...what the relative efficiencies of various drive trains?
Re: ...what the relative efficiencies of various drive trains?
I'm surprised a belt drive is so much more inefficient than a chain.
Re: ...what the relative efficiencies of various drive trains?
Brucey wrote:motorcycle chains are typically a bit less efficient at low powers than bicycle chains, because motorcycle chains are usually 'O' ring type, which incurs a seal drag penalty. This penalty is sufficiently large that racing motorcycles tend to avoid 'O' ring chains.
Also to be born in mind when people complain bicycle chains don't last long compared to m/c chains (along with the "pulse" effect).
Re: ...what the relative efficiencies of various drive trains?
Thread drift here .......... sorry.[XAP]Bob wrote:I'm not sure if a spoon is sufficient is it? Sure there was something in the regs about brakes acting on the tyre... can't remember what though.
You could have a calliper brake on the rear "farthing" wheel to get round the regulations.
Mick F. Cornwall
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Re: ...what the relative efficiencies of various drive trains?
Bmblbzzz wrote:I'm surprised a belt drive is so much more inefficient than a chain.
Is it really? I though belt drives were expensive, so they should be better
Does the belt stretch or give? I can fix my chain if it breaks, what if a belt breaks?
Entertainer, juvenile, curmudgeon, PoB, 30120
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we hate bullies
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we hate bullies
Re: ...what the relative efficiencies of various drive trains?
Cyril Haearn wrote:Bmblbzzz wrote:I'm surprised a belt drive is so much more inefficient than a chain.
Is it really? I though belt drives were expensive, so they should be better
Does the belt stretch or give? I can fix my chain if it breaks, what if a belt breaks?
On a motorbike...
I don't know what it is on a pedal cycle...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Re: ...what the relative efficiencies of various drive trains?
Mick F wrote:Thread drift here .......... sorry.[XAP]Bob wrote:I'm not sure if a spoon is sufficient is it? Sure there was something in the regs about brakes acting on the tyre... can't remember what though.
You could have a calliper brake on the rear "farthing" wheel to get round the regulations.
Yes..
Haven't searched for the source, but the CTC does still have some useful documents:
CTC Construction and Use regs summary wrote:Each braking system is required to be in efficient working order, but apart from saying that a brake that bears directly upon a pneumatic tyre in not efficient,
But also, from the exceptions section:
CTC Construction and Use regs summary wrote:I've already noted that fixed wheel counts as a brake. Taking that a stage further: if one wheel is not only incapable of rotating independently of the pedals, but the pedals are fixed directly to it without any intervening chain or gears, the cycle does not have to be equipped with any actual brakes at all. This is obviously designed to allow various antique machines to be exercised on the highway without adding incongruous modern accessories!
So an ordinary (PF) doesn't need a second brake at all...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Re: ...what the relative efficiencies of various drive trains?
[XAP]Bob wrote:CTC Construction and Use regs summary wrote:I've already noted that fixed wheel counts as a brake. Taking that a stage further: if one wheel is not only incapable of rotating independently of the pedals, but the pedals are fixed directly to it without any intervening chain or gears, the cycle does not have to be equipped with any actual brakes at all. This is obviously designed to allow various antique machines to be exercised on the highway without adding incongruous modern accessories!
So an ordinary (PF) doesn't need a second brake at all...
Like a unicycle?
What happens if the unicycle is a tall one so the cranks are high off the ground and chain-driven to the wheel?
How could you brake it?
Mick F. Cornwall
Re: ...what the relative efficiencies of various drive trains?
Interesting question - the normal 'brake' works, and there is no real way to do anything else on a unicycle.
Of course, the other thing is that they have a brake (fixed wheel) on 'all' axles...
Of course, the other thing is that they have a brake (fixed wheel) on 'all' axles...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
There are two kinds of people in this world: those can extrapolate from incomplete data.
Re: ...what the relative efficiencies of various drive trains?
Cyril Haearn wrote:Bmblbzzz wrote:I'm surprised a belt drive is so much more inefficient than a chain.
Is it really? I though belt drives were expensive, so they should be better
Does the belt stretch or give? I can fix my chain if it breaks, what if a belt breaks?
They are certainly less efficient than a chain is, maybe by a slightly different amount on a bicycle. BTW chains get less efficient again at high speeds because of inertial losses, but even so I am not sure that they ever get to be worse than belts in most applications.
Belts are more expensive but efficiency is not the only arbiter of 'value'. They have other attributes such as cleanliness that appeal to some users, maybe this is enough to make them 'better' for some users. The tension in a belt can 'go off' a bit with use but they can go a long way without being touched.
You can get an emergency belt repair kit for motorcycle use and I think there is something similar available for some bicycle belts. The repaired belt is nothing like as strong as an intact belt and is meant as a 'get you home' fix. In their main target market (urban commuting) a bicycle belt breakage that isn't fixable by the roadside is likely to be a one-journey inconvenience, a bit like an unfixable puncture is. It is arguably tolerable if this sort of thing happens occasionally in this use. If the belt is set up right it is very unlikely to break, anyway.
BTW efficiency measurements are difficult; in an ideal world the losses all go in proportion with speed and load, but seal drag, certain types of viscous drag, bearing/belt preload, certain types of inertial losses all complicate the picture. As I mentioned previously, so does a 'pulsey' load cycle.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: ...what the relative efficiencies of various drive trains?
[XAP]Bob wrote:Interesting question - the normal 'brake' works, and there is no real way to do anything else on a unicycle.
Of course, the other thing is that they have a brake (fixed wheel) on 'all' axles...
IIRC a unicycle isn't even considered a vehicle because the regs say (or at least used to) that you have to have two or more wheels. Years ago a chum enquired at the local police station and was told that all the regs that applied to bicycles didn't apply to unicycles for this reason. He went ahead and fitted lights and reflectors to his unicycle, but (at the time and perhaps still) he strictly speaking need not have bothered.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: ...what the relative efficiencies of various drive trains?
Thanks for the belt drive info, Brucey.
As for unicycles, I'm pretty sure some of the currently popular "mountain unis" do have a caliper brake. Obviously that's just an extra, as you might have a rear brake on a fixie.
As for unicycles, I'm pretty sure some of the currently popular "mountain unis" do have a caliper brake. Obviously that's just an extra, as you might have a rear brake on a fixie.
Re: ...what the relative efficiencies of various drive trains?
squeaker wrote:LollyKat wrote:Cyril Haearn wrote:I am still looking for an old ordinary so the motons will see me, any tips?
Why not get a brand new one? https://www.unicycle.uk.com/penny-farth ... ennys.html
Er, are they street legal (2 independent means of braking)? (just curious )
You can fit a caliper to the rear wheel as an optional extra:
See, you've got no excuse not to get one .
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Re: ...what the relative efficiencies of various drive trains?
squeaker wrote:LollyKat wrote:Cyril Haearn wrote:I am still looking for an old ordinary so the motons will see me, any tips?
Why not get a brand new one? https://www.unicycle.uk.com/penny-farth ... ennys.html
Er, are they street legal (2 independent means of braking)? (just curious )
I did test-ride a 36" ordinary, quite easy to ride
A unicycle can be braked by pedal pressure or by jumping off, two independent means of braking
Saw an ad for unicycle classes for grownups, it was described as evolution: as a baby one sits in a pram with 4 wheels, then one rides a trike, then an upWrong and ultimately a unicycle, +1
Entertainer, juvenile, curmudgeon, PoB, 30120
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we hate bullies
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we hate bullies
Re: ...what the relative efficiencies of various drive trains?
I have taught several people (including myself, armed with no prior information!) to ride a unicycle. IMHO you are better off not bothering with any form of stabilisers; they will teach you habits that will just be counterproductive (and will have to be unlearned) later on.
In essence you are best off finding a corridor you can practice in (so that you can't fall sideways) in order that you get the hang of controlling your front-rear balance, which is completely unlike riding a bicycle. Not falling over sideways is then just a question of steering by twisting your body and pedalling at the right time. If you use a small wheeled unicycle (with say a 16" to 20" wheel) then your feet are only a few inches off the ground (so you can just step off as required) and you will be able to adjust your balance very quickly with a small wheel too. Larger wheeled unicycles are more difficult, and taller ones may fall less quickly but just hurt more if/when you fall off them.
Considering the transmission is so 'efficient', unicycles are surprisingly tiring to ride...
cheers
In essence you are best off finding a corridor you can practice in (so that you can't fall sideways) in order that you get the hang of controlling your front-rear balance, which is completely unlike riding a bicycle. Not falling over sideways is then just a question of steering by twisting your body and pedalling at the right time. If you use a small wheeled unicycle (with say a 16" to 20" wheel) then your feet are only a few inches off the ground (so you can just step off as required) and you will be able to adjust your balance very quickly with a small wheel too. Larger wheeled unicycles are more difficult, and taller ones may fall less quickly but just hurt more if/when you fall off them.
Considering the transmission is so 'efficient', unicycles are surprisingly tiring to ride...
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: ...what the relative efficiencies of various drive trains?
Ah, thanks (But I still won't be rushing out to try / buy one )[XAP]Bob wrote:But also, from the exceptions section:CTC Construction and Use regs summary wrote:I've already noted that fixed wheel counts as a brake. Taking that a stage further: if one wheel is not only incapable of rotating independently of the pedals, but the pedals are fixed directly to it without any intervening chain or gears, the cycle does not have to be equipped with any actual brakes at all. This is obviously designed to allow various antique machines to be exercised on the highway without adding incongruous modern accessories!
So an ordinary (PF) doesn't need a second brake at all...
"42"