H: Hubs, Wheels and Tyres Speedo Drive Gear Attached to the Hub?

[tom wilson]

Thank you guys n gals that was the answer I was looking for thanks to all, no need for more advice/comments.
How is the speedo drive gear attached to the alloy hub and how do I remove it (Vin 'C' Twin)
many thanks

 

[Jez Nemeth]

Hi Tom it's an interference fit relying on thermal expansion -carefully using a blow torch heat the drive gear ring to expand it, going round all the sides, then carefully knock/prise it off the thin lathed shoulder on the hub it butts up against, use wood where possible don't generally need excessive force at all.

Now be careful, don't want to over-heat the hub itself as it may crack during the process. Aluminium, even T6 heat treated/ tempered stuff will give you no indication the metal is melting under the surface, it cracks and breaks up like a thick cheesecake long before it melts properly at around 700c + so care is required. A Butane burner is a good tool for the job as it blows cooler than propane or oxy... you'll have it off in less than 2 mins.

Or pop the hub and attached gear on a baking tray and place in middle shelf of a pre-heated oven at 200c deg for 10 minutes, (180c for 8 mins fan assisted), remove with mrs's best oven gloves and tap off with a wooden block and allow to cool before serving * baking times may vary.

(Same as you would do for fitting/removing an Iron cylinder liner from a Muff, so per lb...hmm.. about 15 mins for that...BTW don't grease the tray, and only do it when Mrs is not around)

 

[Peter Holmes]

So can we assume that the factory fitted the speedometer hub gear to the wheel hub by heating the gear up first, I always assumed they just bashed it on hammer and a circular hollow drift/large socket spanner, pull off with a puller, and bash back on and lightly stake the hub to retain the gear, well thats the bodgers solution anyway.

 

[delboy]

I have replaced ring gears where the interference is lost with the hub. A good grade of Loctite works fine. I've never had one come loose. If you use a nylon pinion on the speedo box, the ring gear will never wear out anyway.

 

[Jez Nemeth]

Maybe a better way of saying it would be 'by removing the gear using heat/thermal expansion there's limited mechanical damage to the mating surfaces when removing/refitting/replacing (heating up new gear ring before popping it on and tapping home), compared to traditional mechanical methods'.

You're probably right Peter, factory likely pressed them on straight off the lathe - assembly time being money...

 

[Alyson]

if the hub has been peened at the gear wheel you might want to relieve the peening some what. A dremel would take care of that. Then don't heat the hub, heat the gear wheel. It's steel and as aluminum will heat up faster I don't think an oven would be the way to go as the hub would
just expand first. Either two large slotted screw drivers, or a couple of tire irons with protection, or, a puller should do the trick after heating of course. Probably wont need much. Mic it if needed to check the interference first.

 

[oexing]

Best to use a two arm puller, but place some spacer over the bearing end, so the bearing is not loaded.

Vic

 

[Jez Nemeth]

if the hub has been peened at the gear wheel you might want to relieve the peening some what. A dremel would take care of that. Then don't heat the hub, heat the gear wheel. It's steel and as aluminum will heat up faster I don't think an oven would be the way to go as the hub would
just expand first. Either two large slotted screw drivers, or a couple of tire irons with protection, or, a puller should do the trick after heating of course. Probably wont need much. Mic it if needed to check the interference first.

Sorry you're quite right -think I used the oven to just put some heat into one once, helps dislodge sometimes as opposed to smacking it with a hammer...please disregard some of my first statement -Blowtorch is solid advice though, oven just for muffs and liners...phew