When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Sorry in advance if this has been discussed in detail elsewhere, but it’s time for new tires and I was thinking about going wider in the back to 305s with the stock forged wheels. Is this possible without any detrimental effects to the car’s performance or safety?
My rational for this is that I’m contemplating buying different wheels and I’d like the option to go wider with those wheels so I might as well get the bigger tires now.
Sorry in advance if this has been discussed in detail elsewhere, but it’s time for new tires and I was thinking about going wider in the back to 305s with the stock forged wheels. Is this possible without any detrimental effects to the car’s performance or safety?
My rational for this is that I’m contemplating buying different wheels and I’d like the option to go wider with those wheels so I might as well get the bigger tires now.
Thanks in advance
I ran 305 with no problems on a BC forged set-up, but my mechanic said overtime its going to throw off the 4matic system
305 needs a min 10.5 inch wheel width. The stock wheel is 10 inch width. So, you are putting stress on the sidewall, in normal daily driving, you may be ok but if you are doing lots of aggressive corners, then the sidewall may result in damage.
305 needs a min 10.5 inch wheel width. The stock wheel is 10 inch width. So, you are putting stress on the sidewall, in normal daily driving, you may be ok but if you are doing lots of aggressive corners, then the sidewall may result in damage.
That’s what I wanted to hear. Doesn’t seem like a good trade off. So either buy the new wheels with the tires or just stick with stock sizes. Thanks.
I kept the rear size the same/stock but went with 10mm wider fronts (I cannot remember what it was anymore). Let's just say my car was a wild pony at speed under acceleration. Once you hit 120mph and above under WOT, it was hard to keep it stable and straight! I wish I had also gone wider in the rear by the same amount because I absolutely hated the out of control feeling. I did it because I bent some old AMG front wheels from the very small profile rubber and wanted to do this as a preventative measure. That part worked, no bent wheels or bubbles on the sidewalls on this car
I do not know if that was the issue or I had defective Michelin Pilot 4s (brand new), which balanced great with zero vibration....but it was downright dangerous feeling at high speeds after multiple alignments and road force balancing. Didn't stop me from routinely hitting 140+ mph though in the name of science
I kept the rear size the same/stock but went with 10mm wider fronts (I cannot remember what it was anymore). Let's just say my car was a wild pony at speed under acceleration. Once you hit 120mph and above under WOT, it was hard to keep it stable and straight! I wish I had also gone wider in the rear by the same amount because I absolutely hated the out of control feeling. I did it because I bent some old AMG front wheels from the very small profile rubber and wanted to do this as a preventative measure. That part worked, no bent wheels or bubbles on the sidewalls on this car
I do not know if that was the issue or I had defective Michelin Pilot 4s (brand new), which balanced great with zero vibration....but it was downright dangerous feeling at high speeds after multiple alignments and road force balancing. Didn't stop me from routinely hitting 140+ mph though in the name of science
Did you have spacers on too as well as the wider tire?
My car is already a handful with 15mm spacers only and I'm going for 285s on the front, I'm 100% betting spacer removal will be mandatory not for clearance, but for safety. It really pulls left/right like mad WOT with spacers unless going 100% straight.
Anyhow I'm going for the 305's and am also upping them to 35 series on the rear. We'll see if it looks OK or turns my wagon into a GLE. LOL
I went for 305, and even taller 35 aspect instead of the normal 30.
Removed the 15mm front and 12mm rear spacers, stock rims.
Put car at stock ride height.
Dealer reports:
Front 285/35 - fits fine! Loads of room.
Rear 305/35 - rub on the inside.
Busy with life I haven’t seen the car yet and don’t know the extent of the rubbing. I preemptively ordered 3mm spacers that should be here Wednesday. I’m hoping that will be enough. More info to come.
Last edited by I.T. Guy; Aug 16, 2025 at 11:39 PM.
The long term plan if I like the look and tire is to widen the stock rims to 10.5" and 11.0" and run 295/305 front/rear which are the perfect "native" sizes tire to rim width.
Swung by the dealer. They had to put the 12mm spacers on for the wheel/rim to even go on! With the 305/35's it just mashes against the inner wheel well without the 12mm. They laughed when I said I orderd 3mm spacers. These Continentalls are fatty-fat-fat! Holy moly.
So I left and they are going to put the other side on and tell me what the rubbing situation is after they drive it. I may need to go down to a 295/35 in the rear.
Agree. It’s a journey and slowly getting there! A lot better today on the ground.
Stock rims stock height, 12.5mm Supreme Power Spacers.
Zero rubbing - after a few days I will start lowering a bit at a time and see how it goes.
I love the overall look however I’m not a fan of the bulge on the rim. So I’m either going to go to a 295/35 tire which has about 1/2” less section width or widen the rims to 11” over winter.
I’m loving the meaty 28” diameter! The 305/35 is 1” taller then 295/305/30. It really fills out the wheelwell properly IMHO and will only need 10mm lowering to achieve the same look as 295/305/30 and 25-30mm lowering.
Last edited by I.T. Guy; Aug 21, 2025 at 12:30 PM.
Weldcraft Wheels will widen stockers (I love them) for $375. I’ve used them before.
Math is:
10” and ET 55 widened 1” on rear face changes centerline and new 11” wheel ET is 67mm.
15mm spacer with the new ET 67 wheel = 52mm ET which is what everyone is running on 20x10.
I just don’t know if 52 ET will work with the 28” tire or if I will have to drop down to 305/30. I love the filling of the arch with the /35 series tire.
Ive been cruising eBay for rear wheels to sacrifice just in case but haven’t found any yet in the aero twin spokes.
Last edited by I.T. Guy; Aug 21, 2025 at 08:43 PM.
When you tested without spacers, did you have any loads (passengers) at the back to confirm ?
Not yet and 100% it's in the back of my mind as we are moving a kid next weekend. Which is why I started dinking with it last night becuase if not rub free before the weekend I'm renting a van.
Today I hit all the agressive dips and bumps that made it rub before and zero rubs. And that's in C where suspension is soft.
Over the next few days I will be lowering with the Cete 5mm at a time and see if it starts rubbing.
With the car on the ground I lay under it with a flashlight looking up all round the wheel everywhere there is lots of room. I can't beleive the dealer couldn't figure it out but I guess that's not really their job. OR they know something that will bite me in the *** any kilometer now.
Why we do this to ourselves is a mystery but hey - it's fun! LOL
That's a pretty big difference in height, both overall and tire.
It would be cool to try that 305 on a 11" rim with ET52 to see how it shapes and if it still fits in the wheelwell or if it needs to step down to a 30 series. There are a few members on here that have 21x11" rims and 30 series 305 and 315 which in mfg specs say are the same size and width as the 20" 305/35 I'm running, so, it _should_ work.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
