A suggestion for coexisting with E-bikes: cheap, simple traction control

Forums Mountain Bike Forum A suggestion for coexisting with E-bikes: cheap, simple traction control

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This topic contains 9 replies, has 4 voices, and was last updated by  schwim 3 years, 4 months ago.

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  • #192925

    I had this idea and don’t see it anywhere out there: Here is my proposal:  E-bikes aren’t going away.  If we want to show that e-bikes can share trails with conventional MTB’s, we have to limit the way they use the trails, regardless of who is riding them.

    In my opinion, positive driven-wheel wheelspin and the subsequent trail damage it causes will be the biggest sticking point between users as e-bikes get more powerful and batteries store more energy, both of which are totally inevitable.

    If the industry starts now, it might be possible to have this feature be expected by everyone.

    ALL newly-manufactured e-MTB bikes should be required that they never let the rear wheel gain positive wheelspin – however it is powered: e-only, or e+pedal – more than ~5% faster than the un-driven front wheel.  This is easy for e-bike manufacturers to implement: as simple as a cyclometer – sensors on front and rear wheels that throttle back the electric assist when the driven wheel speed exceeds the undriven one.

    This is also easy for LEO’s to enforce: Pick up the e-bike, have the rider spin the front wheel while they spin the pedals, and then stop the front wheel with the front brake.  The assist should obviously stop with the front wheel.  If it isn’t funtioning, the rider is sent pushing his bike away, or cited.  Maybe it isn’t even a LEO that does it, but the riders ont he trail who notice someone shreddign the trail up… he who defeats/cheats the traction control it will be ridiculed for just trying it, hopefuly either the law or the cultural rejection or both will keep e-bike trail abuse to a minimum at most.

    Background:
    I’ve been investigating, testing and looking into all options with e-bikes a lot, as I have a long history as an off-road motorcyclist.  I like the idea of enhancing my fitness by being motivated to ride longer than I normally do or can, via electric assist.

    I’m also a career motorcyclist.  Observed trials, a lot of singletrack and off-road racing and some high-speed desert racing, a lot of adventure-style riding and long distance street/dirt riding are all part of my background.  Aside from trials riding, a huge part of the fun of a motorcycle off the pavement(ans sometimes on)is positive wheelspin – exceeding forward traction at the rear wheel.  I have deliberately cooked off many paycheck’s worth of rear tires on my motorcycles over decades with giant smiles to show for it.

    But I cut my two-wheeled teeth on bicycles – and a lot of the early dirtjumping and MTB riding around Arizona, when MTB was still in it’s true infancy.  So I’m partial to MTB, and the trails I grew up on as well as the vast array of plentiful trails that have been developed worldwide since.  I love MTB.  I love spinning, climbing, bikepacking(even though I’ve only dabbled), commuting when I can, and descending with haste and DH just the same.  I like the stealth of a bicycle, and the silence in many ways too.  I like the culture and fitness that it brings to people that are enticed by it.

    I also love horsepower, and wheelspin, and hillclimbs, and whoops, berm-banging, paddles throwing sand in the dunes, and generally ripping about with more power than I really need.  But I also understand that it does not have a place on trails that were built for MTB’s with hand labor and where horsepower and thrashing knobby tires will not and should not be welcome.
    I think this is a possible solution and I’d like to get it out there to see what others think.

    Thuoghts?  Suggestions?

  • #192927

    I don’t own an e-bike, no desire to ever ride an e-bike.

    That said, by your reasoning no e-biker would ever be able to manual (‘pop a wheelie’) on the trails. Seems pretty harsh to me. I can roostertail a berm and thoroughly trash it for the next guy using my own two feet. I can cause trail creep in a week or so of riding. I can do all kinds of damage,… but I don’t. A little knowledge and respect (ending in self-restraint) goes a long way toward keeping our singletrack enjoyable and rideable  for EVERYONE.

    I’m probably wrong, but that’s my opinion.

    • #192940

      There is no right or wrong here.   It’s only a discussion and all scenarios are possible.  And I respect your opinion, but you do lack understanding of what I’m suggesting.

      Nobody has self-restraint when they have unlimited power at their disposal.  Or at least, a rare few will, as has been proven by anythign else motorized when used recreationally.

      You’re only wrong with the reference to popping wheelies.  If you’re already riding along, and go to lift the front wheel with pedal torque + electric assist, it will do it.  It also would have no effect on doing it with pedal power alone.  This would be the case whether it was a power-wheelie, or a balance-wheelie(‘manual’) just the same.  That’s the idea behind the ~5% or whatever close margin.

      Said margin is also needed if you want to make tight turns with the e-assist, too

      It wouldn’t be the wheelie police at all, unless you and your e-motor can break the rear tire loose and exceed the front wheel speed when you lifted it by ~5% DURING the wheelie.  At which point you’re already at the balance point and pedaling or manualling anyway.

      For a short time on dirt or sand, most capable MTBers can make the rear wheel RPM exceed front RPM under pedal power alone by maybe 20% at the most.  And only a short time at that.

      “Roosting” a berm on an MTB is a far, far smaller cry from what you can do with even 10hp on an old XR80 under power.  And e-bikes at ~500+ watts of motor output have enough torque to probably match the XR80 up to say 25mph.

      Chances are if you’re doing a power wheelie long enough for the front wheel to slow down and remove assist(or simply under pedal power alone), you don’t need the e-assist at that point anyway.   By definition, if you are doing a manual, you aren’t pedaling anyway, so it wouldn’t matter or be noticed.  As soon as you set the front wheel down again, speed match, and you get your electric assist back as fast as you can start pedaling again.  The chances of the undriven front wheel slowing down to the threshhold of 5% slower RPM than the driven rear wheel during either type of wheelie are slim to none – unless your front brake is dragging even slightly or you’ve got really bad wheelbearings…which you would have noticed whether it was an e-bike or not.  Or, you use the front brake during the wheelie, which you’d learn not to do or didn’t need to be in the first place.

  • #192949

    500 watt Ebike has about 2/3hp and 8.5 ft-lbs torque.  CR80 has 10hp and 5.5ft-lbs torque, but spinning happens as torque and hp ramp up. Electric motors torque start high and diminish with an increase in RPMs. So even an ebike with a throttle button will spin its tires much less to almost not at all. And the type most are trying to get accepted are pedal assist, so will spin no more than an MTB with a powerful rider.

    • #193095

      I have seen this happen in many many motorcycle scenarios, from local areas that have signs that politely ask “Please do not ride when the trails are wet.” …to sections of a racecourse(through the pits, in transfers at enduros, part of a course that crosses private land) where speed and aggression are asked to be limited – it never works, there is always a contingent who disregards it, and then the rest is history.  Almost all current pedal-only-established MTB trails consititute places that need to be treated with stewardship – especially backcountry ones – and e-bikes will eventually turn them into very different trails even in their current state of “detune” and present natural limitations.

      All due respect, but you’re way off about the CR80 – even a dying one that needs rings has 18+hp on the pipe; a healthy on has 25+.  You are correct in that it’s the delivery(peaky torque curve) of the power(and torque) that promotes wheelspin, but it can be ridden pretty fast without wheelspin.  The “problem” is that it’s just too much fun to light the tire up and let ‘er rip.  Most riders would never have the throttle control to “tread lightly” as it’s easier just to deal with the wheelspin, trail damage be damned, than to try and control it.  And besides, it’s fun to just scream the thing and drift around on the rear wheel if you’ve got the skill.

      An XR80 has about 7-9hp(hence my comparison), equivalent torque and a much smoother delivery, but with some clutching and a lot of revs it can be made to do plenty of what would be considered “severe” trail damage in the eyes of the MTB world.

      Regardless, it is human nature to want “more,” and eventually that will creep in and be doing far more damage to trails than “enough” will.  Hence my reccomendation that some sort of traction control – implemented as standard across the industry, NOW, instead of later, would be a wise move for everyone invovled and in the end, will not have much effect ont he fun factor.

      IME, with a mid-drive e-bike and 500 watts, properly shifted to keep the torque of the motor high, you can induce plenty of “fun” wheelspin where you could not have on a pedal-only bike.  Fun = trail “damage” IME.

  • #193096

    You can clearly see positive wheelspin and moving dirt int his video, FROM BOSCH:

    • #193126

      Tim,

      I was thinking XR but typing CR..   You are correct a CR makes 20+ (never seen one make 25 though)

  • #193111

    Positive wheelspin and moving dirt? It really seems like someone’s trying too hard to find an issue here.

    Seriously. Guys like these move more dirt in a single run than the guys on that video after a day of riding.

  • #193176

    Ascending and spinning is where trails get truly dug up.   On a bicycle, with no motor, you just end up walking/pushing.  With even a little bit of additional power, everything changes and the trails change quickly with it.  Not to mention that the addition of power to riding opens up a greater population of people who want to use the same trails, and more often.

    And power-assist summed with lack of riding skill is very different than skill added to gravity.  Anyone who can descend, and move dirt doing it, will quickly find themselves moving dirt everywhere else when they have even a little bit of power asist at their disposal.

    I think the responses here speak to prove my point:  very few of us see what’s most likely  coming as e-bikes evolve and gain strength in numbers and enthusiasts, and in reliability and power and range and utility.

  • #193178

    I had no idea the level of destruction we are allowed to wreak on the trails depended on whether we were ascending or descending. Your topic has done well to prove my hypothesis as well. Our community will demonize an impending technology with nothing more than a slo-mo clip on a youtube video to prove the “destruction” soon to be wreaked but will watch, participate and cheer for a group of 100 riders destroying a trail system if they have a number twist-tied to their handlebars. One of my local trail systems have still not recovered from a 100 mile race held during rain in 2013. There’s one loop in particular that’s completely remapped, thanks to the erosion, straightening and rutting caused during the race. This isn’t an isolated accident and happens everywhere and often.

    Since it matters, they were all spinning while ascending.

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