Base model rear wheel arch, wheel choice and suspension set up

[Carrot_heed 0]

Hi there

 

I’m building up a fast-road car at the moment and I’ve used a bilstein b4 suspension set up with eibach springs. 

Im not sure if a harder suspension set up would benefit it anymore such as the b6 or group n.

 

I’ve dropped the rear of the car accordingly and it’s all sitting level. The wheels I have a 1.9 GTi wheels with a 185 55 tyre, however these are now starting to rub going over larger bumps and hard cornering.

 

It’s just managed today to actually chip some paint off the offside inner arch, I actually thought it was rubbing on the gti rear bumper but appears not now.

 

Is there a different tyre I can use without compromising the handling? Or would it be better to use a 14” wheel rather than the 15. 

 

Any help and advice would be great.

[Anthony 1,000]

Firstly, are the rear bump stops still present on both sides?  These have a habit of the cups corroding and falling on, and without bump stops you're on a hiding to nothing on a lowered car.

 

Are you still running the base model spec torsion and anti-roll bars, or have you swapped those (or the entire beam) for stiffer GTi spec items?

 

When you say the inner arch, which part do you mean?  What I would call the inner arch - the part that forms the side of the boot that faces the inside of the wheel - shouldn't be an issue unless the beam is goosed causing excessive negative camber.  I'm guessing that you're actually talking about the trailing edge of the lower rear quarter panel that sits forward of the wheel arch above the sill or the inner part of the outer arch lip?

 

Most base model owners normally end up running a slightly lower profile tyre to help with clearance, usually the same sizes that 106/Saxo models use - so 185/55R14 for 14" wheels and (I'm guessing) 195/45R15 for 15" wheels.  That'll help with clearance to the rear bumper/valance and trailing edge of the lower rear quarter panel.  14" wheels are typically narrower too - 5.5" for 1.6 GTi wheels for example - which will help with clearance at the top of the arch.  Some tyres have a much "squarer" profile than others too, which doesn't help.

 

You should find loads of information if you do a search as it has been discussed extensively over the years.  You're always going to be a bit compromised with the base model arches though.

[Henry Yorke 269 3 Cars]

I have been here in the past. 1.9 speedline wheels also have a bigger offset so sit slightly wider, hence catching on the outer arch. If you put 14” Peugeot wheels on, they sit in more and do not catch. Silver XS on 306 harriers on 185/60/14 tyres which are the same as 1.6 wheels. Yellow is on 15” which always caught with 195/50 and 185/55 tyres.