No rest on this side of the planet!
I was thinking that I better have a look at some other disc options for those of you that want to stay with the Standard Commer hubs before I get mine machined shorter for my 6 stud arrangement as you don't seem to be having much luck. I headed off to the wreckers this morning with some ideas after doing some research during the week hoping that unfortunately came to nothing. I was hoping that the front discs off a late model Toyota Camry might do the job, being five studs and around the same dimensions as my Navara disc’s I though this would be a good place to start. Unfortunately the inside diameter is only 140mm, too small to slip over the Commer hub, bugger! I walked around for a while measuring various thing to no avail until I came across a '95 model RAV4 (Toyota Code SXA10), which looked very promising. They're unusual discs as they are large diameter (302mm) vented, but only 18mm thick and they 8mm more offset than the Navara's. I grabbed one to play with and did some machining and think I might have solved the problem.
There was very little involved and took me around an hour or so to complete one side.
Step 1 Remove all the wheel studs from the Commer hub.
Step 2 The hole in the centre of the RAV4 disc is 62mm, so I opened this up on the lathe to 98mm, which is the size of the drum locating boss on the standard hub.
Step 3 The flange of the Commer hub is just a little too big to slip inside the RAV4 disc. It's so close I think I took of about 1.5mm off on the lathe, but you could grid it off just as easily. Now the Hub sits inside the disc located centrally on the boss.
Step 4 As the RAV4 wheel stud PCD is a different offset rotate the disc so the Commer stud holes are located half way between the RAV's and you can now drill you stud holes through the RAV disc. I have a very old 5/8" that is so worn out, but proved perfect of the job as it didn't remove any if the spline in the hub that hold the wheel studs tight. I drilled one, fitted the stud and bolted it up to stop any movement when drilling the others, once all holes were done I fitted the studs and what you see below is the result.
Step 5 You might want to fit some countersunk screws similar to those used to hold the standard drums to the hubs to keep it all nicely inplace when you remove the wheel.
It was that straight forward. I then grabbed my stub axle, still with my Navara Set-up ply calliper mount fitted to see it lined up. There seems to be plenty of clearance as you can see in the pictures below.
I haven't spent any time on callipers or mounts for this arrangement, as I will now re-focus on completing my 6 stud set-up. I think this RAV adaptation has potential and for those running a van or camper would be a simple and effective upgrade, with the parts readily available from wreckers worldwide. Toyota sold RAV4's everywhere. The discs even have the dimples for ABS sensors if you want to get that serious! As for the RAV's callipers, I think they could be a little bulky and the calliper mounting holes seem too far apart, but I could be wrong. I'll leave that part for someone else to work out. There should be plenty of callipers around to suit as many of the earlier small hatchbacks were fitted with discs around 18-19mm thick. Another advantage that I thought of is for those of you with handbrakes on the front wheels. There seem to be a lot more cars these days fitted with narrow vented rear discs with lever handbrake actuators, so hopefully there's a solution to your problems too.
One thing that will need to be checked is wheel/calliper clearance. As these discs are 305mm in diameter, this may be a conversion that only fits inside 15” alloy wheels or 16” steel wheels, if they exist, so do your homework before you commit.
Have fun,
Cheers Stephen
