What do you do when your rear wheels won’t fit on?

Fitting 13 inch wheels over the Sierra rear disc brake setup can be problematic

This depends on your wheels. Some Compomotive CXR for example are supposed to fit fine.

Many others don’t. I have Compomotive Revolutions, and I am quite fond of them so I have a problem!

What binds?

On a Phoenix (and their sylva brethren) the wheel can bind on the rear upright. In my case this binding was at the bottom at the front. A combination of two approaches are used to fix this:
1) adjust the fore-aft position of the bolt (it could also be trimmed down a little, but that is probably overkill as it isn’t massively long in the first place.

2) move the wheel away from the upright. This can be done either:

i) by spacing the hubcarrier itself from the upright (by making up alloy spacers)

ii) by spacing the wheel from the hub (using standard spacers)

iii) by getting a wheel with a larger offset

The next big bind (for me) is that the Sierra disc calliper binds with the inside of the wheel. The revolutions are bad for this as they step in where the 4 spokes connect to the rim, and it is this region where the troubles occur.

Solutions:

1) increase the spacer between the wheel and brake disc. Around 20mm should do the job. Wide spacers need to use hub centric devices (which are around £50 for a set).

2) Move the outer edge of the calliper and pad in. this is done by

a. Trimming the bad of the calliper (there is loads of extra metal here)

b. Trimming the pad backing (it does nothing where it is outside the calliper)

c. Moving the holes where the calliper bolts to the calliper carrier

d. Trimming the inside of the calliper so it can go closer to the disk

e. Trimming the edge of the disk

3) Change the disk

a. Use a ford escort Mk3/4 front non-vented disk

b. Remount the calliper further towards the centre of the car

c. This unfortunately requires the hub to be turned down as the Escort disk has a smaller ID.

1 and 2 can be combined, and clearly 1 solves the problem with the wheel hitting the rear upright! The annoying thing about wheel spacing, is that it should all be done relative to the bodywork for a tidy look. As my bodywork is still a figment of my imagination (hopefully packed perfectly in someone else’s garage awaiting the day when they realise that they won’t get around to building their kit and so flog it to me) this makes it difficult.

So, what am I going to do?

I have tried trimming stuff down, and it is still all a bit too close for comfort. If I trim further will run out of metal (bad). I could use a spacer with this, around 10mm should do the job. But I don’t like that idea much. I thought all this stuff fitted when it was on the bench, but that doesn’t seem to be the case in real life.

The “best solution” is probably to start again and go with Mk Escort disks. I can turn the hubs down, and use normal studs. The disk diameter is smaller (it seemed silly having bigger rear than front disks!), and everything that might need replacing (i.e. calliper, and disk) are stock. This is a nice solution (I think).