Rearwheel constuction

Started by Cees van Rhijn, November 02, 2022, 05:56:03 PM

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Rick Parkington

Good question, Thomas! I do wonder if the club's new sprockets are made to accept a different bearing or the original. Probably the answer would be to modify the sprocket/drum and even the stub axle to take a different bearing if the problem arises - but let's hope it doesn't!
Cheers Rick 
   

Thomas

Ah, very valuable advice which I will follow. I wonder, though, what I need to do if the bearing once needs a replacement... ::) 
Thanks a lot!
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Rick Parkington

Hi Thomas, yes, that's correct - although the actual wheels are the same there is no bearing in the front brake drum. I assume this is because the load going through the rear sprocket is continuous and far greater than that created by the font brake.
Sorry, when I said 'when dismantled' I meant when the hub and drum are separated - that is, there is no external grease nipple that allows it to be done when assembled. Removal of the bearing would probably be difficult and may result in damage - obviously heat won't help as it would with a bearing in an alloy casing and I don't think you can get behind the bearing with a lever or punch. I would wash it out as best you can while fitted and pack in fresh high melting pint grease from the outside. Pushed in with the fingers it will get through to the back okay.
One final thing, in case anybody ha the same problem. On my 9A rear wheel, the three drum to hub bolts regularly came loose. I don't like using loctite on fittings like this so instead I carried around a tool to tighten them in the toolkit. When I eventually looked closer I realised that the holes in the hub had worn slightly oval, that meant there would always be some movement between drum and hub which inevitably loosened the bolts. I bored the holes slightly oversize and made bolts with shoulders to fit the new size and since then it's been fine.
Cheers Rick 

Thomas

Hi Rick!
QuoteThe Sunbeam quickly detachable rear wheel has two bearings in the wheel hub and another in the rear sprocket/brake drum.

That is interesting and I didn't realise that until now because my 1937 front wheel does not have a third bearing, although also quickly detachable. It's obviously time to pay attention to my rear wheel.
QuoteIt can only be greased when dismantled but this should be no problem...

Can you give some information about how to get the bearing out?

Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Rick Parkington

H Cees, I'm afraid I have no experience of the 1936 Model 9 but since nobody else has answered and I suspect it is similar to the earlier bikes, here's my opinion. The Sunbeam quickly detachable rear wheel has two bearings in the wheel hub and another in the rear sprocket/brake drum. The sprocket/drum bearing is an unusual  size that has been unobtainable for a long time. The clearance in it should be no more than in any other journal type bearing so it could be that yours may be worn out although because (I think) it's quite a narrow bearing, it's likely that there will seem to be a lot of movement when it is unsupported. I would check it with the wheel assembled on its axles but without bolting the wheel hub to the sprocket, looking for any up and down movement.
It can only be greased when dismantled but this should be no problem - there's no need to grease it regularly but use a high melting point grease.
Hope this helps and all the best
Rick   

Cees van Rhijn


Hello
The rear wheel brake drum frme my Model 9 is mounted in the frame with a kind of bearing bolt. Can someone inform me if this is really an extra bearing (and if so) what the clearance of this bearing is. It seems to me that this construction relieves the wheel hub against too high torsional forces. Now the clearence is more than 1,5 mm. And if it is a bearing how do you lubricate it.
.

Cees