Anyone know about Moulton F-frames?

[rogerzilla]

What's the wheel size (349?) and are spares easily available?  Pivot bolts and bushes seem easy but I don't know about front suspension.

[slope]

1960s F frames are 349. They will also take 369 (17") with modern DP calipers.

Just in case you fancy another project RZ? I have 2 excellent rust free Mark I F frames which are surplus to requirements - I had a notion a couple of years ago to 'modify' a 1964 Speed (not Speed 6) frame to 17" wheels, DP brakes, and 9 speed cassette! Before I fell out with small wheels and suspensions

[Socks]

Lots of information available through moultonbuzz.com.  There's also a Faceache group.  Worth joining the owners club for extra advice and information.  The f-frames can be complicated to service / repair, especially the suspension.  Worth doing though, they are lovely to ride.

[LittleWheelsandBig]

http://www.bicyclehub.co.uk/front-forks-renovation is a good guide to F-frame suspension overhaul. Instead of their method of stiffening the spring, I fitted a second abutment to boost preload.

Don’t fit 369 wheels. There are better/ faster 349 tyres and rims available. Be careful choosing replacement brakes as the reach and crank and suspension block clearances can be an issue.

Check Series 1 swingarms and F-frame fork crowns. Cracks can happen but a good look can save unexpected pain.

Double check seatpost size as there is some ‘factory tolerance’ there.

Moulton Preservation is temporarily shut, so some spare parts are more difficult to source but the BoA weekend is a week away and most bits can easily be sourced there. If you can’t get there, let me know what you want.

[Gattopardo]

I fancy another F as the two I had have disappeared...

[rogerzilla]

Can I ask stupid questions here?

1. Can the rear rack be removed or does it materially brace the seat tube?

2. Is there a good solution to missing or broken cable clips?  I can buy 10 NOS ones for £50 (!) but they will be almost aa brittle as the originals by now.

3. What does serial number 853165 suggest in terms of date?

[robgul]

Can I ask stupid questions here?

1. Can the rear rack be removed or does it materially brace the seat tube?

2. Is there a good solution to missing or broken cable clips?  I can buy 10 NOS ones for £50 (!) but they will be almost aa brittle as the originals by now.

3. What does serial number 853165 suggest in terms of date?

1 The rack is just fixed to the frame, not structural - BUT the bike looks ugly without it, a tube stick out at the back!

3 There is a book by Tony Hadland about Moultons (I may have a copy if I hunt around for it) which, IIRC, tells you how to interpret the frame number into year, location of manufacture etc (again IIRC a lot were made in a washing machine factory in Kirkby, Liverpool) 

I assume you've come across the Moulton Club, or whatever it's called? - a wealth of info.   LWAB of this parish is the man to ask for Moulton info.

[rogerzilla]

That tube stuck out the back is just begging for a tail light on the end!

[LittleWheelsandBig]

"Can I ask stupid questions here?"
Who better and where better to ask stupid questions?

"Can the rear rack be removed or does it materially brace the seat tube?"
Both. The F-frame was designed without the brace down to the suspension block but the brace was added after a few early frames folded when kids were doubled on the rack. That thin brace can buckle under severe compressive loading but obviously has to add additional strength.

The Speedsix had a removeable rack and removeable carrier beam (from just behind the seat tube) and they held up without issue, even when the seat tube ovalisation was transverse. Your frame's seat tube is ovalised fore-and-aft, so better resists your weight cranking the seat tube backwards. Some very tall and heavy folk who have trimmed off a normal F-frame's rack have bent the seat tube back, particularly if they have trimmed the carrier beam very close to the seat tube and not plugged the hole structurally.

"Is there a good solution to missing or broken cable clips?  I can buy 10 NOS ones for £50 (!) but they will be almost aa brittle as the originals by now."
There were a couple of types of replica cable clips made by Paul Grogan, available from Moulton Preservation. Don't buy NOS (brittle, obviously) but it is possible that they are selling some of those replicas. I will pick up a bag of cable clips at BoA for you, if they are available. There were traditionally also some push-in Land-Rover(?) clips that were a bit big but serviceable.

"What does serial number 853165 suggest in terms of date"
From vague memory (and no better than that, until I eventually check a reference book), frame number 85 of week 31 of 1965. I thought your Moulton was newer than that. The number on the SA hub should put you in the right ballpark.

[robgul]

That tube stuck out the back is just begging for a tail light on the end!

Or a flare/flame-thrower operated from a button on the handlebars 

[rogerzilla]

Hub is 11/65 so that fits.  Fairly early Series 2, then.

There's about a degree of rotational lash in the steering.  Is it correct that this can be fixed by repositioning the splines on reassembly, or is it worth replacing anything?

Plan is to strip it, get the frameset powdercoated (did they come in any colour other than blue?  Metallic red?  I don't like the blue) coat all the heavy chrome bits in vaseline and store them away in case anyone wants to do an authentic resto in future.  Then replace with alloy bits where possible.  I have another mint FW hub I built for a 4-speed Brompton idea years ago, but it was never very successful.

I have ordered a lot of Plus Gas and a super-long Philips no.2 screwdriver 

It rides, but it feels as if it really needs a complete overhaul rather than an adjustment.  Clunks aside, the front suspension is much better than the TSR's.  The TSR friction damping overlooks the fact that static friction is higher than sliding friction, so it will always start moving with a bit of a pop.

[LittleWheelsandBig]

Turn the splined fork bush 90 degrees. They only wear fore-and-aft. They have to be pretty bad to need replacement.

[rogerzilla]

Fork top screw moves without any trouble.  Phew.  It might not be a Kirkby-made dog!

[Socks]

I have had a few f - frames powder coated, it's worked well and even on one that I commuted to work throughout the year seems to provide a long lasting finish.

You'll need to make sure they don't get any powder coating on the fork splines, as well as blanking off the usual places (bottom bracket, mudguard eyes).

A bit of molyslip grease on the spring, splines and that bit of plastic at the top is a good idea before re - assembly.

[rogerzilla]

Now reduced to a pile of parts for the powdercoaters.  Just need to get the remains of the rivets out of the swingarm.  The only things that were really seized were the stay-to-mudguard bolts, but they're all out now.  I really wanted to save the original reflector but the rust has eaten its bolt down to a pointy stump.  The forks hadn't been apart before but most of the rest had.  Even the cotter pins were trivially easy.  Plus Gas was used a lot.

The rubber parts all look fine.  A new s/s suspension plate would make the bottom end look better but I'm not sure how to de-bond the old one.  Any ideas?  Also, am I stuck with the factory headset or can the crown race be removed?

[LittleWheelsandBig]

The bottom half of the headset uses unique dimensions but the top half is normal. I pulled the crown race when I painted my Stowaway many years ago.

I’ve never seen a SS plate on a suspension block and usually a debonded block is a bin job.

[rogerzilla]

They're definitely sold but maybe you have to wait until it debonds to take advantage.

Today's stupid question: what thread are the mudguard eyes and also the three self-tappers that hold the suspension block in place? 

[slope]

Today's stupid question: what thread are the mudguard eyes and also the three self-tappers that hold the suspension block in place?

On my Kirkby 1964 Speed frame they're 2BA bolts and not self tappers as such. But that seems to be "unusual" - as in standards weren't always "standard"?

EDIT: See below GavinC - that's more authoratitve

[GavinC]

On my ‘65 Deluxe they are 2ba bolts for the mudguards and 2ba self tappers for suspension block.

[rogerzilla]

Thanks - 2BA self tappers seem to be unobtanium.  Two of the screws are stainless replacements so are presumably no. something.

Latest question: are the metal bits glued to the rear suspension block galvanised?  I just need to know what primer to use.  Hammerite only sticks to ungalvanised iron or steel.

[rogerzilla]

Definitely galvanised.  I think I'll just do it with cold galvanising paint after I've finished cleaning it up.  This is after a few goes with oxalic acid.

20210911_135333 by rogerzilla, on Flickr

And I did save the original Fairylites reflector in the end.  There is enough thread on the bolt after filing off the corroded stump.  It's a very bright reflector, up there with the B&M Z-reflectors.  There was a piece of white waxed paper behind the red lens which was stained and useless, so I substituted a piece of white plastic from a cosmetics tube.

20210911_151729 by rogerzilla, on Flickr

[CarlF]

Thanks - 2BA self tappers seem to be unobtanium.  Two of the screws are stainless replacements so are presumably no. something.

I don't understand how self-tapping screws are sized, and I'm a bit sketchy on Imperial thread sizing too, so I did some idle browsing to try and learn.

Following which, I am wondering if there was ever such a thing as a 2BA self-tapper? Isn't 2BA strictly a machine screw size?

British self-tappers in inch sizes seem to have been defined in BS4174, and those are available all over the place.

Or was there more than one standard and only one is still in any sort of use?

[rogerzilla]

Major diameter of the original and replacement is 4.70mm, so no.10 self-tappers.  Same as 2BA!

[rogerzilla]

Found that a Kalloy quill adaptor (alloy wedge) and a 90mm Bontrager oversize stem are lighter than the 90mm quill stem I was going to use.  So 31.8mm white dropped bars and stem to match the white rear carrier.

I think the suspension block will look better if the metal plates are painted black over the zinc primer.  Also easy to touch up after re-riveting and panel-beating back into shape.  They have to be bent to get them off the rear trailing arm.

[aidan.f]

If you need a 2BA tap I can post you one. I think all my 2 BA set screws have gone in the 'never going to need them before I die bin' . So why did I keep the tap?