360 Tires, 315s?

Anybody running 315s on the rears, 10.5 width wheels or higher? Trying to plan the most from my OZs and 285 40s are a little tall with small width gain. 300+35s really starts to add contact patch.

 

I'm running 325/25/20's on the rear. I have Novitec NF1's.

 

Ideally a 10.5" wheels should have 275 or even 265 width. Performance wise, I won't put more than 285. You will have roughly the same contact patch running 285 or 305 on 10.5" wheels. Feel wise will be better with 285 or 275 since there will be less sidewall flex.

 

Are you running 18" rims? If 18", there's no interesting tyres available in neither 305/35R18 or 315/35R18. If you want at good tyre like the MPSS you can either run 295/35R18 or 285/40R18 - that's pretty much it. 295 is usually the recommended section for 10.5" rims(which is also what Ferrari uses) The latter will be slightly taller than OE, but the former will be a lot lower than OE. If you want to go wide, you really have to look into something like 11"-11.5"x19" in the rear with 325/30R19 and 245/35R19 in the front.

In any case, what the 360 needs is not wider rears in relation to the fronts. If you want better performance I'd suggest runnig a 285 rear with the widest possible front, as the 360 pushes a lot out of the box.

 

Aha! That's great guys. Thanks a lot. I was thinking more of a 285 40 using the calculators. I have already pushed into under steer twice and I have a good selection for the 8 inch fronts. 235 40 18

 

If your offset allows for it, fit 245/40R18 tyres. The wider the better.

 

Please watch out for rubbing the front fenders with wider tires; there are lots of threads on this subject on fchat.

I have OEM fronts (215/45/18) and despite that the left front tire kissed the front fender last week.

 

True. But if the offset is correct, you can run wider tyres without rubbing. There's also something to be gained by rolling the fenders.

To the OP. What's the offset of those OZ rims?

 

Most people are forgetting a very important issue, axle ratio
You would have Issues with ABS if you do not stick close to OEM's 0.9610 (in my opinion +/- 0.015)
I posted a while ago the generic diameters of all the tire sizes combinations, do your math and try not to be too far from 0.9610, I had 285/40 and 235/40 which gives 0.9414 (-0.0196) and I had problems withABS

http://www.ferrarichat.com/forum/360-430-sponsored-yellow-compass-group/517612-new-tires-3.html
Post 58

 

for 315 , you need 11" rim. I'm running 305 on 11s

 

315/35R18 are made to fit 10.5" wide rims per manufactures specs. So is 315/30R19.

 

According to what I discovered 11.5 or 12 is recommended
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Forget calculators. You need to go by the manufactures specifications. That goes whether we're talking rim fitment, tyre diameter, section idth or tread width.

Here are some examples.
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I would rather go wider than just enough. I think factory 19s are 10" with 285 so 10.5 for 315 I can't imagine. I have 305 on 11" and its square. It doesn't look like the rim is choking .

 

I had 305/25/20" on 11" rims with +30 offset - no problems (245/30/20" fronts on 8.5" rims with +24 offset - I never had them rub but tyres did have a few marks on outside edge??

Have switched back to std modular 18" coz ride was too harsh and rims were not to my taste.

Regards
Chris

 

MPSS 285/40R18 = unobtanium

so for 18" challenge wheels will settle for
MPSS 235/40 + 295/35

Same logic - need some side wall otherwise ride is unbearable in HK.

 

Let us know if you have ABS sensor issues with that setup. The front-to-rear diameter difference is much smaller than the OE setup. 225/40 or 245/35 should solve any such issues.

 

Hey thanks guys. I was able to get out for a drive, and while I like the 18 diameter, the smaller sidewall tuned for the 348 is a bit rough. I think it's better than the 348 because of the suspension but I am feeling it more now after a couple drives. I guess sport mode makes it worse The offset on the OZ's is 49mm front PLUS 11mm spacer on 360. Rear is 68mm PLUS 25mm spacer. I may end up sticking with 275 40 18 to maintain the axle ratio. 225 40 18 is LOWER than stock 360 front and I need to fill that space at least. Rear is currently on 256 40 18 so it's short too. I will go with this:

235/40-18 front 8 inch wide rim
275/40-18 rear 10.5 inch wide rim.

Couldn't find many 285s and larger on Tire Rack. I want to stick with Bridgestones for F1 history sake. SF was winning on them when Schumi was driving.

 

Can't see anything being available in that size. Go with Bridgestone RE-11's in 245/40R18-275/40R18, it's an awesome tyre, and probably the best Bridgestone out there currently. Diameter is as close to stock as you can get with fronts being 25.7" and rears 26.7", and your car will be very well balanced with much less understeer. With an ET of 38 total, that should not be a problem. If you have inside fender issues, just put on a 15 or 20 mm spacer depending on what's needed.

 

Hmm I thought I saw 235s in the RE11. I have 11pm spacer on front and 25mm spacer on rear.

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Yes you're right. Was checking up on something else earlier and had a look. At that time I could not find it.

But why not run the 245 section tyre when it's available? The diameter is closer to OE and tread width is more favorable.

Why I said an ET of 38 was just because you have fronts with an ET of 49mm. Add 11mm spacers to that, and it's the same as an ET of 38mm.

 

Ah, cool, I'll check it out after lunch.

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Let us know what you do and please post some info about how it drives along with final specs.

 

Hmm, just looking at tires again last night and the current pair are kind of close to the fender edge anyway. I wonder if the 245s would be pushing it too much? Wheels are already more flush with finder edge because of higher offset and spacer.

In fact, I tagged the curb in front front of my house parking to get my ramps out! Noooo! But I am almost done sanding and polishing the gouges out. Luckily it was just in the spun lip. Now I know why OZ made the spokes taper like they did. Tire sidewall bumper helped a bit too. Shouldn't have had that second beer with dinner I'll post a new thread on that. Looks pretty good already. If balance is a problem, that will get fixed when the new tires go on. I've been very subtle in my work with dremel grinder, wet sanding and polish. Damn these high granite curbs!

 

What tyre size are you currently running?