[mlifxs]

Hi folks,
I posted in the wheel and tire forum here:
http://www.e90post.com/forums/showthread.php?t=791232

One poster who had concerns suggested I also post a thread here, thinking all of you care deeply about tire attributes and would have some thoughtful comments.

I've got a pre-lci 328i with sport package, upgraded to BMW perf suspension and M3 control arms. I don't track but do enjoy spirited driving. I'll need to buy tires in a few months and have thought about a simple, cheap way to further improve handling and achieve a square set-up for rotation.

I'm thinking of changing my OEM 8 width fronts to 8.5 (same as rear) and increasing the tire width to 255 (same as rear, currently). Thinking: better braking, better handling...

...but I'm also concerned about unintended consequences...perhaps running 255 up front on an 8.5 rim is a bad idea? If so, how wide would you go on an 8.5 rim?

Thank you in advance for any thoughts or suggestions.

[yandy]

That's what I run on my car, 255/40/17 on Kosei K1s. Haven't had an issue to date, and 8.5" is within range of for the wheel size. Could be better on a 9" wheel, but I don't expect you'll have any problems.

[mlifxs]

Originally Posted by yandy

That's what I run on my car, 255/40/17 on Kosei K1s. Haven't had an issue to date, and 8.5" is within range of for the wheel size. Could be better on a 9" wheel, but I don't expect you'll have any problems.

so in other words, worth doing, just not optimal ?

[kenneth]

Aren't the rears already 255 on 8.5 inch rims?

[yandy]

Originally Posted by mlifxs

so in other words, worth doing, just not optimal ?

To me they are optimal, you get less understeer with the square setup, better grip... so nothing but pluses from my view.

[mlifxs]

Originally Posted by kenneth

Aren't the rears already 255 on 8.5 inch rims?

Absolutely they are, which originally lead me to think "why not"?

Still, seems as though people prefer wider rims for that width. My biggest concerns were would it diminish steering responsiveness or make steering a little too heavy for a daily driver? Also wondered, fronts must experience different forms of stress than rears, will the rim width matter?

[mlifxs]

Originally Posted by yandy

To me they are optimal, you get less understeer with the square setup, better grip... so nothing but pluses from my view.

thanks, makes sense. Just figured I'm not experienced and could stumble into an unintended consequence.

should only cost be $50 to $100 to upsize my rims, after selling my 8's. Square setup for rotation, more grip, might even have fronts with less curb rash (at least initially lol )

[3002 tii]

They're optimal if you have enough camber to help with the turn-in.

[mlifxs]

Originally Posted by DSC_OFF

They're optimal if you have enough camber to help with the turn-in.

Thanks.
Someone on my orig thread suggests 'get camber plates for meaningful improvement' rather than go wider.

[mlifxs]

Originally Posted by DSC_OFF

They're optimal if you have enough camber to help with the turn-in.

Thanks.
Someone on my orig thread suggests 'get camber plates for meaningful improvement' rather than go wider.

[neilvosko]

Both camber and wide wheels

[UltraRacer13]

The tires will bubble a bit on 8.5's, but it shouldn't have a meaningful impact. Adding camber will have the most impact.

I run that size on 17x9's for the track.

[mlifxs]

thanks neilvosko and UltraRacer13. I'm going to have an alignment soon. With my M3 wishbones and pulled pins I'm hoping I can get to -1.5. I'm thinking this might be sufficient for 255 all around on 8.5s, or dial back to 245 all around on PSS (they don't make 255 for 17s).

Camber-wise,I could go further with some GC Street or Dinan camber plates, not sure if it's worth the cost / install / tire wear for a DD.

[UltraRacer13]

pretty aggressive for a street setup.

[Mavus]

Originally Posted by mlifxs

thanks neilvosko and UltraRacer13. I'm going to have an alignment soon. With my M3 wishbones and pulled pins I'm hoping I can get to -1.5. I'm thinking this might be sufficient for 255 all around on 8.5s, or dial back to 245 all around on PSS (they don't make 255 for 17s).

Camber-wise,I could go further with some GC Street or Dinan camber plates, not sure if it's worth the cost / install / tire wear for a DD.

According to Tirerack the measured rim width for 255/40 17 is 9. The range is 8.5-10. So the optimal rim width would be 9-9.5 for this tire.

For street driving you will not notice a huge difference between 255 and 245.

[mlifxs]

Originally Posted by UltraRacer13

pretty aggressive for a street setup.

Perhaps not to mention N52. Trying to think of little things I can do to enjoy the car more and ward off the new car bug. Not inclined to spend any money on cosmetic mods. That said, I don't want to degrade the turn-in or NVH of a DD in the process.

Originally Posted by NokTurNaL 330i

According to Tirerack the measured rim width for 255/40 17 is 9. The range is 8.5-10. So the optimal rim width would be 9-9.5 for this tire.

For street driving you will not notice a huge difference between 255 and 245.

From this and your other posts, I think your bottom line is, if 8.5s are the wheel, 255s are too big and thus 245 would be preferable in comparison(?)

[neilvosko]

Originally Posted by mlifxs

thanks neilvosko and UltraRacer13. I'm going to have an alignment soon. With my M3 wishbones and pulled pins I'm hoping I can get to -1.5. I'm thinking this might be sufficient for 255 all around on 8.5s, or dial back to 245 all around on PSS (they don't make 255 for 17s).

Camber-wise,I could go further with some GC Street or Dinan camber plates, not sure if it's worth the cost / install / tire wear for a DD.

95 % of folks need at least 2 neg camber up front for 255s once lowered. I have been on a wild goose egg chase but since have an LSD will settle for a staggered 245 265 setup

[neilvosko]

8.5 rim = 245 mm profile fyi

[mlifxs]

Originally Posted by neilvosko

8.5 rim = 245 mm profile fyi

thanks for your comments. I'm probably around -1.5 camber now. I won't pull the trigger on wider fronts until I decide on camber plates yes / no (currently searching for dinans).

[WesleyC]

Originally Posted by mlifxs

thanks neilvosko and UltraRacer13. I'm going to have an alignment soon. With my M3 wishbones and pulled pins I'm hoping I can get to -1.5. I'm thinking this might be sufficient for 255 all around on 8.5s, or dial back to 245 all around on PSS (they don't make 255 for 17s).

Camber-wise,I could go further with some GC Street or Dinan camber plates, not sure if it's worth the cost / install / tire wear for a DD.

I don't know if you saw my post in my alignment thread, but with my suspension set up (Koni Yellows, H&R Sport, Dinan plates, alignment pins removed), I can max the camber out at -2.3 degrees and -1.7 degrees was as much as I could bring it in. You should have no problem achieving -1.5 degrees.

[mlifxs]

Originally Posted by Wesley Crusher

I don't know if you saw my post in my alignment thread, but with my suspension set up (Koni Yellows, H&R Sport, Dinan plates, alignment pins removed), I can max the camber out at -2.3 degrees and -1.7 degrees was as much as I could bring it in. You should have no problem achieving -1.5 degrees.

yes thanks. Think I'll be buying camber plates regardless of my final choice for tires. Always good to hear what others have done.

[3002 tii]

Originally Posted by neilvosko

8.5 rim = 245 mm profile fyi

But you can't maintain stock height with a 245 so 255/40 is preferred for 17