Tyre Pressures
Tyre Pressures
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Discussion

Chocaholic

Original Poster:

47 posts

236 months

Saturday 31st March 2007
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Just nipped to the garage to check tyres on my recent purchase. (I'm running on newish Firestones). I expected them to show circa 22/24 as quoted in the Chim handbook. Surprised to see they were inflated to 30lbs. Dropping one down to 22 seemed to look a bit low, so I've reinflated and got on line for advice. What should these tyres ideally run at?

Cider Andy

1,889 posts

255 months

Saturday 31st March 2007
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Manual suggests 22 PSI front, 24 PSI rear, rising to 25 PSI front, 28 PSI rear full of luggage or for "continental high speed driving"!

Try different pressures. As an example, some people report that Toyos need slightly higher pressures than the original Bridgestones. In any event I wouldn't think you'd need to stray more than a couple of PSI away from the factory recommendation.

tvr keith

1,912 posts

252 months

Saturday 31st March 2007
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I think that the pressures that TVR recommend for these cars(which work for me), are a lot lower than the norm for the tyre size.
Certainly the tyre fitter expected to be putting around 30 psi when I had mine replaced this week.
Don't know where you got your car from, but if not familiar with TVR's that could be the reason why they're so hard.
IMO I would not drive it like that, sounds like a recipe for falling off the road especially in this coldish weather when the tyres won't warm up as much

tvrbob

11,197 posts

285 months

Saturday 31st March 2007
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tvr keith said:
I think that the pressures that TVR recommend for these cars(which work for me), are a lot lower than the norm for the tyre size.
It is worth saying that the recommended pressures are for original fit tyres, SO1pp's & SO2pp's. If you fit a softer wall tyre the recommended pressures no longer apply. These pressures will be too low for people wanting the ride to be similar to SO#pp's. The ride may still be OK but it will be softer.

bigdods

7,175 posts

257 months

Saturday 31st March 2007
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When I bought my Chim a few years back it had S02PP's on at 32psi all round !. I was wondering why the handling was so bad, it was like driving on ice. And this was a warm summers day. I still find it incredible that people just allow tyre fitters to do their thing then never check their tyres until they are worn out.

Anyway back to the OP, definately try lower pressure, try differnt levels and see what feels most comfortable. I run my pressures 1psi hgher than recommended in the manual. Not enough to make a difference you say ? Well I didnt think so either and I am hardly a top driver BUT any higher and it gets skittish, and lower and it doesnt feel totally planted.

tvrchim

1,136 posts

244 months

Saturday 31st March 2007
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Im on 16s all round and i run my Toyo R888s at 30psi and it drives good and corners like its on rails.

zippee

14,133 posts

264 months

Saturday 31st March 2007
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I run 24 front and 26 rear. This is with Eagle F1s up front and Kalken FK451s rear. handling is spot on.

that daddy

19,458 posts

251 months

Saturday 31st March 2007
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16s all round happy at 24ibs allround

spend

12,581 posts

281 months

Saturday 31st March 2007
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24/26 psi seems a reasonable starting point IMHO. Empirical experimentation is always the best way to derive what suits you - your car - your tyres the best, 1or2 psi either way should give you an idea what you prefer (start high - its easier to let air out when testing on the road). Not sure if 15" fronts would require different pressure?

IIRC were old been reports of problems getting the tyres to bed on to the rims, so fitters overinflate to ensure the tyres 'bond' on to the rims, then if you let them down too low the tyres may slip on the rims. Seem to remember someone posted to mark the rear tyre against the rim to check if it slipped...

Do use an accurate gauge to measure the pressures When you are happy you have the pressures you like, put a note in your handbook so you dont forget.

Dave