Traction issues with thin tire sidewalls

[fly135]

I'm currently running 19'' Advan RZ's (19x8 et45 & 19x9 et50) with 225/35-19 Yokohama Advan AD08's in the front and 255/30-19 in the rear, which are the recommended tire sizes.

My dilemma is that I feel the car isn't hooking up as well as it should be, both getting out of the box at the drag strip and also on the road when max torque kicks in in 1st and 2nd gears. I should mention that I also have a PROcede and catless dp and I'm lowered on KW V2's. It's particularly frustrating when slower cars are keeping up with me in the lower gears simply because I can't get traction down. My mate has an E92 M3 and it puts its power down so much more efficiently than my 135. I realise that a tuned 135 is making much more torque than an M3 and this is a huge factor.

Anyway, my theory is that if I fit a rear tire with a higher sidewall, this will give the tire more flex and considerable more traction. My current rear tire has a sidewall which is only 7.65cm (25.5cm x 30%) which is very thin. They feel like elastic bands with no give at all. This kind of makes me regret getting 19's. However if I fit a 255/35-19 this will have an 8.93cm sidewall (25.5cm x 35%) which would be like running an 18'' wheel. My questions are:

a) Do you think this increased sidewall will make a big difference to traction or am I wasting my time. My other option is to go a 265/30-19 however this will probably rub (even though my fenders are rolled) and I actually think the 255/35-19 will be a better handling setup and a more comfortable ride as well. Keep in mind the 1M has a 265/35-19 rear which has a 9.28cm sidewall (same as M3) which is even meatier again.

b) Do you think I would have any fitment problems with a 255/35-19 as it’s not generally a recommended size for a 1 series. I would obviously have to increase the ride height of my coilovers a centimeter or two as I’m currently sitting pretty low. I don’t see any major problems, apart from the fact I would be increasing the circumference of my rolling wheel from stock and therefore my speedo will be out by about 5% but that doesn’t bother me.

Any thoughts or suggestions would be greatly appreciated.

[VO 1M]

why did you post this in the 1M section?

[Die ///M Rakete]

Originally Posted by fly135

I'm currently running 19'' Advan RZ's (19x8 et45 & 19x9 et50) with 225/35-19 Yokohama Advan AD08's in the front and 255/30-19 in the rear, which are the recommended tire sizes.

My dilemma is that I feel the car isn't hooking up as well as it should be, both getting out of the box at the drag strip and also on the road when max torque kicks in in 1st and 2nd gears. I should mention that I also have a PROcede and catless dp and I'm lowered on KW V2's. It's particularly frustrating when slower cars are keeping up with me in the lower gears simply because I can't get traction down. My mate has an E92 M3 and it puts its power down so much more efficiently than my 135. I realise that a tuned 135 is making much more torque than an M3 and this is a huge factor.

Anyway, my theory is that if I fit a rear tire with a higher sidewall, this will give the tire more flex and considerable more traction. My current rear tire has a sidewall which is only 7.65cm (25.5cm x 30%) which is very thin. They feel like elastic bands with no give at all. This kind of makes me regret getting 19's. However if I fit a 255/35-19 this will have an 8.93cm sidewall (25.5cm x 35%) which would be like running an 18'' wheel. My questions are:

a) Do you think this increased sidewall will make a big difference to traction or am I wasting my time. My other option is to go a 265/30-19 however this will probably rub (even though my fenders are rolled) and I actually think the 255/35-19 will be a better handling setup and a more comfortable ride as well. Keep in mind the 1M has a 265/35-19 rear which has a 9.28cm sidewall (same as M3) which is even meatier again.

b) Do you think I would have any fitment problems with a 255/35-19 as it’s not generally a recommended size for a 1 series. I would obviously have to increase the ride height of my coilovers a centimeter or two as I’m currently sitting pretty low. I don’t see any major problems, apart from the fact I would be increasing the circumference of my rolling wheel from stock and therefore my speedo will be out by about 5% but that doesn’t bother me.

Any thoughts or suggestions would be greatly appreciated.

Are you running some type of LSD?

[fly135]

why did you post this in the 1M section?

I have no idea. Sorry mate, that was a mistake.

Are you running some type of LSD?

No I am not

[M3 Adjuster]

Originally Posted by fly135

I have no idea. Sorry mate, that was a mistake.

No I am not

Then your feeling that its not hooking up is because the car isn't. Save your tire money and get a limited slip differential.