Can I run 305's in the back and 255 in front on 19's? Or it's better to run 275?

[haliski]

I was wondering if it's better to run 255 in the front or 275.

[NYG]

It's kind of more complicated of a question than just that. It's all about balance.

The general answer is more width = more grip/braking but mid-engine and rear-engine cars like 911s, Ferraris, Lamborghinis have skinnier front tires than you would expect. My R8 has 245s in the front and 305s in the rear. So it's not as straight forward.

[Donsta1980]

Originally Posted by haliski

I was wondering if it's better to run 255 in the front or 275.

Originally Posted by haliski

I was wondering if it's better to run 255 in the front or 275.

I'm on 255 and 305 rears. 20" wheels. Zero issues no rubbing

[CanAutM3]

Originally Posted by NYG

It's kind of more complicated of a question than just that. It's all about balance.

The general answer is more width = more grip/braking but mid-engine and rear-engine cars like 911s, Ferraris, Lamborghinis have skinnier front tires than you would expect. My R8 has 245s in the front and 305s in the rear. So it's not as straight forward.

It has a lot to do with how much weight each axle needs to carry. Load vs contact patch area defines how hard the tires need to work to generate grip.

The mid/rear engined cars carry much more weight on the rear axle, hence why they need much wider rear tires relative to the front. The M3/4 remain nose heavy cars, with more weight on the front axle. So ideally you’d want to run a square setup, but is not always practical to do so due to space contraints. I would however definitely not recommend a 255/305 setup as it would push (understeer) like crazy.

[2sporty]

I got laughed out of the X3M forum for even suggesting that ridiculously skinny front tires combined with huge rear tires vs OEM sizes would understeer to the extreme. A lot of people do it "for the looks" and are completely ignorant regarding handling dynamics. Even people with M3/4s.

[NYG]

Originally Posted by CanAutM3

It has a lot to do with how much weight each axle needs to carry. Load vs contact patch area defines how hard the tires need to work to generate grip.

The mid/rear engined cars carry much more weight on the rear axle, hence why they need much wider rear tires relative to the front. The M3/4 remain nose heavy cars, with more weight on the front axle. So ideally you’d want to run a square setup, but is not always practical to do so due to space contraints. I would however definitely not recommend a 255/305 setup as it would push (understeer) like crazy.

Agreed.

255 would not have been enough on my M4CS. I was pretty happy with 275 as I hit oversteer before understeer with that setup.

[FaRKle!]

Originally Posted by CanAutM3

I would however definitely not recommend a 255/305 setup as it would push (understeer) like crazy.

^This. Having tested 20-40mm stagger on the track, 40mm understeered like crazy.

[CanAutM3]

Originally Posted by NYG

Agreed.

255 would not have been enough on my M4CS. I was pretty happy with 275 as I hit oversteer before understeer with that setup.

Agreed, the 275/305 setup worked decently well for me also in terms of handling balance. I worked other tuning elements to compensate for the tires.

However not so much regarding tread wear. The fronts were clearly overworked and I could not get them to wear evenly (would cord both the inner and outer shoulders with plenty of meat left in the middle). I had perfect wear on my rear tires and they would last almost twice as long as my fronts.

[hoppes-no9]

Originally Posted by CanAutM3

Agreed, the 275/305 setup worked decently well for me also in terms of handling balance. I worked other tuning elements to compensate for the tires.

However not so much regarding tread wear. The fronts were clearly overworked and I could not get them to wear evenly (would cord both the inner and outer shoulders with plenty of meat left in the middle). I had perfect wear on my rear tires and they would last almost twice as long as my fronts.

Did you try increasing inflation pressure on the front?

[CanAutM3]

Originally Posted by hoppes-no9

Did you try increasing inflation pressure on the front?

Yes, in various increments all the way up to 42psi hot. I discovered the higher pressures actually made things worse because the tires slipped more, which shredded the tread.

[hoppes-no9]

Originally Posted by CanAutM3

Yes, in various increments all the way up to 42psi hot. I discovered the higher pressures actually made things worse because the tires slipped more, which shredded the tread.

Wow, got to know