tres55

I'm looking at a set of snow tires off of a C63. The sizes are:

Rear: 265/35 R19 (26.34" Diameter)
Front: 225/40 R19 (26.10" Diameter)

Stocks:

Rear: 255/35 (26" diameter)
Front: 225/40 (26.1" diameter)

Will that 0.34" increase in diameter on the rear cause any issues with the 4matic system or is it able to compensate? or is it within allowable thresholds for the different in diameter?

So instead of 0.1" shorter in the rear currently it will be 0.24" taller.

user33

This page will answer that and similar questions quite nicely:
https://tiresize.com/comparison/

tres55

That doesnt answer my question and I already posted those numbers in my original post. I was more hoping to find out if the 4matic system will run into problems over diameter being 0.24" higher on the rear, versus 0.1" shorter on the stock setup.

user33

Well, if you use that chart to compare a C43's front 225/40-19 to the rear 255/35-19, you get 0.1" diameter difference and one can guess that the systems need to allow for new tires on one end and bald tires on the other end, so there's another 0.25" ... so I'd guess "no problem."

What I suspect is happening is that, for traction control, the system establishes a reference at low speed/torque where it knows there's no slippage then uses that as the normal/baseline.

mjs1190

I had the dealer order new tires for my car and assumed they would be the original size but they ordered different ones so I am wondering the same thing.

I now have:
245/35/19=25.8 Diamater
265/35/19=26.3 Diameter

I am concerned the half inch difference will negatively impact the car's drivetrain.

tres55

That seems odd they would do 245/35 and not 225/40 considering 225/40 is stock size and the tire height would've been closer to the 265/35 they ordered for the rear?

mjs1190

Gave them a call to find out why and they said they couldn't order the tires in the C43 size, so ordered them in the C63 sizing. Service manager said that it won't have any negative effect on the car at all. He said there's a bit of a lee-way with the diameters. If that's the case, I would think your tire sizes are also fine.

alexasa

iTrader: (1)

That's not gonna work out well. That's way too much tire for the stock rim width. Plus, the more narrow the tire the better they are for the snow.