wheel offsets

[slideways]

Now I know the et's are quoted at 35 rear 25 front, but i have read somewhere that someone measured 37.5 on the rear so, my question is has anyone else actually measured the et's on the car itself to get a true offset not just what is generally quoted and stamped on the original wheels?

cheers
slideways

[slideways]

I will take that as a NO then!

[dbv8]

Whats the plan Richard?
Seeing how much rubber you can fit under the arches?

[JR]

People could post but there's no point. If someone has measured 37.5 then they're either wrong or there's a variance of at least +/-2.5mm in the manufacture; for the former you don't want to take notice of people who can't measure and for the latter you'd better find out in which part of the envelope your wheels fall or if the envelope is even bigger than stated by measuring your own wheels. I'm quite surprised that you're on standard wheels for a 4.8tt.

[slideways]

dbv8 said:

Whats the plan Richard?
Seeing how much rubber you can fit under the arches?

[slideways]

JR said:

People could post but there's no point. If someone has measured 37.5 then they're either wrong or there's a variance of at least +/-2.5mm in the manufacture; for the former you don't want to take notice of people who can't measure and for the latter you'd better find out in which part of the envelope your wheels fall or if the envelope is even bigger than stated by measuring your own wheels. I'm quite surprised that you're on standard wheels for a 4.8tt.

thats why I asked the question I am in the process of weighing up all the options, I have acquired a set of 18" spiders with et42 and et33 which will require spacers all round so i have to have them machined up, if it all works then great if not i will have a set of wheels made.

[dbv8]

[slideways]

dbv8 said:

sod it why not!
now wheres that angle grinder

[dbv8]

I want my car to good on the road, the track and the strip but i just know that it will end up only good for the 1/4 mile one day.
Such is the sacrifice to run 9's

[dumbfunk]

My understanding is that the factory spec is 37.5 but the closest you can get with off the shelf aftermarket wheels is 35 which is why you'll see this figure quoted often. 2.5mm on the rear is not in my view going to cause any issue and saves the considerable cost of custom rims. There have certainly been no wear, handling or bearing issues on my vehicle equipped as such.


df

[slideways]

dumbfunk said:

My understanding is that the factory spec is 37.5 but the closest you can get with off the shelf aftermarket wheels is 35 which is why you'll see this figure quoted often. 2.5mm on the rear is not in my view going to cause any issue and saves the considerable cost of custom rims. There have certainly been no wear, handling or bearing issues on my vehicle equipped as such.


df

so if i were to use et 42 on an 8.5" wheel with the 6mm spacer i already have that will even things out then, and et33 on an 8.5" wheel would need an 8mm spacer, correct?

[spend]

Silly buggers at the factory designing a car for wheels that don't exist, blame it on Ned possibly?

..sounds a tall story to me!

[JR]

spend said:

Silly buggers at the factory designing a car for wheels that don't exist, blame it on Ned possibly?

..sounds a tall story to me!

As you know they even got confused with fronts and rears.

[JR]

dumbfunk said:

My understanding...

Inch front and inch and a quarter rear was the common quote but the ET33s appear to be heading towards rocking horse... which leaves the majority of the wheels which are inch front and inch and 3/8 rear or 25 and 35 in Deutschland currency.

[JR]

slideways said:

JR said:

People could post but there's no point. If someone has measured 37.5 then they're either wrong or there's a variance of at least +/-2.5mm in the manufacture; for the former you don't want to take notice of people who can't measure and for the latter you'd better find out in which part of the envelope your wheels fall or if the envelope is even bigger than stated by measuring your own wheels. I'm quite surprised that you're on standard wheels for a 4.8tt.

thats why I asked the question I am in the process of weighing up all the options, I have acquired a set of 18" spiders with et42 and et33 which will require spacers all round so i have to have them machined up, if it all works then great if not i will have a set of wheels made.

Hmmm. Funny one that. Normally you'd say 7mm spacers all round but a couple of things come into play. At the rear you may want to increase the offset if you fit rubber wider than 255 to prevent rubbing on the outside of the wheel arch at speed;this will also depend on your spring and damper setting. At the front you need to check that neither the wheel or the tyre stick out from the body; your 8.5 spider ET 33 would be about 19mm further out than standard and there is the oddity that TVR fitted rears to the front at the end of the run. This surprising move by TVR would be expected to cause some handling oddities but none appear to be reported so it's either the best kept TVR secret or the slightly wider front with a slightly increased offset works as well (or better) than the original spec.