Chain for 60s Moulton

[fausto99]

I have a non-compact 6 speed block on my repro Moulton Safari. I use an old 105 derailleur with a DT 6 speed indexed lever to shift. It all works well except that very occasionally the chain seems to ride on top of the teeth on the larger two sprocket of the block (24 and 28, I think) between shifts. I'm guessing that the chains I'm using are not wide enough. I can never get this to happen on the stand though, only on the road.

I was wondering if Mick F or any other Moulton riders had any thoughts on this.

Also, does anyone sell chains long enough to do the long Moulton run without having to buy two and join them?

[Brucey]

you don't say what kind of chain or freewheel you are using or how many chain links you need.

cheers

[iandriver]

Tandem specialists like JD tandems sell some 160 link chains. Perhaps worth an investigation.

[simonineaston]

Not very helpfully for you, I can't remember what I used to do about buying chains for my several F frame Moultons, amongst which is one with a fairly big chain wheel. This is my own Speed look-a-like, which I decided to fit with a souped-up SA hub while I fitted a spare rear fork with a six speed wheel ( say souped up, but actually all I did was strip it and rebuild it with high grade ball bearings!).
I've got a feeling that years ago, I found somewhere near me, here in Bristol that supplied chain by the length, ie you just told him how many links you wanted and he cut it off the reel... On the other hand, I might just be dreaming!

[PT1029]

One of the KMC distributors (Moore Large) offer to the trade workshop rolls of chains.
Back in the day Moulton Speedsixes/Safaris had then standard 3/32 chains. Flush rivets on chains were a thing of the future then, so a modern chain will be "narrower" due to the lack of protruding rivets. Catch 22, if you fit an old protruding rivet chain (to make it "wider"), it probably has the wrong amount of flex to work well with indexing.
Being in the ere of friction chains, back in the day the chain choice was quite simple, 3/32 or 3/32.
Is your 6 speed freewheel index compatible, or is it from the days before indexing? - in which case the sprocket spacing might be very slightly out.

[fausto99]

you don't say what kind of chain or freewheel you are using or how many chain links you need.

cheers

The freewheel is a Regina 5 speed with an extra cog drilled and bolted on to the inside (that was the most effective way of overhanging the SA AW hub it's mounted on). All the cog teeth are old-school; very straight and tall, very unlike modern cassette cogs.

Lately I've been using KMC 8 speed chains. I'll have to go and count links. I would guess about 120-125.

[Brucey]

IIRC regina sprockets sometimes have a groove in the top of every tooth. That was intended to help shifting with 3/32" chains back in the day but it can have the reverse effect with more modern chains. I suspect the chainline onto the #1 sprocket may be horrible; if so that won't help running either. A 6s freewheel is usually mounted onto a hub that is 126mm, and a compact 6 onto a hub that is 120mm wide; how wide is yours?

If the chain and shifting works OK on the workstand but not on the road, consider the possibility that the cables are moving with the rear suspension and this is causing the rear mech to move around (and/or the gear lever to 'pull back') as you go over bumps. If you can use SIS housing and not spiral wound stuff this will help. IME gear cable runs that move around (suspension or even frame flex) can cause endless trouble with pulling friction shifters (or even index shifters) back; the amount of friction required to resist this is sometimes very large indeed, enough to make shifting very unpleasant.

I would have said that KMC 8s chain ought to work OK on a compact 6s freewheel. Is it really a compact 6s one though? To have started with a 5s one and added a 6th sprocket, would the 5s one not have been standard spaced? I say this because I don't remember there being a 'compact 5s' freewheel, unless you made one by removing a small sprocket from a compact 6s one. In any event it is worth checking that the indexing is lining up with the sprockets OK; it is a good idea if you do this with the chain off in the first instance. If there is an error there, the error may be largest on the #2 sprocket, which might also explain the issues you have been seeing.

Re chain length, it is worth seeing if an LBS has a workshop roll of chain as others have suggested. However most of them use pre-cut chains these days, and KMC 8s ones are supplied (unpackaged) for this purpose too, often intended to be joined by pushing a rivet back in. If an LBS uses lots of these chains they will (or could have) have offcuts of chain and you can use these to extend the fixed length chains (116L is common) to get the size you want.

It isn't a brilliant idea to have two or three (potentially weaker) rejoined links in such a chain but it may be the easiest way to get the length you want. If you have an engineering bent you can probably improve the strength of the rejoined links by re-swaging the rivet heads of the rejoined links.

cheers

[fausto99]

Is it really a compact 6s one though?

No. It's "non-compact" as per the first sentence in the OP!! I've never heard of a compact 5 either.

Thanks for all the advice. I'll have to be on the look out for "wide" 3/32" chains, or at least wider shaped outer plates

I won't be able to do anything about the tooth grooves. I have to stick with Regina sprockets. The LBS where I got my supply of sprockets closed down long ago. I don't ride the Moulton that much, so I doubt I'll ever reach the stage of wanting to replace sprockets.

[Brucey]

non-compact... duh! I must pay more attention....

BTW one of the many mad things I have done is I have ground the tops of every tooth on an old freewheel (which took a while... it was about 240 separate grinding operations.... ) to give the freewheel a 'twist-tooth' effect. It did shift better afterwards. Maybe this would counteract the possible effect of the tooth top groove?

cheers

[Mick F]

I was wondering if Mick F or any other Moulton riders had any thoughts on this.

Also, does anyone sell chains long enough to do the long Moulton run without having to buy two and join them?

Sorry, missed this bit.

No thoughts at all regarding your chain widths, but what I do for the length is use two KMC Missing Links and three chain links between them. I need 118 links, and Campag chains like wot I use, only come in 114 links. I have plenty old Campag chains, so splitting three of them off is simple.

[fausto99]

BTW one of the many mad things I have done is I have ground the tops of every tooth on an old freewheel (which took a while... it was about 240 separate grinding operations.... ) to give the freewheel a 'twist-tooth' effect. It did shift better afterwards. Maybe this would counteract the possible effect of the tooth top groove?

Sounds like a job and a half!! I used to like the old twisted tooth Shimano freewheels. Maybe I'll give it a try when I've finished rebuilding my steel tourer ...and run out of other thing to do...

p.s. do you mean grinding on alternating sides from groove to outside or inside, every other tooth, OR, did you mean grinding at alternating angles, across the groove, to get a slight virtual "twist"?

[Brucey]

I ground a small triangular flat both sides of each tooth top, to give a virtual twist. The result was that of four corners of the original tooth top, two were removed and two were left intact. The tooth top that remained had almost a chisel edge: I guess starting with a grooved tooth, the finished article would have an 'M' shape to each tooth top.

I still have a similarly treated freewheel somewhere, if you like I can take a photo and post it.

cheers

[fausto99]

I still have a similarly treated freewheel somewhere, if you like I can take a photo and post it.

Yes please.That would be interesting.

[Brucey]

unmodified and modified teeth, as viewed from above

before and after

found a spare sprocket but not the freewheel itself....

cheers