AdamGreen

I'm in the market for lowering springs and 29800's appear to be my best bet, as they will give my car a lower stance than the 29771 or 29921 can. I've "STFA" many times over, so this I know.

However, what I haven't been able to find is any report on how the ride of these springs feel. Can anybody please give me their opinion/experience/preference/insight on their performance? I currently have Bilstein struts, says a receipt that came with the car's record when I bought it.

Thank you all in advance, I just need some reassurance on my decision before I click "checkout".

UrS4boy

Which Bilsteins? The HD = taller, work with stock springs, including 92 spec 1BE sport suspension. The Sport = works with lowering springs. If you have the HDs they won't work with the H&R 29800s.

Lots of UrS people run the 29800s and like them.

AdamGreen

Thanks Dave, I appreciate your help. Admittedly, I don't know what struts I have. My assumption is that they are HD's due to how ridiculously tall my car stands now. I'm not 100% positive however, as the aforementioned receipt does not specify what kind of Bilsteins were installed. How would I identify what kind they are, do you know if it would be noted clearly on the strut? I will soon be replacing my strut mounts and strut bearings (as per your suggestion on another post regarding a creaking/groaning sound when cranking the wheel at low speeds), so I can look at the struts closely when those are delivered next week and I replace the parts.

Also, if they turn out to be HD's, why are they incompatible with lowering springs? I trust you entirely, but I read elsewhere that they can be used just the same as Sports because they are valved the same. Again, I trust your knowledge and you stated clearly that they won't work, but my concern is making the most out of what I have on the car now. If they turn out to be HD struts it sounds like I'm stuck with stock springs unless I replace them both.

UrS4boy

Shocks are designed to have a certain travel length. By installing HDs in short(er) springs, you are compromising (stealing) some of that travel length from the HDs. As a result, there is a chance that they will be maxxed out under some conditions, banging into their internal bump stops. Not good for the long term.

The shorter Sport versions are designed so they sit normally sit in the middle of their travel range with the shorter springs. As a result, no compromises and longer life.

You can try the HDs. They might make your car sit a bit taller than you expect with the shorter springs (they are acting as hydraulic prop rods).

Good luck.

AdamGreen

Thanks again Dave, that's exactly what I was wondering. It is in fact possible to run the two together although its not ideal and may damage the struts.

4RINGSx3

This is of interest to me as well. The thread entitled "Frt Suspension Noise" below (w/ latest post on 6/13) is mine & we're at the point of replacing the frt Bilstein strut inserts. After driving car with mics attached at various frt suspension points and listening to the noise on different channels its believed the Bilsteins are causing the clunking noise. Replacement of strut bearings & mounts did not cure the problem noise. Torque on all suspension mounting pts, etc. was also checked and found to be OK. Broken frt springs (H&R Sport, one side was broken @ top, the other side @ bottom) were replaced with same (H&R Sport, #29921). Replacement springs do not have vinyl wrap on some of coils (believe upper ones) as the old, broken ones did. Current frt Bilsteins are Series B8 (SP), #P360369 (old part no. per Bilstein website), and will be replaced with same (new part no. is 34-003695). Current Bilsteins that are believed to be causing the noise have 66K miles on them. Seems like low mileage for Bilsteins to go bad, hope we're headed in the right direction.
Assume I have the correct combo: H&R springs (Sports, #29921) + strut inserts (Bilstein: Series B8 (SP), #34-003695).

UrS4boy

The correct Bilstein C4 Audi springs with shorter sport springs are:

Sport Suspension B8 (SP) Front = 34-003695, Rear = 24-020664

Reference: Bilstein US Application Guide No. 308.

60to0in0seconds

i also have the lower H&R springs with the correct Bilsteins to match but one big issue with the urS4/6's is when you lower them you run out of adjustment in the front for camber. you will have to adjust the camber to the far limit and the tires will still have too much camber and you will wear out tires.

There are some remedies such as adjustable strut mounts(beware these are rigid- no rubber). There is a better method in my opinion which is redrilling the top spring plates with a new 3-bolt pattern to give you more adjustment. i had found someone on this forum that had a schematic that you could print out and transfer to your plates so that you can redrill. BEWARE of this. i tried it and it was incorrect. i believe it must have been for a european build or maybe the urS4 and urS6 are different? either way, i have an 1993 urS4 and i just rotated my plates 180 degrees and redrilled using one side plate as the template for the other side plate and vise versa. Mine came out perfect and i haven't had any problems for the last 5-6 years. But it is not easy and you need to measure a lot and think about it before you start drilling. But if you are mechanically inclined and good with tools you can figure it out.

But if you skip this step, you will have tire problems.

good luck!

UrS4boy

The original trick of spinning the upper mounts 180 deg and redrilling them in a specific way so that you can get back into camber spec with H&R C4 lowering springs was done by a well-respected UrS6 owner, Igor Kessel. There were no errors when he created the template. Sometimes people printed out the template and their printer distorted or resized the template. Not Igor's fault.

Here is the original template:

http://12v.org/urs/IgorCamberPlate.pdf

BTW with Eibachs (which didn't lower the car as much), simply slotting the OE mounts was enough to create enough camber adjustment room.