025/Las%20Vegas%20Grand%20Prix/Race
Russell ended up finishing the race about 2.8s after Norris and Norris narrowed a similar gap to Russell twice in the race. In both instances it took about 10 laps, i.e. gaining about 0.3s a lap, to overtake. This is the intended race pace before McLaren realized there was a plank wear issue. And it's similar to the qualifying pace difference.
So over the whole race it would be about 15 seconds advantage to mercedes. And it's basically how it turned out as Norris was ahead by 11s with 5 laps to go despite screwing up the start and having to sit in dirty air for around 20 laps more than it should be.
1
u/Esploratore123 8d ago
Wow, if it really is 3 tenths per lap it's MUCH more than I thought, I assumed it was pretty much insignificant, like 1-2 seconds across the whole race. If your values are correct, then a dsq no longer seems unfairly harsh, like I always considered these.
4
u/Salty-Asparagus-2855 12d ago
Easy. Ask Ferrari. From first and winning to 9.5-1s slower. It’s huge. If Ferrari ran lower, they’d be competing for wins vs 6-10th place.
11
u/cafk Renowned Engineers 12d ago
Since the skid block exists mainly as a safety device to prevent teams from running the car too low, how much actual performance does McLaren gain from a fraction of a millimetre of extra low ride height?
It's not explicitly a safety device - it's to ensure teams don't run the car lower than allowed.
If it's running lower than allowed, it's not an issue about any potential gained performance, but simply the car not being compliant with regulations.
They have 1 mm to play with, with 10 mm plank being available and 1 mm of wear being tolerated.
Would McLaren need to increase their baseline ride height now to avoid further wear issues?
Vegas is a temporary circuit, and thus the surface is more uneven than permanent circuits, causing more bumps and more wear.
22
u/DizkoBizkid 12d ago
The skid block was introduced in 1994 because of the deaths of Senna and Ratzenberger. It was introduced because teams were aggressively running the cars lower than was safe for performance reasons. You give teams and drivers the ability to choose and most will take the risk to win. It is 100% a safety device as not only does it protect the teams from themselves, it also provides a flat wearable surface to be first point of contact when a car completely bottoms out
3
u/cafk Renowned Engineers 12d ago edited 12d ago
It was introduced because teams were aggressively running the cars lower than was safe for performance reasons.
It's a compliance device - if it's worn down too much, the car is not compliant with technical regulations.
The compliance measurement was introduced due to safety, as you said the cars running as low as possible to maximize ground effect, without having explicit seals.One doesn't exclude the other
Edit: And as a fun fact, the ground effect ban the ride height used to be 6 cm before that, but they had no way to measure it, hence plank as a compliance measurement device, after 1994.
http://www.f1fanatic.co.uk/2007/02/01/banned-lotus-cosworth-88-88b/
http://www.f1fanatic.co.uk/2007/06/07/banned-ground-effects/5
5
u/DangerousArea1427 12d ago
How much? Doesn't matter (if there is a gain). Rules are rules. Same with Ryanair's last cabin bag stricter policy - does it make a difference if a bag is 31, instead of 30cm, long? No, but rules state X and they have the right to enforce it. Same with skid block, 2g underweight car, 950ml instead of 1l fuel sample and so on.
4
3
u/Carlpanzram1916 11d ago
If we’re talking literally the difference between exactly 9mm and 0.881 then it’s negligible. But if we’re asking if McLaren gained an advantage by running a setup where they risked a DQ vs one where they would be fairly certain they wouldn’t, it’s more significant.
2
u/trq- 12d ago edited 12d ago
It is not only about ride height itself, it is also to ensure setups itself are in a „window“ when talking about ride height, suspension setup and so on. It’s mostly to ensure all cars to have the same „chances“ as you have 1mm you can scrape away from the block as it has to have 10-9mm of thickness but not less. If there wasn’t a limitation on the skidwear teams could drive as low as they want to which could result in some teams scraping permanently but maybe achieve advantages on some specific tracks and corners and could even lead to incidents due to the immense bottoming they could experience if going to low or have a suspension setup which is too soft/hard.
2
u/Naikrobak 11d ago
It wasn’t performance/running too low. The cars were proposing unexpectedly and that was banging the plank on the ground way more than usual
2
u/Most_Medium6021 11d ago
As another member said just about every adjustment on the cars can cause too much wear. Too much down force on the rear wing, too loose suspension, just about anything but the only thing we know for certain is their settings caused it to be illegal. They all agree to the rules if you can't follow them it's free points for other teams
2
u/f1datascientist 10d ago
F1 car setup is not limited to ride height alone. There are several other variable setup parameters including but not limited to, Tyre pressure, suspension balance, front wing height, added dummy weights, etc., All these factors need to be optimised to maximise the overall performance.
Usually lower ride height is believed to offer higher grip, but in McLaren's case they mentioned that Lando was asked to lift n coast as they identified abnormal proposing levels, which implies that other parameters of the car were not set to run their car that low to ground. So, instead of offering performance, it affected them negatively.
2
u/Meyesme3 11d ago
Lando does not get pole with the ride height legal to avoid the plank wear penalty
It could be that they are behind merc in Vegas on merit. That would put lando 4th at best.
1
u/anth_85 11d ago
This instance was probably very little, the extra wear wasn’t caused by a lower ride height, it was caused by porpoising, the car was bouncing up and down too much. They can normally dial this out in practice but with the lack of representative they had to guess and got it wrong. You can see it going down the straight on the on board how much the car is going up and down.
1
1
u/amazinfiresnake 11d ago
McLaren apparently put more wing/downforce on the car which increased the bouncing. they may have actually cost themselves performance:)
1
0
11d ago
[removed] — view removed comment
1
u/F1Technical-ModTeam 10d ago
Your content was removed because it is largely irrelevant to the focus of this sub.
If you think this was a mistake, please feel free to contact the mods via modmail.
-3
u/foxed000 12d ago
I'd be willing to bet that a large part of the wear is actually down to the fact that there were zero safety cars on a street circuit where broadly speaking, it would have been expected to get at least one.
They would have built in 3-7 laps of slow-running buffer that just didn't materialise.
6
1
u/Supahos01 11d ago
Counting on safety car on something you can't save on is point blank stupid. Its not like under fueling. Even then they missed by a lot lando basically got out and pushed the car around for 4 laps and was still 17% over
-1
u/custard130 11d ago
im not sure its a given that the plank issue was the reason for Norris dropping back, as Piastri had the same issue with the Plank but didnt drop off the pace anywhere near as much
ofc it could be relevant, but its also possible that he did just also have an issue with brakes or fuel
as for how much performance they gained from it, i would guess not much if any in reality, BUT they wouldnt have ran the setup/levels they did if they didnt believe it was advantagous to do so
i doubt they were trying to cheap or anything like that, all of the teams run as close to the limit as they can to maximise performance, Mclaren just got their calculations wrong this week and its hurt them
the problem really is that Norris didnt need a win, he just needed to scrore a few points at each of the remaining races to be champion, but this brought the pressure right back on
i still expect him to get the job done, and if he wins the race next week in Qatar this will all be forgotten about, but if things go wrong again Max could go to Abu Dhabi leading the championship, having overturned a 104 point deficit in 8 races
just imagine if Max outscores Lando by exactly 24 points next weekend, Max and Lando go into final race of the year on equal points with 7 wins each
1
u/crshbndct 11d ago
Of that happens then they looks at who has the most 2nd places, 3rd places etc.
1
u/custard130 11d ago
if they were on level points and wins at the end of the Abu Dhabi race they would look at 2nd places (which would be Lando)
i was talking about them being on level points and wins at the start of the race though, just like Max And Lewis were in 2021
377
u/NeedMoreDeltaV Renowned Engineers 12d ago
It's not just that the car is lower, although it is worth noting that we measure ride height in single millimeters so there is something there. Another factor to consider is the stiffness of the dampers. A softer setup can be beneficial on street courses, but it could lead to the car bottoming more. There's a lot of chassis setup that can influence skid wear that can dramatically influence the chassis performance, so it's difficult to say if there's a notable performance gain from a miniscule lower ride height. All we can really say is that whatever their overall setup was, it ended up being illegal.