Front/Rear tire size difference
Thread Starter
Super Member
Joined: Apr 2011
Posts: 688
Likes: 178
2009 C230
Front/Rear tire size difference
Hey guys, I know the OEM 19s have about a 0.23% size difference between front (225/40/19) and rear (255/35/19)
which is obviously acceptable by MB specs but I'm wondering what % difference starts to be a problem with our AWDs?
I'm looking at front/rear combo that has about 1.07% difference so 0.85% more difference than OEM. Any thoughts?
That's still quite a small difference however thought I'd see what people thought. Thanks.
which is obviously acceptable by MB specs but I'm wondering what % difference starts to be a problem with our AWDs?
I'm looking at front/rear combo that has about 1.07% difference so 0.85% more difference than OEM. Any thoughts?
That's still quite a small difference however thought I'd see what people thought. Thanks.
Junior Member
Joined: Jul 2017
Posts: 71
Likes: 8
From: Washington, DC
2018 Mercedes AMG C43 (sold), 2025 GLC63s Coupe
The dealer mistakenly but C63 tires on my car 245/35/19 and 265/35/19 which works out to a 1.92% difference which is obviously more than yours. However, it was enough for it to throw off the wheel speed sensors that impacts the traction control and cause the engine to cut power when on flat roads and driving normally. The car would be undrivable for a few miles and then would be fine. When they swapped back to the OE tire size, that issue never resurfaced.
Thread Starter
Super Member
Joined: Apr 2011
Posts: 688
Likes: 178
2009 C230
The reason I'm asking is that I run 8.5" rims all around for my summers. I need new tires this summer (Pilot Sport S4)
and my current OEM Pirellis run a bit of a stretch in the front, they work but definitely a bit stretched.
If I went 245/35/19 front and 255/35/19 rear, the look would be much improved!
and my current OEM Pirellis run a bit of a stretch in the front, they work but definitely a bit stretched.
If I went 245/35/19 front and 255/35/19 rear, the look would be much improved!
The reason I'm asking is that I run 8.5" rims all around for my summers. I need new tires this summer (Pilot Sport S4)
and my current OEM Pirellis run a bit of a stretch in the front, they work but definitely a bit stretched.
If I went 245/35/19 front and 255/35/19 rear, the look would be much improved!
and my current OEM Pirellis run a bit of a stretch in the front, they work but definitely a bit stretched.
If I went 245/35/19 front and 255/35/19 rear, the look would be much improved!
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Super Member
Joined: May 2010
Posts: 829
Likes: 190
2017 C43
My first setup had a 2.75% f/r ratio, never gave me any problems even at over 100mph speeds. From what I’ve read, for as long as f/r ratio is within 3% you shouldn’t have any issues.
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Member
Joined: May 2017
Posts: 83
Likes: 11
From: Just outside Oslo, Norway
2018 AMG C43 T
I recently read about this on some Norwegian website. For Mercedes I'm pretty sure the 4wd-system allows up to 5% difference in wheel ratio between f/r axle. I was surprised, because I know 4wd-systems on some other brands don't allow any difference at all.
Member
Joined: May 2017
Posts: 83
Likes: 11
From: Just outside Oslo, Norway
2018 AMG C43 T
Yes, I also thought 5% seems like a lot. I think it was someone from the official MB importer who said it. I have tried to find the article again without luck. Not that it would help you as it is in Norwegian, but to see if I remember correctly.
