OK - even though I have 2 post-graduate degrees I can't seem to figure out the offset issue. So here is what I expect is a foolish question...

I have 17in. S-lites with 205/45 R17 all-season runflats. If my information is correct, the offset on the S-lites is 42mm.

If I put on new wheels with 215/45 R17 summer tires, should the offset of the wheels be the same (42mm) or different? Would a 42mm offset work with no rubbing issues? What would be the best offset for 215 tires?

Thanks for the help!!!

 

i think the offset of those S-lites are 48mm. i thought they were 50, but
some noted to me they are 48mm.

the offset of your wheel does not change because of your tire size.
here's a cool link:
http://www.tirerack.com/a.jsp?a=EZ3&url=/wheels/tech/techpage.jsp?techid=101

 

Thanks for the tirerack site! The picture and description there helped.

OK - I just found a site that says the offset on the 17" S-lites is 50. If I understand this correctly, going from a 205 tire on a 50 offset to a 215 tire on a 42 offset will put the inner (brake side) edge of the new tires 13mm closer to the inner surface of the wheel well? (5mm, which is half of the new width going from 205 to 215, plus 8mm, which is the difference between an ET of 50 and 42 on the new wheels)

So - did I get that right? And more importantly, will 13mm closer to the inner surface of the wheel well cause rubbing?

Again, thanks for the help with what I imagine are dumb questions.

 

yep, but you need to put in the 'real world' width of tires into consideration.

all manufacturer widths are different although they may say 215, it could
be 225-235mm in width.

the wider it gets (to a point) as profile gets higher.

 

Confused? Try giving Alex@tirerack.com a call.

First, your S-lytes have an offset of +48mm. The 215/45-17 tires are a little wider than the stock. If you have a 17x7" rim like the S-lyte or even 17x7.5" rim and if you have the MINI stock suspension then you can consider rims with offset from +38mm to +50mm without rubbing being an issue.

Since there is ample clearance with the stock suspension the wideness of a 215/45-17 tire is not much of an issue. It might start to be from 225 on wider.

So basically just ask yourself if you want to keep the stock suspension and if you do then look for 4x100 bolt pattern rims 17" diameter in 7 or 7.5" wide with offset roughly +38 to +48mm. (few rims come in +50mm).
Most of us choose +42 to +45mm because those rims with the 215/45-17 tires will often still fit with minimal rubbing even with lowered suspension (like H-sport springs- a 1" drop front and rear).

 

he's not THAT confusing, is he?

 

Other than a possible rear sway bar at some point, the suspension is staying stock. Certainly no plans to lower it.

So thanks for the help! It looks like 215/45-17 tires and an ET between 38 and 48 should be easily accomplished in my budget.

Summer tires here I come!

 

The inside sidewall will be farther away from the car by 3mm. The outside sidewall will be closer to the the outer fender (the matte black plastic part) by 13mm. This is all theoretical though, as Ken mentioned; different manufacturers measure their tire widths differently.

 

Now I'm confused again. According to the tirerack diagram linked above, reducing the offset (say from 48 to 42) should move the tire closer to the brake side, not the outer fender. So reducing the offset and increasing tire width should move the inside sidewall closer to the car. What am I missing?

 

48 will be tucked

42 will not

how's that?

 

Duh - I'm a dork. decreasing the offset moves the bolt plate of the wheel closer to the center of the wheel, which would of course move the wheel further out.

I get it now. Thanks for all the patience and help!

 

Thanks for the thread. It helped me out, too!

 

Alex

 

The smaller the offset number the farther out your wheel will be.

Now what does ET stand for, I know its offset but what does it stand for?

 

The offset is described by the term ET, which is from the German word 'Einpresstiefe' translated as 'insertion depth'.

 

okay, you guys are talking about 17' wheels but maybe you can help me out. I just bought a set of 18X7.5 offset 42 what size tires should I get if i plan on getting lowering springs at a later date to prevent rubbing.....

Thanks for any advice

Kouper

 

Insertion depth???? hehehehe






Thanks for the reply mini