Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 5 of 5 Posts

·
Registered
Joined
·
4,215 Posts
Discussion Starter · #1 ·
on my fast runs at brunters I was experiencing some severe vibrations ..thought the bonnet was going to fly off !!


so what is causing it
first thought out of balance wheels
but at pe the previous day it was running up to 170 on the rollers no probs ..
so Are my shocks nixxed ?

only thing I can thing of
I tried upping from almost full soft on the koni's to full hard with no difference

anybody got any ideas
 

·
Registered
Joined
·
16,524 Posts
Water hammer?

Seriously though, could there been a build up that was a sort of aquaplaning with an element of resonance?

I say this because the final straw for the Primacys on my old 9-5 2.3SE was a wet drive back from Devon where on very wet roads the tyres "throbbed" and I had to keep below 60 to stop it.
 

·
Registered
Joined
·
4,895 Posts
Hmm, the resonance effect could be the one...

Now "Z" rated tyres are approved for speeds up to 200mph, but does that assume dry-damp conditions? It was exceptionally wet on Sunday and as Brunters is flat (normal roads being cambered) would mean that there was possibly more standing water than the tyre is designed to displace. Up the rate at which the tyre has to displace the water and voila, you get resonance.

Perhaps a certain Viggen owner could do a little scientific research on this issue, coz I can't be arsed.
 

·
Registered
Joined
·
4,215 Posts
Discussion Starter · #4 ·
Maybe thats the answer

I should have let some air out of the tyres...

they are z rated...

however the vibration was around 120
which I managed to re-produce on the private stretch of the A1 on the way home


so back to o/b wheels..

the suspension is clonking again now...

I will investigate this w/e
 

·
Registered
Joined
·
1,044 Posts
however the vibration was around 120
which I managed to re-produce on the private stretch of the A1 on the way home  [/b]
I have the exact tyres as you George and my car hit 145 down the straight thru all the same standing water and it was okay. I am running 35psi, don't think it was the tyres or water IMO
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top