• This topic has 46 replies, 24 voices, and was last updated 4 years ago by 40mpg.
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  • Why no 2WD e-bikes?
  • molgrips
    Free Member

    There have been a few attempts at 2WD bikes in the past, they are a bit complicated but apparently brilliant to ride. But with an e-bike you could just have a little hub motor and everything else you need is already present.

    Great idea no?

    epicyclo
    Full Member

    I actually tried to make a 2wd years ago, so obviously I agree with you. 🙂

    With modern electronics and load balancing between the wheels it should have incredible grip/drive.

    molgrips
    Free Member

    Yeah you could have dynamic torque distribution like cars have.

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    cynic-al
    Free Member

    Really?

    You actually think there would be significant benefits for enough riders?

    Bez
    Full Member

    You actually think there would be significant benefits for enough riders?

    Since when did that have anything to do with selling new bicycle parts? 😉

    molgrips
    Free Member

    You actually think there would be significant benefits for enough riders?

    I think it would be fun, and that’s what recreational bike riding is about isn’t it?

    The problem of maximum utility for humanity from bikes has already been solved. Doesn’t mean we can’t invent new cool stuff does it?

    PJM1974
    Free Member

    Unsprung weight – most e-bikes have the motor located around the bottom bracket, with drive going to the rear wheel via a conventional drivetrain.

    Potentially, you could take the torque from the rear axle and feed it to the front wheel with a system of bevel gears and telescoping shafts as per Christini 2wd bike, but the same issues of maintenance remain with potentially far greater torque from a motor to deal with.

    Chrisitini AWD Fatbike

    It’s a brilliant idea in concept though, imagine the extra traction and control with climbing an enduro bike if you could direct some torque to your front wheel…

    tomhoward
    Full Member

    Looks like there’s plenty of ‘home made’ options, mostly BSOs with 2 hub motors and a million batteries.

    Reckon a 2wd car would be of comparable weight…

    db
    Full Member

    HOME

    Not really a bike, more motorcycle but I like the idea.

    cynic-al
    Free Member

    It’s a brilliant idea in concept though, imagine the extra traction and control with climbing

    Given that nearly all your weight is on the back wheel, bugger all?

    hot_fiat
    Full Member

    It’s a great idea. The Yamaha/Öhlins 2wd Enduro / MX / street system was very good indeed, especially uphill, off-road, but probably failed in that arena because of market timing. It’s certainly a technology that is going to come back in motorcycling, so why not mountain biking.

    Öhlins bike

    molgrips
    Free Member

    Given that nearly all your weight is on the back wheel, bugger all?

    Ever ridden up something very steep? You put your weight over the front so you don’t fall over backwards, and this is when your rear wheel slips and you stop. From reading reviews of previous 2wd attempts, they climb up anything.

    kevs
    Free Member

    My cargo bike is basically 2wd, hub motor on the front wheel and human power rear?!

    Its helpful getting up muddy slopes that you normally wouldnt make it up with slick tyres. Tbf just putting a mountain bike rear tyre on would Make more difference.
    Wouldnt like the extra weight of a hub motor on a normal bike though.

    cynic-al
    Free Member

    You can’t get your weight over the front on anything REALLY steep, it’s still over the back.

    In the scenario you describe, which I may have experienced once or twice in 30+ years of riding, I guess it might help.

    BUT you are saying you have enough traction to wheelie and fall off the back, then you move your weight forward to avoid that and you get wheelspin? Move your weight back…basic climbing skill.

    epicyclo
    Full Member

    PJM1974
    …Potentially, you could take the torque from the rear axle and feed it to the front wheel with a system of bevel gears and telescoping shafts as per Christini 2wd bike, but the same issues of maintenance remain with potentially far greater torque from a motor to deal with.

    A certain amount of that torque also acts on your steering whereas a 2wd eBike would not have to cope with it.

    I suspect we’ll see it first on offroad eMBikes.

    It should simplify steep offroad climbs. At the moment expertise is required to avoid the backwards loop on loose steep climbs when trying to finesse between traction and forward progress.

    Not a replacement for a ‘proper’ bike but another fun toy.

    Nobeerinthefridge
    Free Member

    Ever ridden up something very steep? You put your weight over the front so you don’t fall over backwards, and this is when your rear wheel slips and you stop. From reading reviews of previous 2wd attempts, they climb up anything.

    Mates of mine with FS ebikes can get up anything anyway, with the right tyres.

    To have 2wd, you’d either need two batteries, meaning even heavier, or run off one battery, and deplete the range.

    chiefgrooveguru
    Full Member

    There’s a reason that although almost all off-road vehicles are AWD, off-road motorcycles remain rear drive!

    JAG
    Full Member

    Don’t forget the impact a driven front wheel would have on steering and control.

    There would be an increase in gyroscopic forces that would make the steering heavy and awkward.

    For that reason (among others) I’m out :o)

    HoratioHufnagel
    Free Member

    eh? People already use front hub motors on bicycles

    thisisnotaspoon
    Free Member

    Don’t forget the impact a driven front wheel would have on steering and control.

    There would be an increase in gyroscopic forces that would make the steering heavy and awkward.

    I’m not sure it would, those hub motors used on things like the Ribble bikes are tiny. Barely bigger than a dynamo and put out 250W. It might be noticeable as unpsrung weight, but not enough to be detrimental I’d have thought. No one ever decided SID’s were better than Lyrics because the lowers weigh half a lb less.

    A better control system might be a sort of reverse-abs that adds extra power up front (in addition to the normal torque/cadence sensing on the cranks) when it senses the rear wheel moving significantly faster.

    To have 2wd, you’d either need two batteries, meaning even heavier, or run off one battery, and deplete the range.

    Same power output, just split between two motors. You could probably save some of the weight from the ‘main’ motor too if it was an integrated system.

    In the scenario you describe, which I may have experienced once or twice in 30+ years of riding, I guess it might help.

    You’ve only spun the rear wheel out on a climb, twice, in 30 years?

    Roots, rocks, steps, muddy bits, none* of those have ever brought you to a standstill because the back wheel spun on them?

    Having a bit of ‘pull’ to offset those times when you have to back off and unweight the rear of the bike over stuff would be pretty cool.

    *well I suppose one or two of them might have contributed to you’re only 2 failed climbs.

    brant
    Free Member

    I crashed a JUMP ebike with a front hub motor on wet cobbles last year. That was definitely a power/steering/traction issue and not the £8 craft beer I had been drinking.

    singletrackmind
    Full Member

    They exist. I have ridden one. A 2wd fat bike on snow in the alps
    Grip was amazing you could climb things that would not have been possible on a bike ever
    Heavy as though with 4″ tyres 2 motors and battery
    We reckoned you go from led deux alps to alpe d huez and back on a single charge

    cynic-al
    Free Member

    Molgrips that’s not what either of us said.

    molgrips
    Free Member

    Move your weight back…basic climbing skill.

    FFS. I’ve only been MTBing all over the UK for 30 years, what do I know about climbing? If you don’t run out of traction on steep stuff then you aren’t riding steep stuff. There are tons of trails that people only ride down because it’s simply not possible to ride up them – on a 1WD bike, that is.

    Read the stories about 2WD bikes that already exist, before theorising.

    mmannerr
    Full Member

    Well-timed thread, there is now Christini 2WD e-bike on the frontpage.

    Olly
    Free Member

    I had an urban arrow cargo bike, which was great, but at a max GVW of around 200kg, the 250w support could have been more effective.
    Considered getting a Front wheel motor to complement the rear driven mid motor. Would’ve been a total 500W 2WD.
    Our Yuba El Mundo is FWD electric assist. I thought it was going to be awful, but im pretty impressed. Its been solid so far and pulls well. Its a rigid town bike mind, there is no way i would want that weight on an off road wheel.

    Nobeerinthefridge
    Free Member

    Read the stories about 2WD bikes that already exist, before theorising.

    Mibbe you should read the stories, before starting a thread stating that there are none?.

    hols2
    Free Member

    Abominable
    null

    stevextc
    Free Member

    FFS. I’ve only been MTBing all over the UK for 30 years, what do I know about climbing? If you don’t run out of traction on steep stuff then you aren’t riding steep stuff. There are tons of trails that people only ride down because it’s simply not possible to ride up them – on a 1WD bike, that is.

    Read the stories about 2WD bikes that already exist, before theorising.

    Bit of a one trick pony though… or very niche. Potentially you end up with something that can climb but not descend or jump if its got a front hub…

    Olly
    Free Member

    Eugh, cant work out how to embed it.

    ….oh, it just does it.

    molgrips
    Free Member

    Potentially you end up with something that can climb but not descend or jump if its got a front hub

    Would it really impair its abilities that much? We’re not talking about kgs of metal on the front wheel are we?

    Mibbe you should read the stories, before starting a thread stating that there are none?

    Ok but it’s a bit more social to start a discussion than to just google on my own and keep it to myself, no? Thought we could have a fun discussion about a bit of a novelty idea, not have both my climbing ability and social skills dragged.

    I think even on stuff that is doable on 1WD it’d be easier on 2WD as you could sit and spin and require less body movement. There’d be a switch to engage it, with a few different modes on tap.

    rickonwheels
    Free Member

    I’ve seen someone locally heading up the hill to Ashton Court trails riding a cruiser/ clunker with front and rear hub motors. He looked happy.

    philjunior
    Free Member

    It’s not quite the same unfettered benefit as AWD on a car/truck though – if you wheelspin the front wheel loses lateral grip and you can’t balance.

    I guess cost/complication/lack of market. Or they’re waiting to release it next year when all the trend following sheeple have bought ebikes so they can sell them a new bike 😉

    cynic-al
    Free Member

    Even if a 2wd bike would make a tiny number of climbs easier, I quite like to practice/use skills, or just walk, rather than spend £££ on a heavy bike with more to go wrong and lug it round lots of rides for that tiny benefit (sorry, I am based!)

    tjagain
    Full Member

    I don’t think 2wd would make a huge difference to steep climbing – when you are on that point where its spin the rear wheel or loop out there is no almost weight on the front even with your chest on the bars.

    ta11pau1
    Full Member

    Meet the all-wheel drive, 68lbs Abominable e-fat bike!

    A 2wd fat bike does make the most sense, no shortage of traction to tractor up snowy hills. Imagine passing stranded cars on that thing 😁

    Nobeerinthefridge
    Free Member

    That Rokon riding looks bloody dull! 🤦‍♀️

    singletrackmind
    Full Member

    Snow biking on the Rossignol 7G

    This is an article on the 2wd Ebikes me and Debz hired in France

    TJ . Thats a fail. We were climbing up a snow and ice covered GR up a real mountain. You would have struggled to walk up it, with the assist turned down to 1/5 and pedaling away to maintain some balance it was possible to climb stuff that would have been impossible on a man powered bike

    Thses were so heavy that there was enough weight to maintain traction. We got buried waist deep at one point and man handing them through the snow was nearly impossible

    The grip from a 4″ tyre was huge , there was another GR we rode down with switchbacks , perfectly ridable on a FS , we didnt attempt it on the Ebikes , too unweildly

    molgrips
    Free Member

    when you are on that point where its spin the rear wheel or loop out there is no almost weight on the front even with your chest on the bars.

    Normally you feather your weight between keeping the front wheel down and keeping traction on the back wheel. That’s why the front lifts. If you had drive on the front wheel, you could lean on it as much as you want. From what I’ve read that’s what you do with them.

    stevextc
    Free Member

    Would it really impair its abilities that much? We’re not talking about kgs of metal on the front wheel are we?

    I guess it depends but I guess what I mean is the last thing I want on a big drop off when I’m tired is a nose heavy bike but I’m picturing something like a hill climb specialist bike for offroad (or reverse DH bike). At the moment for example I see stuff that is “possible on a ebike” or even possible on a XC bike with a grippy tyre… and what I’m thinking is if you want to go beyond what a ebike can currently get up then you’d change a lot of geometry on the “normal trail/enduro” spec as well. I can see a fun niche where you climb the near impossible then decend the fireroad type thing…?

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