G-tech bike,has anyone seen a proper test

flecc

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Oct 25, 2006
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Look up Hebie Chainglider. It can be fitted to a chain driving a Nexus 8 Inter (or Rohloff) and achieves the same goal as a belt drive for much less €$£. You need a frame with horizontal dropouts for it to work
Yes, a good product. Chains and sprockets don't really wear each other out to any degree, it's the fine atmospheric dust and road dust that does the damage, forming grinding paste with any oil or grease traces present.

Just excluding the dust multiplies the chain and sprockets life.

Hebie Chainglider
.
 

RobF

Esteemed Pedelecer
Sep 22, 2012
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Gates quote the belt life as 'about twice that of a chain'.

Not much when you consider a good chain is about £20 and the belt is closer to £100.

Grit does nothing for the belt, so even on road there is a chance one will mash itself and leave you both stranded and with a big repair bill.

Maintenance would be simpler, a chain requires some cleaning and lubing, whatever your chosen regime.

The belt can be fussy about tension, but I doubt it requires tensioning very often.
 

Wisper Bikes

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Apr 11, 2007
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The carbon belt is a little under 2% less efficient than a conventional chain (according to Gates), so it's unlikely we will see them on racing machines any time soon. When used in conjunction with the Nuvinci hub and an electric motor they work brilliantly.
From 2015 a groove was added to the centre of the belt to fit over a ridge on the chain drive, this effectively negated the need for a belt guide.
A few bikes such as the Riese and Muller Charger and Pony have a raised rear stays so there is no need to split the frame, this was the main reason the Charger won a Gold Award at the 2014 Eurobike. In my opinion, belt dives are great on an ebike with hub gears, next year I understand even Rohloff will have a belt drive sprocket.
 

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Wisper Bikes

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Regarding tension, Gates have produced a great app for iPhone and Android. Simply turn the app on "twang" the belt with your finger whilst offering the phone's mike to the belt. From the frequency of the "Twang" the app will let you know whether to tighten or loosen the belt! Genius!
 

Wisper Bikes

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Having read the above report and finding it very different from Gates' claims I wrote to them to query the discrepancies.

You may be interested in their answer?

Hi David,

Ah, that old Friction Facts “study”… This thing comes up occasionally, and it is an example of you can’t trust everything you read on the internet. That test was poorly designed, and the results were not entirely correct, and stated in a way that made them more sensational. Both synchronous belts and chains are about 98-99% efficient when properly designed and installed.

Jason was using an older Carbon Drive system, with too high of tension, as he didn’t follow our recommendations correctly. We had already commissioned two other studies before he decided to do his own, and our studies provided different results. We studied his test, and talked with him, but decided not to publish an official response. Later on, we actually hired Jason and his lab equipment to do a new study to prove our other tests were correct, and to test our then already seasoned Center Track system at proper tension levels. Our new test showed the expected results – that belts can be just as efficient as chains, or even more so.

He did get some things right in his report. Belts at very low loads are not as efficient as chains due to the slightly higher installation tension. However, once the loads start ramping up, belts become more efficient than chains. This happens due to the differences between slack side and tight side tension. Chains don’t require significant installation tension, and therefore have two ‘slack’ spans at rest. Belts do require installation tension, and therefore have two ‘tight’ spans at rest. When load is applied, however, the chain gains a tight side (the top span on a bicycle drive). The bottom span on the belt, actually goes slack – transferring the tension to the tight side (top span). How slack the slack side gets depends on installation tension. Our recommended installation tension levels see the slack side approaching zero tension at maximum expected loads from cyclists. There is also frame flex happening, also decreasing the tension on the slack side of the drive. This means that all of that installation tension that was causing inefficiency is now in the top span and transmitting load. This is also the reason that we use an 11mm tooth pitch with a specialized tooth profile. Our pitch and profile were chosen to keep our belt from jumping teeth as the belt approaches zero slack side tension. Smaller and different tooth profiles are more prone to tooth jump at that moment.

Let me try to give you a better idea of what I mean by low loads, and high loads. Loading depends on wattage and rpm. For someone very casually strolling along, imagine say 50 watts at 60rpm. At these loads, you will be losing a very, very small amount of efficiency with our belt drive and recommended installation levels. However, if you imagine an enthusiast or racer who is constantly putting in 200-250 watts at 100rpm, the belt will actually be more efficient than a chain.

Keep in mind, this is with a clean and properly lubed chain. Once chains become dry or dirty, they can lose significant amounts of efficiency, much more than the 1-2% they are rated at when new.

Finally, it is important to understand his reporting of the results. Chain and synchronous belts when designed and installed properly are both about 98-99% efficient. I believe that he stated something like this in his report – I think he called belts maybe 97% efficient? Let’s do an example. For this example, let’s assume that chains are 99% efficient, and belts are 97% efficient. This means that at 200 watts, a chain would lose 2 watts, while a belt would lose 6 watts. If you take 2/6, that is a 33% difference. Jason used this to claim a belt is about 33% less efficient than a chain, even though a belt is really about 97% efficient in this example. That 33% SEEMS like a huge amount, but it’s only a difference of 4 watts, which most riders could not even feel. Keep in mind, that this is all from his original data, which used over tensioned belts, and clean and lubricated chains. In the real world with a bike that is set up properly, and ridden outside of a lab environment, things start to change pretty quickly.

Efficiency is important. It’s also a very difficult topic. When comparing a single speed belt to a single speed chain, the differences on a new, properly installed system (properly lubricated and cleaned chain, and properly tension belt), can be minimal to non-existent, depending on loading and other factors. Or the belt can even be more efficient. But that’s not the whole story, it never is. The benefits of a belt can be huge. Longer life, no lubrication, little to no maintenance, no problem with rain or snow, quieter, smoother, lighter…. For a commuter, these things are extremely important, and worth way more than the tiny amount of inefficiency that you get a very low loads. To the road racer who needs gears, the addition of a heavier (than a derailleur system), less efficient internally geared hub is not worth the fact that the belt will last longer, or doesn’t require lubrication. To the single speed cross or mountain bike racer, the performance of the system in dirt and mud is a definite plus.
 
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Cyclezee

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I also notice that Cyclezee do not seem to sell the Emu brand any more. That appeared to be a useful bike, attractive, but a bit dear for what it was/is. The marketing men were thick on the ground with that one as well, I think. (My Woosh Santander had done over 5000 miles on the original chain when I sold it).
Just to clarify, we don't and never did sell EMU bikes directly, we have only ever been a demonstrators for EMU.
My opinion was that they were nicely made, the integrated battery is very neat and appeals to those that have seen it and subsequently bought one.
When launched at £999 I thought it was good value and a much better buy than the Gtech, e.g. 10Ah battery, Nexus 8 speed etc.
My opinion changed somewhat when earlier this year I was informed that the price would rise to £1499. I couldn't quite believe it as it was around the time that Gtech made a substantial price reduction, later however the price of the EMU came down to £1299 which is more reasonable probably worth the extra £300 on top of a Gtech.

As for carbon belt drives, I think the jury is out on that one and will be for quite a while.
 
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Wisper Bikes

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The original concept at Emu as with Gtech was to sell directly to the public, cutting out the dealers and therefore bringing the price of their bikes down. As we all know this simply does not work in the electric bicycle industry for all but the very cheapest ebikes.
An electric bicycle is a complex piece of machinery that needs to be serviced regularly to get the very best out of it. The features also need to be explained to a prospective customer and we all advocate a customer tries the bike before they buy. Selling directly is not the way to sell a lot of vehicles.

I believe that...

Emu finally have realised they have to sell through the trade and put up the price of their bikes to be able to do so.
GTech are still struggling with the retail shop concept, they used to sell their cordless vacuum cleaners through the likes of Currys but realised that if they sold directly, there were a number of advantages. Such as improved cash flow, reducing the price of their machines to the public and keeping more profit for themselves to market and pay dividends. They have dramatically reduced the price of their bikes for one of two reasons. 1. To start moving the substantial stock they may have in their warehouse. 2. To pull out of the market completely.

Both these companies, much like the car companies that have entered the market simply don't understand it and are unable to give their customers the care they need both pre and post sale. The Smart bike was another complete failure. I have one in my warehouse and it looks beautiful, but doesn't ride well. Smart also tried to sell it outside the bicycle trade, it didn't work for them either.

If you are thinking of buying an ebike, you will get the best service, advice (independent from any manufacturer) and choice by going to a local electric bicycle retailer. Sit down with them, discuss what you need from from the bike and they will recommend the best bikes to suit. Test ride a few and make your choice. You will then be able to go back with your bike for advice and servicing.

In my opinion it's the only way to buy a car a motor bike or an electric bicycle.
 
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RobF

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Sep 22, 2012
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The original concept at Emu as with Gtech was to sell directly to the public, cutting out the dealers and therefore bringing the price of their bikes down. As we all know this simply does not work in the electric bicycle industry for all but the very cheapest ebikes.
An electric bicycle is a complex piece of machinery that needs to be serviced regularly to get the very best out of it. The features also need to be explained to a prospective customer and we all advocate a customer tries the bike before they buy. Selling directly is not the way to sell a lot of vehicles.

I believe that...

Emu finally have realised they have to sell through the trade and put up the price of their bikes to be able to do so.
GTech are still struggling with the retail shop concept, they used to sell their cordless vacuum cleaners through the likes of Currys but realised that if they sold directly, there were a number of advantages. Such as improved cash flow, reducing the price of their machines to the public and keeping more profit for themselves to market and pay dividends. They have dramatically reduced the price of their bikes for one of two reasons. 1. To start moving the substantial stock they may have in their warehouse. 2. To pull out of the market completely.

Both these companies, much like the car companies that have entered the market simply don't understand it and are unable to give their customers the care they need both pre and post sale. The Smart bike was another complete failure. I have one in my warehouse and it looks beautiful, but doesn't ride well. Smart also tried to sell it outside the bicycle trade, it didn't work for them either.

If you are thinking of buying an ebike, you will get the best service and choice by going to a local electric bicycle retailer. Sit down with them, discuss what you need from from the bike and they will recommend the best bikes to suit. Test ride some and make your choice. You will then be able to go back with your bike for advice and servicing.

In my opinion it's the only way to buy.
No doubt correct for the realistic customer who is prepared to pay for what he wants and accepts everyone has to make a living.

Too many people are driven solely by price and buy the cheapest bike they can find online.

It will be a pile of cack, but those sort of customers get what they deserve.

As, one hopes, does the other type who is prepared to spend a few quid with a local dealer.
 
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RoadieRoger

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All very well to say support local Dealers and for this reason I originally bought my Batribike from a local Dealer , well 15 miles away . Within a couple of years two successive Dealers had folded and the last time I looked the current and third Dealer sold a few Electric Bikes but mainly gadgets for the older person like commodes etc . Luckily in nearly 6 years I haven`t needed a Dealer . When a Family Member wanted an Electric Bike , I advised him to get one through the mail from Woosh . He kept the packaging just in case , but after over 3 years he hasn`t needed it .
 

flecc

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I once bought from a good brand 150 miles away. Ten days and 200 riding miles later I drove a 300 mile round trip to have a new hub motor fitted.

The moral?

Even the best can fail prematurely at times.
.
 
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Cyclezee

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Emu finally have realised they have to sell through the trade and put up the price of their bikes to be able to do so.
Not quite correct David, EMU don't actually sell through the trade and never have, they have what they call demonstration centres and customers order direct from EMU https://www.emubikes.com/the-emu-experience/demonstration-sites
Personally I don't think this is a bad thing as customers are not blindly buying they haven't seen or ridden.

From the demonstrators point of view, a bike is provided at no cost and there is no pressure to sell sell sell. The demonstrator gets a modest commission if a sale is generated, not the sort of markup that a dealer would get.
 
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trex

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the EMU model is excellent for two reasons: the customer avoids buying the wrong bike plus he/she can ask questions and get replies from someone like John. IMHO, this is way better than going into a general bike shop where e-bikes are treated like poor relations or all the models they have are expensive. Secondly, if the customer subsequently buys at internet price then the savings can be substantial. This buying pattern would easily suit someone who is already familiar with looking after a push bike.
 
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mike killay

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What does surprise me is that with the huge growth in electronics in all walks of life, businesses have not been started by electronic gurus to repair and service all these things.
probably because we live in a throw away age.
 
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flecc

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What does surprise me is that with the huge growth in electronics in all walks of life, businesses have not been started by electronic gurus to repair and service all these things.
probably because we live in a throw away age.
Even the costs in repair time are often not recoverable within a price acceptable to a customer, let alone the necessary profit to provide a living.

The frequent inability to get single spares at a low enough price is an added difficulty.
.
 

Kudoscycles

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What does surprise me is that with the huge growth in electronics in all walks of life, businesses have not been started by electronic gurus to repair and service all these things.
probably because we live in a throw away age.
One of the reasons why e-bikes have a short life is the cost of replacement batteries. When the bike is a few years old and some parts need replacing it seems pointless when a replacement battery is £500 plus.
It seems only Kudos and Woosh have cheap replacement batteries,the Kudos battery cost is between £160.00 to £250.00,
KudosDave
 
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Cyclezee

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One of the reasons why e-bikes have a short life is the cost of replacement batteries. When the bike is a few years old and some parts need replacing it seems pointless when a replacement battery is £500 plus.
It seems only Kudos and Woosh have cheap replacement batteries,the Kudos battery cost is between £160.00 to £250.00,
KudosDave
36v eZee 11Ah VP battery Sony 18650 cells, 2 year warranty £275.
Larger capacities are available up to 28Ah.
Yes of course we do get people coming back for replacement batteries, in some cases the bikes are over 10 years old.
How many other brands have been around that long and just as importantly, the current battery case will still fit a 10 year old bike?
 

trex

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to be fair, Jimmy @ Insat-International can probably fix an 11AH battery for less than £275 on most Chinese bikes.
 
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Cyclezee

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to be fair, Jimmy @ Insat-International can probably fix an 11AH battery for less than £275 on most Chinese bikes.
No doubt Jimmy can, but we were talking about brand new batteries with 2 year warranty, not refurbished.
 
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