Moulton TSR rear pivot

[Mick F]

The parts arrived fifteen minutes ago, and they are now fitted.

I must say, that feeling the bosses on the sleeve whilst in my hands, they felt a little disappointingly loose. However, after fitting them into the frame, the sleeve is very tight indeed. In fact, I thought it was jammed and used a drift to drive it out and then back in again to make sure all was well. All is well, thank goodness!

It feels very taught and should build into a taught suspension pivot. This will have to wait a couple of days, as I'm busy all day tomorrow, but not too busy to buy a grease gun.

I measured the new sleeve with my micrometers, and it is 1.5thou less than the nominal half inch. The old sleeve is 2.5thou less than half an inch on the ends, though the middle is fine of course.

[deliquium]

The parts arrived fifteen minutes ago, and they are now fitted.

I must say, that feeling the bosses on the sleeve whilst in my hands, they felt a little disappointingly loose. However, after fitting them into the frame, the sleeve is very tight indeed. In fact, I thought it was jammed and used a drift to drive it out and then back in again to make sure all was well. All is well, thank goodness!

It feels very taught and should build into a taught suspension pivot. This will have to wait a couple of days, as I'm busy all day tomorrow, but not too busy to buy a grease gun.

I measured the new sleeve with my micrometers, and it is 1.5thou less than the nominal half inch. The old sleeve is 2.5thou less than half an inch on the ends, though the middle is fine of course.

Goodo Where did you get the kit from Mick? And how much?

[Mick F]

Goodo Where did you get the kit from Mick? And how much?

Avon Valley Cycles.
I emailed them, then ordered by telephone.

Hi Mick, we do indeed £29.99 for the bushes x2, pivot bolt x1 and crimp washer x1.
if you'd like to order one drop us a line on 01225442442 and we can get one despatched for you.
Postage £3.99 mainland uk.
Best regards
Luke
e: shop@avonvalleycyclery.co.uk | t: 01225 442 442 | f: 01225 446 267
Avon Valley Cyclery | Brunel Square | Bath | BA1 1SX
http://www.avonvalleycyclery.co.uk

£29.99 plus a cable splitter for £9.99 is tuppence short of free postage, so I bought a gear cable for £3.99
Total bill £43.97

Ordered on Monday afternoon, arrived this afternoon.

Had I gone to Fudges, the pivot kit was £50ish and the cable splitter £15ish.

[Brucey]

....and there was no spring in there!
Dunno if there should be one, as there's nowhere for one to go.
The only "spring" could be the rubber seal.....

I think like you say the rubber seal is meant to be a bit springy in your chuck. Maybe it has worn a bit, or shrunk, or something. Typically once there is a fair bit of pressure, the pressure helps the sealing by deforming the rubber part.

Possibly you can make the thing a tight fit again by

a) grinding the three jaws a bit shorter on the back and
b) shortening the nose housing slightly.

All a little academic if you are getting a new grease gun anyway. You get several chucks with that kit; if they are any good then it is worth it just for those....

cheers

[Brucey]

.... feeling the bosses on the sleeve whilst in my hands, they felt a little disappointingly loose. However, after fitting them into the frame, the sleeve is very tight indeed...

the bushes will deform slightly if they are any kind of press fit into the frame, which I think is why Brompton recommend that their bushes are reamed in situ as part of the fitting process.

cheers

[rjb]

....and there was no spring in there!
Dunno if there should be one, as there's nowhere for one to go.
The only "spring" could be the rubber seal.....

I think like you say the rubber seal is meant to be a bit springy in your chuck. Maybe it has worn a bit, or shrunk, or something. Typically once there is a fair bit of pressure, the pressure helps the sealing by deforming the rubber part.

Possibly you can make the thing a tight fit again by

a) grinding the three jaws a bit shorter on the back and
b) shortening the nose housing slightly.

All a little academic if you are getting a new grease gun anyway. You get several chucks with that kit; if they are any good then it is worth it just for those....

cheers

Sometimes the jaws in the connector chuck are reversible, so you can make it like new again. Interesting video here. https://m.youtube.com/watch?v=m_v0ptMU0DI

It reminded me about connecting and disconnecting the chuck at an angle to the nipple not inline. BTW the tecalemit chuck also has an internal spring as well as a seal on the chuck.

[squeaker]

...the bushes will deform slightly if they are any kind of press fit into the frame, which I think is why Brompton recommend that their bushes are reamed in situ as part of the fitting process.

Looking on the bright(?) side is there now a risk that the bushes will be forced to rotate in the frame housing?

[Mick F]

Just a quickie.
Been out most of the day, and I'm only home for an hour before going out again shortly.

Whilst out, I called in at Screwfix for the grease gun, but they don't have them in stock and you have to order them.
Unperturbed, I went off to Machine Mart and bought a better grease gun and a cartridge of grease.

Just got home and poured myself a beer whilst taking the gun out of the box, assembling it and priming it, then offered it up to the nipple ................ good God it was a tight fit, and so tight, it was a devil to take off!

The frame is in the stand upside down without the rear triangle on. I connected up and pumped ...........................

After four or five pumps, there was a weep of grease showing, and after a two or three more, the bushes started moving out!
I had to take out the sleeve and tap them back in with a soft mallet.

Moral of this, is to connect the rear triangle before pumping grease in there.
That's a tomorrow job.

This is the grease gun. I'll give a report on it on the Grease Gun thread possibly later this evening.
https://www.machinemart.co.uk/p/cgg400- ... rease-gun/

[Mick F]

Right ........... done it.
Assembled and greased.

Frame upside down in the workstand clamped solidly onto the seat tube.
The rear triangle went on easily enough and the self tappers fitted into the rear cone. Then I connected up my new grease gun.

I pumped a few strokes, then hit a brick wall of pressure. I squeezed as hard as I could, and it seemed to me that there was hydraulic lock. By gritting my teeth and resting the the gun on my shoulder then using two hands on the lever, and squeezing for all I was worth, I saw the tell-tale signs of grease weeping out the sides. It hurt, TBH, and wasn't a job that I'd like to do again ............... but I must, and from what I've learned, it needs doing regularly.

I had planned on greasing the pivot each time I cleaned the bike because I expected it to be a two minute job, but I think I'll be doing it every month or two upside down in the workstand. Hopefully, the pivot will wear in a bit and it'll be easier as time goes on ................. but not too worn and too easy of course.

[Mick F]

Moulton fully assembled.
There is now zero play in the pivot.
I will check this weekly(?) and if I find any at all, I'll be buying new bushes from Simply Bearings. Maybe replace them annually(?) as the cost isn't so much if you buy the bushes separately. The sleeve won't last forever, but if the bushes are changed before there's too much wear, it could last for years.
https://simplybearings.co.uk/shop/p1205 ... _info.html

Test ride later, or more likely tomorrow.

[Brucey]

Right ........... done it.
Assembled and greased.

...I pumped a few strokes, then hit a brick wall of pressure. I squeezed as hard as I could, and it seemed to me that there was hydraulic lock. By gritting my teeth and resting the the gun on my shoulder then using two hands on the lever, and squeezing for all I was worth, I saw the tell-tale signs of grease weeping out the sides. It hurt, TBH, and wasn't a job that I'd like to do again....

It might be that your grease gun is not one that easily develops very high pressures (*). It might be that the clearance in the new bushing is really very small indeed. As you say it may well ease itself with use.

BTW if you can articulate the pivot whilst greasing it (which would probably require that you disconnect the rear suspension sphere temporarily) then the shearing action in the grease film may allow the grease to flow through the bushing more easily, at a lower pressure.

(*) some posh grease guns come fitted with a pressure gauge; this can tell you if the delivery pressure is so high that something (e.g. the nipple) must be clogged, or avoid damage to a vulnerable (but clogged) assembly through overpressure. Some grease guns develop pressures that are so high you can break stuff with them.

cheers

[deliquium]

Right ........... done it.
Assembled and greased.

What grease did you use Mick? I've got a tub of lith-moly at the ready.

Moulton fully assembled.
There is now zero play in the pivot.
I will check this weekly(?) and if I find any at all, I'll be buying new bushes from Simply Bearings. Maybe replace them annually(?) as the cost isn't so much if you buy the bushes separately. The sleeve won't last forever, but if the bushes are changed before there's too much wear, it could last for years.
https://simplybearings.co.uk/shop/p1205 ... _info.html

I'm thinking along the same lines

Having to wait at least until the end of next week for my 'kit'. Looks like you bought the last from AVC's stock. Ordered mine form Cyclesense in Tadcaster - slightly more at £42 inc post, but a lot less than Fudges at £48 + £7.99 postage

[Mick F]

Right ........... done it.
Assembled and greased.

What grease did you use Mick? I've got a tub of lith-moly at the ready.

I have partial tub of Duckams multi-purpose grease that I've used for most things over the years. I reckon that had I filled a new grease gun with it, I'd only have half filled it, so I thought I'd buy new for the gun.

The Clarkes gun will take a cartridge, so in for a penny, in for a pound, I bought a Clarkes cartridge to suit. It was simple and easy and far easier than trying to get grease in manually.

This is the stuff I bought.
https://www.machinemart.co.uk/p/400g-mu ... cartridge/
From what I remember from the label ............ I'm not taking it out to check! ............ it had EP additives and was lithium based and ideal for wheel bearings, suspension and chassis. It seemed ok for what I wanted it for, and I expect to inject the stuff as often as I feel I can do it.

[Brucey]

in fairness if you have one grease gun that you intend to use for several different applications, it makes sense to use a single multi-purpose grease in it. And like you say, I agree that regular greasing (with anything) is better than infrequent greasing. But if you intend to use this grease gun on this pivot and nothing that is built differently (or other stuff that will be more tolerant of variations in lubricant) you could well be better off using something else.

Multi-purpose greases that are suitable for car wheel bearings typically have specifications that are dominated by the need to work OK at several thousand rpm, and at relatively high temperatures. They are prohibited from having solid lubricants in any useful quantity (because they cause troubles in high speed rolling element bearings) and they have little need of anti-corrosion additives. All of which means that such greases may be adequate for bicycle use in many cases, but are far from optimum for such purposes.

If choosing a grease for suspension pivots I would probably choose a grease with a high content of solid lubricants and that has a good amount of anti-corrosion additives too. You will know if it has enough of the former because it will probably say that it is not suitable for car wheel bearings... . Such greases work OK (arguably better than most) in rolling element bearings too, provided they are relatively low speed as per bicycle use.

cheers

[PDQ Mobile]

MBS2 or Graphite?