Belt Drives - the future?

Mark T said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in their
way?

Initially, inertia from the innate conservatism of the bike market.
There will naturally be suspicion of a New! Improved! Thing replacing
something that, for all its faults, works pretty well and we're familiar
with it. Fixing something that doesn't seem to be borken, in other words.

But I think that if it's as good as they say (okay, getting on for
almost as good as they say...) then it will gradually appear in more and
more bikes, so if it's going to conquer the world I'd expect it to do it
like alloy rims replaced steel, rather than overnight. But to start
with it does have to be that good, or it will be like DAB replacing FM
(or not, as the case seems to be...)

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch said:

Mark T said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

Initially, inertia from the innate conservatism of the bike market.
There will naturally be suspicion of a New! Improved! Thing replacing
something that, for all its faults, works pretty well and we're
familiar with it. Fixing something that doesn't seem to be borken,
in other words.

It will be a shame if belt drives just die through the conservatism of the
bike market. For a utility bike, a belt makes a lot of sense - no oil and
should last longer. I can see how it may work well off-road. I can't see
it ending up on race/audax machines (even though it is carbon fibre!),
except, possibly, in the recumbent arena.

But it will be some years in changing.

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

In news:[email hidden],
Mark T <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
tweaked the Babbage-Engine to tell us:

Quoted message said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

o Can't be retrofitted to an existing bike (or can it?)
o hub gears only so gear range is of necessity limited even if one can
afford a Rohloff

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Trees, once grown in large numbers, make perfect forests.

Nigel Cliffe said:

It will be a shame if belt drives just die through the conservatism of the
bike market. For a utility bike, a belt makes a lot of sense - no oil and
should last longer. I can see how it may work well off-road. I can't see
it ending up on race/audax machines (even though it is carbon fibre!),
except, possibly, in the recumbent arena.

I can see them being popular in commuting / city bikes. The width of
the belt, and the lack of lateral flex, means a fixed chainline and no
derailleur, so it'll only work with hub gears. But that's not much of
an 'only', considering there's a big market for people who only need a
few gears. As you say, for a utility bike it's seems like a good
thing. Oh, and it won't rust in the winter, which reminds me I need
to do some chain TLC this weekend...

Colin

Nigel Cliffe said:

Peter Clinch said:

Mark T said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

Initially, inertia from the innate conservatism of the bike market.
There will naturally be suspicion of a New! Improved! Thing replacing
something that, for all its faults, works pretty well and we're
familiar with it. Fixing something that doesn't seem to be borken,
in other words.

It will be a shame if belt drives just die through the conservatism of the
bike market. For a utility bike, a belt makes a lot of sense - no oil and
should last longer. I can see how it may work well off-road. I can't see
it ending up on race/audax machines (even though it is carbon fibre!),
except, possibly, in the recumbent arena.

Efficiency, beloved by racers and marketing droids, will be a big issue.
Bigger than it should be, probably; and murkier, certainly.

My recollection is that previous versions of belt drives were estimated to
be less efficient that a well-lubricated new roller chain. Belts do not
lend themselves well to derailleur gear systems, and that would add the
typical lower efficiency of hub gearing.

Cleanliness is a possible advantage - but if you are going to have a hub
gear, you might as well have a chaincase; which would probably also remove
or reverse any durability advantage.

Howevere, this will be (sort of) "new", and manufactures love "new" - it
means that they can sell stuff to (some of) the installed base.

_ said:

Efficiency, beloved by racers and marketing droids, will be a big issue.
Bigger than it should be, probably; and murkier, certainly.

My recollection is that previous versions of belt drives were estimated to
be less efficient that a well-lubricated new roller chain.

But a lot of the point of this new one is it's meant to be just as
efficient as a chain.

Quoted message said:

Belts do not
lend themselves well to derailleur gear systems, and that would add the
typical lower efficiency of hub gearing.

It is typical, but it's also changing. Hubs have come on a long way in
recent years while derailleurs haven't really changed /that/ much. if
they continue to improve (particularly the likes of the NuVinci CVT hub,
which just needs to get lighter AFAICT) this may start to be less of an
issue.

Quoted message said:

Cleanliness is a possible advantage - but if you are going to have a hub
gear, you might as well have a chaincase; which would probably also remove
or reverse any durability advantage.

I don't think so. An enclosed chain still needs lubrication, while a
drive belt doesn't.

It does have some clear advantages... as long as you don't particularly
need derailleurs for your particular application (and "need" can be
factored in as cost: they're popular at the low end in part because
they're not very sophisticated and thus cheap).

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Dave Larrington said:

o Can't be retrofitted to an existing bike (or can it?)

Retrofit would require a splittable (or spliceable) belt. Not impossible, but not yet here.

Dave Larrington said:

o hub gears only ..

You need to consider that snowmobiles, certain cars and various other vehicles have been using belt drives for years under the catchy phrase of CVT (continously variable transmissions).
Granted, an entirely different kind of belt compared to what usually discussed as the potential future of bicycles, but still a belt...

I wonder how the bike (marketing) industry would cope with a CVT-equipped bike? With no longer being able to use the number of gears to separate categories, what would they do instead?

dabac said:

I wonder how the bike (marketing) industry would cope with a
CVT-equipped bike? With no longer being able to use the number of gears
to separate categories, what would they do instead?

Google NuVinci, it's been released in the fairly recent past and
according to all the reviews I've seen thus far works very well indeed.
the current Gotcha is the hub weighs about 4 Kg, which is a lot in bike
terms. But it's version 1, I imagine it will improve.

Personally, I'd love CVT, just as soon as the costs and weights come
down (previous implementations have been rather inefficient AIUI, but
from what i read the NuVinci has got at least most of that sorted).
Rather than say "27 gears" you could differentiate bikes with practical
gear range, which unlike the "27 gears" would actually impart some
useful information... so I guess marketing might not like it so much... ;-/

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

dabac said:

Quoted message said:

o hub gears only ..

You need to consider that snowmobiles, certain cars and various other
vehicles have been using belt drives for years under the catchy phrase
of CVT (continously variable transmissions).

IIRC such transmissions have losses that aren't
acceptable on a HPV.

BugBear

Peter Clinch said:

dabac said:

I wonder how the bike (marketing) industry would cope with a
CVT-equipped bike? With no longer being able to use the number of gears
to separate categories, what would they do instead?

Google NuVinci, it's been released in the fairly recent past and
according to all the reviews I've seen thus far works very well indeed.
the current Gotcha is the hub weighs about 4 Kg, which is a lot in bike
terms. But it's version 1, I imagine it will improve.

Personally, I'd love CVT, just as soon as the costs and weights come
down (previous implementations have been rather inefficient AIUI, but
from what i read the NuVinci has got at least most of that sorted).

Well, it's about 8 lbs and there's a suspicious absence of efficiecy
figures on their website, which typically for lubricated CVT drives is in
the range of 80-90%. Roller chains (can) do much better.

Dave Larrington said the following on 01/02/2008 13:42:

Quoted message said:

o Can't be retrofitted to an existing bike (or can it?)

Not unless you take a hacksaw to your chainstay. Orange basically did
this, then cut'n'shut the join.

--
Paul Boyd
http://www.paul-boyd.co.uk/

Nigel Cliffe said the following on 01/02/2008 13:23:

Quoted message said:

I can see how it may work well off-road.

I'm not so sure - what happens when a great big splot of mud or a stone
lands on the belt? Where does it go when it reaches the pulleys?

--
Paul Boyd
http://www.paul-boyd.co.uk/

Dave Larrington said:

In news:[email hidden],
Mark T <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
tweaked the Babbage-Engine to tell us:

Quoted message said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

o Can't be retrofitted to an existing bike (or can it?)

Oooo, yes.

That'd have to be a design challenge; either a separable belt, a detachable
chainstay, or a frame made to be disposable if the belt should fail.

I bet Shimano goes for #3.

Mark T said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

Some questions that come to mind:

1) Has it been independently tested to see if efficiency really is as high
as with a conventional chain - and at high torque? Or do we just have the
designer's word for it?

2) Could the belt ever slip?

3) How critical is belt tension? Will the usual methods of tensioning be
adequate?

4) How long will it last? Will it wear out from friction?

5) What kind of sprockets will be needed, and what chainsets and hubs will
they fit?

6) How much will the chain and sprockets cost?

~PB

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

Dave Larrington said:

In news:[email hidden],
Mark T <pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>
tweaked the Babbage-Engine to tell us:

Quoted message said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in
their way?

o Can't be retrofitted to an existing bike (or can it?)

Oooo, yes.

That'd have to be a design challenge; either a separable belt, a detachable
chainstay, or a frame made to be disposable if the belt should fail.

I bet Shimano goes for #3.

Or:
http://mos.bikeradar.com/images/news/2007/Eurobike/Wednesday/Cannodale-
conceptedit-798-99.jpg
--
Cheers,
Mark

Paul Boyd usenet.is.worse@plusnet said:

Nigel Cliffe said the following on 01/02/2008 13:23:

Quoted message said:

I can see how it may work well off-road.

I'm not so sure - what happens when a great big splot of mud or a stone
lands on the belt? Where does it go when it reaches the pulleys?

mmm yes, think just water on the fan belt in a car.

roger
--
www.rogermerriman.com

Mark T
<pleasegivegenerously@warmail*turn_up_the_heat_to_reply*.com.invalid>

Quoted message said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Now that there's a new standard out there, does anything stand in their
way?

needs to be a fair bit cheaper to make or make faster bikes? hopefully
both. being simple and easy maintain probably will not sell at least
well.

the problem is the chain is attually very good.

roger
--
www.rogermerriman.com

bugbear bugbear@trim_papermule.co.uk_trim said:

dabac said:

Quoted message said:

o hub gears only ..

You need to consider that snowmobiles, certain cars and various other
vehicles have been using belt drives for years under the catchy phrase
of CVT (continously variable transmissions).

IIRC such transmissions have losses that aren't
acceptable on a HPV.

BugBear

on a about town bike, i'd be quite happy to take some losses for some
conviences

roger
--
www.rogermerriman.com

Pete Biggs said:

Mark T said:

<www.bikebiz.com/news/29367/Carbon-belt-drives-are-standardised>

Quoted message said:

Now that there's a new standard out there, does anything stand in
their way?

Some questions that come to mind:

2) Could the belt ever slip?

It looks like a toothed belt to me so no, it will never slip. (Much as
the cambelt on a car never slips - at least, if it does you've got a
very expensive problem to sort out)

Quoted message said:

3) How critical is belt tension? Will the usual methods of tensioning be
adequate?

Probably not very although efficiency might vary a lot if it's not
quite right. On something like a Brompton where you have to have a
chain tensioner then the tension should always be right.

At 95% of the efficiency of a chain, and no maintenance or oil at all
I'd be very interested in this on something like the Brompton which is
a "get me about" bike. At 99% efficiency I'd want this on the
Brompton. Not sure about my other bikes - would be nice on the
windcheetah but the width might be an issue and there would have to be
some sort of different gearing.

Tim.