Alloy wheels causing handling problems BX 19 auto

charlotte001 · Post by **charlotte001** » Wed Feb 20, 2008 8:56 am

I've been told/Read that fitting certain alloy wheels will cause my BX to have handling problems if I go above the recommended width is this true or bunkem?

What is the average you all fit to BX 19's ?

Charlotte001

Philip Chidlow · Post by **Philip Chidlow** » Wed Feb 20, 2008 9:43 am

Best results are obtained by using BX alloys, be they 5.5" GTi ones or 6" 16v ones. Apparently all are 4x108 ET15-22 14" sized, wearing eithr 185 or 195 60 R14's. Some have fitted 15" alloys wearing 195 50 R15's but I don't know if this will cause a problem other than a slightly harder ride?

M · Post by M » Wed Feb 20, 2008 11:36 am

Got 6J alloys on mine with 195 rubber, handles fine, very grippy on corners, just not keen on the looks myself (but thats a personal thing).

tim leech · Post by **tim leech** » Wed Feb 20, 2008 1:00 pm

Fitting wider tyres can possibly give a firmer ride but you wil get more grip, as Phil says if you get some GTi or 16v alloys with 195 section tyres you shouldnt notice too much loss in ride comfort and it will handle better.

All BX19 petrol non GTi had 175/65 R14, you could easily fit 185/60 R14 in its place with ease and it would be cheaper as they are a more common size, I know Ian Fearn has this size on his TZD turbos with no problems.

jeremy · Post by **jeremy** » Wed Feb 20, 2008 7:14 pm

There have been reported problems (with rapid wishbone bush wear) where wheels with a diameter in excess of 14 inches have been used. I think its fair to say that this problem was never satisfactorily resolved - as with a suitably low profile tyre its possible to have the same overall diameter as a 14 inch with a higher profile.

It may be that the BX doesn't appreciate ultra low profiles - but you won't have any problems if you stick to the sizes as originally used.

The BX probably has fewer variations across the whole range than any other car ever made (same brake pads for all, discs and calipers except 16 valve front etc, hubs, suspension except anti-roll bars and spheres etc.) which means that wheels that fit one will fit another (Estate back possibly excepted.) Safety is of course another matter (ie wheels and tyres from a 14 shouldn't be put on a 16 valve)

MULLEY · Post by **MULLEY** » Wed Feb 20, 2008 9:28 pm

Perhaps with larger grippier tyres, those owners were driving their cars a lot harder than with standard tyres, which could increase the wear rate on bushes.

I dont have any personal evidence of this myself, but worth thinking about i guess. Not relevant if you drive very sensibly of course.

Not had any probs with 185/60's, i wouldnt even personally call this spec of tyre to be very sporty by modern standards anymore.

The standard tyre sizes look worryingly narrow, 165/70's, i'm sure my bicycle tyres arent far off that size

jeremy · Post by **jeremy** » Wed Feb 20, 2008 11:33 pm

The classical car design theory is that the king pin axis should intersect with the centre of the tread. This means that you should be able to draw an imaginary line from the top of the strut (top bearing) and the lower swivel - and extend it to the road. This point should be the centre of the tyre tread.

Car designers may move this point for their own reasons and strict observance of it doesn't seem to be essential - but moving it ( by for example fitting a taller wheel/tyre combination) may cause problems.

Fitting a wider wheel (of the same diameter) won't cause a problem as the centre of the tyre will be in the same place. (assuming offset and wheel/tyre diameter is the same)

Kitch · Post by **Kitch** » Thu Feb 21, 2008 10:21 pm

I find the profile makes the biggest difference. Handling is no different, infact with a lower profile tyre and a 15inch rim it's better.
But the ride suffers. Although BX's are superbly dampened compared with conventional rivals, they're also more fidgety over smaller rutted surfaces and the ride isn't very refined. The lower profile tyres make this worse, so overall the ride feels off. A bit like your spheres are on the way out. Could be countered with softer spheres, but then it'll lean like a 2CV, and BX's don't exactly resist body roll all that well as it is

As said, GTi or 16v alloys and original sized tyres are probably best, although my dad has some of the metric-looking imperial alloys and has increased from a 165/70 setup to a 175/65 setup and the difference is pretty impressive. Certainly rides very well.