Moulton TSR rear pivot

[Mick F]

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.

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.

Had a go at it.

I fitted one of the worn ones as per Brucey's idea, and fitted it into the chuck of a mains powered Black+Decker, which I then mounted vertically in the bench vice, and switched on using the lock button ........................

I took a 12" medium file and set to with it. After a few minutes, I switched off and measured the flange thickness to find I'd taken off 9thou.
It was easy enough, but it took some concentration to keep the cut level on a spinning disc. I've no doubt whatsoever that I can complete the job well enough on the real thing.

No rush for this as I probably have up to two years before the existing bushes wear, and now I'm confident in greasing the pivot properly and frequently, it could be three or four years. You never know, they could last for years and years and years and years and years.

[gazza_d]

The new bushes for the APB from SimplyBearings have worked a treat. They were fitted by the framebuilder who also reassembled the rear suspension, so no photos, but I have ridden it and it is as before. It's a lovely smooth supple ride, which is IMO better than the TSR

I ordered a TSR pivot service kit from Moulton themselves which arrived within a couple of days for £38 including 1st class postage. Those bushes have definately been turned down. the chamfer on the outer edge of the flange has gone.

I'll have to hang onto the bushes from Simply and hope I can track down a friendly lathe user and get them turned down to size.
Odd that Moulton decided to do that rather than just amend the design to use standard bushes

[Mick F]

Thanks for the update.
Yes, it's odd that they don't use standard bushes. There's not much difference and the ears wouldn't be that difficult to be redesigned a tad wider apart.

[igauk]

Thanks for the update.
Yes, it's odd that they don't use standard bushes. There's not much difference and the ears wouldn't be that difficult to be redesigned a tad wider apart.

Unless it is a standard bush and we just haven't found the OE supplier! Or it was a standard bush when the rear suspension was designed and Moulton bought thousands of the things, but no longer available. Of course it could also be one of those custom Moulton bits.
I've not fettled my rear suspension yet but noticed that a previous owner has chewed the head of the pivot bolt a bit so I might invetigate if the SST bushes et al are a direct fit to the TSR.

[Brucey]

is it possible that the TSR pivot assy benefits from being a bit narrower than the APB one?

Given that the TSR pivot is alongside a part of the chainset that always has the chain on it (by contrast with the APB pivot which doesn't) could this be the reason?

BTW the 'impromptu lathing' will be about x100 quicker if you use an angle grinder on the work, as previously suggested.

cheers

[fossala]

Thanks for the update.
Yes, it's odd that they don't use standard bushes. There's not much difference and the ears wouldn't be that difficult to be redesigned a tad wider apart.

Unless it is a standard bush and we just haven't found the OE supplier! Or it was a standard bush when the rear suspension was designed and Moulton bought thousands of the things, but no longer available. Of course it could also be one of those custom Moulton bits.
I've not fettled my rear suspension yet but noticed that a previous owner has chewed the head of the pivot bolt a bit so I might invetigate if the SST bushes et al are a direct fit to the TSR.

The surface area of the rear pivot increased by 150% on the SST so I'm guessing a different bushing would have been used.

[igauk]

Thanks for the update.
Yes, it's odd that they don't use standard bushes. There's not much difference and the ears wouldn't be that difficult to be redesigned a tad wider apart.

Unless it is a standard bush and we just haven't found the OE supplier! Or it was a standard bush when the rear suspension was designed and Moulton bought thousands of the things, but no longer available. Of course it could also be one of those custom Moulton bits.
I've not fettled my rear suspension yet but noticed that a previous owner has chewed the head of the pivot bolt a bit so I might invetigate if the SST bushes et al are a direct fit to the TSR.

The surface area of the rear pivot increased by 150% on the SST so I'm guessing a different bushing would have been used.

That's what I thought at first but from the SST pictures I can find online there doesn't appear to have been any changes to the frame. This makes me suspect they have just increased the internal diameter of the pivot tube/bolt and used thinner walled bronze bushes.

[Mick F]

Just resurrecting this thread.

I've been injecting a couple of strokes of grease into the pivot nipple every couple or so weeks. Nothing regular, just when I think about it, but it has been every couple or three weeks though I haven't noted the mileage between the injections. I wipe off the excess as it emerges from the sides.

Dunno if this is going to increase the longevity much or not, but it's worth trying maybe.

[Mick F]

Just done it again.
Moulton sits upside down very well and stable, and I've just been tinkering with the rear mudguard. Whilst upside down, I gave it a few strokes of grease.

Still nice and solid with no wear that I could see or feel, though only done 850miles since renewing it in January (six months ago).
It took 4,400miles (34 months) before I noticed the wear in the first place, so plenty time left!

[Mick F]

Greased it again.
Done 1,000 miles since renewal.

Still not the slightest play.

[NetworkMan]

Just curiosity really since I know little about Moultons. Is that poor design a result of Pashley cheapening things? I thought Moulton was a competent engineer!

[Mick F]

Yep.
Cost is the thing in all things.

The price of a low-end Moulton is still high, so you would think that they could at least fit something a bit better. At least they fit a grease nipple.

You can take a horse to water, but you can't make it grease the rear suspension pivot!

I reckon, that if I lavish lots and lots of injected grease every month or so, it will be fine.
I didn't do it properly or thoroughly or frequently enough, so mine failed at 4,000miles.

It's done 1,000 miles now, but what it was like at 1,000 miles when the bike was new, I don't know, but I hardly ever greased it, and the grease gun I used when I did think about it, was rubbish.

Fingers crossed, it'll be fine for years now, but it will cost a tub of grease a year maybe.

[gazza_d]

The bearing on my APB seems to wear better than the TSR.

I think that's for a couple of reasons.

The pivot is now below the BB and exposed to all the road spray and dirt
The bushes are not as long as the ones in the APB, so any wear may show up as slight play where the APB longer ones didn't allow lateral movement until much more worn.
I do wonder if the move of the pivot location has allowed slightly more load and wear, but I'm not sure why that would be.

The grease pivot was never fitted as standard to APBs and they don't seem to have this issue to the same degree. The basic pivot design is the same. I understand that in the latest redesign in the SST the bushes have been enlarged and lengthened again

[1066enthalpies1939]

Yep.
Cost is the thing in all things.

The price of a low-end Moulton is still high, so you would think that they could at least fit something a bit better. At least they fit a grease nipple.

You can take a horse to water, but you can't make it grease the rear suspension pivot!

I reckon, that if I lavish lots and lots of injected grease every month or so, it will be fine.
I didn't do it properly or thoroughly or frequently enough, so mine failed at 4,000miles.

It's done 1,000 miles now, but what it was like at 1,000 miles when the bike was new, I don't know, but I hardly ever greased it, and the grease gun I used when I did think about it, was rubbish.

Fingers crossed, it'll be fine for years now, but it will cost a tub of grease a year maybe.

There is a pivot bearing on bromptons , if you remove one of the bolt on the bearing would inject grease into the bearing would it reduce wear?

[fastpedaller]

Yep.
Cost is the thing in all things.

The price of a low-end Moulton is still high, so you would think that they could at least fit something a bit better. At least they fit a grease nipple.

You can take a horse to water, but you can't make it grease the rear suspension pivot!

I reckon, that if I lavish lots and lots of injected grease every month or so, it will be fine.
I didn't do it properly or thoroughly or frequently enough, so mine failed at 4,000miles.

It's done 1,000 miles now, but what it was like at 1,000 miles when the bike was new, I don't know, but I hardly ever greased it, and the grease gun I used when I did think about it, was rubbish.

Fingers crossed, it'll be fine for years now, but it will cost a tub of grease a year maybe.

There is a pivot bearing on bromptons , if you remove one of the bolt on the bearing would inject grease into the bearing would it reduce wear?

I may be incorrect, but isn't the bushing on the Brompton nylon (or similar) Greasing it (with anything other than silicone grease) may destroy it?