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Discussion Starter · #1 ·
Hi all,

I'm doing a carlimits airfield activity day on Friday. Carlimits recommend inflating your tyres to the maximum rated pressure stated by the tyre manufacturer to protect the tyre wall. I phoned Toyo and the maximum rated pressure for a CF1 is 37.5 psi. However, the guy also said that inflating to this pressure would be a bad idea as the carcass would deform as the tire increased in temperature and pressure went up higher. He recommended staying at the 'street' pressure of 26-28 psi, aiming for a 'hot-pressure' of 32psi.

Has anyone any experience or advice on this? Do I take carlimits' advice or Toyo's?! My main worry is with tyres coming off the rim, although maybe that's a little paranoid!

Many thanks,

N
 

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Carlimits. 26-28 psi will trash them - you'll be running around on the outside shoulder and the sidewall lettering at those pressures. Toyo man wants you to buy new tyres...


Tyre pressure ratings are for COLD tyres and take into account the temperature rise in use. I'd start at 33-35 psi COLD and see how it runs.

Drop the rears to 20 psi for dragging down the strip and bump (an old set of ultra high treadwear rating jobbies) up to 40 psi cold for drifting. (keep the fronts at 33-35psi when doing that)

http://www.2pass.co.uk/tyres.htm
 

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Definitely pump them up much harder than for road use - the car park sections of the area used by Carlimits is very bumpy and you will be pushing the car very hard. You could damage your wheels and/or wreck your tyres using road pressures.

I saw an Evo trash an alloy there on one of the days I've been on.
 

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Hey N. I'm there on Friday as well. AND I have CF1's on my car! Last time i went i just pumped those badboys up to 40psi. I must say I gave the car a right leathering and the tyres held up great. Tomorrow will probably be the last outing for them though.
See you there!
 

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what the tyre guy you spoke to doesn't realise is that the tyres barely get warm on a carlimits day. you'll typically work them for far less than a minute before giving them a rest. it's completely different to a track day. i'd say stick them at 36 (cold) or so. too much more and you'll just have no grip as your contact patch will be tiny.
 

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Brilliant!

Thanks guys that answered my question perfectly. I'll go for a slightly conservative 35psi and go from there!

See you there notorious!

N
Good to meet you NDNDNDND if that is your real name! Seems your tyre psi's were spot on!.......I didnt notice any tumbling fireball wrecks rolling down the runway anyway!
Had a great day but I'm sure i can go faster
 

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Discussion Starter · #8 ·
Brilliant!

Thanks guys that answered my question perfectly. I'll go for a slightly conservative 35psi and go from there!

See you there notorious!

N
Good to meet you NDNDNDND if that is your real name! Seems your tyre psi's were spot on!.......I didnt notice any tumbling fireball wrecks rolling down the runway anyway!
Had a great day but I'm sure i can go faster

[/quote]

Hi Rob (that is your real name!)

Yep that was a fabulous day! And at least that weird clonking noise didn't mean my wheels were about to fall off!

When I got to my mate's house I tested the pressure at only 33.5 psi and the sidewalls hadn't been marked, despite my best efforts! Next time, I'll pump them a bit higher, possible 35 again in the front and 38 or so at the rear - see if that helps with turn in. Of course, my best bet might be to just to drive better....!

If you haven't found them yet, I've posted my vids of the day in the 'driving stories' section. Where are you vids, huh?!

And that guy was lying about my times! He added ten seconds to each of my short-circuit runs!!!
 
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