Dziner82

has anyone run this size?
i did a search and only found one person that ran them, seemingly with no issues in the front.

im looking to upgrade my whole set for track day/autocross use. currently i have the 225/40 fronts are street summer tires, 300 treadwear, and they just dont provide enough grip, especially the driver side tire (im making a lot more right turns than lefts!)

i want to go to a 140-200 treadwear range tire, Yokohama AD08, Falken RT615K, Bridgestone potenza RE-11, etc.

i know the compound will be better on these than true street tires, also on some of these im assuming will have more rigid sidewalls? but if im looking for maximum grip would it make sense to go to the wider fronts? the overall diameter is a few mm smaller but still in the acceptable range. i guess its more about inside outside clearance. I would need to have them mount a tire in that size first to see if it will fit ok on the inside and outside edge.

I have euro springs and bilstein sport shocks. running 255/35/R18 in the rear, im happy with those.

I also intend to run a bit more negative camber at some point, probably via the KMAC setup. but the fronts just feel so overwhelmed when i autocross or track the car. I have gotten much better as a driver and it definitely helps keeping the car balanced, but 225 i think is still a bit narrow for a 3400-3500lb car.

any feedback or advice? this car is 90% for autocross use, a few track days a summer, and maybe drive to work a few days a month, summer only use.

popey24

Why not?
But pay attention... 245/35 and 255/35 might not fit together. Better use 245 or 255 on all 4 wheels.

Dziner82

why would they not fit together?

i know the 245/35's will be slightly shorter than the 255/35 rears, but i dont know of any problems this would cause. they are still within the acceptable range of the overall diameter. the speedo is tracked from the rear wheels right?

popey24

If you have difference of more than 1% your electronic will generate an error.
What exactly the difference is, you can not calculate. Depends on the tire. You need to ask manufacturer for real values.
I use 245/35 in front but combined with 285/30 rear wheels.

KJI3jflarryfe93

does 245 sized front tires fit w202?
i thought 225 was the best tire size w/o rubbing issues?

Dziner82

ahh, ok. i had wondered about that.

yes i also looked a the 285 size in the rear, but so few tires choices available there.

i will look at whats available in those sizes again here soon. the 225 is just so narrow for our heavy cars

dls55amg

width and rolling circumference r big facters ,if I may take a guess application and what your priorities r concerning tires and competition,also wondering r u running compressed air or nitrogen in your tires,not that I race or even run on a track but moreso lerning more about mb s

Dziner82

im using compressed air. car is mostly used for autocross, some track days (2-4 a summer) and very little highway driving.

503C43 ////AMG

That's a shame, IMO the C43 performs best on the highways

dls55amg

a possible option could be to get a infrared therm and take tire temps,not sure how costly they are but could be a valuable tool ,dziner82 are you near gingerman tack?ive heard a few guys in the Detroit area talk about running there,sounds interestimg

Dziner82

yes im about an hour away from gingerman. thats where i did my first track day. from talking to more people with experience there i guess gingerman's surface is especially hard on tires.

as far as the temp gauge, i think it would be a very useful tool for me, especially in determining if the camber adjustment will help. i haven't looked into how much they cost but have seen a couple guys using them at the track.

Dziner82

ive found that on the highway there really isnt a TON of difference between the C43 and my DD (when following state law) compared to the track, thats where it gets really fun

Dziner82

so i did research a bit on the wider width tires.

the 245/35/18 and the 285/30/18 are almost identical diameter, so those sets will work together as front and rear. though both of those have about a 1 inch overall wider section width than 225/40/18 and 255/35/18, so have to mount first then check clearances for the extra half inch on either side.

the other issue is that going to 245 fronts and 285 rears there are VERY FEW matching sets of tires in both of those sizes, especially anything in the 140-200 treadwear range. In more of a normal street tire (300+ treadwear) there are more options, but at that point i would rather go with the stickier rubber in the lesser size. though i think the hankook RS-3 tires were available in both sizes, so i may end up trying that.

popey24

Calculated values are almost identical yes... but you need to ask the manufacturer for the real values. The range is +1,5% -2,5% that means 4% difference possible with same tire dimension. If real difference is more than 1% your electronic will fail.
Also for the width there is a big range. My first 285/30-18 was Hankook K104. Hankook told me the real tyre width is 286mm, I measured and it was correct.
Years later I changed tyres front Hankook V12. Unfortunately the V12 in dimension 285/30 is not specified for Europe, so I can not use her (in USA should be available), so there was only the old K104.
I searched for other tires and bought Bridgestone RE050 (front+rear). unfortunately the were much wider than Hankook and did not fit uunder my fenders...
Next I asked many manufacturers for real tyre width. But they don't tell you or they tell you trash... Bridgestone told me the Potenza S-02 should be 284mm, but when I baught was much wider than Hankook as well.

Now I have the widest 285/30-18 I believe that is Conti SC2... check my other thread: https://mbworld.org/forums/c36-amg-c...onversion.html
Mounted on 11x18 it is 309mm and it overlaps the 11x18 rim more than Hankook mounted on 10x18 rim.
I am sure, if you order the Conti SC2 as 295/30-18, you will receive same tyre, only with other lable.

Dziner82

I did try to check the tire dimensions directly from the manufacturer info, thats the best i can do for now.
Im most concerned about the section width than the overall diameter as that seems like its much more consistent tire to tire vs the width which varies a lot. but you are right that it will vary depending on the rim width they are mounted on. I have 9.5 inch rear wheel, most of the manufacturers sites list the width based on what size wheel they have it mounted on.

raw1879

I will be fitting 245/35y18 tyres to the front of my w202 c55 next week the rims are 8.5 wide et25. I read in a auto car review this this size was a option with the BBS AMG split rims that I have. 245/35y18 on the front and 255/35y18 on the rear. ill post some pics when done

popey24

Different diameter front/rear is no good idea.

Dziner82

i don thtink it will be much of an issue. i see your point, but when you look at the stock size tires 225/45/17-F and 245/40/17-R, there is already a 7.5mm difference in the diameter, fronts being taller.

going to 245/35/18-F and 255/35/18-R there is only a 7mm difference in diameter there, but this time its the rear being taller.

given, these are generic measurements and a specific tire may be 1-3 mm variance.

would that swapping of the front/rear heights make the electronics be off? 7mm is not much difference either way. Do we know of anyone in a w202 that has had this problem, maybe not even a C43 but other C class?

Raw1879, i would definitely like to know how this turns out. im assuming worse case scenario an indicator light would come on in the dash? at least with a variance this small.

Dziner82

of course if i could only find a matching set of 245/35 and 285/30 i would just start there, but there aren't any in the type of tire i want. i will probably just end up getting extreme performance summer tires in the 225/255 setting, and try to run more negative camber.

popey24

Never trust on calculated diameter. Always ask tyre manufacturer for real value. The maximum difference the W202 can handle is about 1%.
So even using stock size you can have bad luck. So my advice: Always ask tyre manufacturer!
245/35 & 255/35 can work, but it can also disturb your traction/cruise control.
Even when using same dimension f+r but different manufacturer or tyre model I suggest to compare diameter.
The European standard ETRTO (unfortunately this norm was defined by tyre manufacturers, so it is good for tyre manufacturers but bad for cunsumers... it allows them to sell same tyre as different dimensions, so you can buy 245/35 and 255/35 and you receive same tyre - only label is different) allows manufacturer to vary diameter +1.5 -2.5%, so total difference can be up to 4%.

Just pay attention and be ensure your tyre combination will work before you buy.

Dziner82

I believe the USA standard for tire measuting is somewhat similar, at least in terms of how each manufacturer determines size can vary a bit.

the worst part is that it seems to me that Discount Tire (largest tire retailer in my area, perhaps entire USA) doesn't seem very willing to buy a set of tires just to 'test' if the size will fit, they seem to want me to be financially tied to whatever tires i ask them to order. But that was when i just went in to discuss, if i go in actually ready to buy they may allow me to buy 2 different sets of front tires and go with the ones that work best.

popey24

In Germany all tyre manufacturer have an online form you can fill and they will confirm you the tyre specification. Maybe there is something similar in US.

raw1879

ok ive had the front tyres fitted 245/35r18 with no problems all working fine no lights. just slight rubbing