Spring Rates and Specs

WEAVZ79

Registered User
Please help me with this as my tyre's are constantly rubbing the arches over bumps in the road. Specifically I am trying to find any information on the 'rough road' specs for the C5 Quattro. Also with regards to the weight ranges / categories am I right in assuming the higher the number or alphabetic letters e.g. DQ the more weight that component can take.
 

couchie

Registered User
What wheels do you have please ?
Width , diameter and offset (et) ??
What tyres please ??
Width , diameter and aspect ratio please ?
I have lowered suspension with 235’s on 18’s and there is plenty of clearance !!
 

WEAVZ79

Registered User
Hi Couchie.

Wheels are genuine Audi 18 x 8j with a ET43 offset.

The tyres are 235/45/18 on the front and 245/45/18 on the rear but its the front thats the issue.

What model is your car?
 

couchie

Registered User
Hi ,
I drive a A6 2.5tdi quattro , and you ?
Do me a favour and take a photo of the tyre data behind the fuel cap please ?
Ta
 

couchie

Registered User
I think I see your problem , 45 on the aspect ratio is a bit much , I think it should be 40 !!!!
I run 235 40 18 summer and 235 45 17 for winter .
 

WEAVZ79

Registered User
Why would summer and winter have any difference? 40 / 45 is such a small margin. What info is the fuel cap going to give you if im not running a standard set up?
 

couchie

Registered User
You have just answered your own question !!
You are running the wrong size tyres , the fuel cap numbers will give you the size you need to match from , if you have not got 18’s on your fuel cap then you would need different suspension uprights to accommodate them ,
So looking at the fuel cap sticker tells us everything !!
I don’t need to look at it , I can tell you your non standard set up is not compatible !
It’s not rocket science , leave your suspension alone and fit the right size tyres !!
 

WEAVZ79

Registered User
Couchie, its called modifying. A small increase in height will fix the issue and provide a better set up for my **** local roads. Reducing the aspect ratio will get me round one issue but cause exactly what I am trying to avoid as there will be no flex in the sidewall. The original question was to do with spring rates.
 
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