[ozinaldo]

Originally Posted by M3 Adjuster

I drove my car for quite a while with 265/s all around. on 18 x 10 Arc-8s (not 19s!). I have also used 275s.. When i switched to 285s I realized I actually have GRIP in the rear when in the past the tires were spinning. This was immediately something I noticed when accelerating uphill (from Wagon wheel to Ricochet at Motorsport ranch Cresson.). I didnt REALIZE how much they were spinning until i went with the 285s.

if you are speaking from Theory... then that is fine.. but from an EXPERIENTAL (no.. that's not a made up word..) perspective.. I think you are incorrect. The " optimal traction footprint" for the 1M is likely acheived with wider tires.. PARTICULARLY in the rear.

please do not ASSUME (that others are drivers " obssessed with tire width" )
I am not obsessed with tire width and nor is Robert... having both run 15s on our E30M3s for years. Like Petevb.... I would prefer to run smaller tires... First off.. they are cheaper... Second .. they have less unsprung weight.. as you mentioned.. For a long time E30 M3 owner.... that last part is VERY important..






The 1M does NOT lack power. it LAUGHS at a few additional pounds of unsprung weight and says.... (scharzenegger voice) I got TORQUE baby.. get on my back and LET's GO! make no mistake... I am not saying that the unsprung weight isnt a factor... of course it is... but this car is FAR less affected by a few pounds of unsprung weight than probably any BMW before it.... ( E30M3.. E36M3.. E46 M3..E9x.. Z3..Z4.. you name it.)

harold of HPA motorsports has commented in the past as well that wider is better on the 1M... and IIRC he felt the best grip on the car would be with 10" wheels up front and 11" wheels in the rear. Personally. I didnt really subscribe to this either.. until I put 285s on the back of my car. Now... i concur. if I were racing and wanted to go FASTEST with respect to putting power the ground.. ... I would keep a staggered setup and go as big as possible in the rear.

However.. I do feel that the car * handles* best with the least understeeer by using a SQUARE setup however... and i very much recommend that to others. The car turns in SO much better with a square setup with camber plates than it does stock or on a stock setup with wider front and rear tires that it's a night and day difference. Here locally in DFW we have about 16 owners with 1Ms... and about 4-5 of us all are close friends and have shared our cars with each other so we can feel different setups.

Still not a believer? Grab a stopwatch and borrow some wheels and tires and let us know what you find from experience.

Well written and good inputs here, they make good sense to me; thanks Mark.

As a relatively ordinary driver and with no chance of a good track around I feel that stock sizes or 255/275 sizes of good tires like PSS on stock wheels and camber plates dialed for 'more fun and agility' are all I need here.

But should I go further and on track for fastest possible, not necessarily being more fun, than I would probably choose 18' wheels with a 265/285 or 285 square set up, semi slicks and more camber than I actually have. You can't put too wide of a tire at the rear of the 1M; 295s with stock 19s, 285 with most 18s and 305 or 315 with 10.5 or 11 inch wheels would definitely give quicker times. Just plain meaningless on essentially street/back road driven 1Ms imo because those are places where stock 1M's trade mark behaviour (of playfullness) should be preserved over 'grippier/quicker'.