View Full Version : tyreleader cups performance on track :(
khooni
04-08-2015, 08:33 AM
with a set of "new" 2012 Michelin pilot sport cups from tyreleader, i went to silverstone GP yesterday to try them out.
Other than the bonnet catch issue (thanks Shimmy), the cups started ok but degraded consistently throughout the day with even weather conditions and track becoming grippier due to laid rubber. I went from a 2.40 to a 2.49 from 1st session to the final session at 4pm. Dropping at least 1 sec per session of about 5 laps. The car got noticeably edgier, I couldn't turn in as well and once turned in , I couldn't get on the power as much. I also couldn't trail brake very well into the lower speed stuff. It stops ok but I think that was because of my inability to carry enough speed.
This is my second set form tyre leader. The first set was great. I had no issues and they performed flawlessly for 5 trackdays. Even at the end, it felt loads better than the new ones I had, except maybe for the first session. The last time out I got 2.38 so I am bit annoyed that with new tyres I am slipping backwards.
Any suggestions as to why? Have the tyres been heat cycled to death (why and how?). Are they simply too "old" such that the compound hardens right after the first layer wears off? If you ask me now, I'd only be buying proper NEW tyres i.e. made in 2015............... too much of a gamble for me.:(:(
alexk
04-08-2015, 09:09 AM
What tyre pressures ?
What suspension ?
What geometry settings ?
What tyre temperatures ?
Rick H
04-08-2015, 09:25 AM
I bought a similar set from Tyreleader.
I'm not really any good as a judge, but my car was recently driven by a racing driver on Anglesey and he remarked specifically on the huge amount of grip the car had.
You got 5 trackdays from a set of Cups ? ? ? ? ? ? Is that normal ? ? ? ?
khooni
04-08-2015, 11:26 AM
tyre pessure is 35psi all round.
suspension is kw clubsport (gen 1) non adjustable
track geometry setup by simpson motorsport
none of the above had changed. I just went on a track day at Snetterton 2 weeks ago and the grip was fantastic.
Yes.. 5 trackdays on a set of cups.
Yes the previous set had a huge amount of grip as well. Maybe this is a 1-off... but.. wtf.
billyboysm3
04-08-2015, 11:35 AM
tyre pessure is 35psi all round.
suspension is kw clubsport (gen 1) non adjustable
track geometry setup by simpson motorsport
none of the above had changed. I just went on a track day at Snetterton 2 weeks ago and the grip was fantastic.
Yes.. 5 trackdays on a set of cups.
Yes the previous set had a huge amount of grip as well. Maybe this is a 1-off... but.. wtf.
I run 30 psi hot, how hot was it yesterday.
billyboysm3
04-08-2015, 11:38 AM
And how many laps per session,
khooni
04-08-2015, 11:49 AM
5 laps.
22deg ambient temperature.
It just wasn't turning in and when I put the power down it just wanted to understeer. My car is setup to understeer so I can brake as late as possible and trail. It's gives me great confidence in that the tail won't snap on me and just gives me the extra turn in required when trailing the brakes. Yesterday it was just a pig, and when i gave up setting times and wanted to hoon, I discovered that because my front end doesn't grip, I have difficulty booting the tail out. The symptoms are that the tyres are fooked.
I'm buying a new set now. ............. but i'd appreciate if anyone thinks it could be something else..
oh, 1 more thing. that bonnet is really irritating me... I'm gonna tape it shut with masking tape.... is it ok to use masking tape on the paintwork?
billyboysm3
04-08-2015, 12:02 PM
Grant went to Silverstone a few weeks ago and that had poor grip, Id say tyre pressures to hot and track had poor rubber laid down on it.
khooni
04-08-2015, 12:42 PM
9 to 10 secs is a lifetime Billy....... with consistent temps and low numbers of cars on track, I can usually lap to within 3/10s.
Anywho, I'll try again with newer tyres.
khooni
04-08-2015, 02:36 PM
one other thing. The tyre pressure light kept coming on despite re-setting and manually checking of pressures using a gauge. What is this for? I never knew what it did nor how it read low tyre pressures.
alexk
04-08-2015, 02:45 PM
The pressure is very high in my opinion.
5 laps is nothing.
I tend to do 15-30 laps in a row and I have no such issues even with old cups.
In Monza I do 30 minute sessions.
khooni
04-08-2015, 03:18 PM
I didn't realise that but point is it is consistent to all my other track days. That's what I find puzzling
mattCSLnut
04-08-2015, 03:19 PM
Your tyre pressure was too high @ 35 psi (hot or cold) and Cups are very sensitive to both pressures & temperatures. Sounds like you were overheating them from the start.
On track the correct tyre pressure for Michelin Cups is 26 psi (cold) and should hover around low 30's psi hot unless there's something amiss.
The 2012 DOT is perfectly acceptable as the rubber life span of these tyres is around 5-6 years (if they were heat cycled correctly from the start) although they don't phisicaly tend to last that long if you track your car frequently :supz:
khooni
04-08-2015, 04:18 PM
Hi Matt,
I accept that the pressures could be a bit high. What it doesn't account for is consistency of the track and why it degrades evenly through out the day.
It should be a 1-time.. oh that's bad and remain the same. But it doesn't, it just constantly goes down. NB I have tried these 35 psi HOT temps for 8 trackdays now and have never felt the tyres going off the way they are doing now. Gradually rubbing off performance the entire day such that at the end, it was basically understeering everywhere.
I'm going to try again and see if i can get new cups on soon and report back.
alexk
04-08-2015, 04:34 PM
You are starting with wrong tyre pressures and I believe this is making everything else irrelevant.
One more point.
What do you mean with your car is setup to understeer ?
Again I am puzzled because I have a setup in my car, it doesn't understeer nor oversteer and I go fast with it.
Edit: obviously it can drift when I want it to drift but not on it's own (like KITT)
mattCSLnut
04-08-2015, 08:12 PM
Hi Matt,
I accept that the pressures could be a bit high. What it doesn't account for is consistency of the track and why it degrades evenly through out the day.
It should be a 1-time.. oh that's bad and remain the same. But it doesn't, it just constantly goes down. NB I have tried these 35 psi HOT temps for 8 trackdays now and have never felt the tyres going off the way they are doing now. Gradually rubbing off performance the entire day such that at the end, it was basically understeering everywhere.
I'm going to try again and see if i can get new cups on soon and report back.
Unfortunately there is no "could be" about it ;) You've run these Cups now (over inflated) for 8 track days, overheating & over working them (due to the wrong pressures) so you've probably altered their compound in the process. Now they are at the very end of their life it's natural for them to behave the way you've described. They are telling you it's " GAME OVER " ;)
Don't forget to "Heat cycle" your next new set of CUPs before any track action :beer:
estoril
04-08-2015, 08:21 PM
Don't forget to "Heat cycle" your next new set of CUPs before any track action :beer:
Just for the record, how is this best done?
s.mac
04-08-2015, 08:42 PM
Agree with all, pressures too high. Also suspension set up, this can be different on the same track on different days. Needs tweaking to suit on the day.
If you are that keen you should check the tyre temp across all tyres and 30 to 32 psi max HOT, I would be closer to the 30 :)
Lap time could drop because you are over driving chasing times. You might not think it but been there done it. Lacking confidence on grip could also hinder times.
Rick H
04-08-2015, 08:52 PM
8 tracks days - same set of Cups? Is this realistic? I was expecting 2 maybe squeeze 3 at most?? what's normal for somewhere like Oulton?
billyboysm3
04-08-2015, 09:18 PM
Just for the record, how is this best done?
Me, shimmy and Duncan paid track group to do ours or alternatively go for a very long drive heating up the tyre gradually. Spa would be good or drive to track night before.
This saves them from going hard, I managed to wear mine down to canvas with little loss of grip.
I'd say 7-8 track days if all dry, plus a couple of wet ones.
khooni
04-08-2015, 10:26 PM
Sigh.
This phenomenon is on new 2012 cups. Previous 7 track days were on 2 different sets of 2012 cups. Yes I am on my 3rd set this year. And I just ordered a proper new set.
I am not sure we are all on the same page here. All I am pointing out is the inconsistent performance which may be due to a freak set
khooni
04-08-2015, 10:42 PM
You are starting with wrong tyre pressures and I believe this is making everything else irrelevant.
One more point.
What do you mean with your car is setup to understeer ?
Again I am puzzled because I have a setup in my car, it doesn't understeer nor oversteer and I go fast with it.
Edit: obviously it can drift when I want it to drift but not on it's own (like KITT)
what i meant was that at the limit it has a tendency to understeer and that it is very difficult to provoke the tail to move under trailing brakes. The converse side of it is that I can brake very late and very hard and come off the brakes quite easily to provoke the turn without being afraid of it snapping on me.
I think standard CSLs are more neutral than my cars you can have fun more easily under braking. But, they all react the same way to throttle.
I asked Anthony the same question and he said we all set them up to race this way. hmmm.
mattCSLnut
04-08-2015, 11:38 PM
Me, shimmy and Duncan paid track group to do ours or alternatively go for a very long drive heating up the tyre gradually. Spa would be good or drive to track night before.
This saves them from going hard, I managed to wear mine down to canvas with little loss of grip.
I'd say 7-8 track days if all dry, plus a couple of wet ones.
Run to the Ring on a fresh set day before the On track hooniganism usually does the trick :supz:
khooni
05-08-2015, 12:23 PM
it took me 75miles to drive to Silverstone on the new set so it is effectively heat cycled. But for arguments sake, I'll try an evening at Brands before i change over to the new set and run it at 30psi HOT to see if it feels better.
billyboysm3
05-08-2015, 12:33 PM
What sort of lap times can your beast get round Snetterton, hoping to go end of month.
khooni
05-08-2015, 03:21 PM
I am not a good driver by any means but I did manage a 2.20 flat last wednesday.
let me know how you get on. I don't see many CSLs out there anymore. only the extreme modified e46/e36..
when are you thinking I might join you. It's a pretty cool circuit.
octainejunkee
05-08-2015, 03:27 PM
Pretty sure your problem is down to high pressures.
(always adjust once hot after a few laps) 26-28psi hot,is good for cups.
You should put a few mild road miles and a couple of heat cycles on the tyres to bed them in before tracking them also.
Not sure they'll behave properly regardless of what you do to them if youve cooked them now.
Keep them for road use only if they dont behave well at Brandshatch.
You should be in the 51-53 second a lap on the indy circuit with coilovers and a bbk.
khooni
05-08-2015, 05:16 PM
pretty sure it is NOT only due to high pressures.
I have explained time and again that my previous 2 sets of 2012 tyres didn't behave this way. The 3rd set did.
I may be running high pressures but I have been consistently running high pressures for the last 8 trackdays. and only the last one did this crop up.
And I can ususally lap to within a couple of tenths on average so 10 sec is a lot of ground to cover.
khooni
05-08-2015, 05:20 PM
51 to 53s on a standard CSL is pretty good going. My best time was 55 sec so far.
s.mac
05-08-2015, 09:27 PM
I did a set of front cups in 1/2 a day, it was due to incorrect camber for the track. Knocked them well out and got through the afternoon.
IMHO it's not down to the tyres but the set up, which is a combination of the lot.
You need to alter everything on the day but if you are normally a tenth out lap to lap you know all this :)
khooni
05-08-2015, 10:26 PM
didn't do anything on setup. Don't know how to.
I just wanted to ask if you guys thought it was strange to have performance degrade so much from session to session from a new set of tyres all things being equal.
Guess I must the first person to get a bad set of 2012 cups. maybe it is indeed a fluke set. hopefully. as 2015 sets are pricier by ~£150
s.mac
05-08-2015, 11:23 PM
I think you've answered your own question, it's fuck all to do with the tyres and all to do with set up ;)
Chappers
06-08-2015, 09:16 AM
I think you've answered your own question, it's fuck all to do with the tyres and all to do with set up ;)
Unless, as he seemed to be repeatedly saying, the only thing that's changed are the tyres (and the track temps) in which case it's everything to do with the tyres (and how he's using them). Whilst a vehicle set up will probably improve things, from an engineering point of view if it hasn't changed it's not the issue.
We're not trying to diagnose vehicle performance here, we're trying to work out why there's a massive difference in tyre performance between apparently identical sets. My guess is track temps and slightly high pressure.
A video would be good so have a look at your steering inputs, just for interest's sake.
khooni
06-08-2015, 12:03 PM
thanks for that. At least someone is paying attention. Indeed, I've booked an evening at Brands next week to see if running at 30psi magically solves the issue.
I don't do setup. I let the pros do it. I just try to improve my own so-so driving and to have a bit of fun at the same time. You guys know, there's just so few places to push the car on our roads and feel the sublime balance that they are capable of.
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