Dunlop M section CR65 tyre Pressures

[Mike Bell]

Originally Posted by pattlega

Picture of me struggling to get anywhere near apex at Hairpin at Cadwell Park - Look at tyre.

Rgds

Graham

Graham, your first post, so welcome! As has been said earlier in the thread, required pressure is dependent on several factors- car weight, ratio of tyre to rim size, track temperature, suspension geometry / settings, driving technique and probably more I have forgotten! The left front tyre in your pic does look well distorted, but it is a hairpin and there is no side slip, I guess. Would be good for you to see a pic on a higher speed corner for comparison.

I tend to run Ls harder than some people, but again, depending on car. Track temperature the big factor to be taken into consideration....

A lot of trial and error required!

[Robyn Slater]

Thanks Mike.
So i WAS doing 119mph when the transmission blew up!!!!!

[simonb87]

Graham - we have run a vast range of tyre pressures on Imps without it seeming to make a lot of difference. So I tried measuring the temp across the tread and stuck with pressures where the temps were quite consistent at the end of the race - it seems to work OK though a certain Cortina was closing at the end of the 2nd race at Cadwell due to his laptimes falling, perhaps the tyres were a bit late coming in!

Cheers - Simon

[Nick JM]

I note the title of he post is £"m" section . Presumably you mean "L" section?

[Mike Bell]

Originally Posted by Nick JM

I note the title of he post is £"m" section . Presumably you mean "L" section?

Being a Griffith, I would guess the car in original post would run Dunlop 'M' section CR65s. If regs allow, you can try the equivalent size to 'L' on your B, but wheel arch clearance will be a problem!

[Nick JM]

Thanks Mike. That might explain my slightly raised eyebrow at running the 'B at north of 30 cold!

[terence]

Originally Posted by Mike Bell

Being a Griffith, I would guess the car in original post would run Dunlop 'M' section CR65s. If regs allow, you can try the equivalent size to 'L' on your B, but wheel arch clearance will be a problem!

Only as far as the shocker bolts are concerned Mike.Just needs slightly thinner headed bolts fitting.Depending on ww or disc type wheels the arches might need a bit of tweaking, something one would assume to have been done at build time?

[Mike Bell]

Originally Posted by terence

Only as far as the shocker bolts are concerned Mike.Just needs slightly thinner headed bolts fitting.Depending on ww or disc type wheels the arches might need a bit of tweaking, something one would assume to have been done at build time?

Is that why some Bs have rear arches that seem a bit distended... The Gilbern definitely has a clearance problem, and not much can be achieved attacking the fibreglass with a hammer!

[Mike Bell]

never had that before!

[terence]

Originally Posted by Mike Bell

Is that why some Bs have rear arches that seem a bit distended... The Gilbern definitely has a clearance problem, and not much can be achieved attacking the fibreglass with a hammer!

Exactly why Mike, some even remove the outer section of inner arch, but only on non fia cars of course.

[pattlega]

Mike & Simon, thanks for the replies. Made a few more calls & spoken to Neil Brown who suggests our 28/9 Cold into 34 hot is not far wrong. Think you are both right in that it needs a bit of trial and error, & that weather & track conditions impact. Good even tyre temps, good even wear are as good a sign as any. Simon is right in suggesting my tyres did come to me later in the race but it was also a case of finally working out my way around a relatively new circuit to me.

[simonb87]

So I guess I won't be beating you again, if you have started to get tyres sorted etc., it was good while it lasted