going back to basics - centering front hub

this is a chicken and egg topic... did Norton go to the wonky offset front hub to accommodate the rather rotund lockheed disk and caliper? it would seem to be the case since the front drum on the 72 et al i believe is centred .

so with the proliferation of compact disk brakes now available, what is stopping us from respoking the wheel on centre and using a more compact disk and caliper? or is the limiting factor that there is not enough width between the fork tubes/stanchions.

or am i out in left field playing hopscotch???

Well, I'm not sure what you have in mind, but wd point out that the wheel (rim) is already (or should be) centered between the fork legs to be aligned with the frame and rear wheel. The disc being bolted to the hub means that the disc position is independent of how the wheel is laced.
Don't feel bad about playing hopscotch around it: it took 2 experts on this forum to clue me in.
And yes, it was of course designed with that exact caliper in mind, mounted just the way it is.
The lower mudguard stay comes into play also, as you'll see when looking at alternate setups...

what i want to discuss, is that since a number on this site have already replace the brake disk but used a space to maintain the same wonky Hub offset. has anyone considered relacing the hub/rim to get the hub on centre of the rim and which would allow using a brake rotor with no/or minimal offset to achieve the installation....

Take a look at the front hub on a Commando Production Racer. It came from the factory with the arrangement you are thinking about. It had a Campagnolo front hub, and was laced to the rim with no offset, so hub and rim are both centered between the forks. It used a racing Lockheed caliper and a splined (floating, sort of) disk carrier, and the spokes just barely cleared the caliper. The caliper side slider was slightly machined on the inside to clear the disk. Worked fine.

These pictures of my PR at Willow Springs back in 1982 show the front wheel fairly well. The bike has some other mods, but the front end is still the way it came from the factory, except for swapping the disk and caliper to the left side.





Ken

You can still buy all the parts to convert a Commando to the PR front wheel and brake setup.

Ken

You can even fit a dual disk conversion in with the stock fork width, like this one on Steve Maney's bike.

If you hunt around here on the forum, you will find more examples of folks who have fitted other combinations with centered hubs to Commando forks.



Ken

thanks Ken, so if i was to use the stock hub but want to relax the spoke positions i would need to get a rim with different hole punching for the nipples...? or can the current wonky offset rim still be used?

850commando said:

thanks Ken, so if i was to use the stock hub but want to relax the spoke positions i would need to get a rim with different hole punching for the nipples...? or can the current wonky offset rim still be used?

Click to expand...

If you want to use the stock front hub, you pretty much have to stick with the "wonky offset" rim to keep the rim central in the forks, unless maybe you plan to machine some width off the disk mounting surface. It is possible to fit the Lockheed racing caliper, using the PR fork slider, with the stock front hub. Norvil sells a disk adapter to fit the splined PR disk to the stock hub. That's what I did on the MK3 that I built with my grandson for him to ride. This is a picture of that front end arrangement. It uses a stock MK3 front wheel.

I read that the Syd Lawton entered 650SS in the Thruxton 500 miler had the wheel offset. No less a rider than Phil Read observed in standard trim it did not handle. This was attributed to the rotor and alternator in comparison with the previous magnet fitted machines... This surely must apply to the Commando with a heavier inertial loading from the otherwise excellent clutch and possibly a heavier rotor.