Hi,
I recently have been practicing riding backwards. Little by little I am getting better but during the last session the pedals loosened and subsequently stripped out the crank arm. Was thinking of switching to sealed bearing pedals… Has anyone ever had this problem? Is there a common solution or do I just need to be extra careful and check the pedals all the time?
If you’re riding backwards more than you’re riding forwards, it’s expected that your pedals will loosen–after all, if you put the wheel on backwards and ride forwards, the pedals loosen. I suppose, if you’re practicing riding backwards a lot, you could put the wheel on backwards so that your pedals think you’re riding forwards.
The bearings of the pedals don’t make a difference.
One thing you can do is to use blue loctite on the pedal threads. Other than that, either ride forward more often, or occasionally tighten the pedals.
Some cranks, like the Qu-Ax ones, are made of very soft aluminum which makes it easy for the pedals to loosen and strip out. Steel cranks will do better.
loose pedalls
I would use a bit of thred lock adhesive,and make sure the pedals are done up tight.
Rather than Loctiting the pedals, just turn the seat around for casual backwards riding practice. For serious, tons-of-backwards riding do what Tom suggested by turning the wheel around (that way the frame still faces forward).
Thanks for the help!
Thanks guys, your answers are valued. The reason I thought sealed bearing pedals would help is because my pedals don’t turn totally smoothly which had to be a contributing factor to the un-threading. I will try these very sensible ideas. The cranks are aluminum (Torker) and were very soft compared to the steel pedal spindle. I already ordered the identical replacement part but if it happens again I’ll get the steel ones.
I really have to wonder about this. If the bearings in your pedals are adjusted properly, how is it possible to put enough force on the spindle to unscrew from the crank? I mean the crank is put on with a wrench directly on the spindle, it seems very improbable to me that you could unscrew (a properly setup/lubricated/seated) pedal by just riding backwards. I can see in the “olden days” when bearings/lubricants were not what they are today, but come on!
I’m not saying it doesn’t happen. Is it possible that people are just riding around on pedals that are not properly screwed in to the cranks?
Pedals unscrew due to precession (look it up). It has nothing to do with how smooth or un-smooth the bearing action is. If you notice, the rotation of the pedals against the spindle (when riding forward) is in the same direction you would turn them to unscrew them.
I don’t know about the pedals having been “properly adjusted and lubricated”. They are cheap plastic pedals that came with the ride. They were tight before I started trying to ride backwards and this happened after a few sessions without me realizing it until it was too late. Both pedals did back out but only the right side came out enough to strip the crank arm. I knew this could happen in theory but didn’t believe it really would. The pedal spindle doesn’t turn that smoothly I have noticed after investigating. Interestingly I have spent some time riding my bicycles backwards down hills and have never had this issue but my bike pedals are sealed and smooth.
(somewhat) Sound logic if indeed axle friction were the force causing pedals to floop unscrew themselves and fall off, but entirely more spooky forces are at work, namely precession, a by-product of things traveling in circles. The pencil demonstration toward the end of that article demonstrates this effect in the most concrete manner I’ve seen yet.
“Just keep tightening them” and “turn the seat around” both seem to be excellent options for casual backward practicing, and in practice you usually have some warning by “feel” of when a pedal or a crank is working its way loose. (Perfectly excusable in the case of actual backward-riding practice while you’re still uncomfortable enough to not get much smooth riding between funky backward jogging/falls.)
Checking that pedals and cranks, seat post and bumper bolts, and even bearing holders are properly held together is good practice to be in… at least periodically if not every single ride.
FOR SCIENCE!,
billnye
John M
I would have to argue that if the bearings were frozen it would unscrew right away so I think resistance would have to be a factor. Pedals are meant to constantly tighten themselves when pedaling forward.
Pedals DO constantly tighten themselves when you pedal forward. If the bearings were locked (let’s say super stiff) and you rode backwards they would stay nice and tight.
That was a great article on precession, BTW, Bill.
Thanks, I’ll check out the link. The awkwardness of this new activity is exactly why I didn’t notice earlier. Really, thanks to everybody - I am new here but it looks like we’ve got a good community situation. I actually don’t even know any other uni riders.
I have read your statement several times and can’t make sense of it. If the bearings were perfect they would unscrew riding backwards but if they were locked they would stay tight. Meanwhile if I pedal forward in either case they also tighten? Well obviously I need broken pedals. 
Oh, of course!
Once again, I’m trying to bake a cake with only half the ingredients!
Thanks John for getting me the rest 
Sorry, still wrapping my head around all of this. reading the article and checked out the pedals. They DO rotate in the direction that “would” unscrew while riding forward. Didn’t expect my brain to hurt. gotta let this kinda sink in.
If this is the case then using pedals with a circular edge inside of the pedal wrench flats, or using steel washers between the pedal and crank should help ensure proper torque, decrease fretting and thus lessen the chance of pedals loosening.
Keep in mind that the pedals are not in contact with the spindles. The pedals are in contact with the bearings and the bearings are in contact with the spindles. The balls rotate in a direction that is reversed with respect to the pedals. It is the rotation of the balls in the bearings that apply the force to the pedal spindle which tends to tighten it when pedaling in the forward direction.
Thanks Ḡℜễɠ that makes it much easier to understand what is going on.
Are we sure that the term “precession” is being used accurately here? I always associated the term with some of the effects that can be seen in gyroscopes and similar systems.
Has the cycling community grabbed hold of the term and redefined it for their own use?
I would have thought that the tendency for pedals to unscrew when riding backwards was quite simply that by pedalling backwards a couple is being applied to the screw thread in the “unscrew” direction, due simply to frictional forces in the system ( The small value of the couple being helped by flex in the components.)
This is what I fall back on when I get confused with this:
100+ years of worldwide cycling says the right pedal is righty-tighty. We know this to be correct.
the locked bearings example is silly because if the bearings are truly locked you could only ride in the direction that unscrewed them. The othe way you’d just stop.
As for the proper meaning of precession, I’m not sure. I learned that word in terms of when your diabolo goes crooked. By letting one of your handsticks gently drag on the correct edge (either front or rear) of the diabolo, it will “precess” back to facing the way you want.