Author Topic: Moulton Experiences?  (Read 2530 times)

Re: Moulton Experiences?
« Reply #25 on: October 12, 2018, 09:55:38 am »
I reckon you can go a lot bigger than 58T if you run it as a 1 x something, so the front mech is presumably the limiting factor?  I'm running a 56T as a single chainring (43.5mm chainline to line up with the middle sprocket) and there's still plenty of daylight between the ring and the chainstay.

Given that these bikes come with a built-in weight penalty, I reckon they're ideal for a 1 x 11 setup.  I only didn't do it because I was offered 9 speed cassettes for free and a 9 speed shifter for not much.  You could get away without the special clutched rear mech too, as a big front chainring shouldn't drop the chain over bumps like a tiny MTB ring tends to.  A normal 11sp road mech would do, probably a GS version if you wanted something like 11-36.  56 x 36 gives you a 28" bottom gear which should be enough for anything except cycle-camping.
Never tell me the odds.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Moulton Experiences?
« Reply #26 on: October 12, 2018, 11:28:24 am »
My only experience of a small wheeled bike was a Dahon that I rode once, didn't like and then sold again.  I'd bought it because it was foldable.  What I can't tell from either the website or pics on here, is are they foldable, or in the case of the space-frame models just disassemblable?
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Moulton Experiences?
« Reply #27 on: October 12, 2018, 12:43:00 pm »
Moulton enthusiasts tend to get a bit sniffy (like the man himself did) when asked if they like their 'folding bikes'....  the term they prefer is 'separable'.

Not all space frame models are separable, and on some it is an option to have the same bike with or without the separable joint.  You can see which is which even in pictures because on separable models there is a large knurled nut on the lower tie rod.

cheers

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Moulton Experiences?
« Reply #28 on: October 12, 2018, 02:09:44 pm »
Are they foldable in the same sense as a brommie or dahon?
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Moulton Experiences?
« Reply #29 on: October 12, 2018, 05:59:59 pm »
not really.  They pack down pretty easily and the parts go into a relatively small bag. If you just separate the two halves then you have something that will fit very easily into the back of even a very small car. This means that they are suitable for occasional transport rather than daily commute in most cases.


separated spaceframe


bagged spaceframe, rear section


new series dual pylon, ready for packing


AM7 separation diagram; APB and TSR centre joints are similar


AM14 centre joint showing cable joiners


TSR 2

The TSR 2 has no cables joining the front and the rear sections (backpedal brake and two speed kickback gear), so separation is easier; it literally takes a few seconds.  A derailleur gear equipped machine has either two or three cables with joiners to separate at the joint; it doesn't take long but it is a bit fiddly.

Unlike nearly all folding machines, the ride qualities of the machine are in no way affected by the presence of the joint; the only difference is that separable models  (where there is a choice) cost a little  bit more.

cheers

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Moulton Experiences?
« Reply #30 on: October 12, 2018, 06:37:28 pm »
Thanks, for the explanation, I've always been impressed by the engineering approach, but never really knew much about them.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Moulton Experiences?
« Reply #31 on: October 12, 2018, 06:43:16 pm »
You have to be careful how you lock them, lest some wag with a 6mm allen key steals half your bike.  Actually, a Moulton "cut and shut" in two colours would look quite cool.
Never tell me the odds.

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Moulton Experiences?
« Reply #32 on: October 13, 2018, 08:13:50 am »
Rhubarb and custard, anyone?
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

LittleWheelsandBig

  • Whimsy Rider
Re: Moulton Experiences?
« Reply #33 on: October 14, 2018, 07:04:29 am »
The Moulton jigs allow variations in orientation of the kingpin, so combining the halves of different Moulton frames may have a less than perfect match. In the factories, they construct one frame half (can't remember whether front or back) and then braze up the other half against the first. The two halves then remain together all the way until the bike is sold.
Wheel meet again, don't know where, don't know when...

bludger

  • Randonneur and bargain hunter
Re: Moulton Experiences?
« Reply #34 on: October 14, 2018, 08:52:28 am »
The "collabsable audax bike" I've long been interested in are the airnimal series. I've seen them around on brevets. One of the main advantages I can see are larger wheels than on moultons - 24"" versus 20"" (though the moulton rhino, which is full-sus, is 20" - http://airnimal.eu/products/rhino/white/). I would have to do a few test rides before I'd be happy about committing myself to >200 km rides with cargo on 20"" wheels!



But then it can't be ignored that the moulton is a full 4 kg lighter than the airnimal (though how much of that is due to the wheels?). I think this must be from how the airnimal is an actual folder, with a steel hinge, in contrast to the moulton's "snap away/together" connection.
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LittleWheelsandBig

  • Whimsy Rider
Re: Moulton Experiences?
« Reply #35 on: October 14, 2018, 09:29:58 am »
Moultons have very strong, superlight wheels but the frame and forks (particularly separable frames) are very heavy. The old rule of thumb is an ounce off the wheels is worth two off the frame, so Moultons ride 'lighter' than you'd expect when you pick them up.

HK and I have done the majority of our 1000+km brevets on Moultons, nearly 2 dozen each on all machines over the past 8 years. The combination of easy transport (even compared to S&S-coupled 700C) and additional comfort is worth a little loss in climbing speed for us.

The Airnimal is an aluminium frame and most of them (not their fully suspended 20" jobbie) should be a little lighter than most Moultons, 17" or 20". Bigger wheels roll a little better, unless you are very careful with small tyre choice. There are plenty of audaxers with 24" Airnimals, so they work quite well.
Wheel meet again, don't know where, don't know when...

Re: Moulton Experiences?
« Reply #36 on: October 14, 2018, 09:59:31 am »
The Moulton jigs allow variations in orientation of the kingpin, so combining the halves of different Moulton frames may have a less than perfect match. In the factories, they construct one frame half (can't remember whether front or back) and then braze up the other half against the first. The two halves then remain together all the way until the bike is sold.

you mean the 'timing' of the angled faces in the kingpin joint?  (as visible in the AM7 diagram above)

If so I can see exactly what you mean. I didn't know that before.

FWIW I recently worked on a friend's machine and (in something of a time crunch) I discovered a 'clunk' when the front brake was applied.  It wasn't obvious where it was coming from, so bearing in mind my friend's time crunch  I was half-tempted to leave it for another day.

I am rather glad I didn't do that though; after a little while I found the source of the clunk; the knurled nut on the lower tie rod had backed out a little. Whether this had loosened in riding of the bike or had been tampered with when it was parked I am not sure.  I don't think the frame was in immediate danger of folding up around the kingpin joint but the thought of that happening gave me the absolute willies.

cheers

LittleWheelsandBig

  • Whimsy Rider
Re: Moulton Experiences?
« Reply #37 on: October 14, 2018, 10:03:24 am »
Yes, the 'timing' of the kingpin joint.

The lockring is to take out the play in the hook joint. By design, it is impossible for the hook joint to come apart without undoing the kingpin first, so it is safe enough to ride though the kingpin joint will wear if the bike is ridden that way for a long time.
Wheel meet again, don't know where, don't know when...

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Moulton Experiences?
« Reply #38 on: October 14, 2018, 10:09:49 am »
I've seen a few airnimals around me as well, they're made not far from me.  Had a nice chat with a bloke on a train about his custom specced paint job as he went direct to the factory.

As with other small volume jobs, expensive, and like most 'bents seem to hold good second hand value.

DAhon also do a few folding 24" MTBs, but they look very heavy.
“Procrastination is the thief of time, collar him.” –Charles Dickens

Re: Moulton Experiences?
« Reply #39 on: October 14, 2018, 10:54:47 am »
Yes, the 'timing' of the kingpin joint.

The lockring is to take out the play in the hook joint. By design, it is impossible for the hook joint to come apart without undoing the kingpin first, so it is safe enough to ride though the kingpin joint will wear if the bike is ridden that way for a long time.

Do you think I am I right in suspecting that if the knurled nut is backed out and the lower tie rod takes a knock upwards, it might pop out at the (worn) hook? Albeit this isn't likely and would require that the tie rod would be flexed/bent I suppose...?

I am not (I think...) by nature a complete worry-wort, but I do check the nut on my spaceframe pretty much every time I ride the bike.

cheers

LittleWheelsandBig

  • Whimsy Rider
Re: Moulton Experiences?
« Reply #40 on: October 14, 2018, 11:07:32 am »
Different models have the lower tie rod triangulated or not. I don't think you could get an unsupported tie rod to bounce out (the hook comes round a long way and the end can't get worn off) but I've been wrong before now.

The nut has to be backed off a very long way to unhook the frame. The joint starts to knock as soon as it loosens a little, so there is a lot of warning that things aren't right and should be checked. I look at that sort of thing similarly to a 'stupidity tax'.
Wheel meet again, don't know where, don't know when...

Re: Moulton Experiences?
« Reply #41 on: October 14, 2018, 12:47:21 pm »
I wouldn't call my chum daft, and they have owned their (much cherished *) Moulton for over ten years, and ridden it extensively (most parts of the running gear have worn out and had to be replaced; it is a real trigger's broom...). I was surprised that they had ridden it with the nut loose, I would have expected them to have noticed. 

It is an APB frame, so no bracing on the tie rod.

(*) they have had the frame refinished in powder coat paint that looks like metal (a bit like McLaren used on their race cars for several years). From five yards or more you would assume it is a stainless model. I'm not normally swayed by fancy paint jobs but this actually looks pretty special... It is about the nicest APB I have seen; it runs 28mm tyres and has mostly ultegra running gear.

cheers

Re: Moulton Experiences?
« Reply #42 on: October 14, 2018, 08:20:41 pm »
Looking at the TSR "spaceframe", I'm not convinced it's a real spaceframe.  The infill struts - solid rods on a TSR, I think - would be useless in compression.  It probably derives all its lateral strength and stiffness from the outer "hairpins", which are widely-spaced.

Bradford-on-Avon "real" AM bikes are a bit different - no hairpins, so narrower overall, and actual tubes for the infill struts.  I can believe the struts are both necessary and functional on AMs.

People like me buy them for the looks and the suspension anyway;  there's not much point having a frame that's super-stiff laterally when honking (which is what really twists frames) is discouraged by the front fork bobbing.
Never tell me the odds.

LittleWheelsandBig

  • Whimsy Rider
Re: Moulton Experiences?
« Reply #43 on: October 14, 2018, 08:37:26 pm »
The Pashley-built Moultons have enough wall thickness on the hairpins that they could do away with the diagonal bracing (wire) completely but the wire has enough resistance to tension to measurably change frame stiffness. The BoA Moultons have very thin walled tubing and they'll eventually break if the diagonal bracing (tubing) isn't functional.

I regularly ride my Moulton hard out of the saddle in a big gear but sit down when I hit a resonant frequency.
Wheel meet again, don't know where, don't know when...

Re: Moulton Experiences?
« Reply #44 on: October 14, 2018, 08:56:50 pm »

APB


TSR

Arguably the 'zig-zag' braces may help prevent the hairpin tubes from buckling (midpoint deflecting sideways) when they see a large compressive load. However in the APB design, one side of each hairpin has no zig-zag brace attaching at the midpoint, so this can't help. 

I also note that in the APB the lower tie rods don't make a straight line (later rectified in the TSR) which means that there is a net compressive load on the two braces running up to the kingpin. Really I think these braces would be better made as tubes in the APB design.

In early APBs the swingarm has zig-zag braces in which were soon redesigned. The stress concentration arising from the early braces occasionally causes the swingarm to break.

cheers