Moulton TSR rear pivot

[deliquium]

It's be useful if someone with a set of TSR bushes on the bench could check the measurements

My original 2106 TSR bushes (replaced a few months ago) measure:

The bush is 11.9mm long, inc flange
External diameter that's inserted in frame is 19.03mm
Flange diameter is 25.40mm
Flange thickness is 2.52mm

The original sleeve outside diameter measures (in the unworn middle section) is 12.64mm
The original sleeve length is 55.0mm

[Mick F]

Just been washing Moulton and considering the bushes.
I'd like to fit new ones from Simply Bearings to see if they are exactly the ones required, then if they are, I'll have a brand new sleeve and a pair of good bushes.

How do I get the bushes out?
When I took the worn ones out, I whacked them out with a big flat bade screwdriver and a mallet. They came out ok, but they were damaged by the screwdriver of course.

How to get them out undamaged?
If I remove the rear triangle, I can pump them out by pressured grease maybe, but knowing my luck, only one will move!

[fastpedaller]

Just been washing Moulton and considering the bushes.
I'd like to fit new ones from Simply Bearings to see if they are exactly the ones required, then if they are, I'll have a brand new sleeve and a pair of good bushes.

How do I get the bushes out?
When I took the worn ones out, I whacked them out with a big flat bade screwdriver and a mallet. They came out ok, but they were damaged by the screwdriver of course.

How to get them out undamaged?
If I remove the rear triangle, I can pump them out by pressured grease maybe, but knowing my luck, only one will move!

And once that one is out, just use an 18mm drift to punch the other one out having removed the sleeve!

[Mick F]

Yes, an idea I suppose.
I'll order the bushes - probably this afternoon - and I'll take it from there.

At this present time, my pivot consists of the new bushes from the repair kit, but the old sleeve. It could be possible, that the sleeve will outlast three or four - or more - pairs of bushes providing they are kept clean and lubricated.

[Mick F]

Ordered.

Two to seven days free postage.
£6.04 including VAT for a pair of them.

https://simplybearings.co.uk/shop/p1205 ... _info.html

[gazza_d]

Yea, you carefully need to tap the bushes out with a drift and a hammer. They should not need much persuasion. If they are not badly worn and only slightly damaged by the removal process, you may be able to reuse by reaming once refitted or even filing any burrs off. The bushes are a simple pressfit, but just ensure they go on straight. You can use a vice with soft jaws.

As for mine, the APB is still with the framebuilder (hopefully back this week). He is fitting the bushedand I am not touching the TSR until the APB is back on the road.

[Mick F]

Ordered.

Two to seven days free postage.
£6.04 including VAT for a pair of them.

https://simplybearings.co.uk/shop/p1205 ... _info.html

The bushes arrived earlier today.

I gave them a good looking-at and compared them to the worn bushes.
The new bushes are identical is all ways except one.

The flanges are 125thou thick whereas the old ones ...... and from what I can see of the new fitted ones ........... are 115thou thick.
The land that inserts into the frame is the same, it's just that the flanges are thicker.

This means, that when the bushes are fitted, the sleeve won't protrude and mate with the fixed part of the frame. The length of protrusion is quite small normally, and I guess quite a bit less than 10thou per side. More like 5thou perhaps.

Therefore, I will have to experiment. I had decided to leave it and only fit them when the present bushes wear out, but now I'm going to have to bite the bullet and remove perfectly good bushes to insert a pair that I'm guessing won't fit.

Advice please.
What should I do?

EDIT
Added some photos by way of illustration.

[Mick F]

Some measurements:
I stood the TSR upside down outside in the sunshine and removed the pivot bolt and allowed the rear end to move away a little bit.
I measured across the outer faces of the bushes side to side, and found (using my digi callipers) 54.5mm.
Measuring the the new sleeve I have, it is 55mm ............ meaning that the sleeve protrudes 0.25mm either side of the bushes.

The old bush flanges are 2.34mm thick.
New Simply Bearings bush flanges are 3.15mm thick.

This means that the new bushes will stick out 0.81mm further than the old bushes, meaning that the sleeve will be "buried" inside by 0.5mm.

Not good.

[Brucey]

'Mr File' can soon fix that....

cheers

[Mick F]

Oh yes, of course.
There's many a way to get them thinner. Lathe would be best ......... not that I have one, but I do have access to one if I ask nicely.

I had wanted to find a cheap simple basic way of replacing these bushes, but not everyone has access to a workbench, and vice, and a file ............ or a lathe. Let alone the skill of hand.

I wonder if some of the expense of these things as Moulton spare parts, is the machining to get the correct thickness from the SB blanks?

Piccy of the underside with the pivot moved away. You can see that the sleeve is slightly wider.

[gazza_d]

thanks for the update Mick, and for being the guinea pig.

I wondered if the out flange was thicker but could not measure accurately enough with the bike together
I don't think filing the flange is a great idea as it would need to be perfectly straight to avoid damage over time to the pivot bolts.
I may just order some bushes from Moulton as I don;t know anyone with a lathe either.

[Mick F]

I've been thinking these past couple of days, and scratching my (bald) head about this issue. Like you, I'm not too happy to just file them. Mind you, the flange thickness isn't critical so long as they allow the sleeve to contact the frame tightly but not be so loose that the frame moves side-to-side noticeably.

If I had a bigger electric drill chuck, I could mount a bush in it, get the drill whizzing vertically in the vice, and use a file. Sort of improvised lathe. Without a bigger chuck, I may be able to do some more head scratching and devise another way of mounting them to use the drill.

Failing that, I'll give up on the idea until I need them (year or two?) and get them to a lathe. Locally, I know two people very well who would be delighted - for a beer or two - to turn them down.

For the moment, there's no rush for me.

[Brucey]

Filing is exactly as good as the fellow wielding the file.

BTW a 1/2" drill chuck will accommodate the centre sleeve, and (e.g. using a turn or two of PTFE tape) the bush can be made a tight fit on the sleeve. Then impromptu lathing can ensue.

I have a couple of lathes but tbh it is often quicker and easier to set up certain jobs using a drill like this. I often use a grinder (carefully, with a fine wheel) on the rotating part; the contact to the work can be radial rather than tangential and the contact load can be very low. With a bit of cunning you can do all kinds of clever stuff this way.

cheers

[Mick F]

Filing is exactly as good as the fellow wielding the file.

Very true.
I did Engineering Workshop Theory and Practice O Level - otherwise known as Metalwork - and did a full engineering apprenticeship in the RN eventually specialising in electronic engineering. I still have one or two things from school, plus all the trade tests from my apprenticeship - we had to file the fittings to less than 1.5thou by file and get them flat and true. Smack on got you more marks of course.

BTW a 1/2" drill chuck will accommodate the centre sleeve, and (e.g. using a turn or two of PTFE tape) the bush can be made a tight fit on the sleeve. Then impromptu lathing can ensue.

Excellent idea.

May have a play in the workshop in the next day or two.

[Mick F]

Chucking it down today, and had a good hilly ride yesterday, so today it's indoor stuff.
In the process of redecorating the kitchen (slow job), but I could get to have a play with the "sleeve in the drill" idea later. I've already checked that it'll fit in there neatly.

What I plan in doing, is seeing how I get on with one or two of the worn bushes. Nowt to lose with either of them, so I can have a good practice before I'm let loose on the real things.