What are the standard rim widths?

[Gary Stockton]

I suppose I could google this, but hey ho...

Can someone please let me know standard rim widths for a 16" alloy on an 80 and the standard rim (18"?) on a 100. I know the 120 is a 17" x 7" wide rim.

Starting to get interested in replacing my 265 Coopers with 285s and just want to check I won't run into rim width issues - tyre folk tell me I'll be fine, but you never quite know

 

[Jon Wildsmith]

8" for 80 and 100 series. 7" should be fine for a 285.

 

[Gary Stockton]

Thanks Doctor!

And how is the Wildsmith Tardis this morning??

I'm still a bit concerned about inboard clearance on the rims & 285 tyres - I think I still need the 30mm spacer but I'm not 100% positive. However, I just do not seem to be able to find a suitable replacement rim (steel or alloy) that would have a 0 degree offset (I think) and comes in a 17x8 inch size. Maybe I'll have to tackle the calipers so I can put on 80 series rims??

Sigh...

Decisions, decisions. Maybe I should really just leave it all alone.

Nah - didn't think so

 

[Jon Wildsmith]

Do the 17" OEM alloys have a recess between each stud hole? The 100 series 18" OEM alloys do and so I run just 20mm spacers and the bit of stud that is proud of the spacer fits inside the recess on the wheel mouting surface. I'm assuming you're concerned about them sticking out too far with 30mm spacers?

 

[Gary Stockton]

Nope - I've been running the 30mm spacets for over a year now with no discernible issues. The tyre is slightly proud of the fender - the 285 will be more so I guess which is why Arctic clip on bigger fender flares.

I'm more concerned about over-stressing bearings and CVs by running even bigger tyres on the std rim and even larger tyres.

Should I be?

 

[Jon Wildsmith]

Spacers do increase the load on bearings but if your OEM wheels have a positive offset then your offset with the 30mm spacers won't be as bad as say 30mm spacers on an 80 series which has 0 offset wheels as standard. What offset are your wheels?

 

[Gary Stockton]

Ummm - that's the magic question. Which way is positive? I have a deeper rim from the inside, I.e. The face of the rim is flatter. Does that make sense? I think I read somewhere that it was a 20mm offset but don't quote me on that!

 

[Jon Wildsmith]

flatter face i.e. not much 'dish' is positive offset, 'deep dish' wheels are negative offset. If your OEM wheels are ET20 then with 30mm spacers the total offset is of a lower magnitude than OEM by 10mm The force distribution between inner and outer bearings changes a bit with the cross over from positive to negative offset but not to a degree I would worry about.

 

[Gary Stockton]

Phew. Ok thanks Jon. I'll get in one tyre then to spend a day checking fit etc.