Speedometer drive - modifying?

[Rusty_S85]

I bought one of these vintage looking retro speedometers with a odometer (I didn't get the one with the trip as the knob breaks). Problem is the front wheel I got from MBRebel has a taller flange on the hub so the folded over ear on the speedometer drive hits the side of the hub flange so it cant be used with this will.

I wanted to ask what are some options to modify this to make it work?

I thought of using a vice to flatten out the ear and bend it a little higher up. Down side is they put a bead in the crease to strengthen the bend. Another option I had was to simply take and drill holes side by side in the front hub for this ear to fit it. I don't like this option either. I also thought of buying just a drive that is used off ebay from a older assembly that has the ears spaced farther apart. But with this theres no way to ensure the cable and everything will work.

So if anyone has any ideas I am open to some suggestions. I plan on putting the bike together this weekend and need to come up with an idea so I can install my front wheel.

 

[RustySprockets]

Without photos, I can only imagine the exact nature of the interference. Were it my project, I'd probably be tempted to CAREFULLY grind/file the little tab until the hub and speedo peacefully co-exist. This approach would likely prevent using the speedometer drive with any other bike in the future, but I'd be okay with that. Your mileage may vary.

 

[horsefarmer]

Again, it's hard to estimate without pictures. You don't want to connect the drive solid to allow for some runout. Maybe put a small self tap screw into side of hub and drive the speedos flattened or cut ear from that...

 

[Rusty_S85]

Here is a picture of the problem I have. The arm that is supposed to sit over the top of the flange on the hub is actually touching the hub between the spoke holes. It has a bead rolled into it where I am afraid it wont work trying to smash it flat in a vice and then bending it further up. Id also be afraid of it being weaker and bending from use if not just simply breaking. I also don't really want to drill the hub as its between the spoke holes and it would weaken the wheel.

 

[Rusty_S85]

I found some metal vintage ones on ebay that look like the ears are spaced farther out but I don't know if the cable drive threads are standardized or not between new and vintage. Id hate to fork over $40 for a old drive and cant use it as my cable wont screw in or worse yet not read close on speed and mileage.

 

[Dr. Tankenstein]

This is probably a stupid idea..BUT.
If the tab touches the hub, it looks like you could CAREFULLY cut a slot in hub for it to slide into...I told you it could be a stupid idea.....[emoji12]


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[Duchess]

Can you just epoxy or otherwise attach a small extension on the tab? Can you take the drive apart and replace that piece with a custom made one? I imagine it's just a flat donut-shaped piece of metal with the tab connected, which should be easy to remake so that it fits, but I don't know how it interfaces with the gear for the worm drive for the cable.

 

[Rusty_S85]

I talked with a guy on another forum he said use plyers and flatten it out as its soft metal and bends easily. I was able to bend it and get it to fit right.

Now my only problem is the cheap speedometer didn't come with instructions so the only way I could get my front wheel to fit my fork with the speedometer drive attached is to remove the thin metal shim and the grooved jam nut. I don't know if this is proper as every searching online I find is about installing digital and electronic speedometers nothing about the old style analog. I haven't tightened anything down just yet but it is a fairly snug fit but the wheel spins freely at least for now till I go tightening up the axle nuts.

 

[Rusty_S85]

Late update but I resolved my issue my problem was I had to leave the jam nut on and then hold the wheel and stretch the front fork out while sliding down I was able to get it to fit and functions like it should. I already have 0000.8 on my odometer just spinning my front wheel for testing as well as adjusting my front BB7 brake caliper.