Moulton TSR rear pivot

For discussions about bikes and equipment.
Brucey
Posts: 44522
Joined: 4 Jan 2012, 6:25pm

Re: Moulton TSR rear pivot

Post by Brucey »

IIRC the Brompton bushing is another sintered metal bushing but it has a polymer coating on it too, although this may be largely removed when the bushing is reamed during the installation process. I think it needs grease.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
rogerzilla
Posts: 2887
Joined: 9 Jun 2008, 8:06pm

Re: Moulton TSR rear pivot

Post by rogerzilla »

They're plastic, with little indentations in the sueface to retain grease. I think there is a metal backing but it's basically a stainless steel axle in plastic bushes. Horrible design, but they last reasonably well and are cheap to change IF you do the miserable job of removing the old ones* before taking the bike to the dealer.

*usually involves drilling the heads off the two very hard s/s allen bolts. I've done it on two bikes and have the hang of it now!
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

Update.

The new pivot has now done 2,200miles.
This is half the distance the original had done when I found that it had worn.

When the wear actually manifested itself, I don't know. I only know when I found it and noted the mileage.

I've been greasing the new pivot every couple of hundred miles or so. Turn the bike upside down, connect the grease gun, four or five pumps, remove the gun, wipe off the emergent grease. Job done in a two or three minutes.

Absolutely no play that I can see or feel. Long may this continue.
Mick F. Cornwall
PDQ Mobile
Posts: 4659
Joined: 2 Aug 2015, 4:40pm

Re: Moulton TSR rear pivot

Post by PDQ Mobile »

I would say this tells you 2 things.
1 is that any bearing or sliding contact will perform better if lubricated.
Actually I have known that for over sixty years!

And 2 that the design/materials is/are not very good in the first place.

I have a rather neglected mountain bike rear pivot of a similar design. After 20 thousand miles(conservative guess) and occasional stripping and greasing it shows absolutely minimal wear/play.
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

Yep, and yep.
The design is very poor indeed, so it needs lubing very often indeed.
Done it nine times in the 2,200miles.

I'd rather over lube it, than not enough.
Mick F. Cornwall
User avatar
ferrit worrier
Posts: 5503
Joined: 27 Jun 2008, 7:58pm
Location: south Manchester

Re: Moulton TSR rear pivot

Post by ferrit worrier »

Hi Mick

I've just picked up on your tread here. is the overall length of the fitted bearings greater than the length of the pivot?
If not then leave the as they are and fit them.
Have you tried putting a feeler gauge in between the bearing face and the pivot plate thingummy to check the gap?

PS there's a Myford lathe sat here if you need 'owt :D

FW
Percussive maintainance, if it don't fit, hit it with the hammer.
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

HI FW! :D

The pivot system consists of two bronze bushes with a hollow steel sleeve between them.
The sleeve has a bar through it that is Allen at the head end, and threaded into the frame at the other end.
When tightened, the sleeve is solid into the front end of the bike.
The sleeve is a good fit into the bushes, so the rear end of the bike's frame pivots, and the grease lubrication system lubes it nicely.

Main design problem is that the bushes and the sleeve and the width and diameter of all this is way too small. It's the design that's wrong, and wrong completely, but I reckon that with frequent and thorough lubrication, it will survive.

The pivot I now have, is the original sleeve but with new bushes bought specifically for a Moulton TSR. The new sleeve I bought with the kit isn't required as it's only the bronze bushes that wear of course.

Meanwhile, I've bought new bushes from Simply Bearings for the future but they are a tiny bit too wide. Using a former and a drill and a file, they can be reduced to fit and I've proved it with experimentation.

Given the fact that I'm lubing this pivot loads of times, I think that the pivot will last and last and last.
Therefore, until this pivot wears, there is no input required other than shoving more and more grease into it.
Mick F. Cornwall
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

Just greased it again.

Renewed at 4,443miles 19 Jan 2018.
Greased ten times including today at 7,081miles.

New pivot bosses now done 2,638miles leaving 1,805miles left to do before it exceeds the original.
I am in no doubt whatsoever that it will do it ........ maybe even double .............. but it MUST be greased frequently.

Ten times in 20months = every couple of months.
Mick F. Cornwall
rogerzilla
Posts: 2887
Joined: 9 Jun 2008, 8:06pm

Re: Moulton TSR rear pivot

Post by rogerzilla »

I have deliquium's old TSR now. There is no play whatsoever in the rear triangle and I am pumping it with grease regularly. I did dismantle it once, just to have a look. I think it helps if you remove the four Torx screws from the Monosphere housing and work the triangle through a fuller range while greasing it.

Like the 2-to-1 pivot on a Gresley A3's valve gear, it isn't an inherently bad design but it is intolerant of lax maintenance.
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

rogerzilla wrote: ........ I think it helps if you remove the four Torx screws from the Monosphere housing and work the triangle through a fuller range while greasing it.
Excellent idea, and only a few minutes extra to do.
Mick F. Cornwall
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Moulton TSR rear pivot

Post by NATURAL ANKLING »

Hi,
Mick F wrote:Just greased it again.

Renewed at 4,443miles 19 Jan 2018.
Greased ten times including today at 7,081miles.

New pivot bosses now done 2,638miles leaving 1,805miles left to do before it exceeds the original.
I am in no doubt whatsoever that it will do it ........ maybe even double .............. but it MUST be greased frequently.

Ten times in 20months = every couple of months.

A bit like motor bikes then, but on motorbikes there is no design flaw, so no need to grease that often. They don't always have grease nipples so you need a strip down periodically.
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
speedsixdave
Posts: 868
Joined: 19 Apr 2007, 1:48pm
Location: Ashbourne, UK

Re: Moulton TSR rear pivot

Post by speedsixdave »

FWIW the improved pivot on my Jubilee (same as the SST I think) is self-lubricating, but I fight a constant battle against creaking. If the bolts are too loose the back end moves, if they're too tight the thing creaks. Sometimes the creak goes away for a month or so following loosening / tightening, but it keeps returning. Drives me slightly mad and is somewhat embarrassing.
Big wheels good, small wheels better.
Two saddles best!
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

How does it "self lubricate"?
Mick F. Cornwall
User avatar
squeaker
Posts: 4112
Joined: 12 Jan 2007, 11:43pm
Location: Sussex

Re: Moulton TSR rear pivot

Post by squeaker »

Mick F wrote:How does it "self lubricate"?
IIRC, the bearing material is a matrix of, essentially, hard porous bearing material with 'solid' lubricant in the pores.
"42"
User avatar
Mick F
Spambuster
Posts: 56359
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Moulton TSR rear pivot

Post by Mick F »

The bosses for the TSR are these ............. but they need a tiny bit of machining to reduce the length of the major diameter. Can be done by hand - which I will do, if and when they need replacing.
https://simplybearings.co.uk/shop/p1205 ... _info.html
These are "oil filled" just like the original TSR ones ............ that wear out if you don't grease the unit frequently enough.

Are these similar to the ones in the Jubilee and SST?
Mick F. Cornwall
Post Reply