Technical FAQ: Of drivetrains and dismounts

by Lennard Zinn

Dear readers,

Grab the front of the saddle as you swing your right leg over it.

Grab the front of the saddle as you swing your right leg over it.

I know that I promised to describe how to eliminate front brake shudder on a cyclocross bike in today’s column, but I only just got the parts today that I think will definitively eliminate it, and I didn’t have a chance to install them today, much less test them. And now it’s Thanksgiving week. So that column will be coming up the week after next.

I also got such a large number of emails about tubular gluing that I have not been able to get through all of them, but I have answered quite a few. It made the follow-up column as long as three columns should be. So I’ll hold some until next week.

So I got sidetracked a bit, when doing something other than working on or riding bikes. The other night, while dismounting from our very tall (16.2 hands) dressage horse, Luminary (Lu), I suddenly had an insight into a question I’ve received a number of times and didn’t have a good answer to, namely, why is the drivetrain always on the right side of the bicycle?

Move your right hand to the back of the saddle and put your weight on it.

Move your right hand to the back of the saddle and put your weight on it.

I was noticing how dismounting a horse is just the same as dismounting a cyclocross bike at speed for a flat-out dismount. On the moving bike, you swing your right leg over the saddle while holding the bars, then move your right hand to the top tube, put your weight on it, and lean back. Holding yourself up by the handlebar and the top tube, you unclip from the left pedal and hang there as the bike rolls within a couple steps of the barrier and then drop to the ground.

As you can see in this sequence my daughter took of my wife dismounting from Lu, that’s the same thing you do with a horse, except, with reins in the left hand, you lean on the horse’s withers with the left and the front of the saddle with the right as you swing your right leg over the saddle, move your right hand to the back of the saddle and put your weight on it, and slide your left foot back out of the stirrup before dropping down to the ground. And the reason for releasing your left foot from the pedal or the stirrup before dismounting is the same; you don’t want your moving bike, or a horse that starts to move, to drag you along by the foot.

Slide your left foot back out of the stirrup, then drop down to the ground.

Slide your left foot back out of the stirrup, then drop down to the ground.

So this got me thinking of why we get on and off a bike from the left, and I realized I had always thought that we did it because the drivetrain was on the right, but it could be a case of whether the chicken came first or the egg. I am willing to bet that, since the bicycle originated at a time when a high percentage of the population rode horses, that bikes were dismounted and remounted on the left side, since that’s how it’s done with a horse. So then it would only be natural to put the bike’s drivetrain on the right, since one mounts and dismounts on the left.

Follow Lennard on Twitter at www.twitter.com/lennardzinn

Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides “Zinn and the Art of Mountain Bike Maintenance” – now available also on DVD, and “Zinn and the Art of Road Bike Maintenance,” as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn. Zinn’s column appears here each Tuesday.

Categories : Bikes & Tech, Cyclocross, Technical FAQ

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  • AKP
    Which begs the question... Why do you mount/dismount a horse on the lefthand side?
  • ben
    Because it lets you bring your (for most of us) stronger (right) arm to bear? Just a wag from somebody who doesn't have a horse nor a cross bike ;)
  • BeeShoo
    It's from the times when most people riding a horse were wearing a sword, and that sword would be normally worn on the left side. Th e sword would make it very difficult to mount from the right side of the horse.
  • Joe
    With most of the population being right handed, weight on the right arm is more significant with a dismount from either a horse or cross bike on the left as opposed to the right of either steed. Also necessary shifts in arm position on the horse or bike can be made easier with the dominant hand (right) depending on the actions of the steed. If the horse halts and misbehaves, starts walking backwards, adjustments must be made. The same thing can happen if you are a little overzealous and try to ride the runup. If you get so far that momentum can take you backwards, you need to make adjustments and fast. Do you want to do that with your left hand?
  • Dave P.
    Horses get antsy if you try to jump on from the right side!! They are trained to be mounted from the left. Far as I know its just the tradition of training originating with leading/walking and saddling during the braking process.
  • Paul B
    It's all about how they're trained - we have multiple horses trained to be mounted from either side.
  • mttvrtn
    I always thought that it was because the first 2-wheeled variant was invented by a Scot and we drive/ride on the left-hand side in the UK, ergo you mount the bike from that (safer) side, away from the traffic and the chain... However, this could also be wishful thinking!
  • lonefrontranger
    as someone who grew up on a horse farm and rode hunter jumper horses for nearly 20 years before going fulltime as a bike racer, I can tell you that most horses are naturally "left-handed"; i.e. stronger on the left side. There's a lot of stuff I could write here but the bottom line is that this means when/if they decide to move or jump around while you're mounting/dismounting, they have a much stronger preference for shifting to the left first. It's safer for the rider while in an unbalanced position (mid-mount/dismount) if their body moves towards you rather than away (easier to catch your balance). Anyway this is what we were told as kids, and what I saw bear out in practice over the many many times I worked with some hyper nutcase of a horse - it's easier to pull them in a counterclockwise circle and lean into their shoulder as they jump forward, and since they're naturally inclined to go left, that makes the whole getting-on-and-off-on-the-left thing make sense.
  • James
    A horseman here tells me that it is because in the old days horsemen had swords, and swords were carried on the left hip to be drawn with the right hand -- so horses (and people) are trained for right handed swordsmen.

    I'd also throw in that it is easier to yoink yourself up with your right arm if you are right handed
  • Ryan_G
    The reason people dismount from a horse on the left side is because most people are right handed, and carried their swords on their left hip. I dont know many cyclist that still carry swords, so why does it matter what side the drivetrain is on? Why did the drivetrain end up on the right side?
  • markadam
    I mount and dismount, to steal a phrase from skateboarding, "goofy" side. For those of you who aren't uber cool sk8ers, that's on the drive-side. I know it looks Fredly, but it works for me. I race cross single speed and am considering having a custom rear hub made so that I can rub my cross rig goofy too.

    Cheers!
  • jesusnieto
    Which makes me remember, I once saw (early 90's) a Japanese track sprint rider with a left side fixed gear train, and even a brittish guy trying to break the kilo record on a track bike with gears on both sides! None of them too succesful, otherwise we would have seen more of that.
  • Ritchey_BreakAway
    Actually, it has to do with the rotation of the earth. You'll notice that folks in the northern hemisphere dismount horses on the left, while in the southern hemisphere, they dismount on the right. France, being the birthplace of the bicycle, took this northern hemisphere-centric look at the horses and applied it to the bicycle. If the bicycle had been born in, let's say, Argentina, it would be the opposite. Which still begs the question of why drive trains are on the left on a moto.
  • Haha! Yes, that is probably the reason why! But, do you know why it became traditional to mount a horse on the left? There was no drivetrain on the right, but the soldiers had a sword across their left hip/leg. In order to not slice themselves or the horse, they mounted from the left. THAT is also the reason why the manes on on the right! ~Nicky F Rookery Ranch
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