55 replies to this topic

[MAXR]

What a fab track at Rockingham on Sat. They have now changed the circuit layout & we were the first to try it out. There were 7 VX’s there on the day and we all put on a good show. It was nice to put faces to the names from the forums. One big eye opener for me was meeting the head of Toyo Motorsport tyre Division. Up till now I and many others were under the impression that a typical set of tyre pressures for the track should be, give or take a bit 23 psi for fronts & 26 for the rears....How Very Wrong! The Toyo guy carried out much testing & setting up on several cars at the trackside, 3 of which were VX’s and Bugger me! Optimum Pressures for R888 or A408’s should be approx 30 psi for fronts & 32 psi for rears. We were obviously sceptical, but on the track and after getting plenty of heat into the tyres it all made sense. Improvements were very noticeable; grip levels on another level, but only once the tyre tread gets up to a good temperature of 37-40 degrees. I’m buying a tyre temp probe soon, now that I understand what I should be aiming for and how to make adjustments to tyre pressures & damper settings. MAXR

[danger7]

With TR-1's I found on an abrasive track 30 psi fronts 32 psi rear was the best compromise - I did try higher but errr no, so I'm happy I was on the right lines. Thanks for the information, very useful Cheers Ian

[Pidgeon]

Glad Alan was helpful. Toyo sponsor my race series as well as provide the control tyre at a great rate. I am always keen to provide them with feedback and meeting drivers using his tyres and being able to help them is just what is wanted. The 30psi is a hot setting. On the race car I start at 23n/s 24 o/s to achieve that temp. Perhaps for track day use start at 25 psi cold.

[jasvxt]

Glad you clarified the above are hot pressures Partridge Running those pressures (above) cold on road or track, would turn the VX into the ultimate hedge finder/gravel trap finder

[P11 COV]

I did read somewhere on SELOC just the other day that 888's need alot more than 048's. A guy xalled 'Black Potato' on there was suggesting 30's

See here

http://forums.seloc....d=156009&page=1

[Guy182]

on my walshy day i was going well over that little triangle marker near the sidewall.. he pointed it out and said i shouldnt be wearing past there.. so i had to put more air in my tyres to stop it from going that far. ended up with nearly 40psi in but that left hander is pretty harsh

[Mr_M]

One big eye opener for me was meeting the head of Toyo Motorsport tyre Division. Up till now I and many others were under the impression that a typical set of tyre pressures for the track should be, give or take a bit 23 psi for fronts & 26 for the rears....How Very Wrong!

The Toyo guy carried out much testing & setting up on several cars at the trackside, 3 of which were VX’s and Bugger me! Optimum Pressures for R888 or A408’s should be approx 30 psi for fronts & 32 psi for rears. We were obviously sceptical, but on the track and after getting plenty of heat into the tyres it all made sense. Improvements were very noticeable; grip levels on another level, but only once the tyre tread gets up to a good temperature of 37-40 degrees.

Very interesting - thanks MAXR

Do you know if this sort of pressure (30psi) held true for different cars? i.e. turbos / yota engine loti? (just wondering if those of us who have to suffer the presence of Ms Minogue see any different effects?? ) Have to confess it was a long time ago when I last waved a temp probe in the direction of my tyres, but from memory (I'm getting old so I may be wrong) I seem to recall getting high 30's (temp) at lower pressures that 30psi. Time to pay a visit to the demon tweeks site I think.......

Partridge - any chance of getting Alan along to some more track days? (Not wanting to lead in any particular direction, but Donnington on 29/3 might be useful )

[MAXR]

One big eye opener for me was meeting the head of Toyo Motorsport tyre Division. Up till now I and many others were under the impression that a typical set of tyre pressures for the track should be, give or take a bit 23 psi for fronts & 26 for the rears....How Very Wrong!

The Toyo guy carried out much testing & setting up on several cars at the trackside, 3 of which were VX’s and Bugger me! Optimum Pressures for R888 or A408’s should be approx 30 psi for fronts & 32 psi for rears. We were obviously sceptical, but on the track and after getting plenty of heat into the tyres it all made sense. Improvements were very noticeable; grip levels on another level, but only once the tyre tread gets up to a good temperature of 37-40 degrees.

Very interesting - thanks MAXR

Do you know if this sort of pressure (30psi) held true for different cars? i.e. turbos / yota engine loti? (just wondering if those of us who have to suffer the presence of Ms Minogue see any different effects?? ) Have to confess it was a long time ago when I last waved a temp probe in the direction of my tyres, but from memory (I'm getting old so I may be wrong) I seem to recall getting high 30's (temp) at lower pressures that 30psi. Time to pay a visit to the demon tweeks site I think.......

Partridge - any chance of getting Alan along to some more track days? (Not wanting to lead in any particular direction, but Donnington on 29/3 might be useful )

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The higher the tread temp the stickier the tread gets. The tyres apparently work at their best when they reach between 50-70 degrees. Although, even the hardest of drivers will be pushed to get them up to 50 degrees. The a408's (LTS version), from what I was told have slightly softer sidewalls & a slightly different compound to the R888's. The softer sidewall causes more flexing, which in turn leads to hotter tread temperatures.

Using a temperature probe allows you to test the temperature across the tyre when fully warmed. Temps for the inner, outer & centres of the tread can be taken promptly on entering the pits. Again for the fronts R888's 30psi Fronts & 32psi Rears worked well for many of the Tubby cars. If the central area was more than 2-3 degrees or so higher than the outer tread areas, then the tyre pressure should be decreased. If the outer areas are higher, then obviously more pressure is required. Each of the wheels may be different depending on the circuit layout & tyre loadings they encounter. So each of the fronts will vary!

With my A408's on my NA SC & with hot tyres, I found 28psi fronts & 30psi rears allowed me the best overall grip levels & feel. My Nitrons Single way's settings for the rears were (set to from hardest) -3 clicks & the fronts (from hardest) -4 clicks. My Motorsport ARB is set one down from the stiffest setting. This may not work for your car as Plans have done the geo & camber settings front & rear will play a part in determine your ideal setup.

I took Foxey out for a passenger ride at Rockingham and he seemed to be very impressed with the setup. We managed comfortably to keep up with one of the fastest cars there that day, a RX7 wankle engined fire breathing beast with a champion driver behind the wheel. Admittedly, he was out for the day testing his car & his car probably wasn't at its best.

MAXR

[Mr_M]

The tyres apparently work at their best when they reach between 50-70 degrees.

That's an eye opener - have to confess, I didn't think they needed to get that high

Again for the fronts R888's 30psi Fronts & 32psi Rears worked well for many of the Tubby cars.

Thanks for that Definitely time for a pyrometer I think..... (hmm - group buy potential I wonder???)

[Foxy]

I took Foxy out for a passenger ride at Rockingham and he seemed to be very impressed with the setup. We managed comfortably to keep up with one of the fastest cars there that day, a RX7 wankle engined fire breathing beast with a champion driver behind the wheel. Admittedly, he was out for the day testing his car & his car probably wasn't at its best.

I was indeed impressed. Infact (despite the looks ), I'd say it was the most 'together' VX I've been in...by a long way. Reminded me of my old NA The power delivery is awesome and feels like much more than 250(?) odd brake.

If you do trackdays, forget those lardy tubbies, SC really is the way to go

(RX was apparently running in - prob just a racing drivers excuse though! )

[Foxy]

Do you know if this sort of pressure (30psi) held true for different cars? i.e. turbos / yota engine loti?

AFAIAA 30psi works because it is at this pressure that the tyre forms the correct/designed profile and contact patch. I have found it to be about right in the BM too (c. 950kg)...

I think the cold pressure may vary between different cars as the heavier ones put more heat into the tyres. But the optimum working pressure should be about the same. Having said that I seem to remember Alan telling me that some of the heavier saloons run considerably higher pressure...I guess this is to help the tyre maintain it's shape under the greater loads.

[danger7]

What I found with Toyo's is if the car is heavier than a VX they are up to temp much quicker which was proved by a friends car, but the VX struggles a bit on cold tracks to get the heat in to the fronts, especially since I dialled out much of the understeer by using an Exige S geo and 16" 195 sections. I'm running TR-1's at the moment and plan to switch to R888's which I believe will help. Cheers Ian

[Pidgeon]

Partridge - any chance of getting Alan along to some more track days? (Not wanting to lead in any particular direction, but Donnington on 29/3 might be useful )

I am sure Alan would come out, if there were sufficient current or prospective customers present. Toyo are based in Rushden and Alan lives near there, so the nearer the better. I will ask if he will contribute to this thread.

[subseamac]

I'm about to buy a new set of r888s and would also love to know if the new softer compound is available in our sizes (225/195)

[Stu-7]

On track I run the following pressures from cold: 20psi front 18psi rear

[MAXR]

On track I run the following pressures from cold:

20psi front
18psi rear

That sounds low(ish), especially for the rears. I assume your fronts reach about 25psi & the rears 25psi (ish) when hot. What tyres are they? & are you running standard shocks? It obviously works for you!

MAXR

[burnerblowout]

On track I run the following pressures from cold:

20psi front
18psi rear

Stu is being cagey. He knows that those figures will convert to a hot pressure but he isnt going to reveal them

I reckon they wont go up much because he's too slow to get the temps up.........

[Stu-7]

On track I run the following pressures from cold:

20psi front
18psi rear

That sounds low(ish), especially for the rears. I assume your fronts reach about 25psi & the rears 25psi (ish) when hot. What tyres are they? & are you running standard shocks? It obviously works for you!

MAXR

30psi is the key pressure for the rears. Once they go over that, performance drop-off is significant. Last October, that counted for nearly 2 secs per lap @ Spa.

Not running standard setup, no.

[Dynamo]

What an interesting read...good post guys. I was at Rockingham that day too. Good to meet you Max, Foxy and Partridge. Thanks Partridge for pointing me in the direction of Alan from Toyo; it was a step forward in the setup of my car. I'm running 888s and found my turbo handled better on higher tyre pressures....I tried 24/26 psi (hot) followed by 29/31 psi (hot) and found the latter worked better at Rockingham at least. According to Alan the optimum temperature for R888s is between 80-85 degrees C.....interestingly most peoples tyres didn't get anywhere near that....they were on more like 35-50 when measured on coming in to the pits. (although hard to know how much a tyre would cool down when coming in to the pits and it was a cold day)...so for trackday usage it seems the tyres have more to give, and would not start overheating (losing performance) except on all but the hottest days/longest sessions/hardest driving. Guy182 (and anyone else interested): According to Alan @ Toyo, the arrow markers on 888s are apparently there to indicate where the minimum tread depth indicators are (the indicators are in the tread next to each arrow). They are to help determine if the tyre is road legal, not where you should be wearing the tyre down to laterally. Oh and Max, your car is v quick! ..... now the question is what can I do to my Turbo to make it that quick?.... apart from a driver transplant

Edited by Dynamo, 06 March 2008 - 09:47 PM.

[Ferguson]

Guy182 (and anyone else interested): According to Alan @ Toyo, the arrow markers on 888s are apparently there to indicate where the minimum tread depth indicators are (the indicators are in the tread next to each arrow). They are to help determine if the tyre is road legal, not where you should be wearing the tyre down to laterally.

I think the point was simply that the arrows are in a good position to show if you are rolling your tyre sidewall too much with a low pressure. If you see scuffing on the arrows, which are outside the tread surface, then your tyres are flexing too much and you need more pressure. The "old-school" technique (which is still a great way to quickly judge pressures) is chalk marks on the sidewalls and tread; the chalk should just wear off the tread surface.