T1R Tyre Pressures

Techno · Postby **Techno** » Mon Jan 10, 2011 11:04 am

What are the tyre pressures being used for the T1R's for road use, please?

I see from earlier posts that there is a feeling that the T1R's have above "normal" sidewall flex and that they therefore benefit from higher presures.

Are there any comments or experiences to share?

Thanks

Rob

sliq · Postby **sliq** » Mon Jan 10, 2011 11:19 am

*paging regie*

project.r.racing · Postby **project.r.racing** » Mon Jan 10, 2011 5:47 pm

what is the tyre size?

Regie · Postby **Regie** » Mon Jan 10, 2011 7:43 pm

Hello

i rin the T1R's 205 45 16 on a 7" wide rim.

im running 27psi, 1psi more than standard, only cause i have rather stiff suspension, but for spriited driving they go upto 30psi

bigdog · Postby **bigdog** » Mon Jan 10, 2011 11:06 pm

I ran 36 front/34 rear on my T1Rs and run the same on R1Rs. About to put PP2s on the car so it will be interesting to compare them. I find anything below 30 too squirmy for my liking with Toyos. I have also found that they lose grip significantly in the final 25% of their life - ie still above the wear markers, but stuff all grip from standing start and v slippery in the wet (to be expected with lack of tread depth). I have run two sets of T1Rs and one set of R1Rs. Mind you, Babalouie did do a fine job of drifting my car round MDTC for 5 or so laps, so the R1Rs are very predictable

Wish I had photos to show you - it was an impressive bit of driving!

sliq · Postby **sliq** » Mon Jan 10, 2011 11:35 pm

i think that's the same with other toyos, bigdog.

i'm on proxes 4.. tyres are pretty worn, gradually grip fades and increased road noise. not very good in the wet either when they're down to their last 20%

Steve - Toyo Tyres · Postby **Steve - Toyo Tyres** » Tue Jan 11, 2011 9:07 am

For the Proxes R1R on a comparatively light car like the MX5, 36psi front / 34psi rear is too high and will compromise grip.
The Proxes R1R on the track should have hot pressures of no more than 33psi on an MX5.
The Proxes R1R uses the same casing as our now superseded Proxes RA1 street legal motor sport tyre, therefore does not need high pressures for best performance.

The Proxes T1R is currently being replaced by the Proxes T1 Sport (in most sizes).
The Proxes T1 Sport has a considerably stiffer casing construction compared to the Proxes T1R.

project.r.racing · Postby **project.r.racing** » Tue Jan 11, 2011 9:52 am

Pity the T1 Sport does not come in 15 inch sizes. Will lose alot of business.

Techno · Postby **Techno** » Tue Jan 11, 2011 2:45 pm

Thanks for the feedback and comments.

I guess that I should have kept the 36/34 psi that the chaps at the tyre shop put in. AT 28/30 they did feel a bit squirmish.

As far as treadwear and grip are concerned there is a good paper "SAE paper 2002-01-0553" for $30 or look at http://autospeed.com/cms/title_The-Slippery-Stakes-Wet-Road-Tyre-Grip/A_110774/article.html It says that grip loss is somewhat linear with tread loss in the wet ie 50% worn means 50% less grip. So I can understand the commnents amde above.

Regards

Rob