Tire sizing
 

Hi all,

In need of some advice with tires. I’m wondering if I can run 255/40 R17 (semis) just on the rears? I wouldn’t be able to do them all around bcuz it will scrub on the front. Or should I go for the current tire size all around with Michelin pilot sports?

My specs are:
Rims are 17x9 +35
Current tyres are 235/45 R17


Sent from my iPhone using Tapatalk

Is this car exclusively driven on the street, or does it see any track time?

I would suggest running a 245/40-17 square setup so you can continue to rotate, and just dial in negative camber to ensure they clear the fenders. Assuming you are still on stock suspension and do not want to invest in coilovers just yet, you can install camber bolts to get the camber you need up front. The ET35 offset gives you plenty of inner strut clearance to work with, and the 245's will provide you with plenty of grip no matter how you enjoy the car.

- Ryan

This car is turbocharged and is only driven on the street. I’m sitting on pedders coilovers but the front will scrub if I go 245 so yes that’s a great suggestion! ill get the camber bolts and see how I go


Sent from my iPhone using Tapatalk

I dont think it should rub/scrub with 245/40 tires. Maybe you need to run some more camber to tuck the tire in.

I'm running the same specs for wheels and 245/40/17 tires on coilovers.

Currently with zero fitment/rubbing issues. It may depend on your ride height and camber setup.

You may need to alter if you're going for a track setup or want to be a stanceboi.

Not the OP, but when you got that size. Is the handling and turning feel duller? Thats what Ive read people say about that when they go 9” tires. Does the turning feel any different like what ive read about?

My setup will be +400whp. Id like some traction but not change how the car feels when youre going round bends/corners.

If you have the same wheel specs as me I’d say go 245/40 or 245/45 over 255/40 as I’ve heard the Speedo is less accurate and it is slugging in corners. I decided to stay at 235/45 R17 and just got some yoko AD08R for the rears instead. I am turbocharged sitting at 316hp and I’m gripping well in both wet and dry conditions.


Sent from my iPhone using Tapatalk

I'd say the handling is better but the turning feel does feel "duller" imo.
With the wider tires, I have more confidence making tighter corners than I did on stock tires/specs.

Can also confirm that over 225 width starts to feel duller than a narrow tire.

That's unfortunate. I love the look of widebois but I hope I don't regret it because of downgraded feel.

It's still pleasant to drive, just slightly less sharp. It still handles just as well.
I went from 200tw tires to 240tw, so maybe my complaint lies there?

I never noticed any "dulling" of steering responsiveness going to lightweight 9" wheels with good (RE71R) 245/40-17 tires. If anything, ightweight 9" wheels with good 245s should should generate more lateral grip per degree of slip angle and hence feel *more* responsive.

I just switched from 225 RS4s on 17x8 +35 Rota Grids to 255 RT615K+s on 17x9 +35 RPF1s and they definitely feel very different. There's less sharpness/directness to the inputs but it doesn't necessarily feel bad. The car actually seems to want to rotate more on the 255s, which is the opposite of what I expected. I'm on TRD springs and running 3.3F/2R for camber and -0.10F/0R for toe. I was worried about rubbing but have no issues at all.

Won't really know how I feel about the setup until I track it this Saturday. I got the wheels intending to run 245s, but the 255s they came with have a lot of tread left so I'm gonna give them a shot first.

All of what you are feeling can be attributed to the change in tire/compound.

In my opinion any dullness or lazy initial response is probably more of a function of a few extra pounds gained between a wider wheel and tire combo vs anything to do with the extra width. Hard to tell without an apples to apples comparison (weight, compound etc.).