Vintage FF - Change front wheel bolt circle

[Robert J. Alder]

I have a vintage FF which uses the ubiquitous Triumph upright, rotor, and hub. Here's a picture of the hub


The hub bolts to the rotor and provides the wheel studs, now 4 x 3 3/4" bolt circle and 3/8" studs.


I'm wishing to mount a set of nice Revolutions which have, wouldn't you know it, a 4 1/4" bolt circle with 7/16" studs. It's easy to press out the 3/8" studs and replace with 7/16" studs which are available. But getting the 4 1/4" bolt circle is the real problem.

Anyone have experience with making such a change? If there another Triumph hub with a 4 1/4" bolt circle that would be easy? Unfortunately, I think TR-6 hubs are 4 1/2" b.c. and thus of no help. Or are un-drilled (for the stud bolts) hubs available that could be drilled for a 4 1/4" bolt circle?

I could always create an adapter that attaches to the existing hub via the existing studs and then has the 4 x 4 1/4" b.c. & 7/16" studs in it. But that would increase the track. I'd rather not go that route unless it's the only practical way to proceed.

Any first-hand solutions are welcome.

[Jerry B.]

Robert........
I took a 4 spoke Revo., 4 x 4.250", and dimensioned it out as to center hole and found that a 3.750" b.c. wont fly on that wheel as the center bore of the wheel is to large to accommodate the smaller b.c.
And it looks like the Triumph hub wont carry the larger (4.250") b.c.

But wait!!

Chekered Flag in Chatsworth, CA (Joe Siam, Prop.) has had a machined run of Al Triumph hubs made for his Spitfires customers and rentals. he can do a larger o.d. to accommodate the 4.250" b.c. and fit with 7/16" wheel studs. He has a website I believe. but they are not cheap. Let me know if you cant find Joe.

Plan B might be to sell the Revos and buy something that fits...OR get a set of 3.750" of good used Revos...there out there.

If yours have a rear spacing of 2.5" I might take them off your hands.

JB

[scorp997]

you could probably use the TR-6 hubs (confirmed the hub I have in my spares is a 4-1/2" BC) and offset bore the holes to the 4-1/4" pattern and tack weld the stud in place. If you use a larger diameter knurl (Summit has some up to .594" dia) you can probably get a pretty good press fit and the tack would only be there to keep it from turning.

I have seen some 'alloy' Triumph hubs for sale and if they are CNC produced they may be able to make some with your pattern

[Robert J. Alder]

Thanks for the lead and info. I'll post my solution when I figure it out.
Bob

[Lotus61J]

Early FF's, Lotus 51's and 61's and maybe others came with a 4.24" bolt circle rather than the 3 3/4 because those cars were sold in England with Cortina wheels - which came with the larger bolt circle.

But then pretty quickly cars started coming with the smaller bolt circle and Spitfire wheels. Unfortunately they were not up to the stresses of slicks and would break.

So anyway, if you could find an older FF whose owner would part with the hubs you need, you'd be in business. Alternatively, you could just sell those Revolutions and buy some wheels with the smaller BC - there were a lot more wheels with that BC in use and made than the larger version.

If you decide to go that route, let me know how much you want for the Revolutions you have.

Jay Stannard

[Robert J. Alder]

Thanks for the input. I apologize for not posting solution I found. For the fronts I was able to buy some alum billet hubs form a UK outfit (Canley) for the early Spitfire uprights. They were undrilled for wheels studs so it was simply a matter of drilling them for the correct bolt circle and pressing in some ARP off-the-shelf knurled studs.

For the rear of the car, fortunatately it used a 1" thick wheel spacer that actually holds the wheels studs. So simply a matter of removing that spacer, pressing out the old studs and drilling the spacer for the correct bolt circle (as to miss the old holes) and pressing in the same ARP studs.

[Ralph Z.]

I don't mean to hijack your thread but I am facing a hub problem of my own and I thought that the viewers of this thread may have the answer.

I have a 1968 Alexis MK14 and I'm trying to find a rear brake rotor hub. This, of course, is the splined hub. Does anyone know who made these hubs and where to find replacements?

The fronts look like Triumph but not sure of the rears.

Many thanks for your help. Now, back to our regularly scheduled program...

[Robert J. Alder]

Ralph Z,

When I first got my Russell-Alexis 10 years ago, I broke a rear upright on its first outing. Holy crap!!!! Mercifully, I was able to buy two brand new, unmachined replacement Alexis rear uprights from some guy in the UK and had 'em on hand in a week. Amazing. (Don't recall name of the guy off hand. Would have to research it.) The uprights were then sent to Wayne Mitchell in Calif. who had previously re-engineered the bearing/stub axles on some other Alexis rear uprights to get rid of the less then cool (some would say "crap") Imp axle components which came in those uprights. I suspect that is the splined component you're struggling with. So maybe your solution is to find the Imp replacement parts or bite the bullet ($$$ and not real fast to turnaround) and see if Wayne can help you out with a very good retrofit alternative.

As to the front upright on the Russell-Alexis, it turned out they were "an early" spitfire upright. All "ubiquitous" Triumph front uprights seen on so many FFs are not identical. My source of what I had came from a guy in the UK at Canley (wee web link below) who was most informed and most helpful. Send 'em some pics and inner/outer wheel bearing measurements and they can tell you exactly what you're dealing with and no doubt sell you what you need. Their prices were very reasonable. The billet alum front hub (for my earlier front uprights) was cheaper than some US folks selling alum triumph hubs.

The above is rather cursory. Call me if you want more detailed input. 303-981-6364

[Ralph Z.]

Robert:

Thanks for the information. I will give you a call when I have a few minutes.

Ralph