Smaller diameter wheels in back?

AshwinLB · 07-18-2023, 09:51 AM

Recently I’ve learned about how more sidewall can affect your straight-line grip more than wider widths? It would be been nice to learn this before installing 370mm M-Performance calipers and rotors on my 135i so I just could run a 17” set all around lol

Anyhow, I wanted to get some feedback on if anyone has run a setup with 18” wheels in the front and 17” wheels on the back for street and track use? I know this is done on the drag strip but I wanted to know if this would bring any negative effects in regards to handling?

Tell me why I shouldn’t be considering this lol (except because of the look)

whyzee125 · 07-18-2023, 10:56 AM

It should work fine as long as you get the overall rolling diameter after tires roughly the same. Some cars come from the factory with larger wheels in the rear. Keep in mind drag tires will obviously not handle well on the street and track so you'd negate some of those effects by running street tires all around even with more rubber out back but yes, it will provide some amount of additional grip. I've never heard of this being done but I don't see an issue with it.

07-18-2023, 09:51 AM	#1
AshwinLB Private First Class 68 Rep 105 Posts Drives: 2008 BMW 135i 6MT Join Date: Jan 2018 Location: Toronto iTrader: (0)	Smaller diameter wheels in back? Recently I’ve learned about how more sidewall can affect your straight-line grip more than wider widths? It would be been nice to learn this before installing 370mm M-Performance calipers and rotors on my 135i so I just could run a 17” set all around lol Anyhow, I wanted to get some feedback on if anyone has run a setup with 18” wheels in the front and 17” wheels on the back for street and track use? I know this is done on the drag strip but I wanted to know if this would bring any negative effects in regards to handling? Tell me why I shouldn’t be considering this lol (except because of the look)
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07-18-2023, 10:56 AM	#2
whyzee125 Brigadier General 1697 Rep 3,670 Posts Drives: Dinan stage 2 335i Join Date: Jul 2014 Location: Chattanooga Tn iTrader: (0)	It should work fine as long as you get the overall rolling diameter after tires roughly the same. Some cars come from the factory with larger wheels in the rear. Keep in mind drag tires will obviously not handle well on the street and track so you'd negate some of those effects by running street tires all around even with more rubber out back but yes, it will provide some amount of additional grip. I've never heard of this being done but I don't see an issue with it.
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