Folding Bikes - Moulton 64 F-Frame rear flex question.

I just received a 64 Moulton F frame which I got off eBay. http://www.bikeforums.net/showthread.php?t=569835 The bike seems to be in pretty good condition but I have not put it back together yet. I noticed that by hand I cannot flex the rear forks. I do not know if they are frozen or it just takes a lot of force. I can flex the front fork by hand. Disassembly of the rear forks looks like it may be somewhat tricky but I will do it if that is what has to be. The only thing I can see that provides the flex is about 3/4" solid thick piece of black nylon so it may just flex less hard. The front fork I think uses springs inside fork support or head tube.

Currently I am cleaning it up a bit before I reassemble.

Anyone have one of these that knows?

I know its not a folder but it does have 16" wheels.

You should be able to flex the rear suspension easily. It probably just needs some lubrication.

The Moulton Bicycle Club has some info on F-frame front and rear suspensions. Check under the "Tech Topics" heading:

http://www.moultoneers.info/

The Yahoo forum below has lots of discussion on new and old Moultons. Many of the members ride and restore older F-frames.

http://groups.yahoo.com/group/moultonbicycle/

The rear forks are a very simple design, there is only a block of rubber that is used as suspension.

If I understand correctly, the rear forks are attached to the frame, but the bike is not fully built up yet? Maybe you will get a better idea once you have the bike put together and are able to put some weight on the saddle?

One of the F frames that we recently bought had bent front forks so I replaced them with a spare set. It was a bit awkward the first time we stripped the suspension (to fit the forks) as the exploded view illustration I was working from didn’t show the exact placement of the parts.... but now we know what we are doing it is a lot easier.

While you have the bike stripped, it is worth taking out the metal and rubber spring to grease it.
http://www.tomkiss.net/images/uploads/2008/09/steering_column_assembly.jpg all you need to do is taken out the “Brake Bush & Spring Abutment” and the spring should come out. It is under pressure so take care!

If you find there is wear in the front suspension I can talk you through a total strip step by step, including how to deal with the “Rebound Stop Retaining Screw” that will very likely be seized.

Hopefully people will not object to small wheeled Moultons on this section of the forum.:)

congrats!! hope the rear supsension is working good.... any updates? how much did your moulton go for?

congrats!! hope the rear supsension is working good.... any updates? how much did your moulton go for?

It will probably take a week or so before I have it together. The price is in the link at top of the message.

PDR, is there any likelyhood or anything that would cause rear forks to freeze? They appear from the outside to be in good condition. The nlyon seems seems stiff.

Have you seen a parts diagram of the rear fork on the net?

Yeah I saw it on the bay before igot mine, thk god we didn't together. Mine had a sniper @ the end

I loosened the rear fork bolts and get some flex now by hand. In looking at the design I think the rear suspension works as much by deflection from shear as it does in rotation. Something that I can confirm really by just riding it.

I loosened the rear fork bolts and get some flex now by hand. In looking at the design I think the rear suspension works as much by deflection from shear as it does in rotation. Something that I can confirm really by just riding it.

So would you say its simple, and works ?

So would you say its simple, and works ?


From what I can tell with it in the stand and stripped down (no wheelss on yet). I may or oil the bolt that the forks pivot from.

Looks simple on the outside but I am not sure what is inside that why I would like to see a schematic parts break down.

If you join the Moulton Yahoo Group there are photos of old published info on the various different models. I found a couple for you on flicker.
http://www.flickr.com/photos/bikerescue/2859813356/in/pool-moulton_bicycle
http://www.flickr.com/photos/bikerescue/2858984207/in/pool-moulton_bicycle




http://www.flickr.com/photos/57997293@N00/826267319/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826267419/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826267435/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826267533/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826267567/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826267575/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826314097/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826314131/in/pool-moulton_bicycle
http://www.flickr.com/photos/57997293@N00/826516093/in/pool-moulton_bicycle

I did see the other night a cut-away photo of the rear end of an F-frame which shows how the suspension is constructed... but I can’t spot it now searching the thumbnail images.

PDR (or others who may know)

See in this cutaway. That the fork axel fits into a tube that runs through the tubes on the chain stays.
http://www.flickr.com/photos/57997293@N00/826267533/sizes/l/in/pool-32268695@N00/

Does the fork pivot on this tube or the axel bolt?

PDR (or others who may know)

See in this cutaway. That the fork axel fits into a tube that runs through the tubes on the chain stays.
http://www.flickr.com/photos/57997293@N00/826267533/sizes/l/in/pool-32268695@N00/

Does the fork pivot on this tube or the axel bolt?

hey bro! PDR is giving us some nice pics! ive seen many people on the net asking for this diagrams :love: and here they are!

as for your question im gonna wait for PDR, cause right now you know more than me about Moultons, im still waiting for the mail :thumb:

http://www.moultoneers.info/bikes/moultons-on-ebay/

The rear suspension is very simple...but it may not move as much as you are expecting?....sporting models even had friction dampers to stiffen it up!.....It does work though...ken