Moulton SST -- reasons (not) to buy?

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

Post by Brucey »

reohn2 wrote:
Brucey wrote:faster for less effort? Keeps you warmer/drier in winter? On the downside the fairing will get damaged in a prang and may make some drumming noise. But if they were legal for racing every wiggo-wannabee would buy one in seconds flat; they make much more difference than any amount of 'special aero design' to the bike that lies within present UCI rules.

cheers

That being the case why doesn't every knowledgeable cyclist use one?
As I posted.....


you could say the same thing about a motorcycle fairing too; fact is that practically no-one goes racing without one. In bicycles there is a lot of herd mentaility; you get a lot of weekend riders who say they 'would do anything to go faster' but it would never occur to them to use a recumbent machine, for example.

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

Post by reohn2 »

Brucey wrote:you could say the same thing about a motorcycle fairing too; fact is that practically no-one goes racing without one. In bicycles there is a lot of herd mentaility; you get a lot of weekend riders who say they 'would do anything to go faster' but it would never occur to them to use a recumbent machine, for example.

cheers

Motorcycles are a completely different machine to a bicycle,motorcycles are far heavier so are less affected by sidewinds,and far more powerful and faster which makes aerodynamics more of an advantage to them,infact the only thing the two have in common is two wheels and a very general shape.
I agree about the recumbent and speed,though there are other different and reasons that make 'bents less attractive to DF riding cyclists.
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Brucey
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Re: Moulton SST -- reasons (not) to buy?

Post by Brucey »

the notion that motorcycles are somehow not terribly vulnerable to side winds is one that is quickly dispelled by riding one in adverse conditions. They vary considerably too.

You are going to be more likely to get into trouble on a bike whenever the CoP is well ahead of the CoG; however this situation is commonplace on bikes which carry luggage at the front, so I don't think it is always a show-stopper. I regularly ride a carrier bike where the windage of the luggage (up front) is greater than that of a proper fairing and I've yet to 'have a moment' as a result. In fact I've been wondering about fitting a (QD) full fairing to the beast anyway.

One thing I would say is that I just don't fancy anything where the fairing/luggage is well ahead of the steering axis and it turns with the steering; that does invite trouble; for that reason I just don't like bar bags for example. It is a much better idea on a bicycle to have a fairing mounted to the frame, like the Moulton one.

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

Post by Mick F »

Speedsixdave:
Very good summary of the issues.

The SA hub isn't much of a drag at all. You can tell that by spinning the wheel - though smaller wheels don't rotate as much as a larger wheel of course - so difficult to make a comparrison. It must produce drag, but not enough to make climbing hills slow.

When I first had Moulton, I was bobbing like a good 'un on hills, but tightening up the damping on the front suspension, and pedalling better has eliminated it to almost zero ............ or maybe not zero, but I can't see it now.

I have said on occasion, that riding my Moulton is like riding through treacle. Exaggeration of course.
When I ride Mercian, it's more like it's self-propelled and goes like a rocket in comparison.

In summary, I have no real idea why the bike is hard to climb hills. I can only put it down to excess weight, as the Mercian and Moulton are identically set up. I spent ages measuring and adjusting, so I know they are the same - even down to the shape and size of the dropped handlebars and the identical saddles.

Another theory, is that 531c is very light springy and Moulton's heavy CroMo frame is "dead" except for the absorbent suspension.

Probably, the real answer is a combination of the lot. I doubt the SA hub has any contribution though, other than weight as it weighs 1Kg or so. If you subtract the weight of a normal hub, it probably works out to less than half that.
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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Post by Mick F »

PS
As for drag of a SA hub, one comparison I can make, is comparing front vs rear.
Front has a hub dynamo.

Rear spins far better, meaning that the hub dynamo produces more drag than the SA hub.
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reohn2
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Re: Moulton SST -- reasons (not) to buy?

Post by reohn2 »

Brucey wrote:the notion that motorcycles are somehow not terribly vulnerable to side winds is one that is quickly dispelled by riding one in adverse conditions. They vary considerably too.

Having ridden motorcycles almost exclusively,of all sizes and power outputs for quite a while up until my early thirties I'm well aware of that fact.

You are going to be more likely to get into trouble on a bike whenever the CoP is well ahead of the CoG; however this situation is commonplace on bikes which carry luggage at the front, so I don't think it is always a show-stopper. I regularly ride a carrier bike where the windage of the luggage (up front) is greater than that of a proper fairing and I've yet to 'have a moment' as a result. In fact I've been wondering about fitting a (QD) full fairing to the beast anyway.

One thing I would say is that I just don't fancy anything where the fairing/luggage is well ahead of the steering axis and it turns with the steering; that does invite trouble; for that reason I just don't like bar bags for example. It is a much better idea on a bicycle to have a fairing mounted to the frame, like the Moulton one.

cheers

Can I put it to you that front panniers by their very nature are low down smaller than a fairing and heavier,so whilst they may catch the wind it's much less so and their weight helps nullify the wind effect somewhat
Whereas a fairing(on an DF bike)like the one in the photo up thread,is high,lightweight and is very like a sail in some adverse wind conditions.yachts lean when their sail catch the wind
As I said up thread I'm not convinced at all by them.On 'bent strikes and low riders it's a different matter IMO.
Last edited by reohn2 on 9 Mar 2019, 10:30am, edited 1 time in total.
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Brucey
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Re: Moulton SST -- reasons (not) to buy?

Post by Brucey »

you are overestimating the effect of height on windspeed and completely ignoring the fact that the panniers/bar bag are connected directly to the steering (and therefor affect the balance directly in the worst way possible).

FWIW I made two points re motorcycles; the second is important, being that they vary. If you have a poorly designed fairing (eg a huge flyscreen attached to the handlebars on a rear-heavy motorbike) it is little more than a liability when it is windy. However a well designed fairing is something that I would sooner be with than without. Similar considerations may well apply to certain bicycles/riders. Don't let your thought processes be limited by the UCI's blinkers.


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

Post by Brucey »

Mick F wrote:PS
As for drag of a SA hub, one comparison I can make, is comparing front vs rear.
Front has a hub dynamo.

Rear spins far better, meaning that the hub dynamo produces more drag than the SA hub.


A good portion of the drag in an IGH is in the gear transmission; this doesn't turn during freewheeling, so doesn't add drag. Try turning the rear wheel backwards and see how you get on.

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

Post by reohn2 »

Brucey wrote:you are overestimating the effect of height on windspeed and completely ignoring the fact that the panniers/bar bag are connected directly to the steering (and therefor affect the balance directly in the worst way possible).

FWIW I made two points re motorcycles; the second is important, being that they vary. If you have a poorly designed fairing (eg a huge flyscreen attached to the handlebars on a rear-heavy motorbike) it is little more than a liability when it is windy. However a well designed fairing is something that I would sooner be with than without. Similar considerations may well apply to certain bicycles/riders. Don't let your thought processes be limited by the UCI's blinkers.


cheers

The bicycle fairing/flysceen up thread is very similar to a motorcycle flysceen
We'll agree to disagree eh?

EDIT,I'm prepared to accept that a very much smaller double curvature screen on say a TT bike that could smooth the airflow over the riders torso and arms could have beneficial improvement on speed,but we started this discourse on the fairing/screen in the Moulton photo up thread which is in normal everyday use of no advantage at all at best and could in adverse conditions change a nice handling bike into a 'bit of a hand full' to keep control of.
All IMO of course.
Last edited by reohn2 on 9 Mar 2019, 10:43am, edited 1 time in total.
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Brucey
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Re: Moulton SST -- reasons (not) to buy?

Post by Brucey »

reohn2 wrote:The bicycle fairing/flysceen up thread is very similar to a motorcycle flysceen
We'll agree to disagree eh?


look closely; it is attached to the fixed part of the frame, not the steering.

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

Post by reohn2 »

Brucey wrote:
reohn2 wrote:The bicycle fairing/flysceen up thread is very similar to a motorcycle flysceen
We'll agree to disagree eh?


look closely; it is attached to the fixed part of the frame, not the steering.

cheers

See my edit.
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Brucey
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Re: Moulton SST -- reasons (not) to buy?

Post by Brucey »

all the evidence is that the moulton fairing is very far from 'no advantage at all' and that adverse windage on it is not likely to be a major problem.

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

Post by reohn2 »

Brucey wrote:all the evidence is that the moulton fairing is very far from 'no advantage at all' and that adverse windage on it is not likely to be a major problem.

cheers

Show me the evidence
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Mick F
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Re: Moulton SST -- reasons (not) to buy?

Post by Mick F »

Brucey wrote: Try turning the rear wheel backwards and see how you get on.
Backwards with the chain on or off?
With it on, I'd be turning the cranks as well as the chain through the rear mech.
Is that what you mean?
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Re: Moulton SST -- reasons (not) to buy?

Post by Mick F »

Another PS.
Just having a cuppa.

The bike is in bits at the moment, and I'm giving everything a good clean.
Chainset off and stripped, cassette off, chain too. I'll be stripping and cleaning the rear mech next.

I've greased the rear suspension pivot and I'll be giving the bare frame a good wash.
After that, I'll be reassembling the whole lot including swapping from Chain B back to Chain A. Two Campag chains, swap from time to time.

When it's all clean and shiny, I'll do some experimenting with wheel-spinning.
Mick F. Cornwall
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