Should I go for larger tyres?

[skendrick]

Hi all,
It's getting to that time of year when my front tyres will need replacing, I have 205/50/17 on the front and 255/40/17 on the back of my C4. Some say that the front tyres should be 225/45 for the C4 as the 205/50 are for a C2 set up.
Is this true?
I find the car under-steers when pushed into a sharp bend or roundabout but is this better than having the back come out because there is too much grip on the front?

Advise welcome.

 

[Dave Wilkinson]

Steve,

A lot depends on what size wheels you have. IIRC the standard Cup 1 front wheels are 7J and the rears 8J. If this is what you have you cannot fit a 225/40 tyre to a 7J wheel - at least it's not recommended. You ideally need a 7.5J wheel for that tyre size.

Certainly a bit more grip up front will help reduce the tendency to understeer although the C4 will always have a stronger tendency to do so than a C2.

Regards

Dave

 

[964rh]

Steve

I've got 225's on my 7J front wheels and the extra size does help with the understeer.

Still haven't managed to get the back to step out (C4's traction control?!?!) sorts it out before I can get there.
I know Dave's said that it's not reccommended to use 225's on a 7J wheel but I've had not problems.
I've run about 7 trackdays with these tyres again with no problems.

My geo has been set up for track as much as a C4 can be so this may be one reason why I've not experienced any issues.
You may have to install 5mm shims though to stop the rubbing.

Rob

 

[Alexander_Drobik]

If you start to turn whilst still on the brakes the awd will not operate and not try to steer ahead. As you get a bit of the turn, boot it and the awd will engage, and give you full traction and away you go. A track thing more than normal road.

 

[skendrick]

Thanks Dave and Rob,
I believe thay are 7J wheels but can't find the ref.
Any clues?

 

[Steve Brookes]

ORIGINAL: skendrick

Thanks Dave and Rob,
I believe thay are 7J wheels but can't find the ref.
Any clues?

Steve if they are genuine wheels you will find the width and offset embossed either side of the tyre valve e.g. 7 and 55. If they are replicas you'll have to take the wheel off and you'll find the measurements embossed in one of the spokes on the inside.