Attaching Rim to Wheel??

[Ian_dw]

Hi, I am restoring a 1923 McKenzie motorcycle, which has a belt rim, which should be attached to the rear wheel spokes. Has anyone got any recommendations of the best way of doing this, as obviously it needs to be secure enough so it doesn’t break spokes etc??

[cardan]

Hi Ian,

Most lightweights used plates and screws. Here is the Chater Lea version, but many were just a plain 'racetrack' shape, with the holes about 1/2" apart. The screws were most often 5/32" BSW.

If your belt rim isn't drilled, spoke the wheel first, then mark out the holes to suit your spoke pattern. If the belt rim is close to the wheel rim, make a cutout to give you enough room to get the air chuck onto the valve before you attach the rime to the spokes.

Have fun,

Leon

[Ian_dw]

Thanks for the info, I have seen a bolt type arrangement with a hole in the shank, which the spoke passes through, but at £20 for 4 seems an expensive way to do things especially as
You have to take the wheel apart to access the spokes.
Your idea seems a better solution, I guess I just need to find some small
Plates now!!

[cardan]

Triumph were big users of the sleeve/bolt arrangement that clamps onto the spoke. Very neat, and it has the advantage of giving the belt rim some extra stand-off from the spokes. The Triumph ones came in two lengths. Ideally the hole through the sleeve and the bolt should be just big enough for the threaded part of the spoke to fit through.

Worth checking that your belt rim has enough width for the belt to clear the tyre if it is clamped directly to the spokes, otherwise the sleeve-bolt-stand-off-doo-dads (they probably have a name?) might be a good option. Fitting them to an existing wheel with thin spokes is not as hard as it sounds - you can do it one spoke at a time without disrupting the alignment of the wheel. The spokes in the McKenzie wheels are probably only 13g or so, so once the nipple is off you can ease the spoke out of the rim, fit the stand-off, ease it back in and re-tension it.

The other common way to mount a belt rim is with an extra set of short spokes to the back rim. It's a bit fiddly to make the short spokes, particularly when the spokes are too short to be mounted in a standard thread rolling tool!

It might be fiddly, but there's a lot of fun and satisfaction to be had playing with wire wheels. How about a photo of the McKenzie?

Leon

[Ian_dw]

Hi Leon, thanks for the Info and as you can see I have about 60% of the whole thing!! I have a lot  of items missing, Brakes, Saddle Stem, Handlebars etc, but I am gradually getting the missing items, once I have identified what they were originally!! I have tracked down the right saddle and more importantly the Albion Type C gearbox which is right for the era, so slowly we advance!! The frame of the bike only allows the width of the rear wheel to go through it, so I am guessing I have to pass the rim through the narrow part of the frame, then the wheel then join the 2 together in situe!! Let’s hope there is never a puncture as changing the wheel is going be a right pain!! Thank again Ian

[cardan]

Hi Ian,

That looks cute! I've done a bit of 211cc-powered two-stroking and it can be very good fun.

Did it have a gearbox? The one they tested in The Motor Cycle 24 August 1922 was direct drive from the engine to the back wheel.

Speaking of the drive, you'll find that the belt rim snugs in to the wheel so there is just enough clearance for the belt to pass the tyre on its way to the engine pulley. The wheel and belt pulley will slip in just fine if everything is kept narrow.

Cheers

Leon

[Ian_dw]

Hi Leon, the standard model as per your photo came without a gearbox, but for an additional £7 6s they would braze a mounting to the front of the frame, re-enamel it and give you a new gearbox, which sat in front of the frame and just behind the front wheel!! A metal chain connected the engine to the gearbox, which then powered the rear wheel via a belt. Why it all wasn’t a chain, I don’t know, I suspect might have been for better traction, but just a guess on my part!! Anyway my bike has the bracket on the frame so has been converted. I know i could have sawn it off, and gone back to standard, but as I have found the right gearbox, why not go the extra mile!! I just have to work out where I can get the right drive pulley and Cog which fit on the gearbox drive shaft and all should be good one!! Ian

[cardan]

Brilliant, and certainly worth pursuing. I assume there is no clutch, which was the Douglas setup so popular at the time. The belt is needed to make the drive more forgiving, particularly for clutchless gearchanges.

The gearing (in top) was probably about 6:1, and with the gearbox you can spread the reduction between the primary chain and the belt, so you won't necessarily need the really large pulley on the rear wheel. Whizzers in America used a lightweight belt drive, and I think you can buy new pulleys.

Have fun!

Leon