Tyres on 2003 ZT CDTI

[french dave]

Having just purchased a zt+ CDTI 2003 with 126k full service history for £400, I have brought it to France for its MOT.
The tyres on it are 225/40/18. Yet the car should have 225/45/18

It passed, but the inspector said one front shocker is gone, and the tyres are near the end of thier life. Also the cat pipe has a leak on the flexi.
for this I have brought a flexi repair section costing about £30.
it looks like there sin't enogh behind the old flexi before the cat to fit this repair?
Any ideas should I have gone for a decat?
Anyway back to the tyres
The ride seems like you feel every pimple in the road. Not the smooth ride I get from one of the other 75s I have here.

I suspect the very low profile tyres are making this worse, but is the main problem the shocker?

Any comments from people that have tried 40s instaed of 45s?
many thanks

[mrvandango]

You'll never get as smooth a ride from a ZT as you would from a 75, the ZT is a totally different animal!

Reports suggest that 40's only make the ride even more harsh.. they are more like a coat of black paint around the edge of the rim. You should notice a difference going back to original sizes. I'd imagine your speedo may be out a touch more with the lower profiles too. At a guess I'd say it will over-read more with your current tyres, but I'm no expert.

[french dave]

Thanks I will go back to 45s.
i have to say with the flexi pipe leaking, there dosn't seem as much power as my 75 CDTI.
i wonder how much the leak costs in BHP terms.
Or if MAF or other issues exist. That being said it still pulls ok.
As I need front shocks on the passenger side, and funds are tight, might go for a second hand unit. I assume the struts on a zt are the same as a 75? Or are the springs different?
Dave

[bl52krz]

I would imagine that the springs are different since the the tourer is made for carrying more weight. You can find the number and colour of the springs under the rear seat. Just lift the seat up.