Tyre stretch safe for track use?

[wenguin]

Hi folks

I abandoned the idea of getting rev5 wheels and painting them when a nice set of Enkei Circlars came up. The sizes are:

17 x 8 ET35
17 x 9 ET38

they come with two tires on the rear, 215/40/17. I understand there is a bit of stretch on them.

I intend to bring the car to track with these wheels on at some point, and am wondering if this stretch is up to it.

Would these tires be better on the front wheels instead of the rear?

Or would I just be better selling the tires and buying a matching 'ideal size' for all wheels?

Cheers

[Howlin_Mad]

Hi folks

I abandoned the idea of getting rev5 wheels and painting them when a nice set of Enkei Circlars came up. The sizes are:

17 x 8 ET35
17 x 9 ET38

they come with two tires on the rear, 215/40/17. I understand there is a bit of stretch on them.

I intend to bring the car to track with these wheels on at some point, and am wondering if this stretch is up to it.

Would these tires be better on the front wheels instead of the rear?

Or would I just be better selling the tires and buying a matching 'ideal size' for all wheels?

Cheers

No!

I wouldn't be happy running 215's on the road on a 9J rim for pootling around, let alone at speed!

If you are going on track with those J wheels i'd suggest 225 fronts and 245 rears as your minimum widths.

HM

[wenguin]

cheers mate

from the sticky in this forum i see:

17x8 ET35 215/40/17 front
17x9 ET35-ET38 245/35/17 or 245/40/17 or 255/40/17(may rub the arches depending on offset and ride height) back


this suggests putting the 215 on front is okay, with one of those tyres listed going on rears

maybe i am missing something though?

[Howlin_Mad]

I'd go with 225 on the front at 8J but you could get away with the 215's. Nowhere near a 9 J rim though!

I ran a 205 on an 8J rim and ( it was really stretched - waiting for my tyres to be delivered the next day ) pootled back from work at 30mph and it came off the rim. Completely. Don't compromise if you are going on track!

I'd had the car a day or so, so wanted them changed ASAP, I was lucky!

HM

[jimGTS]

Don't think many folk run 225s up front. Least I can't think of any.
Assuming the 215s are good quality makes and life left. You should be fine to stick on the front.
But as hm says. Do not leave them up the back!

[MRturboTom]

215/245 is the best combo.
Seen it several times on track, people pulling tyres off the bead in the corner having stretched tyres.

In fact, known people do it running too high a profile too

[parker455]

I run 215/245, can't remember my offset but the rears scraped before rolling the arches and the fronts has scraped recently on big hits. Depends how low you are, normal use should be fine!


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[baileydom]

I have 215/245 on 8j ET33 and 9j ET43 rims. Whether they scrub or not depends on the offset of the alloys. I have no scrubbing at all. Win!

[wenguin]

Thanks for the tips.

I'm inclined now towards putting the 215 on the front now as suggested, and then buying new 235/40/17 for the rear.

To complicate things slightly, I have just grabbed a set of -30mm lowering springs, which I understand will mess this plan up.

Am I right in thinking that I won't be able to lower the car with those, and the 215/235, without rolling the arches?

It's factory struts, with -30mm apex springs.

Also, I've been running T1R Proxies on my standard wheels which I enjoyed, sadly they don't seem to do a 235/40/17, so any other suggestions for track friendly road tyres in this size?

[TonyleFrog]

Jay's Silverstone track days. First one July 2013. Second October 2013.

Rev 4 - 17x8 ET35 215/40/17 front & 17x9 ET35 235/40/17 rear


Rev 5 - 17x8 ET33 215/40/17 front &17x9 ET43 245/40/17 rear
@1:04 - http://www.youtube.com/watch?feature=yo ... ahuVhudgk0

Both cars on Goodyear Eagle F1s and are lowered on coilovers. Neither has rolled arches. No rubbing issues at all. Though there might be on the Rev 4 due to the lower offset number if I were to fit 245s.

[firebobby]

Jay's Silverstone track days. First one July 2013. Second October 2013.

Rev 4 - 17x8 ET35 215/40/17 front & 17x9 ET35 235/40/17 rear


Rev 5 - 17x8 ET33 215/40/17 front &17x9 ET43 245/40/17 rear
@1:04 - http://www.youtube.com/watch?feature=yo ... ahuVhudgk0

Both cars on Goodyear Eagle F1s and are lowered on coilovers. Neither has rolled arches. No rubbing issues at all. Though there might be on the Rev 4 due to the lower offset number if I were to fit 245s.

The red one looked fastest

They all sounded nice as well

[sinjen]

I ran 205's on 8J enkei for both silverstone runs, absolutely fine. 245/35 on 9J at the back. Needless to say 215 on 8J is also perfectly fine and for me the sweet spot.


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[TonyleFrog]

I ran 205's on 8J enkei for both silverstone runs, absolutely fine. 245/35 on 9J at the back. Needless to say 215 on 8J is also perfectly fine and for me the sweet spot.

205 on 8J is below the recommended minimum
http://www.tyres-pneus-online.co.uk/tyr ... dvice.html

For recommended and permitted tyre/rim combinations, consult the current E.T.R.T.O. Standards Manual.

What you do on the track is up to you but be careful of doing this on the road. If you have a prang which involves loss of control you might just find yourself on the receiving end of some awkward questions from a PCI.

It also gives your insurer a handy way to avoid an own damage claim (you have declared the use of a non-recommended tyre/wheel combination, haven't you?).

There is also the possibility of a potential prosecution.
- C&U Regs 1986 Section 27(a).
- Road Traffic Act 1988 section 40A

Section 40A offence = £100 FPN + 3 points. To overturn the FPN you would have to go to court. Fitting tyres which are outside the wheel/tyre manufacturers's recommendations could be sufficient evidence to tip the scales against you.

I don't know anyone who has been done for this but that doesn't mean it hasn't happened.

[dawesy]

^this. I'm sure it's only a matter of time before its in the news.
There was a vid on FB of a stanced IS200 loosing control and a lot of the cause was put down to excessive camber and stretched tyres b


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