Tyre sizes for BBS 108s

[Phil Coleman]

Just got some used 108s for the Z, they need a refurb but they'll be OK for now until winter has passed. The wheels came with tyres on the front (Falkens) 225/40/18 but the rears didn't so I bought some part worn 255/35/18's.

Was wondering if I can put either 255/40/18 or 255/45/18 on the back as the 255/35/18 look rather skinny compared to the front.

Thanks

Phil

 

[Steve84N]

I use 245/40/18 which is a slight increase in sidewall.

You don't need more than 245 with this much power/torque, the speedo is then much more accurate with this size and it reduces understeer as you have less F/R stagger.

 

[Z4 Gaz]

255 35 is the correct size and only 0.07cm smaller than the 225 40 sidewall.
Have a look here to see the differences aspect ratio changes make.
http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

 

[Steve84N]

True but if you want something else the 245/40 has a lot going for it.

 

[philbo909]

True but if you want something else the 245/40 has a lot going for it.

255 on 8.5j looks a bit over-rubbered too, 245 could be a better shout

 

[Steve84N]

Yep, 255 is the limit of what's recommended for 8.5J and most manufacturers run at least a 9J if they spec 255. A 245 still overhangs slightly so you get rim protection.