Folding Bikes - Modded R20's are old news, let's talk Hotrod F Frame Moultons

The thread about the spaceframe Moulton (slaver, drool) reminded me of something I'd almost forgotten; the fact that I have two Moulton Mini's sitting in the back of my garage. I got the pair for £8, the gold one (a 3 speed, if memory serves, though I suppose it might be 4) is useable, but the rack is broken. The other is covered in stickers, and is in need of a complete strip down, but still has the rack. I'm thinking that when I'm done with my 20, (and perhaps I've completed a couple of other projects that are half done), I'll turn my attention to these. Having checked, it seems they run the same rim size as Brompton, so rims and tyres are readily available.

I though I might build the one with the rack still on it into a reasonably faithful but mildly warmed over restoration. I'm thinking a respray, alloy rims (I can't remember if they have alloy or steel at present), a Brooks, but perhaps replacing the AW with an FW four speed, or even one of those twin chain 5 speeds. This would be a period appropriate upgrade, but give it a bit more useability.

With the gold one, I'm thinking maybe I'd just clean it up, and build it into some sort of speed machine. It's already lost weight by losing the rack, and is never going to be "perfect" because of that. I'm tempted to imagine fixed gear, but I suppose a derailleur system could work. That, and Schwalbe Stelvios perhaps. I can't think of a reason I'd need either of these bikes, really, but they could be fun. Anyone got any experience?

Sammyboy,
Ouch, that title hurts......especially since I recently missed out on a F frame on eBay by only a few dollars.
Why stop at a 4 spd hub.....get a Rohloff

Hahahaha - well, the reasons are twofold. 1) They cost a bleedin' packet, and the bike only cost £4, really. 2) It doesn't fit with my idea of a period appropriate upgrade......


What about my speed model though. I have a nice Dura Ace rear mech with drilled jockey wheels, whaddya reckon? And drop bars maybe......

8 quid :eek: !!!

Nice 1 - the gold one still looks modern, ditch the mudguards and start pimping.
I got rid of my last F frame a few years ago (before bitten by the folding bug) .. dang !!

Sammyboy

This my Moulton F frame.
I was looking for a twenty but got this instead.
Suspension is good, lots of info on the web and parts available.
Well worth the effort.
Integrated racks, low centre of gravity of load, low step over height and I will say it again Suspension!!
They are a bargain for doing a 'Hotrod'.

Edd

How do you find it running a derailleur rig on that? And what sort of ratios do you have on the back? Also looks like you've put in a cotterless crank, I assume it's a standard BB (I've had these things for a couple of years, and haven't got round to finding anything like that out yet!). I've ridden the gold one a fair bit, and I'm quite impressed.

I have a Sram dual drive with 52 tooth front chain ring and 355 wheels. Its been awhile since I rebuilt the bike and I can't remember the actual gearing. I replaced the bottom bracket which was a *** unit (68/110 but my chain line is not perfect) and replaced it with one I got from a local frame builder. The cranks are Tru Ativ Touro, has a two chainrings, I wasn't sure which I would need so I put both on. If you have a 4 speed SA I would stick with it, it was a fair bit of work to spread the rear forks and weld on the hanger etc. My wife as an F frame with a four speed SA and it goes very well.

Edd

One has a 3 or 4 speed (I can't remember, and they're right at the back of the garage, behind around 20 other bikes), but the other is single speed. That'd be the one to go to derailleurs with. I have a set of Shimano 7 speed cassette hubs around, and I'd probably use an old-fashioned claw hanger (of which I also have several) rather than try to braze or weld anything on. My main concern is getting high enough gearing! An SRAM dual drive is waaaay out of my price range, unless I could find one supercheap on the Bay, and I'm just wondering whether I could get sensible gearing with a 52 tooth chainring - I suspect what I have on there is considerably more.

A quick look at Sheldon's gear kwakulater indicates that 52 x 14 on a 16 inch wheel is a mere 59.7 gear inches, which is Italian for Not Enough. Even 60 x 13 only gets you to 74.2

If I could bodge a 5 speed freewheel onto an SA AW, which Sheldon has done, we're up to 79.6 for 52x14. Assuming that, as I suspect, the chainrings I have are 60 tooth, if I don't go to cotterless I can get 91.6 gear inches that way, with 30.1 on the bottom end, which is quite useable.

Edd - your Moulton is rocking! Any chance of sharing some more pictures?
Sammy: What about a Carpreo 9 speed gruppo? Little wheels aren't too happy with standard derailleurs..

Darnit this thread has got me wanting one (again) now! [fires up ebay]

The more I look at this, the more it's got to be internal hubs all the way. The only way either is gonna get a derailleur is if I can tackle Sheldon's "mount a freewheel to an AW" thing, which frankly looks quite tough.

I've reworked a few '60s Moultons - 2 drop-bar SA 8sp conversions and a drop-bar Duomatic Stowaway (now fitted with 56 x 13 fixed wheel). A few tips:
- SA 8sp hubs are a good match for small wheels, using normal chainrings gives about 100" top gear and don't require widening the rear fork.
- The wheel of a Moulton is closer to the nominal 16" than a thin 700C tyre is to 27", so the gearing difference isn't quite as much as it may sound.
- Stelvio tyres will lower your gearing (smaller overall tyre diameter) compared with Brompton or Primo tyres.
- Watch out for cracked Series 1 swingarms and cracked BB mountings on all F-frames.
- The BB is always English-threaded but often only 66 mm wide, shorter on the RH side.
- An 11t top cog will usually fit on a Shimano 7sp cassette hub.
- There is a (rare) 11-28t Shimano freewheel.
- Stiffening the front suspension can be helpful.

I'm a longtime Moultoholic.

Here's the 24-speed Deluxe I rode from Boston to Montréal in the early '70s




http://sheldonbrown.org/moulton-deluxe.html (http://sheldonbrown.org/moulton-deluxe.html)

Here's my '62 Stowaway (take-apart) fixie



The 53/12 fixed gearing sounds impressive if you don't take the 349 mm wheels into account!


Sheldon "16 Inch" Brown

+------------------------------------------------+
| Nobody who has anything to do with bicycles |
| has _all_ of their marbles, and some of us |
| are certifiable! |
| --Sheldon Brown |
+------------------------------------------------+

Did you catch what A to B magazine said about the new BikeFriday tikit? "We’d go as far as to say that the ride and handling is the best we’ve seen with (ISO349 wheels), with the exception of the classic Moulton..."

BikeFriday tikit: 2007
"classic" Moulton: 1962

Would it be safe to say you're ahead of your time when it takes others 45 years to catch up? :)

TCS



"If Alex Moulton was never knighted, he should have been." John S. Allen, Bicycling magazine, upon being corrected for making the common 'Sir' Alex Moulton mistake.

Just adding this to the mix - A really nice bare-bones nice fixie F-frame (http://www.fixedgeargallery.com/2007/may/b/DaisySharaf.htm) that cropped up on the FGG earlier this year:

I'm a longtime Moultoholic.



Sheldon, just how difficult was it to do your multispeed freewheel on a Sturmey Archer job? The more I think about this, the more it looks like a really cheap project, if I could do it that way. I have several AW's hanging around, plenty of derailleurs, a bar end shifter with no home in view, plenty of drop bars. I'd need to buy a pair of rims, and some spokes. Things I'd like, such as a Brooks, cotterless cranks etc could wait, but I could have it built up and rolling for next to nothing. So do tell, is it within the scope of an amateur? It sounds like the only remotely hard bit is countersinking the hole in the derailleur claw (no problem), and chamfering the nut (harder, but I can do it).

just how difficult was it to do your multispeed freewheel on a Sturmey Archer job? <SNIP> So do tell, is it within the scope of an amateur? It sounds like the only remotely hard bit is countersinking the hole in the derailleur claw (no problem), and chamfering the nut (harder, but I can do it).

It is generally tougher than you might think. Fitting two cogs on a SA is trivial but more than that usually requires a hub with a threaded driver (old), a long axle (fairly rare) and often an old freewheel with large remover such as an old Normandy.

Well......

I have several 60's AW's, and I can order the axles straightforwardly. If the bike had a derailleur hanger, even the chamfering probably wouldn't be necessary. I don't suppose you know when the change from threaded drivers happened?

In the 50s AFAIR. Getting an old freewheel in rideable condition is getting more difficult.

That part I can definitely manage. Not only do I have connections, I almost certainly have a couple of old ones around.

I've a lightly modified, very low mileage, 1970 Moulton Mk III. A morbidly obese woman I know bought it new, because she could get a leg over it. She quickly destroyed the rims and hung it in her attic for 30+ years.

Mods.
Alloy rims, Brompton tyres, 1953 alloy 36h AW shell with S5 guts, alloy front hub (18 spokes, radially laced), Shimano V-brakes on the rear, BMX front brake, alloy seatpost, Brooks B-67, alloy bars and stem.

The reason it is still "Low Mileage" is that I like riding my R20 so much more.

I have a 3 speed midi moulton also. They're ok but they do have scaled down frames, to give a 'ladies size' & 14in wheels. I'd have thought that your updrade options were limited, can you fit gears and hanger etc to 14in wheels ? If you're going to refurbish a moulton, I'd have thought getting a full size F-frame & forks would be a better long term starting point. Only my opinion though, the 4 speed 14in bike was a sweet little thing, and I think they also did a two speed automatic model, but to be honest from riding mine around, you do need to be quite small of stature.

Ah - they're 14 inch on the Minis are they? Just goes to show I should've got it out. That said, I rode the gold one quite a bit last summer, and found it very pleasant, so I might just go with it anyway. What do I have to lose!

Hmmmm. Sheldon's site doesn't acknowledge the existence of any 14" wheels. Tricksy.

There was a post on the moulton message board about upgrading mini / midi wheels a while ago. The mini wheel is 298mm, and there was a view that 305mm rims could be made to work, with the added advantage of a better selection of tyres being available. St John's Street cycles seem to be the people to speak to, they list 305 rims. There was also talk of Japanese moulton fanatics who had fitted 16'' wheels to the mini / midi models, along with other tricking out. I don't know how you would access Japanese moulton boards or clubs, but it must be possible.

I have a Stowaway, same color as Sheldon's, that I modded up with all lightweight parts, SA-8 hub, SA Dynamo/Drum and excellent (12v) lights, and it was a great ride. But having cables running from the handlebar to the back wheel (both shift and brake) ruined the look, and made it a hassle to take the frame apart, and the whole thing was just a little less than satisfactory. So one day not long ago I polished up all the old chrome parts and put the Stowaway back together the way it came from the factory, and I really like it this way. One of these days I'm going to rebuild the new alloy wheels, replace the SA-8 with a coaster brake so I can use the new alloy wheels and have lights on it again... but I think that will be as far as I go.

Sammyboy, if you can keep the fenders on your Mini, do it; they're really good. Oh, sorry, I meant mudguards.

... The mini wheel is 298mm, and there was a view that 305mm rims could be made to work ...

For what it's worth: I have a Primo Comet 16 x 1.35 tire on the 305 mm rear wheel of my Downtube Mini. The diameter of the whole wheel, tire and all, is a little tricky to measure, but looks to be 370 mm.

A morbidly obese woman I know bought it new, because she could get a leg over it. She quickly destroyed the rims and hung it in her attic for 30+ years.


How does "morbidly obese" fit with "hung it in her attic for 30+ years"? Damn Doctors don't understand a thing about human bodies! If I new as little about my business as they do about theirs, I'd have been fired years ago.

Hmmm. Oddly, the more innappropriate this seems, the more I want to build at least the gold one as a hot-rod. If we're getting down to 305 rims, then even an AW with a freewheel down to 14 teeth still only gets you 76 gear inches max, so the derailleur/AW combination is off the menu. Shame really, as the idea of the Dura Ace RD on their was rather appealing. It looks like the best approach is probably a Sturmey Archer 8 speed, because of the way it all goes up from 1-1, but they're a tad spendy. I'd need to find one on the cheap somehow.

On the plus side, the 305 tyres and rims are cheap as chips, so it all looks doable. What kind of shifters are there for the SA-8? Is there anything that works on drop bars? I'll definitely remove the mudguards from the speedster one, but that would allow me to use them on the other, which I'd be building up with more like period kit.

There is only one shifter available for the SA-8, and it does not fit on drop bars or moustache bars.

Consider a used nexus 4-speed hub if you can find one; like the SA-8 it starts from a 1-1 and goes up from there. Also, even though it doesn't start from 1-1, the gearing of the Nexus 7 and 8 hubs isn't too bad; you can put a fairly small sprocket on them, and with a 52-T in front, your gear range will be acceptable. The SA-8 only takes larger sprockets.

Let's see. These are the sort of ranges you'd get with a 52 tooth front and a 14t rear:

Nexus 7 - 31.6-77.2
Nexus 8 - 26.3 - 80.7
Nexus 4 - 50-92
SA AW - 37.5 - 66.6
SA FW - 33.3 - 63.3
SA 8 Speed - 50-152.5

The Nexus 4 would do the job, but I'd quite like more than 4 ratios. If it's anything like my Nexus 7, I can't see how I could do Sheldon's multi speed freewheel bodge. The 7 and 8 don't really get high enough. I'm also extremely pleased to find that the SA 8 is relatively inexpensive, compared to a Nexus 8 at least. I'd run it with an 18 tooth sprocket, which would give me 38.9 - 118.6. It's tempting.

Hmmm. As cheap as an SA8 looks at £155 (how can that seem cheap to me, when I got my brand new Nexus 7 for £33?) a new Nexus 4 with fitting kit can be had for £69.99. Is there no way at all that I could bodge a cassette onto that? Also, does anyone know what the OLD is on the SA-8. The Nexus is 130, which is bound to mean some spreading.

The last of the Moulton Majors, built by Rayleigh, had the SA four spped hub, and 14in wheels, why not see if you can source a rear wheel on its own ? That would be about the cheapest gearing upgrade I'd have thought.

Actually, the 4 speed, whilst it gives slightly more range, and obviously closer shifts, gets a slightly lower top ratio. On a 14" wheel bike, top gear is the challenge.

Let's see. These are the sort of ranges you'd get with a 52 tooth front and a 14t rear:

SA 8 Speed - 50-152.5
I'm also extremely pleased to find that the SA 8 is relatively inexpensive, compared to a Nexus 8 at least. I'd run it with an 18 tooth sprocket, which would give me 38.9 - 118.6. It's tempting.

You can't fit an 18t to that hub, it has a different size of spline. 25t, 23t or (rare) 19t cogs only.

It's as though the world was against this happening. 19t would do, 23t would be less good.

Hmmm. Oddly, the more innappropriate this seems, the more I want to build at least the gold one as a hot-rod. If we're getting down to 305 rims, then even an AW with a freewheel down to 14 teeth still only gets you 76 gear inches max, so the derailleur/AW combination is off the menu. Shame really, as the idea of the Dura Ace RD on their was rather appealing. It looks like the best approach is probably a Sturmey Archer 8 speed, because of the way it all goes up from 1-1, but they're a tad spendy. I'd need to find one on the cheap somehow.

On the plus side, the 305 tyres and rims are cheap as chips, so it all looks doable.
What kind of shifters are there for the SA-8? Is there anything that works on drop bars? I'll definitely remove the mudguards from the speedster one, but that would allow me to use them on the other, which I'd be building up with more like period kit.

Sammyboy,

SA 8 speed has a grip shifter, which I have on the Wasp. I'm using narrow 70's steel drops which I cut, installed the shifter, then mig welded the bars back together. It's working fine, but Sheldon's reply in an email about fatigue failure makes me worry....a little. Not sure if the shifter will fit on more modern drop bars as they are of a wider diameter.
There are other ways to have drops with the SA shifter, namely, if you are using a long 22.2 quill stem the shifter will fit on it, even if you have to use a shim....a strange place, but it works.
Sheldon's red R20 has it mounted at the end of the bull horn bars...a matter of personal taste.
Another way is using a hubbub which attaches to the stem near the headset, but it looks like an alien growth hanging out in space. ;)
To me the best solution is using MTB flat bars and a set of drops bar ends from Origin 8, that way you have the shifter where you can easily reach it AND the advantage of the drops.

Actually, I have a plan to manufacture a stand-off to mount twist grips on drop bars - I can prototype on this, potentially. I need to do some investigation though, because I suspect that a Minoura computer/light mounting bar will do the job, providing that A) it's not too large a diameter, and B) it's sufficiently robust to deal with the torque.

Let's see. These are the sort of ranges you'd get with a 52 tooth front and a 14t rear:

Nexus 7 - 31.6-77.2
Nexus 8 - 26.3 - 80.7
Nexus 4 - 50-92
SA AW - 37.5 - 66.6
SA FW - 33.3 - 63.3
SA 8 Speed - 50-152.5

... I'm also extremely pleased to find that the SA 8 is relatively inexpensive, compared to a Nexus 8 at least. I'd run it with an 18 tooth sprocket, which would give me 38.9 - 118.6. It's tempting.Alas, not possible.

The Nexus hubs require a 16 or larger sprocket. That's the smallest size that is dished, and the Nexus requires a dished sprocket to clear the shift cable linkage.

The Sturmey-Archer 8-speed uses a MUCH larger driver than the other models in your list. The smallest that exists for that model is 19 teeth.

Sheldon "Epicyclic" Brown

The SRAM S7 doesn't require dished cogs. 53/14 gives you an 88" top gear with 305mm wheels. From Sheldon's calculator:
88.7
75.4
63.2
51.0
41.3
34.6
29.0

I've a lightly modified, very low mileage, 1970 Moulton Mk III...

The reason it is still "Low Mileage" is that I like riding my R20 so much more.The Moulton Mk III (the version built by Raleigh) has a triangulated rear end, which is way stronger than the classic Moulton rear fork, but it uses a rubber ball as a spring, instead of the rubber shear block used on most of the classics.

There's a neat trick for improving the performance of the Mk III: wrap a worm-drive hose clamp around the equator of the suspension ball. This will allow you to fine-tune the rear suspension (tends to be a bit too soft & mushy without this.)

Sheldon "Performance Tuned" Brown

I have to ask...
Have you considered holding off a bit and seeing if Sturmey comes through with the "new" ASC?
That'd be your hot rod hub, wunnit?

I don't think it would. I'll level with you here, I'd like this to be a nice fast city bike, but I also have this vision of myself hanging with groups of roadies riding my 309 wheeled bike, and that's not going to happen without a decent top end, and much as I enjoy fixed gear riding, it doesn't make me go faster. Of course, there are other barriers to me frightening the carbon and lycra crew, mostly my own ability, but it'd be nice if it were possible.

Ok. A 23 on an SA 8 gives me 30.4 to 92.8, and a 16 on a Nexus 4 gives me 43.7 to 80.5. For comparison, a road bike in 52 x 13 on 700 c's gets 105.1. It takes a lot of cadence to make up for 15 gear inches, and still more for 25! However, if I retain the existing cranks, or spring for cotterless where there are 60 tooth rings available, I'm better off. That would make the Nexus 4 50.5 to 92.9, and the SA8 35.1 to 107.1, which is a lot more like it. Hmmmm.

The Sturmey-Archer 8-speed uses a MUCH larger driver than the other models in your list. The smallest that exists for that model is 23 teeth.

Are you sure? I mean, absolutely sure (http://harriscyclery.net/itemdetails.cfm?ID=2459)? :)

Best,
TCS

Also, does anyone know what the OLD is on the SA-8.

There are two axle lengths/hub shells/OLDs for the SA-8. The narrower one has a nominal 116mm OLD.

HTH,
TCS

PS - If the urge to fit a Nexus 8 or SRAM P7 is uncontrolable, you should know that spreading old Moulton rear forks is rather more involved than cold setting a normal bike's rear triangle. Check in with Moulton Preservation (http://www.moultoneers.info/preservation/).

With a 19 tooth sprocket, it's the perfect hub for the job, assuming I can do something clever to mount the shifter. Now to the infinitely harder job of finding a cheap used one. I might be able to get hold of some more cheap Nexus 7's, which I might be able to trade if I could find someone with an SA8.....

Ok. A 23 on an SA 8 gives me 30.4 to 92.8, and a 16 on a Nexus 4 gives me 43.7 to 80.5. For comparison, a road bike in 52 x 13 on 700 c's gets 105.1. It takes a lot of cadence to make up for 15 gear inches, and still more for 25! However, if I retain the existing cranks, or spring for cotterless where there are 60 tooth rings available, I'm better off. That would make the Nexus 4 50.5 to 92.9, and the SA8 35.1 to 107.1, which is a lot more like it. Hmmmm.

Four suggestions:
1. I frankly don't believe you need such high gears. The SA range you describe above would probably be enough most of the time; and though the Nexus-4 range doesn't have the top end, you'll really miss the bottom end. I'd try to get it down to 35 or so.
2. Compare the shifters and how well they'll fit different handlebar options. I had little trouble mounting the SA-8 perpendicular to the handlebar, but once that was done, I had a very hard time shifting it. It's a stiff shifter anyway, and I did not have it at a place where it was easy to shift.
3. Include, in your consideration of the shifter options, the Nexus Auto-D system, if you can find it. Some parts are available now:
http://cgi.ebay.com/Shimano-Nexus-4-Auto-D-Sensor_W0QQitemZ120038979913QQihZ002QQcategoryZ77590QQtcZphotoQQcmdZViewItem
Even if you can't find it now, you may find the whole auto-D system later (knowing your luck, I guess you will). You could mount the auto-D shifter anywhere, like somewhere you don't need to reach it, because it would do the shifting for you (just when you least expect it, no doubt).
4. consider what brakes will fit on those hubs. The Nexus-4 came in both a coaster and roller brake version. I have the latter. I have heard people complain about them, but I found it an excellent brake. I'm thinking on your Moulton mod, you will have a hard time mounting good brakes, so this is important. If you got a coaster brake and an Auto-D system, you could have a very clean looking bike.

Thanks for this, and indeed all the very helpful stuff you've posted in response to my threads. I'll take these one at a time:

1) Maybe I don't need such high gears, but what I've got in mind is a small wheeler that's as near as possible the equal of a road bike on the long country road routes I ride, as well as being super-nippy in town, and there are large sections of my regular ride where I'm cranking along in 52 x 13 on my road bike. I know it's kind of a stupid aim, but it's just a fun thing to do with such a little bike. I don't think I'd miss the bottom end too much, I'm a strong climber, but I could be wrong.

2) I want to construct a shifter mount for revo-shifters; because this is such a common problem, I suspect it would sell well. My idea is a strong drop handlebar sized clamp with a tube coming out from it about 6-8 inches forward, and then a 90 degree bend. This would be in 25.4mm tube, and would act, effectively, as a stand-off for the shifter, meaning it was mounted in it's natural orientation, just in front of the flat of the bar (which is probably where you'd want it if you could bar mount it). Then it should be simple enough just to reach forward to shift.

3) The idea of auto-shifting does not appeal to me one little bit.

4) Looking at the Moulton, it appears that the dual pivot caliper brakes I'm using for the R20 would work even with the current wheels. Move up to 305's, and I would've though there would be plenty of calipers that would fit. I haven't looked closely though - is there something unusual about the brake mounts, or is it just a matter of reach? All that said, I'm not opposed to drum brakes, although they do add weight to a bike which could concievably end up very light indeed......

Are you sure? I mean, absolutely sure (http://harriscyclery.net/itemdetails.cfm?ID=2459)? :)Actually, I had forgotten that they started offering a 19 some time after I got my S-A 8-speed.

Sheldun "Infalabble?" Brwon

How does "morbidly obese" fit with "hung it in her attic for 30+ years"? Damn Doctors don't understand a thing about human bodies!You can't blame the doctors in her case. She was well aware of the benefits of exercise. She was very active in running our bike club and a large X-C ski club. Her husband is now in his sixties, bikes, skis, runs marathons and has about as much body fat as Lance had during the last week of a TdF. She never let on that she'd ever owned a bike, until she could no longer work and needed money.


If I new as little about my business as they do about theirs, I'd have been fired years ago.Good ones and bad ones. Mine have been great. Cardiologist is a runner and my new GP does triathlons. My old GP commuted on a Raleigh 3 speed in the winter.