BlackBear

Hi,

The only reason I'm considering changing rims and tires is to improve traction.

My question to all xyz55 owners:

How much did your bigger 19s or 20s improve your traction in turns and straight line?

On the factory 18s I constantly spin out of turns and during straight line WOT. The traction control kicks in and catches it again but I would like it better if the car just had more traction.

What are the widest front/rear tires and offsets combinations an E55 and CSL55 can acommodate?

I don't want to end up with rims/tires that don't fit.

Thanks,

Oliver

rbc55

i have 245/30/20 and 285/25/20 on mine and the traction has improved from the factory set-up,but it will still light them up with esp off. it may be possible to put 295/25/20 on the rear but mine with kleemann lowering module fit perfect,if you're not lowering it ;you'll probably be alright.for the cls ibelieve the set-up is 255/30/20 and 305/25/20.

Hardrivr

hmm... good question.. so what happened to those Chrome rims...

Rafal

I went from 265/35/18 Conti 2 to 275/35/18 PS2 and improved my traction by 200%. The ESP hardly ever lit up after the upgrade. Lateral G (cornering grip) improved by 9%
Now I upgraded to 19" and got even wider tires, but offset is critical:
Front 255/35/19 ET35 (but could run ET30, as there is no risk of fender rubbing)
Rear 285/30/19 ET38 (leaves 2 mm clearance from tire to fender, all around the top outside of the tire, under maximum compression, one wheel on high curb) No rubbing whatsoever!
Some guys went with 295/30/19 on the rear and it rubbed, triggering ESP on full acceleration, resulting in the infamous rear "wiggle " for a few hundred meters.

BlackBear

Great information. That was exactly what I was looking for.

One more question: Do the 255/35/19 and 285/30/19 maintain the same roling radius relationship so that ESP and ABS still work at optimum performance?

rbc55

to match factory diameter,you need 245/35/19 and 265/30/19; the 285/30/19 will slightly change the overall diameter but not enough to notice any effect on esp function.

Rafal

Factory diameter on the rear 265/35/18 is -1.5% smaller than the front 245/40/18, because of the Extra Load requirement. Now that I moved to 19" PS2's, both tires are XL, with load rating exceeding OEM 18" and they are both the same diameter (measured precisely 658mm R and 659mm F =25.9") That is less than 1% "oversize" and hardly worth worrying about, especially since the mechanically identical CLS55 rides on the same tires stock!

BlackBear

I forgot to ask if your rims are 8.5 and 9.5 since that is important when comparing offset/ET.

Thanks.

Rafal

Yes they are just that. Remember that OFFSET is not related to the width of the wheel, as it is measured from the mid-line of the wheel to the mounting plate.
What the width does do, is either stretch or compress the tire to give it a different sectional width from the nominal 245, 255, 275, 285 mm etc.
My front 255/35/19 on 8.5" rim are 255mm wide but the rears 285/30/19 mounted on 9.5" rim are "only" 279mm wide. They will only "stretch" to 285mm width on a 10" wide rim.
You add/deduct 5mm/0.2" from the sectional width for every 0.5" of rim width
deviation from the "ideal" size. That recommended size , as well as the maximum and minimum rim width is listed on every manufacturer's tire sizes table. l