huff3r 347 Report post Posted January 28, 2011 (edited) Can someone please outline for me the legalities around tyre sizing? i.e Allowable difference in rolling radius Allowable difference in tyre width Allowable tyre widths on tyre rims etc As I have currently got 195/60/14s and new rims, so need new tyres. Looking at getting (If it's allowable) 205/50/16s on a 7.5" wide rim on the rear 205/50/15s on a 7" rim on the front. (Weird sizes due to me having the unfortunate combination of 2 15x7s and 2 16x7.5s) Edited January 28, 2011 by huff3r Quote Share this post Link to post Share on other sites
gouba 0 Report post Posted January 28, 2011 Someone please correct me if im wrong but from memory you cant have two different diameter wheels on your car. Quote Share this post Link to post Share on other sites
kinetik 4 Report post Posted January 28, 2011 (edited) http://www.nzta.govt.nz/resources/virm-in-...l-hubs-v4a1.pdf That covers most of it, but for allowable widths on the rim it's pretty vague. Edit: There was a post in this section with a list of allowable widths, but I can't find it right now. Edited January 28, 2011 by kinetik Quote Share this post Link to post Share on other sites
jimbo01 0 Report post Posted January 28, 2011 Someone please correct me if im wrong but from memory you cant have two different diameter wheels on your car. Damn someone better tell Mercedes Benz and Audi then. Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted January 28, 2011 (edited) Damn someone better tell Mercedes Benz and Audi then. Jim, you thinking diameter or width? Can't say I'm aware of different diameter Edit. Mean different overall diameter. Usually a different rim diameters will have different profile tyres to maintain overall circumference Edited January 28, 2011 by hotwire Quote Share this post Link to post Share on other sites
Gotheschu 1 Report post Posted January 28, 2011 JJJJJJJOOOOOOOOOHHHHHHHHHHNNNNNNNOOOOO!!!!!!!!!! Quote Share this post Link to post Share on other sites
huff3r 347 Report post Posted January 28, 2011 Someone please correct me if im wrong but from memory you cant have two different diameter wheels on your car.Had a look through the wof manual, couldnt finnd any reference to not being allowed two diff sizes. As long as they are the same on each axle. The reason for running the same profile, and therefore different radius is purely cosmetic. So i dont have two higher profiles looking strrange as lol. Quote Share this post Link to post Share on other sites
zenetti 0 Report post Posted January 28, 2011 (edited) Can someone please outline for me the legalities around tyre sizing? i.e Allowable difference in rolling radius Allowable difference in tyre width Allowable tyre widths on tyre rims etc As I have currently got 195/60/14s and new rims, so need new tyres. Looking at getting (If it's allowable) 205/60/16s on a 7.5" wide rim on the rear 205/50/15s on a 7" rim on the front. (Weird sizes due to me having the unfortunate combination of 2 15x7s and 2 16x7.5s) Why do you want to run those two sizes? The 205/60/16 is over 10% taller than the 15" (650mm diameter vs 585mm) so it is going to look very very strange. You can run different size rims ( we do a few 18" front 20" rear combos on old yank tanks) but the goal is to try and keep the total overall diameter as close as possible to OE, so the rear tyres will be a lot lower profile than the fronts. If it were me running those two rim sizes on an e30 I would be looking at a 205/55/15 front and 205/50/16 rear as they are very close to each other in terms of overall diameter. You coud run a 195/55 at the front but it is slightly smaller than the rear. Edited January 28, 2011 by zenetti Quote Share this post Link to post Share on other sites
huff3r 347 Report post Posted January 28, 2011 (edited) Why do you want to run those two sizes? The 205/60/16 is over 10% taller than the 15" (650mm diameter vs 585mm) so it is going to look very very strange. You can run different size rims ( we do a few 18" front 20" rear combos on old yank tanks) but the goal is to try and keep the total overall diameter as close as possible to OE, so the rear tyres will be a lot lower profile than the fronts. If it were me running those two rim sizes on an e30 I would be looking at a 205/55/15 front and 205/50/16 rear as they are very close to each other in terms of overall diameter. You coud run a 195/55 at the front but it is slightly smaller than the rear. Sorry i screwed that up. Shouldve said the 50 profile on the rear so that the tyres look the same on the two rims, with the front being 25mm smaller. So a 4.6% difference? I think...Edit: 50 profile on both so a 1" difference in overall diamter. 610 vs 585. Edited January 28, 2011 by huff3r Quote Share this post Link to post Share on other sites
kiwi328i 118 Report post Posted January 29, 2011 Can someone please outline for me the legalities around tyre sizing? i.e Allowable difference in rolling radius Allowable difference in tyre width Allowable tyre widths on tyre rims etc As I have currently got 195/60/14s and new rims, so need new tyres. Looking at getting (If it's allowable) 205/50/16s on a 7.5" wide rim on the rear 205/50/15s on a 7" rim on the front. (Weird sizes due to me having the unfortunate combination of 2 15x7s and 2 16x7.5s) 1, According to Table 10-1-1 LVV certification is not required if your outer circumference is no greater than 5%, so do your maths, the WOF guys probably wont unless it looks a bit silly, it could be peace of mind for you...it aint for many, but thats up to you. 2, As far as I know there is no allowable tyre width 'difference', per se, you have to look at the other conditions, i.e. be appropriate for the rim it is attached to, sufficient clearance for brakes, body etc, oh and possible the 'no more than 25mm from OE track width' caveat which is indirectly related to the width of your tyres, more to do with the offsets of your rims etc. 3, I think this has been covered here before, I dont know if it is actually legislated, but there are harder rules regarding tyre width/rim width approximations based on some Aussie regulations, but its mostly covered by our 'looser' "appropriate selection for rim width" regulation. You may have to think about speed/load ratings too, with very little leeway with tyres on the same axle, i.e. try to ensure they are the SAME. In any case, I would suggest talkin to Johnno or someone else in the Bizo who knows his sh*t, before forkin out on this set-up. After all the combo's I have been through mine is pretty standard now for ease of rotation, spare, blah blah, and yeah go talk to someone. Cheers my 2c...I could be absolutely and totally wrong by the way. Quote Share this post Link to post Share on other sites
Docile 64 Report post Posted January 29, 2011 doesnt s2k run a smaller diameter rim up front and bigger at the back? Quote Share this post Link to post Share on other sites
