rims and offset

[haggus]

After searching and looking through calculators I am still trying figure this out. I have a 89 525i with 15x7 et 20 rims. I have a set of rims that are 16 x7.5 et 35. The calculator says it will be 1.4 mm more towards the shock /strut this doesn't seem like a big deal. It will be out towards the fender 11.8 mm again there is space with the tire size it says no issues with clearance I will loose 25 mm of clearance. A quick measurement with a straight edge confirms this. However this is with no spacer and I read that wrong offset equals bad handling.

Question then is do I need spacers even though the tires dimensions fit and there is no interference and does the wider tire offset some the difference in the centerline of the tire.

Thanks

[genphreak]

Yes you will need spacers as the track will increase enough to make it tram-line badly. Where I live an increase in track of 25mm is illegal. An insurance company however may view a modification like that something which would need to be disclosed and/or void a claim (but few allow spacers either).

Re the clearance, your ET20 are already very close to the strut. BMW minimise this dimension. In real terms 7.5" is not maxing out the factory size but tyre choice may still affect the chance of rub. Probbaly be ok as the factory fitted 8" ET20 rims with 235 tyres front and rear on some e34s. Go wider than that and the rims will need to have less offset (eg commonly ET13 & even ET10). This goes for front and rear but the front tyres may not bulge as much (so 235 is the max, some report 245 is sometimes possible) but these may not be safe in emergency conditions. Wider tyres will make the tram-lining worse too, but increasing offset is the surest way to make it hard to handle over bumps.