Questions about 255/30/20, Eibachs, square set ups and optimal rears.

Koldun · 06-20-2013, 01:55 PM

So when I bought the car, it was running an almost square set up (OD-wise at least) of 245/30/20 and 295/25/20, with a light stretch on the tires and H&R springs.

I love the look, but Houston roads are proving too brutal on the rims for stretched tires, so I'm trying to get a little more rubber on there. I've put 305/25/20s on the rears, which is perfectly flush with the rim, looks great, and the car seems to run better (DSC was almost always going on before, is this because the original set up didn't have the factory's OD stagger? If so, why/how do people run square set ups?).

255/30/20 would give me the same flush fit in the front, but I'm running into several issues:
1. The 255s rub pretty bad (3/4 to full lock), so I'd have to change springs. Would Eibachs, or perhaps even Dinans give me adequate clearance?
2. The overall diameter of the 255s is 26.02", almost identical to the 26" of the 305s, essentially giving me the same square set up I had except now the fronts are 0.02" bigger. Could I expect traction/handling issues to crop up again, perhaps even worse than before since the fronts are taller?
3. Should I switch the rears to 315s, to give me almost factory OD in the rear (26.2 vs oem 26.3)?

Please share your knowledge and deliver me from ignorance! Thanks in advance!

06-20-2013, 01:55 PM	#1
Koldun Banned 10 Rep 651 Posts Drives: 2011 E92 M3 Join Date: Oct 2012 Location: Houston, TX iTrader: (0)	Questions about 255/30/20, Eibachs, square set ups and optimal rears. So when I bought the car, it was running an almost square set up (OD-wise at least) of 245/30/20 and 295/25/20, with a light stretch on the tires and H&R springs. I love the look, but Houston roads are proving too brutal on the rims for stretched tires, so I'm trying to get a little more rubber on there. I've put 305/25/20s on the rears, which is perfectly flush with the rim, looks great, and the car seems to run better (DSC was almost always going on before, is this because the original set up didn't have the factory's OD stagger? If so, why/how do people run square set ups?). 255/30/20 would give me the same flush fit in the front, but I'm running into several issues: 1. The 255s rub pretty bad (3/4 to full lock), so I'd have to change springs. Would Eibachs, or perhaps even Dinans give me adequate clearance? 2. The overall diameter of the 255s is 26.02", almost identical to the 26" of the 305s, essentially giving me the same square set up I had except now the fronts are 0.02" bigger. Could I expect traction/handling issues to crop up again, perhaps even worse than before since the fronts are taller? 3. Should I switch the rears to 315s, to give me almost factory OD in the rear (26.2 vs oem 26.3)? Please share your knowledge and deliver me from ignorance! Thanks in advance!
	Appreciate 0 Tweet Quote