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Help! Torn between 245/265 vs 255/275 tire widths!
Ok, I've been thinking about this for a while and I can't make up my mind. Someone help save me from myself! As you folks know on a sedan, the OEM tires are 245/35-19 and 265/35-19. These are on an 8.5 front and 9.5 inch rear rims.
I know I can do wider safely at 255/35-19 front and 275/35-19 rears. They will obviously look better as they fill in the gaps. But would they actually give better grip? Logic says yes due to the wider footprint... BUT the AMG engineers spec'ed the smaller size for a reason. They have access to measuring devices that none of us could afford. Maybe they found the OEM contact patch to give better grip or maybe better economy. I don't think it would be for economy since...AMG. We could care less! So maybe they did spec it for better grip or cornering balance? What do you think?
Uggh...! I can't decide...someone help me save me from myself....
Well, the stock tire sizes on the stock rims have a little bit of stretch baked into the setup. This is supposed to help cornering feel, make things feel a little tighter, and reduce sidewall rollover. In my personal experience 255/275 tire sizes are more available than 245/265 in my zip code, don't know if that carries over everywhere. Upsizing just the rears may help with traction as our cars struggle with that, but it may also alter the balance and rotation of the car in hard cornering-and I'm not sure you would want that as our cars are very easy to control in a drift. Honestly, making a 10mm change on either axel, or both axels would probably be imperceptible to most drivers under most conditions. The 1cm would theoretically only come into play with an experienced driver on a set of properly warmed up tires.
In short, do whatever is more convenient and more affordable for you. Or if you want, try ordering a set of 255/275 tires and let us know how they feel. I have the stock setup as of now and will probably go 255/275 next set for availability reasons if nothing else. Let us know how it goes.
C63S Brabus 600, gated Ferrari 575M; gated Ferrari 430 Spider; a couple of others
In my experience, wider doesn’t always mean better. It can also mean more understeer, scrub, less steering feel, more noise..I think you are right to be wary. The best tyre changes I have done on my cars over the years have always been for better tyres of the same size, recently always to MPS4Ss, which have sometimes made a transformational difference.
It’s also true that manufacturers spec different wheel/tyre sizes themselves so doesn’t always make much of a difference. But I would always go for the best rubber first, then tinker with contact patch size.
In my experience, wider doesn’t always mean better. It can also mean more understeer, scrub, less steering feel, more noise..I think you are right to be wary. The best tyre changes I have done on my cars over the years have always been for better tyres of the same size, recently always to MPS4Ss, which have sometimes made a transformational difference.
It’s also true that manufacturers spec different wheel/tyre sizes themselves so doesn’t always make much of a difference. But I would always go for the best rubber first, then tinker with contact patch size.
Yeap, that's why I' weary. I am leaning towards the AMG engineers doing their homework. Tire-wise, I'm a Michelin Pilot Sport 4S person (until we get the 5 which appears to be out in Europe).
there really isnt a noticable difference 245-255; whoever says there is a difference in handling or whatever is just saying what they want to believe. to see a difference you need to step up 20+mm
so like 245-265 and up you will feel a difference in driveability.
I have 255/275 setup and on initial drive I did notice the steering wasn’t as Precise as the 245 front. The steering was definitely noticeable but I don’t think it makes a huge difference in performance. The slightly wider rear tires felt better than stock so definitely happy with the increase width. Again since the increase was slight I wouldn’t say there was huge difference between stock. I say go for the increase width if you can. Looks wise it does look a little better.
I have 255/275 setup and on initial drive I did notice the steering wasn’t as Precise as the 245 front. The steering was definitely noticeable but I don’t think it makes a huge difference in performance. The slightly wider rear tires felt better than stock so definitely happy with the increase width. Again since the increase was slight I wouldn’t say there was huge difference between stock. I say go for the increase width if you can. Looks wise it does look a little better.
did you get an alighment after changing the size? thall def change the feel...but thats only because its not setup for it lmao
Arguably, the sedan is "undertired". The coupe has 285s in the rear and 255s in the front, but the coupe also has proper wider rear track and a unique rear axle. The sedan and the wagon are the more practical family versions of the C63.Tire sizes are dictated partly by how much room there is. As mentioned above, AMG factors a slight stretch into their tire setup for the reasons mentioned. I'm also not on the getting wider tires bandwagon. Another downside of wider tires is that they are heavier. Adding unsprung weight is not gonna improve the performance. One thing that many don't seem to really understand is just how much heat you have to get into your tires for them to even develop full grip. Most never reach those temperatures. At 100F, which is about the typical temp you get from just daily driving, you only get 80% of the potential grip the tires naturally have. Below is a graph from Michelin to give you an idea. Summer performance tires need to be around 190F to have full grip. They are showing red in the instrument cluster at those temps. I can tell you from experience, you have to drive very hard to get those temperatures. I was there with my front tires last weekend going for a canyon run in 100F weather. The rears reached about 160F. I can always tell when the tires finally get into their zone. The front end with properly warmed tires hooks up very different than with cold tires.
Last edited by superswiss; Aug 27, 2022 at 10:02 AM.
As soon as I wear down the PSS’, my plan is to go 255/275 PS4S (or whatever the new replacement may be) and to see how much negative camber can be dialed in with the factory suspension bits. Would be nice to get around -2.5 degrees in the front.
As soon as I wear down the PSS’, my plan is to go 255/275 PS4S (or whatever the new replacement may be) and to see how much negative camber can be dialed in with the factory suspension bits. Would be nice to get around -2.5 degrees in the front.
Just be careful that your setup is at a good spec and that you aren't dragging the inside of your tires after getting your alignment. I had an alignment at the beginning on this summer and have put 2000 miles on the car since, and while changing front brakes yesterday I found my passenger side tire looking like this.
After 2000 miles use. Was fine pre installation Pre alignment measurement Post alignment measurement
Needless to say that is not normal, especially when "properly" set up. I don't know if I should annoy the shop to replace this, I'll probably ask and see what they say. My next question is, will the new tire I had installed on the driver side (only replaced 1 due to a bubble) suffer the same fate in another 1000 miles or so? I sure hope not at $350 a pop for 245 width ps4s. Anyway, toe-out (or negative toe) is to my understanding what usually wears the inside edge of a tire. That in conjuction with our cars negative camber would accelerate it even more, but my toe is measured as toe-in, which should not cause inside edge wear...does anyone who knows a bit more think this wear could be caused solely by the negative camber? I have a hard time thinking this is only camber related as the wear is concentrated SO far on the inside edge. I can only assume I'm dragging somewhere...maybe their machine is out of spec, 2 days in the same weak they measured the alignment and I got 2 somewhat different measurement each time. Either the machine is off or my suspension has some play in it. Anyway my car is on desk duty until I get that changed.
Back to the point of this thread, as I replaced the fronts one at a time I am using 245s up front, next summer I will need new rears and will.probably go 275, so we will see how that setup works out. More than likely I won't notice a difference, but I'll try to remember to post back on this thread.
C63S Brabus 600, gated Ferrari 575M; gated Ferrari 430 Spider; a couple of others
I would be wary about specifying negative camber like that on a high performance car like ours without a template or proven precedent. Most of the handling we deal with in our cars at road speeds is about response and feel, not ultimate lap times or grip..this can be upset easily.
I am not saying manufacture specs are the best always, far from it, but with suspension and tyres, you need a good tuner to have done the research for you otherwise risk is making things worse.
in particular I don’t think wider fronts do anything except decrease feel and increase undesteer and negative camber can upset road handling character. These are not race cars, we have big heavy cars
If you’re replacing tires might as well buy new wheels.
May I suggest…
Front: 19x9 ET+32 & 255/35ZR19
Rear: 20x10 ET+50 & 285/30ZR20
-> Rear fender might need to be rolled
I think there are a few sets of wheels made to those specs. Custom manufacturers exist. Finding center caps can be difficult or expensive. I really wanted Mercedes center caps, luckily I found them.
Unless you want to go for extreme fitment, these wheels are custom made. It took 3 months to receive them.
Front: 19x9.5 ET+30 & 265/35ZR19
Rear: 20x11 ET+55, 12mm spacer & 295/30ZR20
-> 8mm might work
-> final ET+45 should work
I rolled and pulled the rear fender. Without reshaping the fender these tires would rub, very likely get torn apart. The rear fender needs to get bowed out where the bumper cover connects. Having watched a few youtube videos on fender rolling I gave it a try.
Just be careful that your setup is at a good spec and that you aren't dragging the inside of your tires after getting your alignment. I had an alignment at the beginning on this summer and have put 2000 miles on the car since, and while changing front brakes yesterday I found my passenger side tire looking like this.
Some tires are not designed for this much camber. It is my guess- There is too much toe in on that wheel. 2 Mercedes dealerships and 1 independent shop could not perform a proper alignment. I went to the 3rd Mercedes dealership in my area and they actually knew how to do an alignment on C63. Had mechanics and salesman with C63 & E63 working there, Mercedes enthusiasts at a Mercedes dealership- Go figure. It took them half a day loosening and torquing bolts to get the car alignment perfect- Which they did. There is very little play in the suspension- You can get adjustable camber arms, bushings and bolts. Adding wheel spacer also reduces the camber angle.
When the dealership doesn’t perform the alignment correctly and you burn through tires you just go back and buy more tires from them.
Today’s models the often quoted, reassuring “FULL FRONT & REAR ‘4’ WHEEL ALIGNMENT” - The reality is it is only Toe directional adjustment !
No longer essential Camber and Caster allowing to adjust tire contact angles, spread load more evenly.
Catering for other then showroom height conditions - day to day commuting encountering excess inner edge tire wear passengers side through high cambered roads or wheel squat through lowering or load carrying . Fitting wide profile tires. No longer ongoing adjustment for curb knock damage.
It’s all to do with cost cutting and ever increasing speed of auto assembly lines.
We saw the need to re instate once again full precise singe wrench adjustable front and rear kits.
Example Front Camber kit all C63/S models (#503316-1) $345 both sides - less then cost of one hi performance tire. Fit on car without need for arm removal.
See spoiler re complete range for C63/S Sedan, Coupe, Wagon
Spoiler
C63/S Sedan, Coupe, Wagon FRONT CAMBER ONLY - #503316-1i $345(Both Sides) .............CAMBER & CASTER #503316k$480(Both Sides)
REAR CAMBER (& Extra Toe to compensate) #502226K $480 ‘S’ Coupe #502326-1K $480
Delivery $40 one kit $60 front & rear
AUDI to VOLVO - KMAC The Experience OF Resolving OEM Suspension Shortcomings Since 1964!
Welp... thanks to the Tire Rack, this pretty much gives a definitive answer. You want the tire to be best supported by the proper wheel width. I was worried that by going with wider tires on the stock width rims, that I would lose "feel" and control. Turns out, I was right. I am keeping my stock tire widths!!!
Welp... thanks to the Tire Rack, this pretty much gives a definitive answer. You want the tire to be best supported by the proper wheel width. I was worried that by going with wider tires on the stock width rims, that I would lose "feel" and control. Turns out, I was right. I am keeping my stock tire widths!!!
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Help! Torn between 245/265 vs 255/275 tire widths!
