[garshtoshteles]

Hey y'all, I just bought my 2013 C30 T5 R at the start of February 2022 with 40k mi on it. I've already ordered myself a do88 intercooler and pipe kit and plan on getting elevate air sus, sway bar, down pipe, and exhaust system. However, all of this is pretty useless if my front tires continue to slip when laying down power from a stop. I know it can only be fixed so much as a FWD car with a decent amount of power, but i figured slightly larger and wider tires could help get better grip.

I've got the Midir 18"s right now, came with the car (obv). They're (from what I can tell online) 18 x 7.5, bolt pattern 5 x 108, offset 52.5, center bore 63.1, weighing ~23 lbs.
I'm considering getting the Petrol P2Bs, Discount Tire | Tires and Wheels for Sale | Online & In-Person , 19 x 8, bolt pattern 5 x 108, offset 40, center bore 72.1, weighing ~23 lbs.

I'll have to get hubcentric rings and roll the fenders somewhat, I'm sure, but is there any glaring reason this would be a bad idea? The other nice thing is that I can always sell the Midirs (probably on here or on c30 crew) and recoup a little of my losses.

 

[Facusan]

I'm sharing my opinion from the performance standpoint. I'm not considering looks:

Your current setup is already one of the biggest wheel/tire combination that will fit on these cars without extreme modification to the body.

I think switching to 19" rims will not be an improvement. To me, it would be the slightly the opposite.

You still will have a 235mm contact patch or 245mm at the best (assuming they were to fit under the fenders). And that's just to get started, 235/35/R19 and 245/35/R19 are 0.4% and 1.6% (respectively) bigger in diameter than your stock wheel setup, this will be the equivalent to having longer gear ratios, and to overcome this your engine will have to apply more power (not that much), making your car slightly less quicker on acceleration.

Also both wheels, as you said, they weigh the same. So, there's no improvement there. BTW, there's a fellow C70 member here with 19's and has to use 225/35/R19 tires and they still rub a little bit.

IMHO I think it would be better to spend that money towards better tires instead. Something more performance oriented, like Toyo Proxes R888R, Michelin Pilot Super Sport, etc.
In case you were already planning this, then consider upgrading the front control arms with the anti-lift kit and polyurethane bushings.

With a tune, all the mods you listed will get you to around 300 HP at the crank. Although is more than enough power to light up the front wheels in 1st and 2nd gear, It also isn't THAT much to make this car a death trap.

 

[garshtoshteles]

dang, that's what I was worried about. : /
you mentioned the c70, just want to make clear I'm referring to a c30

 

[Facusan]

C30, S40, V50 and C70 are based on the same platform. If the front wheel will not fit in one, won't fit in any other. They're basically the same when it comes to suspension.

In stock configuration, front wheel size is limited because part of the spring support is above the tire contact patch, limiting the diameter, and also the width because it's very close to the sidewall.

There is a little bit more space left there, but is not that much. If you swap to coilovers, you may gain a little bit more clearance, but I can't confirm this.

 

[garshtoshteles]

C30, S40, V50 and C70 are based on the same platform. If the front wheel will not fit in one, won't fit in any other. They're basically the same when it comes to suspension.

In stock configuration, front wheel size is limited because part of the spring support is above the tire contact patch, limiting the diameter, and also the width because it's very close to the sidewall.

View attachment 148493

There is a little bit more space left there, but is not that much. If you swap to coilovers, you may gain a little bit more clearance, but I can't confirm this.

Truly grateful for such a detailed answer. Knew S40, C30, V50 were P1 but didn't realize C70 was as well.

 

[Facusan]

2nd gen C70 is exactly the same, with the exception of the rear track width being 10mm wider (it has 5mm spacers behind each wheel hub, they can be transfered to any P1).