Moulton TSR rear pivot

[Mick F]

Hi Mick, the first fudges link was for £12

That's just for the bolt I reckon.
A quids worth of M8 for £12.

[PDQ Mobile]

A gentler extraction method might be a length threaded bar or a long bolt with appropriate spacers and washers.
I guess it depends how tight it is.
If if very tight then some sort of press is usually better than "percussion".

Is it not worth asking Moulton for at least the bits under warranty?

[Mick F]

I don't know.
I bought the bike in March 2016, so it's nearly two years old. I would think they'd want the bike back to fix it themselves under any warranty. That sounds like too much trouble to me.

I had nothing to lose, so I knocked them out. I damaged the inner faces a bit, but they could easily be put back without issue as you can tap them in.

Looking and feeling, it's the bronze that's worn. The steel sleeve seems fine. I may have a go with a micrometer later to see if it's worn. The bearings are only on the outer ends so the inside portion should be as original.

[PDQ Mobile]

Those flanges make pressing them out a bit more tricky anyway.
Hope you get it fixed.

It might be worth asking Moulton all the same.
Tell 'em you'll give 'em a bad press!!

[Mick F]

Tell 'em you'll give 'em a bad press!!

Don't tempt me!

Just had a quick measure with my Imperial one inch micrometer. Actually, it belonged to my late father-in-law who was a fitter and turner in his younger days.

There's half a thou difference between the middle and one end, and a tiny bit more than half a thou at the other.
Moving the bushes to the middle, they are still loose, so both the sleeve and the bushes need renewing.

[deliquium]

Following this post with interest. My TSR was bought in April 2016 and has covered 5473 miles. Last summer it developed a creak when pedaling hard up hill. It took a frustratingly long time to pin point - to the pivot bolt/sleeve/bush assembly. I purchased a small CLARKE CGG120 Grease Gun and a tub of CV Lith-moly goo. After a good few squirts on the pivot housing's nipple, the creak thankfully disappeared.

Just checked the TSR and can't see or feel any play at the moment, but will pay much more frequent attention to it now.

Thanks Mick for the AVC heads up re a new pivot assembly for considerably less than Fudges' price and whopping postage charges

[Mick F]

Good luck with the grease gun.
It's the lack of a decent film of lube that's the issue.

The nipple isn't the correct type IMHO to allow a good seal to get a high pressure injection. Also I think you need a good quality grease gun. Mine blows off when I squeeze really hard. I think it needs a positive lock-on for the gun/nipple rather than a push-on.

You need high pressure to get any lube at all between the bronze and the steel as the fit is very very accurate. Unless they are greased thoroughly, they will wear.

Mine was greased ok, but obviously not enough. If I could have forced lube in through the nipple hard enough to get grease to come out the sides, I reckon the bearing faces wouldn't wear. If you can get it in like that, and do it weekly(?) it'll last forever I reckon.

I wonder if I could inject oil instead of grease?
That could be easier perhaps.

[PDQ Mobile]

It's just a thought (for next time) but what about "upgrading" it to a pair of high quality needle bearings?

[cromo]

I know nothing about Moulton bicycles and I am assuming that the bronze bush is plain inside. So, I was wondering if the bronze bush had grooves in it, running in the same direction as the sleeve, then would those grooves allow grease to reach the bearing surfaces more efficiently. Grooves could be added using a thin needle file? I know that classic minis used bronze bushes on the rear suspension, these had grooves and were lubricated with grease.

[deliquium]

Good luck with the grease gun.
It's the lack of a decent film of lube that's the issue.

The nipple isn't the correct type IMHO to allow a good seal to get a high pressure injection. Also I think you need a good quality grease gun. Mine blows off when I squeeze really hard. I think it needs a positive lock-on for the gun/nipple rather than a push-on.

You need high pressure to get any lube at all between the bronze and the steel as the fit is very very accurate. Unless they are greased thoroughly, they will wear.

Mine was greased ok, but obviously not enough. If I could have forced lube in through the nipple hard enough to get grease to come out the sides, I reckon the bearing faces wouldn't wear. If you can get it in like that, and do it weekly(?) it'll last forever I reckon.

I wonder if I could inject oil instead of grease?
That could be easier perhaps.

I must say I wasn't impressed with the quality of the grease gun or its connection, nor at all convinced there was enough grease getting to where it's needed. There certainly wasn't any coming out at the end of the sleeve. I was just pleased the creak had disappeared.

Now, after your experience and what fossala mentioned, greater attention and thought needs to be applied.

Do you think regular stripping and lubing by hand is the best method?

[Mick F]

I was (and still am, I suppose) a Mini fan. We've had nine of them over the years.
Two vans, two estates, and five saloons.
The rear suspension arm had needle rollers at one end and a plain bronze one at the other. New, they had to be reamed out with a special reamer tool to match the steel suspension pivot shaft. Grease nipple on the outside end.
Last pair I bought went to local garage that used to be a BMC franchise, so they still had the special tools to ream them out.

The Moulton rear suspension does indeed have plain bushes, and no doubt the bushes and the shaft are a matched reamed set because they have to be that accurate I reckon. Getting lubrication in between the shaft and bosses is a big problem, so slotted bosses would help. You wouldn't need such high pressure to inject the grease.

I know that when I get the new parts, they'll be getting as much lube as I can get in there, and TBH I'll be checking it regularly.
One thing that gets to me though, is that in order to remove the rear triangle, you have to undo the rear suspension cone securing screws and these are cheap and nasty self tappers. Ok, they're stainless, but still only self tappers. If I were to remove the rear triangle regularly, the self tapped holes would give up.

Still, regular stripping, cleaning and lubing must be the way forward ................... or spend £30 every eighteen months on new parts.

[Mick F]

Not mine, but a sample photo.
You can see the suspension pivot and the suspension cone and self tappers.

[NATURAL ANKLING]

Hi,
On motorcycles they use plastic bushes greased on a steel collar, the bushes wear the steel, the design worked well, no bronze.
Some have grease nipples, most have sealing thrust washers.
Most if not all are mounted in the swinging arm not the frame.
Small M/cycles use rubber bushes still mounted in the swinging arm.
Larger M/cycles some times use a ball on left and a needle on right drive side.
Some use double needle bearings, but need good thrust support (thrust on swinging arms still need a bearing ideally) and all sealed thrust washers.
Some use opposed taper rollers still mounted in the swinging arm, especially shaft drive bikes.

I have several rear suspension through away cheap bicycles, they all use large plastic bushes, and also have recessed bolts which is part compactness and part a fail safe in slopp, none appear to have been greased, their past life may have been limited also.
They are still mounted in the frame and this is because there is a lack of length between the crank arms.

The Moulten design is poor, with little length in the bush and small diameter, slopp will be exaggerated because of the design.
I would favour a larger plastic bush with increased length and recessed bolting to give full length / rubber design, needle rollers are a bit of overkill and need precise machining, without a good thrust design you need good sealing of moving parts.
Any bronze bush normally needs in line reaming to give best fit.
If the bearing has sealing (rubber lips) washers, this would eliminate the need for grease nipples.

Cheap skimping and nasty is words to describe the design of an expensive road going machine.

[reohn2]

Hi,

The Moulten design is poor,.........

...........Cheap skimping and nasty is words to describe the design of an expensive road going machine.

Throughout this thread I thought the same and THB, this and other Moulton threads have lead me to think I wouldn't touch one with a bargepole(sorry Mick,and other Moulton owners)they seem to have more than their fair share of bad design on them.The suspension design seeming to be the main in problem but there are others Mick has suffered in his two short years of ownership,and I must thank him for being honest about them.

IME small wheels don't ride as well as their bigger counterparts but bigger tyres iron out a lot of that problem,adding suspension to bicycles that aren't being used on really rough surfaces will always be a compromise because of weight issues and is one reason I've steered clear of suspension.
5k mile and 2years use by someone who meticulously maintains his machines isn't good enough IMHO.

I'm sorry to be so negative but it really isn't good enough and as N.A. posts it's a very poor show for a bike costing £2K,very poor indeed IMHO

[Brucey]

FWIW the Mk1 and Mk2 moultons used plastic bushes and a steel sleeve. These also wear (but probably tolerate lack of grease better), and (unless large diameter) probably are not stiff enough for use in a URT pivot.

I'd guess that there are enough steep hills where Mick rides to ensure that the loads on the pivot bearings have been much higher than they would be on flatter roads. Any 'bobbing' whilst climbing would have ensured that peak load would have coincided with suspension movement, too. These bushings don't last forever regardless, but any small problem would have lead to greatly accelerated wear.

BTW (smaller IIRC) bushings of a similar type are used in Bromptons. It is recommended that these are reamed in situ so that the bushings are exactly square to the sleeve.

When the pivot bushings clap out on my ATB, I plan to ream in situ to slightly larger size, and to make a new sleeve that matches the new diameter properly. BTW when my ATB came to me, the pivot bushings were completely seized, through lack of grease/maintenance. Not sure if the rear suspension had actually been moving!

cheers