turbo8765

Looking for recommendations for a wheel tire setup. I was hoping to run 275 square with 19x10 wheels f/r. Is this possible? I've read a number of threads and it seems like most run more narrow front tires. Hoping 275 square is possible.

It seems as though the best rear offset would be +55, is this correct?

If not 19x10 is there an option in an 18x10?

///AMG 6.3

Have a set of Forgestar CF5v's on our C63. 19x10 +52 and it is pretty perfect. Run 275 PSS and I was worried about them looking too stretched but they look good. I wouldn't say they are completely square though.

CarHopper

He is asking 275's in the front and rear I believe.

275's up front wont work

Diabolis

255 Michelin PSS on a 9" custom offset front. Tight squeeze but no rubbing on OEM AMG sport suspension. There's no way you could fit anything larger in there without rubbing. Rears are OK with 275 PSS on 9.5" rim.

olszowa12

What would be the reason for using such a setup on a RWD car?
It would only add rotational mass on the front axis.

b16

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VividRacing

It's possible, just requires fender work and stretched tires.

Diabolis

Reducing understeer at high speeds thus allowing you to (enter a) corner faster.

turbo8765

Exactly.

Whats needed to fit 275's up front? Is a basic fender roll enough?

olszowa12

Are you kidding me? 275 in the front reducing understeer on a C-class?
You get more grip but you add more weight in the front.

Why do all powerful RWD use narrow wheels in the front and wider in the back?
Just my 2 cents.

Good luck.

Goni C63

^^ agree mine 2 cents is well way to big for front 275!

turbo8765

What were your lap times for the different front tire sizes you tested?

Data is appreciated.

Diabolis

No, not kidding you. The extra 5-6 lbs of weight that you might add is negligible compared to the extra grip you'd get. Am running 275-series R-compounds front and rear on my 928 track car (roughly 350 rwhp, <3200 lbs and 50/50 weight distribution, corner balanced). The difference in grip is astounding. Easily shaved off 3-4 seconds off my lap times with the wider fronts. OEM was 225, was running 235 at the front before getting the wider rims - the difference is between exactly the same R-comp tire in 235 vs. 275 width. The wider the tire, the larger the tire's friction circle.

The reason why OEM manufacturers use narrower tires at the front is because it allows for lighter steering, no tramlining and automatic re-centering of the steering wheel when you are reducing steering lock (you don't lose your scrub radius), and besides you'll never reach corner entry speeds on the street where this becomes an issue (if you do, chances are you're having a crash).

Diabolis

Not if you're going to track it. It's a pretty nose-heavy car so it becomes even more important to maximize the front grip.

CarHopper

I know I'll likely get flamed for this... But IMO the c63 has no business having 275's up front ripping around track. If you want a car that will mess your insides up get a lotus/gtr whatever and have fun. C63 (again, IMO) was designed to lay rubber down in a straight line while you squeal away from that civic and pat yourself on the back for a huge kill.

Unless you have some kind of insane deal on 275's all around don't do it. Or, get that deal, sell the front tires, and get 245/255.

turbo8765

And the fact that 99% of cars are setup to understeer stock.

VividRacing

All there is to say here is, to each his own.

I could see the fun of tearing up the track in a C63 but I also can see where PurpleHeart is coming from. Both ideas sound great to me!

turbo8765

The chassis in the '12 and later cars is quite good.

But to see your argument through... given that your burning the rears off wouldn't it be nice to be able to rotate tires front to rear?

Diabolis

I agree that the C63 perhaps isn't the best platform for a dedicated track car, with or without 275s up front -- but going by that logic, neither is a "street" M3 or RS4. Having said that, it's quite a decent performer on the track, and on fast, sweeping tracks in capable hands it can easily outrun an E9x M3. It's a little nose-heavy for shorter, tighter tracks and that's exactly where the wider fronts come into play.

If you're a track junkie I'm all for having a proper track car, but that certainly doesn't mean that the C63 should live exclusively on the street.

Diabolis

Correct. Understeer is deemed to be much safer to the "untrained" driver who is likely to lift off when they realize they're going in too fast.

turbo8765

So what's the consensus on a 10" wheel with a 275 tire up front? What is the ideal offset and will it fit with a fender roll or is additional work necessary?

Diabolis

It's surprisingly good. Have only taken it out once (just turned 3000km on mine) and was expecting it to be a pig but was VERY pleasantly surprised instead. My properly modified Audi S4 (full KW V3 & Stasis suspension) handled like a boat compared to the C63. It's a very capable car, and even better with the MCT - the only issue being the high oil temperatures that sometimes plague the MCT-equipped cars.

Dads C63

A simple fender roll will not cut it for a 275 up front. It will require the BS front fenders which requires a new BS front bumper and some side rocker panel matching. Then you can add all the BS front oil/tranny coolers to keep the temps down on track days. Been there done that. You also need the KW front suspension set up so you can get some serious camber which will help incredibly. Good luck!