A suspension question for those who know about these things?

[Charlie Farley]

I am in the process of of trying to get these darn rims to fit but want to be sure on the measurments before I order spacers.
the new rims I have are ET40 so 3mm less than standard fitment et43's , current fitted rims are Et35 (8mm more than than the ET43's but 5mm more than the new rims ET40) still following me, good.
to get the new rims on and clear the caliper carrries widest point by 2mm I need a 10mm spacer, this will effectively increase the offset to an ET30 which is very close to the inner arches , doable but its close.
So the key part of the equation is this, on the front suspension does the front wheel stay in a vertical position under suspension compression or does it move out of vertical and inwards to the wheel arch, I know it may sound obvious but I cant remember , same with the rear, as the suspension is compressed either by bump or cornering does the wheel moveupwards and inwards into the arch, if it moves inward marginally then the distance from the inner lip of the wheel arch will only be relavant as when the wheel moves it moves inwards away from the inner arch edge, well that's what I am hoping.
if anyone can clear this up for me i'd be very gratefull.
rgds
rob

 

[carlcall]

Don't take this as gospel as I'm still amazed at how over engineered the suspension is.....but with the fronts having the two top arms I would say that they will remain vertical. As for the rears I know that it is different on a Quattro compared to a FWD variant and that they also stay in a vertical position.

I'm hoping that I'm wrong for your sake Rob.....but wasn't Dimitar running an 8.5J on ET29 on his quattro?

 

[ajax1976]

Front and rear suspension cambers inwards the lower you go so yes under compression it will move slightly further away from the wheel arches. The lower you go the further away it gets from the arch to the point that really low a4s need adjustable arms to get the camber with in the specs. From my normal ride height to when I fully air out and drop the car the wheel moves a good 30mm in away from the arch.
I'd be very surprised if you'll run into issues running 8j et40, that's just a shade less poke than 8.5 et35 which has always been the safe ground for B6 and B7 A4s. I'm sure I'm running 8.5j et25 and only scrub the rear liner when I run quite low and hit a compression in the road and that's with the compression set close to the softest setting.

 

[stu-evans]

I'm running 8.5j ET32 on the front and have plenty of space to the arch. Could come out another 5mm easy (that would be equal to ET27). I'm low as well (tucked). Worst case scenario you may need to remove the screw at top centre of the arch holding the arch liner in.... It's not actually the screw that's the problem, it's the silly plastic retainer clip that goes with it, which is quite chunky.

Re the rears, don't even worry about it.... There's more than enough room and you only need to start thinking about offset carefully if you go up an inch on your rim width!..... I'm 9.5j ET35 on the back and still tuck!

 

[stu-evans]

Should have added..... Wheel size is less of a problem.... It's tyre size that causes people issues. I've seen some really silly tyre size selections!!!!

 

[Charlie Farley]

Front and rear suspension cambers inwards the lower you go so yes under compression it will move slightly further away from the wheel arches. The lower you go the further away it gets from the arch to the point that really low a4s need adjustable arms to get the camber with in the specs. From my normal ride height to when I fully air out and drop the car the wheel moves a good 30mm in away from the arch.
I'd be very surprised if you'll run into issues running 8j et40, that's just a shade less poke than 8.5 et35 which has always been the safe ground for B6 and B7 A4s. I'm sure I'm running 8.5j et25 and only scrub the rear liner when I run quite low and hit a compression in the road and that's with the compression set close to the softest setting.

thanks , I may have worded my original message incorrectly ajax, the new rims I want to fit are ET40 8j , but wont go on due to the carrier contact, so after doing some fitting etc I need to fit a 10mm min, but better with a 12mm spacer which will effectively make those ET40 rims an ET30 or with 12mm spacer ET28, do you think they will still be a possible fit .

 

[carlcall]

They should still fit fine Rob since you are only going for the 8J rims they are roughly 6mm narrower on either side compared to the 8.5J

The offset will be the same with regards to the centre of the rim but the rim edges will be pulled in.

 

[ajax1976]

That was my bad, actually meant to write 30 instead of 40. As above though even with another 2mm you should still be fine, that I think will take you to pretty much the same as 8.5j et35, just don't go crazy with your tyre choice.

 

[Charlie Farley]

well its a final desiscion time for the rims now, been out side today and done a final set of measuring and have come up with this new data so hoping with the aid of some pics added aswell someone can clarify if fitment is going to be good to go or problematic.

First pics with tyres fitted to rims are of my current ET35's with 5mm spacer extra added, this is effectively where my new rims will end up after fitting 10mm spacers, an ET30 (8j) , it looks like the tyre will rub to me, a fair bit , or is this about right given the movement of the wheel etc.

pics of rims without tyre fitted are the new rim with 10mm spacer, does this look about right bearing in mind the tyre will add a few mm to the width aswell.

My conclusions are this to get these on , wether they rub or not is yet to be determined, I will need 10mm spacer on the front to get my new ET40 rims upto ET30 , and rears need 15mm spacers which will bring the ET40's upto an ET28 , anway it all seem to calculate on paper but not sure it may fit though so any more help to clarify would be great chaps, I don't want to be ordering spacer before I am sure this is going to work out.

rob

 

[Charlie Farley]

to be safe I am going to go with 8mm (thinnest I can fit) on the fronts now, means some very carefull fitting but 2mm may just be the the critical bit.