Comment by bri3d
1 day ago
Friction drive e-bike conversions were popular years ago.
They generally:
* Wear tires surprisingly quickly
* Absolutely suck in any form of weather or terrain condition (dirt, rain, etc.)
* Have ~20% less efficiency than any other drive form.
But, they are easy, and they do work.
This bike booster will probably come in at less than half the cost but the Bimotal kit is another option that doesn't have the tire wear issue, offers better performance, and the form factor is much nicer.
https://bimotal.com/products/elevate
Wow, $2k? You could get a decent ebike for that money. And the installation doesn't look any easier than a hub motor... Only seems worth it if you already have an extremely nice bike. I think of friction drives as being aimed at budget-conscious commuters, not serious mountain bikers.
I think in nyc I'd prefer to lock my $100 dumper of a bike on the street and be able to take the expensive component with me, if this thing is as detachable as it seems
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I was shocked by the price, too. I mean a motor and a battery can't be so expensive, especially such a "small" battery (300Wh).
That being said, having driven electric bikes for a while, here in France they're ridiculously limited in speed and power. 25km/h limit on flat land usually makes sense (except on long straight lines), but when you get climbing even slightly you get down to ~10km/h and have to provide more effort. I guess that's where the 750/1250W 70Nm unrestrained motor comes in handy, and if you live in a place with lots of small hills the choice is either that kind of motor or a car, not the 1000€-total Decathlon/Carrefour electric bike.
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Mountain bikes one level down from professional tier start at 6-8k. If I could pay 2k and get a nice electric bike from my nice muscle bike it would be a bargain.
However bimotal is not that nice - adding a motor to rear triangle alters weight distribution and adds unsprung weight. Also unlike actual nice MTB e-bikes it cannot use chain/casssete for gearing, so gearing is fixed at the factory. If you’re used to nice bikes you will want your ebike to be dialed in just right.
One place where it makes sense is as an alternative to shuttling on forest roads / lifts for downhill-focused riding. F you’re going strictly downhill you can move the motor to the backpack after finishing the climb to reduce unsprung weight. This opens up a large number of trails where forest roads are blocked to car traffic. It also allows dh riding on trail where motor bikes are prohibited.
> Only seems worth it if you already have an extremely nice bike
How nice should one's bike be that you'd rather turn it into a mediocre ebike for the price of buying a good ebike?
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$2k makes sense only if the bike underneath it is valuable enough that you specifically want to keep riding that bike
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Bike equipment is ridiculously high margin. Motorcycles and mopeds are extremely common commuting vehicles in much of the world, yet i'm surprised motorcycles aren't more popular since they offer much more capability and are a better value.
You can get a nice ebike for that money if you're even slightly patient in waiting for a sale to hit.
Bimotal is removable after the installation: the motor and battery can both be taken off in under 30 seconds and you're left with just the cables and a specialized brake disc. I'd say that's its main differentiator. It is definitely more for premium bikes though and even then isn't for everyone.
As a mountain biker I don’t see the appeal of this. Yes, this rather expensive solution could transform my nice bike into a shitty e-bike, but the point of having a nice bike is to avoid a shitty experience.
A proper e-bike needs to be designed as an e-bike from the beginning.
Shuttling? Once you remove the motor and put it into a backpack downhill riding should be quite decent. Decent enough I think to make it worth it for the space and cash saved.
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Oh I like this idea. Looks simple and lightweight.
Expensive as f though. Also the gear-thingy looks proprietary (=expensive).
That's a terrible kit that should never be considered. You can get 6kW monster kits like the CYC X1 Pro, and battery, for that price!
About tire wear, I know a guy who did custom "Solex" type bike racing, with a small, friction drive petrol engine on the front wheel.
It was so bad that the rear wheel ended up getting bigger at the end of the race, as it picked up rubber deposited by the front wheel!
Keep it mind it was custom bikes though, the front tire just had to finish the race, they used a roller made of hard materials and knurled. I don't remember the reason, but it probably had to do with the fact their engines were quite a bit more powerful than traditional ones despite having the same displacement.
Had to look this up: https://www.youtube.com/watch?v=xmKoC57UWUI
Also:
* you cannot install them on bikes with a rear rack. Here most city bikes have them.
That made me question who this is for. Looks like it's only for racing bikes that have taken off the rear mudguard. And those bikes are typically used to exercise..
Which makes me wonder about the cleaning after it rained..
Nobody who rides a road bike would be seen dead with something like this. There are proper road ebikes for that.
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Only commuter and bikepacking bikes have mudguards, almost nobody puts one on a mountain bike or a proper road bike, regardless of whether they’re electrified. This looks like it’s more for these “sporty” categories of bikes.
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What I've noticed in my area is that people just don't ride on rainy days. If I'm at work and it starts to rain, someone will offer me a ride. It doesn't occur to people that a bike can get wet.
Bikes are sold without mudguards, and the aftermarket ones are flimsy and don't fit very well. (The steel ones that came with my 1983 Schwinn frame being the exception).
"Who this is for" is the great un-answered question in American cycling. The reason is that our biggest untapped market is people who don't ride at all. The marketing looks like lifestyle marketing: Here's what's wrong with cycling and how we solve it. Here's what you will look like.
Removing a rear rack is a few minutes with a screwdriver. I have my stuff in a rucksack. Good to point out, but will not stop most users I imagine.
The point of a rear rack is to use it, it's not there for style points.
Absolutely.
A Skarper system [0] that drives through an adapted brake rotor sounds [1] like it is the way to go if really want [2] a well thought close to non-permanent conversion solution.
[0] https://skarper.com/
[1] https://road.cc/ebiketips/review_v2/skarper-ebike-drive-syst... .
[2] Compared to other conversion options they are currently expensive https://road.cc/ebiketips/content/advice/buyers-guide/best-e...
And, don't forget: easy to steal off even a well-secured bicycle.
That's not a problem in Asia.
Only because there are so many targets to steal from. And by Asia you mean China, where E bikes are rarely very fancy and often the size of a moped (except for the ride shares, which are still bricks and GPS tracked). And judging by the noise level at the hotel I stayed at in Chengdu a couple of weeks ago, they definitely come with theft alarms.
"A team of Vidyadhar Nagar police arrested a bicycle thief and recovered 19 high-end cycles stolen from various neighborhoods in Jaipur Monday. DCP (North) Karan Sharma said that the accused, Rahil Swami alias Kabbu, is a resident of Old Vidyadhar Nagar and admitted to stealing over 50 bicycles." (https://timesofindia.indiatimes.com/city/jaipur/police-arres...)
False. I recently saw a bike frame tied to a railing and there were not even wheels left. If it was not tied there would be no bike
They will even steal a helmet off a parked bike and that's way cheaper. Just look how many helmets are left on bikes in different parts of different towns (because there is literally no advantage to take your helmet anywhere other than for theft protection)
Bike theft common in Japan
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I'm curious what the implication of this blatantly false* statement is.
*At the very least, you have to worry about Jackie Chan "borrowing" your wheels for a wacky chase scene. Based on my knowledge of Hong Kong cinema, this must happen at least once per week. Dude is a menace and a fiend.
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Yeah. I don’t see weather or theft addressed in this design.
I recall a wheel-mounted rotor system from a few years back that did address theft, tire-wear, and weather, but it suffered from far too little torque and very limited battery life.
It looks like their solution is to make it easy enough to install and remove you take it with you. My thought would be security bolts so the pool of thieves is at least limited to people with the right bolt head. Also it has a big battery built in so
Thieves will just take the whole bike.
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Can't use with mud guards
These sorts of seat mounted mud guards would work: https://ass-savers.com/ (yes, the URL is funny and seems a risky click)
And WTF is it about mud guards now?
When i was young all bicycles came with mud guard (then called "fenders") front and rear. Now they seem to be anathema.
Every bike I rode w/o fenders put a stripe of mud up my back!
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Millions and millions of people live in places where theft isn't a concern.
I live in the city considered to be one of the best to live in Europe. Bike theft is absolutely an issue here. I'm afraid to imagine what happens in other countries.
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Looks like you can't have a passenger anymore either. I like to have my kid on the backseat of my e-bike.
I'm not in the market for this, but I am in the market for making my cargo bike electric. Having to slow down at a traffic light and then start from zero absolutely sucks. It goes very slow, it is rough, and you won't have time. I'd use it just for that specific use-case.
Conversion kits that add a front hub motor are relatively affordable and easy to install. Should work with most cargo bikes if you can find one that's compatible with your wheel size. Something like: https://swytchbike.com/
Here's my cargo bike: (non-e variant): [1]. The company got bankrupt a couple of days ago.
It has three wheels. Two smaller ones at front, one back. As such, I'd prefer to install the motor on the back. We do have that speed limit of 26 km/hour (my current e-bike has it as well), but since more force is required, the kit would need to know this as well.
I got it second hand, same as my e-bike. Otherwise, these aren't affordable for me. 6k EUR for a cargo e-bike is just insane IMO.
[1] https://www.babboe.nl/media/akeneo_connector/media_files/b/a...
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Also: I'd not recommend hub motors with cargo bikes. There is a reason all cargo bike makers switched away from hub motors. They're low-power and often not strong enough mechanically.
Swytch are great in marketing, not so much in engineering. Very proprietary system that keeps changing every year or so. We have one kit, but I'd not buy from them again.
If it’s for a chill cargo bike, just get a hub motor kit. It’s the proper solution, there are tons of them and they are cheap and durable.
Front mount or trailer for kid could work, but this seems inferior to your ebike.
Do they work with mountain bikes? As stupid as this sounds I like mountain biking but I don’t have stamina to climb up hills and then keep doing for a long time. I have an electric bike but designed for road
I'd be quite worried about breaking it in the not unlikely event of a crash, additionally it looks like it could quite significantly limit how low you could put your seat down on a mountain bike, so that would get in the way. Even if you got your seat down, it would add a significant amount of height above the tyre so you mighn't be able to move your arse far enough back to shift your weight property. It's also adding nearly 4kg weight relatively high up which probably isn't the end of the world but would be better if it wasn't so high up.
It says on the website it will fit hardtails but not full sus, and that it isn't recommended on knobby tyres due to performance which isn't ideal either.
I could be wrong on all of this but those are just the concerns coming to mind as another mountain biker.
When going downhill, any bumps which result in severe movement in the frame that bring the rear wheel closer to the saddle might be problematic, even without full suspension. Hard to say. I’m a road bike guy but I’ve definitely seen some forms of non-full suspension when working on mtbs which would result in that kind of movement.
I think the tyres would limit the power output most. Probably quite annoying to have no rear mudguard in anything but the driest conditions. You’d be spraying a lot of crap up at the motor (and probably your back).
Attaching and detaching it looks relatively simple, though - removing it for downhills doesn’t look arduous. You could probably 3d print a clip for the frame.
Given the likely reduced power, and that the spec seems to be saying ‘500w peak, but 250w is sensible’ - probably up to the user’s needs whether the hassle is worth the extra watts per kilo. For those without mobility issues or longterm injuries, it’s usually best to optimise the rider rather than the bike for that.
I feel like off-road climbing would necessitate really wide, sensitive speed variance that this motor is likely not great at supporting. It strikes me that you’d want more direct pedal feedback.
Really fun bike design problem.
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Maybe get an E-MTB instead?
Wet-weather performance in particular seems like the thing I'd want to see independently tested
Personally I also don't see the niche they serve. If I'm going far away I take a train or a car. I pretty much exclusively use my bike to ride to a nearby grocery store or do other close-by errands. If I'm doing short errands like this, I really prize being able to get on and off quickly and lock my bike up quickly. A device like this needs to be taken with you when you leave your bike to prevent theft. It's a whole nother step and a lot of extra weight
Are you elderly, differently able, live in extremely hilly or hot terrain, or only willing to bike if it’s half the current effort?
That plus “already has a bike” is a massive market.
Fair enough. I guess I should've said the niche in my own life.
> That plus “already has a bike” is a massive market.
I imagine people who are elderly or differently abled would benefit more from an e-bike which is competitively priced to a bike + this device which will likely cost more than $1,000.
Pedal-assist electric rental bicycles are huge here in London.
It’s a relatively big city geographically, and it’s really nice to be able to do 5 - 10 miles in jeans and a long-sleeved shirt and not arrive at a social event in a sweat. The tube is really hot (high 30s!) in the summer and generally quite unpleasant (fleas in the upholstery!). So cruising around in the sun is a really big urban niche for rentals. Those that do lots of miles per day seem more likely to own e-bikes - delivery guys who probably average 50+ miles/day will absolutely feel the difference in their legs, and need to control their tiredness for their safety.
When I read your comment before the article I thought it was some sort of complicated contraption in multiple parts. Instead it seems pretty compact and easy to disengage. I’m not sure what you’re missing in terms of a niche either. Anyone who just wants to ride with less effort but use their existing bike?
You mean ebikes in general? I use one to commute to work in good weather. It's 8km and I'd be quite sweaty and impresentable for my work day without electric assist. In the evening I'm happy to ride back home with minimal or zero assist as my shower's waiting for me once I arrive.
What? No, I'm talking about the main link in this post
People who already invested in an expensive traditional bike and want to have the option to add electric support to make trips easier and faster without having to deal with selling their current bike and buying an even more expensive e-bike.
There’s also the fact that many people have bike racks that are fine for traditional bikes but not the additional requirements necessary for some (most?) e-bikes such as weight and strength.
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Just because it doesn’t work for you and your specific worldview doesn’t mean others wouldn’t see value in it.
Plenty of people in cities commute less than 10 miles and can bring their bikes into their work to keep them safe.
I had a gas powered goped that worked that way years ago. Had all those problems but it was fun. The second you hit any water the drive shaft would just spin against the tire.
Are there any mechanically coupled solutions that can be field installed by the owner?
There's a bunch of motors installable instead of the bottom bracket. E.g. from Bafang. You just connect it to a battery and that's it. The controller's inbuilt.
Swytch Bike is one. Hub motor.
I remember back in the 90s some guys at my school fitted a whipper snipper motor to a 12” kiddy bike with a friction drive (I think it was a skateboard wheel fitted to the output shaft).
I made one in 1985 for my 10 speed bike, it was pretty fun for a while. I was in my early teens at the time.
They could have made basically the same thing except with a sprocket to help drive the chain.
Chain moves side to side with gear changes, and adding extra chain tension with an extra drive sprocket could make the deraileur angry. Also, chain-tube geometry varies a lot. Not impossible, just more complicated than it might seem.
I ride an all-original 1970s steel-frame road bike, which seems like a prime candidate for this sort of product. I'm certain no sprocket-based design would fit it. I'd buy one of these if there was any way to lock it up.
It does not if you use hub gears.
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Go ahead, sit down with a piece of paper and try to design it in a way that doesn’t prevent shifting, doesn’t skip under load, doesn’t require you to use a longer chain, works with rear suspension and doesn’t interfere with your legs.
Tires wear out super fast. It's hard to say there is a market for this other than the uninformed.