mroberts

Am I right in assuming that the "ET" value is the offset ?

My current wheels are ET45's, but the set I just picked up have two ET45's, and 2 ET37's. Should I take them back ? They are second hand, so it's going to be all or nothing. How bad is it to run the wrong offset (by 8mm?) ?

I'm assuming I should at least put matching wheels on the same axle, but should I put the "correct" ones on the front ?

Thanks,
Mike.

520

Think like this....first of all you need to know that ET(offset)37 means that your wheel is sticking out more towards the wheel arch than stock(et 45), so you coud put them either in a back if you want your back wheel track to be wider or in a fron if you want oppsite, also make sure it can fit without rubbing. People also make asumptions a lot on a basis of offset only without asking how wide the wheel is. Its big diff. if wheel is 7" or 8", and you can fit 235 wide tire on a 7" wide wheel as well on a 8" one....so lots of options!!

mroberts

So it's definitely OK to use them with non-stock offset ?

Will it affect the steering / alignment ?

AlanBDahl

If you are planning on running in SCCA's H Stock class you can't use the 37mm wheels since the maximum offset variance allowed is 1/4" which is a little over 6mm. If your car came with 45mm wheels then you'd need to run wheels from 51 to 39mm offset.

If you are running some other SCCA class, say Street Touring or if you are running in some other autocross series then the rules may be different. Check with the sanctioning body involved to find out for sure.

mroberts

Thanks, that's gonna suck getting bumped up a class !!!

MikTip

Re: 37mm is OEM for 1993+ Audi 90's! ;o)

mroberts

How do the teck inspectors know what is "standard" for a car ?

Regardless of the offset, theoretically 15's aren't "standard", so I'm out of HS anyway. I know inside the fuel cap it lists two different tyre sizes - does the fact that 15" aren't listed mean that there was no 15" option for the '88 90Q ?

How do they know the stock offset ? Even if I can get the 15's past them, the fact that there are two different offsets hoses me anyway, unless I can just make that part of the rim so grubby they can't read it

Any auto-x gurus here ? Alan ?

AlanBDahl

Tech inspectors don't know what is legal for a particular car usually, it is up to your fellow competitors to police and protest you. If you are running local races and not winning no one will probably say anything and if they do it will be a simple "better fix that", not a protest. On the other hand if you are winning National Tours, ProSolos or Nationals then you would for sure be protested for incorrect or mis-matched wheels.

IMHO it all comes back to sportsmanship. On the one hand I would never protest a local competitor for something so trivial but on the other hand I trust that no one will take advantage of me either.

My advice? Either use the right size/offset wheels for race tires (you can then save the 15" for street use) or run in the Street Touring class which allows changes in wheel size and offset but allows street tires only.

mroberts

It just kinda sucks that things like the Mini are in the same class as me, and get stock 16 inch tyres !!!

I feel a lot safer on the wider, lower profile tyres, and I'm not in any danger of winning even HS yet. I guess I'll jsut suck up the higher class.