Gate Drive Belt

[Brucey]

interesting, and pretty much what you might expect. My understanding is that all belts meant for dirty conditions should have Kevlar fabric facings, but that the lengthwise fibres in the belt (which carry the service loads) are varied between glass fibres, Kevlar and carbon, in order of ascending cost and stiffness.

FWIW I have seen several belt drives which failed because the sprocket wasn't a snug enough fit on the IGH driver and wore at the interface. If there is a bad fit here, you can set a preload tension, only to have it vary in service because the sprocket won't orbit concentric with the hub when it is under service loads.

IME most belts appear to be sized/constructed with relatively low service loads in mind, i.e. seated pedalling, steady state. This means that when you stand on the pedals, the belt (elastically) stretches appreciably and load transfer is no longer shared as well between more than one tooth on the belt and the sprocket, because the pitches don't match any more; this is likely to kill the belt and the sprocket far more quickly than normal, dirt or not. [As a parallel, if you run a worn chain on a new sprocket, it soon knocks the hell out of the sprocket, for similar reasons.] The fibres that make belts stiff enough lengthwise are one of the expensive parts of the belt so it may be that they are the first things to be skimped on. I have not done any measurements of 'stretch' but it wouldn't surprise me in the slightest to find that some belts stretch by about 0.5% under 'standing pedalling' loads; this discrepancy would be plenty enough to cause accelerated wear at the interface with a chain, and I don't see any reason why a belt should be any different.

BTW whenever you see manufacturers data on belt drive transmission efficiency, you should assume that (unless stated otherwise) is has been obtained under constant load/relatively high speed conditions. These conditions flatter belt drives, so you can see measured efficiencies of over 90% quite easily. However if you use a 'pulsy' power source (like a motorbike engine or human legs) belt drives typically start to look a lot less efficient. IIRC independent testing of motorcycle transmissions (with motorcycle engines driving a belt final drive) gives losses of several tens of percent. I don't recall seeing any 'real' efficiency testing of bicycle belt drives; I expect the results of such testing to be execrable; were it otherwise the manufacturers would undoubtedly have published data to back their product up. That they appear not to have done any such thing may be all the evidence you need of the likely outcome.

cheers

[zenitb]

The sprocket is different, there must have been a older style one. Is the internal part of the sprocket which grabs onto the hub also plastic? Hard to tell from the photo, looks metal inner plastic outer.

....

yes Jupestar exactly that. Metal inner plastic outer.

Showing metal inner, plastic outer and CDN branding.

[cycle tramp]

This guy likes belt drive: https://www.cyclingabout.com/belt-drive ... rivetrain/.

...indeed, and his trip is sponsored by Koga, and it appears that they have undertaken to produce handlebars using his design. At this point, while I'm not suggesting a conflict of interests, i would be surprised that an essay on the benefits of chains was any more thoughtful..

One missing benefit of chains is that with a deraileur bike, should the chain snap a number of times during a tour it may be repaired and repaired again (although you may loose some gear ratios in the mean time) until you get to the next bike shop....

Another missing benefit is than as you can change the length of chain without too much bother thus making it alot easier to play around with your gear ratios when using single speed or an internal geared hub..

Whilst I appreciate that the belt drive requires less maintenance than a chain I never understood why that was, from a human emotional point of view 'A Good Thing'. (Although interestly he does admit to cleaning the belt with water and a tooth brush to reduce the rate of wear on the rear sprocket) Self empowerment, self belief and learning new skills are key points to better mental health. What we need are more bicycle maintenance courses. If you want a less crusty chain then may I suggest front mudguard, a very long front mud flap and a decent rear mudguard.

[cycle tramp]

...let's not forget Koga is a bike manufacturer... if they had wanted too they could have cut through the chain vs belt arguement by using a single chain ring/ hub drive system and encased the drive chain in a complete chain case. That way the chain could have even run through an oil bath in a dust free environment, extending its life, cutting down on maintenance and providing a drive system which was more efficient and also silent in use...

[Brucey]

^ ah, but that wouldn't be 'progress', would it..?.

cheers

[Si]

Various posts removed. Please refrain from the petty name calling and nitpicking. Thank you.

[Billy007]

Deleted.

[zenitb]

Interesting. I think Gates decision to use plastic for it's sprockets was regrettable as the material is clearly not up to the demands placed on it. It was probably a cost decision that has created sprockets that are not fit for purpose. I have heard of a few instances where they have worn away seemingly prematurely even with just urban riding and little grit or mud to get onto them to increase wear. I think a metal rear sprocket preferably stainless steel is definitely a necessity.

Rather than wait for mine to wear out prematurely I have purchased a stainless steel one albeit at a cost to me rather than Gates.

.. interesting Billy - was it easy to find and was it expensive/cheap ?

An all encasing cover would be desirable. Maybe one will appear on the German market soon as this is where most belt drive bikes seem to be ridden?

Btw is your bike a Cube as I can see what looks like a Cube logo in one of the pics and the frame looks like a Cube. If it is a Cube Hyde Pro with Alfine 8 speed then the sprockets and belt would have been CDN as mine are/were.

I am impressed you identified it from the pics Billy. Yes, it is essentially a Cube Hyde but with mudguards, lighting and rack, called the CUBE Travel Pro. It has Nexus 8 rather than Alfine 8 though. Ironically I originally ordered the 2017 model (that came with a chain) but that went out of stock and I was "upgraded" by the Halfords Cycle2Work scheme onto a 2018 model (with a belt drive and nominally £150 dearer) at no extra charge but something like 8 months wait.

my Cube Travel Pro 2018 fresh from Berkshire Bikes

I think maybe exposing your bike to so much mud and grit went beyond the capabilities of the CDN spec sprockets and belt? Just a thought.

You may have a point ...

Route to work - typical winter conditions

Of course the reason I went for this bike in the first place is that it was advertised as a low maintenance commuter bike. I had already been cycling to work on my canti braked, derailleur bike and had to do quite a lot of drive-train and (rim) brake pad maintenance. What better I thought than a hub gear, disk braked dedicated commuter bike with built in lighting ? And when the belt drive was added to the spec I just though that was another labour saving low maintenance feature ...

It's a bit naughty of Cube using the CDN set up when it is clearly not of sufficient quality or durability for even normal everyday riding. To market the bike for touring/trekking as mine is, is plain disingenuous. The Gates CDN components are just not up to the job.

Based on my experience I am going to agree with that. It would be good to hear other people's experiences of this though. I am prepared to accept my use of the bike was out at the "heavy" end of the spectrum, and with a demanding job with long hours I expected the bike to look after itself rather than have to be laboriously cleaned after every day - much like my previous Cannondale MTB/Tourer/Commuter bike had done. (In fairness since swapping to a chain drive it has been all that .. the upright design, convenient hub gears and powerful brakes have been just the job and I have happily slung it in the garage every night - now the belt has gone. Ok a bit of chain oiling every day or so in winter...)

Here is a pic or two of my 20T CDX:EXP rear sprocket. I have 22T sprocket on my bike at the moment. I think it is stainless steel, but could be wrong. Certainly a lot more durable than plastic!

DSC_1035.JPG

DSC_1036.JPG

Ok that looks interesting. You and me have both stuck the cash down to try out the technology and for me its intersting to get feedback from someone like me using it in the real world. It is not out of the question I might go back to it... but this time better informed and maybe with some serious upgrades to the components.. as you have done. Do update this thread to let us know how you get on with this stuff Billy .. and in the meantime I would be interested in anyone else's experience of the Gates drive. I suspect some people have got on just fine with it.. otherwise we would hear of more issues ?

[Jupestar]

I see is the unavailability of parts will cost them. And has already, if the bike shop had a belt, it would be on the OP bike (Cube Hyde Pro) now, and Gates would have sold another belt. The bike would be a belt drive bike.

Basically now it’s a chain drive, with a bolt in the seat stay, when it next goes to a bike shop what are they gonna do, even if he asks for a belt it’s what a week?.... £100 and wait a week or £20 while you wait... path of least resistance.

He talking about getting a belt ‘in stock’ but even that is not easy, it needs to be imported from Germany.

a couple of years ago if Cube did a steel version of this bike I probably would have brought it. I could still be interested, depending on the price obviously, but like a lot of these bikes there are parts that I would ride to failure then replace (like a cheap freehweel, or a cheap tire) I suspect this would have gone the same way...

[zenitb]

I see is the unavailability of parts will cost them. And has already, if the bike shop had a belt, it would be on the OP bike (Cube Hyde Pro) now, and Gates would have sold another belt. The bike would be a belt drive bike.

Basically now it’s a chain drive, with a bolt in the seat stay, when it next goes to a bike shop what are they gonna do, even if he asks for a belt it’s what a week?.... £100 and wait a week or £20 while you wait... path of least resistance.

He talking about getting a belt ‘in stock’ but even that is not easy, it needs to be imported from Germany.

Yes this is the issue I had on my first belt failure. I returned the bike to the dealer and it sat there for something like 2-3 months while the correct parts were obtained... I had retained my original commuter bike so was fine but someone taking up cycling and buying the bike on a cycle to work scheme would have been grounded..

a couple of years ago if Cube did a steel version of this bike I probably would have brought it. I could still be interested, depending on the price obviously, but like a lot of these bikes there are parts that I would ride to failure then replace (like a cheap freehweel, or a cheap tire) I suspect this would have gone the same way...

Serviceability is as important as durability and if you cant readily buy the parts, or the skills required to fix it are tricky and/or not generally available then the serviceability becomes low. My first bike (bought new in 1971) was a near indestructible 3 speed Sturmey Archer geared Raleigh Wayfarer roadster* and it scored really highly on both these points. As a ten year old I could maintain the whole thing with the cheaply stamped "free tool" that came with the bike and apart from the time a car ran over one of the wheels it never saw the inside of a bike shop until it was stolen 16 years after purchase - by then way too small for me but still being used to get to work. Really in buying the Cube I was hoping for that level of durability and serviceability again. Ironically I have had to go back to pretty much the same 1/8" chain I had in 1971

* like this one https://farm4.staticflickr.com/3119/242 ... 5aaa_z.jpg

[bgnukem]

I think maybe exposing your bike to so much mud and grit went beyond the capabilities of the CDN spec sprockets and belt? Just a thought.

You may have a point ...20200114_083727.jpgOf course the reason I went for this bike in the first place is that it was advertised as a low maintenance commuter bike. I had already been cycling to work on my canti braked, derailleur bike and had to do quite a lot of drive-train and (rim) brake pad maintenance. What better I thought than a hub gear, disk braked dedicated commuter bike with built in lighting ? And when the belt drive was added to the spec I just though that was another labour saving low maintenance feature ...

Given the state of that trail, or even just the roads at this time of year, I think the best thing you could do to prolong the life of your drivetrain is to fit a long mudflap to the front mudguard, else there's a steady stream of muddy water and grit heading directly for your front ring, belt and bottom bracket bearings (and your feet!).

[zenitb]

I think maybe exposing your bike to so much mud and grit went beyond the capabilities of the CDN spec sprockets and belt? Just a thought.

You may have a point ...20200114_083727.jpgOf course the reason I went for this bike in the first place is that it was advertised as a low maintenance commuter bike. I had already been cycling to work on my canti braked, derailleur bike and had to do quite a lot of drive-train and (rim) brake pad maintenance. What better I thought than a hub gear, disk braked dedicated commuter bike with built in lighting ? And when the belt drive was added to the spec I just though that was another labour saving low maintenance feature ...

Given the state of that trail, or even just the roads at this time of year, I think the best thing you could do to prolong the life of your drivetrain is to fit a long mudflap to the front mudguard, else there's a steady stream of muddy water and grit heading directly for your front ring, belt and bottom bracket bearings (and your feet!).

Good spot big nuke em . .as you have seen on the pic it inexplicably didnt come with a mud flap. I wondered at the time whether the regulation sensitive Germans at Cube were worried about toeclip overlap and subsequent product liability. However as you point out its desperately needed for my work route so its the first thing I added..see pic. Whether people consider this long enough would be interesting to know ... there is only so much the front mudflap can do of course when the rear wheels are also picking up crud. At least the bike came with mudguards I suppose...

[cycle tramp]

..Its a good looking bike, and I'm envious of your commute. You are right, a front mud flap can only do so much. Given the nature of your commute and the fact that you're using a hub gear, have you ever considered a herbie chain case? http://www.hebie.de

[zenitb]

..Its a good looking bike, and I'm envious of your commute. You are right, a front mud flap can only do so much. Given the nature of your commute and the fact that you're using a hub gear, have you ever considered a herbie chain case? http://www.hebie.de

Interesting product cycle tramp... looks cheap enough to just try ...

Hebe Chainglider

Best case the chain would stay nice and clean. Worst case (plus my luck?) would be the whole Chainglider became clogged with oozing mud !!! Obviously with Covid I am not commuting any more but I was thinking of repurposing the bike for touring so it may be worth a try....

[ElCani]

..Its a good looking bike, and I'm envious of your commute. You are right, a front mud flap can only do so much. Given the nature of your commute and the fact that you're using a hub gear, have you ever considered a herbie chain case? http://www.hebie.de

Interesting product cycle tramp... looks cheap enough to just try ...

hebe.JPG

Best case the chain would stay nice and clean. Worst case (plus my luck?) would be the whole Chainglider became clogged with oozing mud !!! Obviously with Covid I am not commuting any more but I was thinking of repurposing the bike for touring so it may be worth a try....

I'm a happy Hebie (Chainglider) user. Slightly fiddly to fit and take on and off, but not too bad and seems sturdy. Noise is a bit unsettling when you test it on the stand, but I don't notice it when riding. Keeps the chain clean and will not fill with mud/water unless submerged.