Knocking front Prodrive springs, WRX 05.
 

Just fitted 4 brand new Prodrive springs to a WRX 05, and the front 2 knock over speed bumps, also the bottom of the front springs have a smaller diameter than the strut base, is this normal? Also, the coils at he top of the spring are touching, hence, I would presume, the knocking sound.

Car handles perfectly and steers dead straight, it's just the annoying knocking which I'm sure they shouldn't do.

Any ideas please? Thanks!:)

In addition to my above post, I've just realised that additional bump stops for the front should have been supplied by the dealer where I bought the springs, and they weren't, so I will need to get them and remove the springs again, grrrrr! My fault for not reading the instructions thoroughly!:freak3:

I've got exactly the same noise on my MY07 WRX. Got Prodrive springs fitted when I bought it last year (it had done around 3600 miles) and it has done it ever since.

It's worse on low speed roads that cause large spring compression and rebound but as with your car mine handles and steers superbly. Seems to do it on front and back as well although front might be the more noisy of the two.

Interestingly I used to have a 2004 WRX with Prodrive springs (with non inverted dampers) and that did it as well although maybe not as much but it had 17 inch alloys as opposed to the 18 inch ones on the 07 car which I suppose contribute to reduced compliance of the 07 car.

Mine were fitted by a main dealer and include the new bump stops so I guess it must be a characteristic of the setup.

Make sure the spring is seated correctly in the base of the strut, i had this on my 04 WRX and in the end i cable tied the spring in place and it seems fine now

try wrapping the top and bottom of the springs or use some heat shrink should more or less cure it

Has anyone tried to speak to prodrive about this and ask what they think?
If you do a search it seems to be a very common problem, I certainly don't want to upgrade my springs to have knocking noises!
Granby, if the spring doesn't fit correctly to the strut there must surely be something wrong, cable tieing a spring doesn't sound safe...

The usual cause of the knocking is failure of the rubber protective 'cap' in the seat. The PD springs have almost zero preload and so will always be prone to some movement in the seat.

Simon

So is it normal for them to knock or will replacing the cap fix it?
I would appreciate if you could post a picture as I am not sure what you mean with 'protective cap in the seat' :wonder:

Hi fpan,

The problem is the front springs in my case. The top 2 coils on the springs are completely touching each other, zero gap between them, plus there is no plastic shrink wrap on them like there is on the rear springs, which i believe is added to elliminate any knocking noises.

As for the front springs sitting correctly on the base of the strut, they are. The diameter of the spring base was quite a bit smaller than the base diameter, but not the springs are settling down and seem to be 'spreading out' as I can no longer fit my fingers between the gap of the spring base and strut base.

Do Eibach springs knock as well?

Sorry should of read the title first as i have eibachs

The springs do seat properly on the strut base but they seem to twist a little, when i used a cable tie it was a experiment but it did seem to work :)