Moulton SST -- reasons (not) to buy?

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Sidlaws
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Re: Moulton SST -- reasons (not) to buy?

Postby Sidlaws » 3 Mar 2019, 11:13am

iandusud wrote:

Some people don't like the feel of the suspension when pedalling hard but if you pedal with a fluid efficient style there's no problem, and in fact it encourages good pedalling IMO. To counter this I've seen some people when they first get a Moulton run the front suspension with a lot of preload, but the suspension actually works when run relatively soft, with appropriate damping.


I wonder which front suspension spring people are running, the firm or the (stock) soft? I'm a lightweight (62kg) so imagine it'll just come down to personal preference in the end. Being so lightly built though means I have no option but to spin up climbs, and am not generally one for standing out of the saddle except perhaps to crest a small rise, so I am hoping that the front suspension and I would get along just fine.

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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Postby Mick F » 3 Mar 2019, 11:14am

reohn2 wrote:EDIT:- All that said 700C wheels and bigger tyres at lower pressures allow for a lot more heat build up than 406's would,how much is anyone's guess but there'll be a formula for it.
No doubt! :D

Someone will be along shortly with chapter and verse! :wink:
Mick F. Cornwall

roubaixtuesday
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Re: Moulton SST -- reasons (not) to buy?

Postby roubaixtuesday » 3 Mar 2019, 11:16am

Nothing to do with thermodynamics


If you descend a hill at the same speed and thereby same air resistance, the same amount of energy must go into the rim. This applies entirely regardless of the model of brake used.

Conservation of energy.

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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Postby Mick F » 3 Mar 2019, 11:26am

Correct.
So what?

Time and Space.
The better the brakes, the less braking required for any given speed.
Therefore less heat built up.

Not saying that the heat isn't there, it's just that it doesn't build up and overheat the rim.

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Sidlaws wrote:I wonder which front suspension spring people are running, the firm or the (stock) soft? I'm a lightweight (62kg) so imagine it'll just come down to personal preference in the end.
Mine is the standard spring.
https://fudgescyclestore.com/index.php

The main thing to remember, is that the suspension linkages are adjustable. The damping can be altered from bouncy to stiff.
Mine was too bouncy before and going up a hill I could see and feel the front bobbing up and down.
Tightening up the adjustment, seems to have removed that. Tighten up too much, and the suspension is almost useless.

I would expect the different springs will need different damping depending on the ride quality you want. Personally, what I have now and the adjustment I have now, is fine for me. 70odd Kg.

I repeat, my TSR is a delight to ride.
Since buying it, Mercian has taken it easy.
Mick F. Cornwall

thirdcrank
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Re: Moulton SST -- reasons (not) to buy?

Postby thirdcrank » 3 Mar 2019, 11:27am

Re the slower progress on a Moulton, I fancy that it's to do with hilly terrain. My only experience of a Moulton dates from when the original models were the latest thing, but I think any front suspension makes climbing steep hills harder. NB I'm not saying impossible, or anything like that but simply harder, probably in proportion to the steepness of the climb. I suspect this is something to do with the likelihood that the steeper a climb, the greater the effort a rider makes with their arms. It would be interesting to hear some comparisons from riders living where it's relatively flat.

And as I posted earlier, ye cannae change the laws of physics. Different equipment may lead to a different riding style but that's a different matter.

reohn2
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Re: Moulton SST -- reasons (not) to buy?

Postby reohn2 » 3 Mar 2019, 11:31am

roubaixtuesday wrote:
Nothing to do with thermodynamics


If you descend a hill at the same speed and thereby same air resistance, the same amount of energy must go into the rim. This applies entirely regardless of the model of brake used.

Conservation of energy.

Length of time of braking also comes into it to.We decided to agree to differ on this subject on another thread.Mick's problem was inefficient brakes that needed to be dragged(on a 406 high pressure tyred wheel) to achieved anything like efficient braking power,with a different more efficient brake he doesn't need to to drag the brake so can pulse it,and no doubt alternate between front and rear to allow even more time for each wheel rim to cool.I think he's proved the pudding in the (h)eating
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Brucey
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Re: Moulton SST -- reasons (not) to buy?

Postby Brucey » 3 Mar 2019, 11:34am

If the tyre (and the air in it) is to act as a heat sink/heat dissipation surface you are in big trouble. Tyres are made of materials that get somewhat weaker and less reliable at any kind of elevated temperature and those materials also don't conduct heat well. You get a substantial benefit simply from having heavy rims and also from having rims that are better cooled by airflow around them. Tyres are almost certainly much less important.

Concerning airflow and cooling there isn't good agreement about what makes for a well cooled rim; 'aero section' rims have a larger surface area but it isn't clear that the heat transfers to that surface area before it heats the tyre and tube. In more boxy rims the heat is more likely to flow where it can be dissipated and the (non aero) 'corner features' are liable to be the best cooled parts of the rim.

It is unlikely to be a major effect in this case but if the process of shearing the brake block material absorbs a lot of energy then the assumption that all KE is turned into heat and that heat is conserved won't be true any more.

BTW it is easy to see the front suspension bobbing on climbs but in most moulton designs the chain tension compresses the rear suspension and you get pretty evil rear bobbing when climbing, which really does soak up pedalling effort like a sponge . The TSR design (with a high pivot URT) is an attempt to address this but even if successful it will only work properly on one chainring size.

cheers
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roubaixtuesday
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Re: Moulton SST -- reasons (not) to buy?

Postby roubaixtuesday » 3 Mar 2019, 12:02pm

to allow even more time for each wheel rim to cool.I think he's proved the pudding in the (h)eating


It matters not a jot. There's still the same amount of heat from the same descent, and the time to lose the heat is the same if descent is at the same velocity.

But as you say, we've been over this before. I'll leave you to it!

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Gattonero
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Re: Moulton SST -- reasons (not) to buy?

Postby Gattonero » 3 Mar 2019, 12:18pm

Sidlaws wrote:Hello everyone,...currently riding a Brompton M6L which I have found to be the only bike I have ridden that offers a posture which doesn't result in sciatica after a couple of hours in the saddle...


Can I give you my 2c advice?
I used to suffer from sciatica, sometimes being so bad that I couldn't get off the bed and had to roll off it :(
Then I took action, went to the doctor and found that I've a mild scoliosis, this cause a pressure point on the spine and it all goes downhill from there. I was advised to improve my flexibility and to strengthen the core muscles, back and abs.
It's really far from me the desire to become "Mr. Muscle" so I've never got any far, in fact still had a bit of sag belly :lol: but after 1 1/2year the results were already showing up. Aside from the benefit of losing 1st (dropping to 12) which was greatly appreciated going uphill :D the recurrent back pain/sciatica and stiff neck have disappeared ever since. On top of this, my arms and wrists got a lot less fatigue, because the upper body can support itself a lot better.
I never though to change bike to cure the problem, because the problem was in me not in the bikes.
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

PDQ Mobile
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Re: Moulton SST -- reasons (not) to buy?

Postby PDQ Mobile » 3 Mar 2019, 12:21pm

Is it possible that different brake blocks also have a small effect?
A block that makes a rough braking surface is tearing bits of rim off and that physical grinding/flaking produces additional heat?

Certainly red Koolstops, used with care to dry the rim before really hammering on the stoppers, seem to result in a nicely polished braking surface.
I have a 20" (406) wheel that does the lions share of stopping a fair bit of weight, has always had red Koolstops with Magura hydraulic rim brakes and it has covered 10000 plus miles yet shows very little wear.
image.jpg

hercule
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Re: Moulton SST -- reasons (not) to buy?

Postby hercule » 3 Mar 2019, 12:57pm

A couple of observations from my experience... caveat again that mine is a 17" wheel bike

- it seems no slower than my Thorn XTC SWB on Panaracer Paselas, 26 x 1.5"... and I consider that a fairly quick bike! It's more comfortable on forestry tracks for sure, when it gets softer then the bigger, fatter tyres have better floatation.

- I consider it a pretty good hill climber, most of your effort goes into forward propulsion rather than flexing the frame (as I've found with other 531 tubed conventional designs)

- Positioning relative to front/back can make a difference. I find I get the best comfort and efficiency with a combination of a short stem and proportionately more saddle layback, with the front suspension set relatively soft: the approved way of setting the suspension height is to have the leading links horizontal when you are sitting at rest on the bike.

- it definitely rewards spinning with a "circular" pedalling style rather than mashing in "squares". My default cadence is about 90 rpm on flat/rolling roads.

- I've never had reason to be worried about the brakes which has included the experience of a high speed descent down Mount Teide. I've had exploding tyres on the tandem but not on the AM.

Mine is now fitted with the progressively wound "race spring" which I did find a useful upgrade over the plain vanilla original version. It's worth noting that the properties of the rear rubber suspension cone do vary with production batches and age and so this can lead to variations in characteristics between machines. I have two Mark 1 Moultons of similar age, one feels like you're riding on a pillowy mattress (not at all inappropriate for the style of the machine), the other is much more taught and racey. Reports from other Moulton riders with multiple space frame machine suggests this is true too of the more modern rear cones.

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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Postby Mick F » 3 Mar 2019, 1:35pm

Brucey wrote: ......... but in most moulton designs the chain tension compresses the rear suspension and you get pretty evil rear bobbing when climbing, which really does soak up pedalling effort like a sponge . The TSR design (with a high pivot URT) is an attempt to address this but even if successful it will only work properly on one chainring size.
I don't know much about "most Moultons".

On the TSR, chainset and BB are in the same rigid triangle as the back wheel, so the chain tension cannot compress the rear suspension.
You could say that your leg tension expands and contracts the rear suspension as your weight comes on and off the saddle.
Mick F. Cornwall

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deliquium
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Re: Moulton SST -- reasons (not) to buy?

Postby deliquium » 3 Mar 2019, 1:54pm

I bought a new caliper braked TSR frameset in April 2016, just before Moulton appeared to have 'insisted' their dealers only sold complete bicycles?

(I didn't want any of the standard components they used)

It was sold last summer having covered 5905 mostly enjoyable miles.

But it was never quite what I wanted from a bike for so many reasons, even though I was drawn to its quirkiness and aesthetics.

I found the suspension was at times annoying, both in use and maintenance. Why complicate a simple well proven bicycle design for such little gain (if at all)?

By far the most comfortable all day <100 miles bike is a much lighter and springier (arguably better then suspension joints/systems)? 1948 Percy Stallard 'Montlhéry', Accles & Pollock Kromo SAQ tubed frame with modern 8 speed components and 700c x 32mm supple Vittoria tyres.

And for intermediate load carrying - or not = (touring bike) a 1992 Longstaff 531 suits me very well.

For even more loaded/heavy shopping, a 1987 Raleigh 'Avanti' 531 (ex mountain bike with larger diameter tubes) is also far better and can cope admirably well with any off road stuff where 32mm tyres and 26" wheels can venture.

As Mick F has pointed out - Moulton TSRs get filthy, and are somewhat tedious to keep clean.

I don't regret my Moulton phase. It took 2 years to evaluate and move on (or more accurately, stay back).

But to conclude (personally) Percy's 1948 frame is like riding a magic carpet which eats up the miles with great aplomb and my other large wheeled bikes are also easier to maintain and more efficient for what I want
Current pedalable joys

"you would be surprised at the number of people in these parts who nearly are half people and half bicycles"

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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Postby Mick F » 3 Mar 2019, 2:06pm

deliquium wrote:I don't regret my Moulton phase. It took 2 years to evaluate and move on (or more accurately, stay back).

As I said on Page 1.
Mick F wrote:Do I regret the two grand I paid?
Still not sure with respect to being a bike, but it's kept me sane working out the problems and difficulties. The whole thing is fun to work out the foibles and it's an endless conversation on here too.

Has it been worth it?
Dunno really, but I'm a tinkerer and fiddler and enjoy fixing things, so maybe I don't regret it at all.

The alu mudguards are on, adjusted, and ready for a test ride ........... when the weather clears.
Mick F. Cornwall

Brucey
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Re: Moulton SST -- reasons (not) to buy?

Postby Brucey » 3 Mar 2019, 3:53pm

Mick F wrote:
Brucey wrote: ......... but in most moulton designs the chain tension compresses the rear suspension and you get pretty evil rear bobbing when climbing, which really does soak up pedalling effort like a sponge . The TSR design (with a high pivot URT) is an attempt to address this but even if successful it will only work properly on one chainring size.
I don't know much about "most Moultons".

On the TSR, chainset and BB are in the same rigid triangle as the back wheel, so the chain tension cannot compress the rear suspension.
You could say that your leg tension expands and contracts the rear suspension as your weight comes on and off the saddle.


you are quite right, silly me, I was thinking of elevated swingarm pivot rather than the URT on a TSR. Other Moulton designs with the swingarm pivot behind the BB and at about the same height suffer bobbing rather more easily. But yes even with the TSR design you can still bob simply because one's legs going up and down are not mass-balanced and they are not going at constant speed either. FWIW I've owned about half a dozen bikes with rear suspension and there has only been one where I felt like I could usually pedal (in the saddle) with 9/10ths effort without dramatic bobbing. Even then it took 'careful pedalling'.

cheers
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