Track tyres size and load rating

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McTrucky
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Track tyres size and load rating

Post by McTrucky » Thu Jan 18, 2018 10:29 pm

About to invest a set of wheels and boots for the track. Car is a 140 on Billy b12 suspenders.

I will buy 8jx18 with et of 40 or 42 depending on which rim I end up with.
Intend fitting 245/35/18 all round.
Any problems so far? That ET on an 8j ideal all round?

Tyres are likely to be Federal 595RS-R 245/35 R18 88 W
But the 88w concerns me. They dont seem to come in a heavier rating, so is 88 enough? If so, why is this ok on track tyres but not on road tyres?
M140i Auto; Met Grey with Black Interior; MPower LSD; Bilstein B12; Lots of bells and whistles; Could do with a wash;

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Re: Track tyres size and load rating

Post by marco_polo » Fri Jan 19, 2018 11:45 am

88 for track tyres should be plenty, unless you're planning on running 5 up plus luggage? They're much tougher than road tyres, stronger tyre walls.

245/35 should be ok assuming stock wishbones/camber.

If you've been adding front camber, I'd buy just a pair of tyres at first. Try them on the front, see if they rub, and buy 2 more if they don't.
Silver F21 M135i - ManBox - HK - Adaptive + Eibach Pro's - BBS CH-R's - BMWP Drexler LSD - TMC Piggyback - M4 LCA's - aFe Dry Filter

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Re: Track tyres size and load rating

Post by McTrucky » Fri Jan 19, 2018 12:33 pm

Thanks MP. Saw the other thread in the M140 section confirmed et40 is good with 245 all round, but like your suggestion of just buying two to try. Good plan.
M140i Auto; Met Grey with Black Interior; MPower LSD; Bilstein B12; Lots of bells and whistles; Could do with a wash;

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Re: Track tyres size and load rating

Post by marco_polo » Fri Jan 19, 2018 2:16 pm

McTrucky wrote:
Fri Jan 19, 2018 12:33 pm
Saw the other thread in the M140 section confirmed et40 is good with 245 all round
The thing with track tyres is, a 245 isn't a 245. They tend to run a bit wider with squarer shoulders, so just because a road 245/35 fits, it doesn't follow that an R Spec will. Hence the caution.
Silver F21 M135i - ManBox - HK - Adaptive + Eibach Pro's - BBS CH-R's - BMWP Drexler LSD - TMC Piggyback - M4 LCA's - aFe Dry Filter

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Re: Track tyres size and load rating

Post by McTrucky » Fri Jan 19, 2018 3:36 pm

marco_polo wrote:
Fri Jan 19, 2018 2:16 pm
McTrucky wrote:
Fri Jan 19, 2018 12:33 pm
Saw the other thread in the M140 section confirmed et40 is good with 245 all round
The thing with track tyres is, a 245 isn't a 245. They tend to run a bit wider with squarer shoulders, so just because a road 245/35 fits, it doesn't follow that an R Spec will. Hence the caution.
Thanks for that - so on a 245 road tyre at et40 all round, where is it close? inside against the strut or outside against the arch? Is it better to err towards an ET42 or on as ET38?

AND Is it really better to get a non square wheel set - say ET38/ET40 on the front and ET 44/ET50 on the back - even if the tyres are all the same 245?
M140i Auto; Met Grey with Black Interior; MPower LSD; Bilstein B12; Lots of bells and whistles; Could do with a wash;

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Re: Track tyres size and load rating

Post by marco_polo » Fri Jan 19, 2018 4:02 pm

I like square personally, gives you options to rotate if you need to.

Are your wishbones/bushes stock?
Silver F21 M135i - ManBox - HK - Adaptive + Eibach Pro's - BBS CH-R's - BMWP Drexler LSD - TMC Piggyback - M4 LCA's - aFe Dry Filter

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Re: Track tyres size and load rating

Post by McTrucky » Fri Jan 19, 2018 5:02 pm

All stock except the B12 kit.

If I destroy shoulders I may look to LCAs or other camber adjustment - but only if I need to. Would prefer to keep as stock.
M140i Auto; Met Grey with Black Interior; MPower LSD; Bilstein B12; Lots of bells and whistles; Could do with a wash;

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Re: Track tyres size and load rating

Post by marco_polo » Fri Jan 19, 2018 6:13 pm

I'd stick with ET40 square.
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