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Yesterday when I was biking my mountain bike on level paved path, I would pedal but get no power to the wheel. To use a car analogy, it was as if I had the clutch in and was apply gas. It seemed to happen most often after I coasted and then went back to pedalling. I would pedal and realize that no power was going to the wheel. The chain was definitely on the sprockets and moving. I could change gears no problem while I had no power. Sometimes stopping the bike and starting again would work, or just trying again. Needless to say, I'm taking it in as I'm not mechanically inclined, but I'm hoping to learn something. Perhaps a link to a site that explains the problem?

So my questions.

  1. What is going on? I have heard of something called the "freehub". I really don't know how bikes work though, so I'm hoping for an explanation of how one can pedal and give power to the wheel and then stop pedalling and the wheel just keeps moving (without the pedals moving).

  2. If you are on a ride, is there any emergency adjustment to make?

For what it's worth, it's an old bike. Circa 1993 Performance Mtn Bike. So it's not too surprising that it's falling apart. I haven't used it a whole lot, and have tried to wash and oil it, but I probably haven't taken the care that a biking aficionado would. Also, besides losing power after coasting, one time I was pedaling and suddenly the pedals weren't powering the wheel. I almost went over the handlebars! So, I definitely want to get it fixed. I'd just like to know a little bit about what is going on.

Thanks,

Dave.

Bonus question: If there is enough info to make a diagnosis and you have ideas on costs to fix, perhaps you could comment on whether it's worth fixing. Like I said, it's circa 1993 and cost about $450 then. No shocks or anything. Just 21 speed Mtn. Bike.

  • My guess is you need a new freewheel (given the age of the bike), which is about 15 dollars for the part and then probably 15-30 dollars for labor (or you need a freewheel tool + big wrench). They will likely want to throw on a new chain (another 10 bucks), which requires a chain tool. – Batman Nov 16 '15 at 20:13
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    The giveaway for me here is that you say you haven't really looked after the bike. At that kind of age, there are probably a half-dozen things that need maintenance. Chain, brakes, cables etc. over and above the possible problem with your freehub. I don't want to put you off self-maintenance, as it can be very rewarding, but in this instance it might be easier to take it to a shop – PeteH Nov 16 '15 at 20:36
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    Lift up the rear wheel and spin it by hand. You should hear a steady, light clicking sound coming from the gear assembly on the wheel. If the clicking is not steady, or seems to skip at times, the freewheel mechanism is probably stuck as the answers state. Notice the sound and also listen for it when riding. – JPhi1618 Nov 16 '15 at 21:01
  • @JPhi1618 It can click and still not engage – paparazzo Nov 16 '15 at 23:59
  • It's clicking, but no as audibly as other bikes.... As I mention in response to Frisbee, lots of WD40 got it working. For how long, I don't know.... – Dave Nov 23 '15 at 18:41
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Most likely duplicate but I cannot find it.

In the free hub / free wheel you have pawls that are the coast / drive mechanism. Most likely they are gooked up or just plain broken. Some are serviceable and some are not. FREEHUB SERVICE You can also search on youtube. Or just take the wheel to a bike shop.

You might be able to free it up with a bit of WD40. Remove the wheel and spray it down the axle.

As for worth fixing. If it is just a service it would be like $40? But you take the risk the service does not fix it. You can get a cheap wheel for less than $100. No shocks makes it more worth fixing in my opinion as you have less other stuff to go wrong. If other than that is runs OK I would fix it.

  • Thank you for all the comments. All great answers and comments but I can only pick one! I was able to get things working by following Frisbee's suggestion of taking the wheel off and spraying the heck out of it with WD40 (all over axle). I'm sure I will need to take it in for service at some point. – Dave Nov 23 '15 at 18:38
  • @Dave WD40 is not a lubricant, it is pretty good at dissolving grime and old grease, but you will need to follow it up with something. Maybe Phil Woods Tenacious Oil (amazon.com/Phil-Wood-Tenacious-Oil/dp/B003UWHNIM) or slightly lighter. – BPugh Nov 23 '15 at 20:00
  • @BPugh WD40 is also a lubricant but not long lasting. I agree the oil should help but it also might gook it up again. I think he needs break it down and service it property or just keeping hitting it with WD40 until it dies. – paparazzo Nov 23 '15 at 20:15
  • Fear not BPugh, I let the WD40 sit for many hours, and then hit it with some bike oil. And I agree with Frisbee that I need to take it in. I don't want to be on a long ride and suddenly have the same problem. That said, I took it for a 12 mile ride and no problems! – Dave Nov 24 '15 at 0:39
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This sounds like a issue in your freehub/freewheel (both are mechanically the same for this question). This is what allows you to coast without pedaling. Inside these bodies are a set of "pawls" which will flip down and engage a series of splines when rotated "forward", and propels the bike forward. Then, if you move them in the other direction "backwards", the pawls are designed to be pushed out of the way of the spline. Given how old your bike is, there is probably a build up of dirt and drying out of grease inside these that are causing the pawls to be stuck in the "up" position and not able to grab the splines. In this case, your local shop should be able to fix that right up by replacing the part.

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    Relevant google image search: google.com/… – BPugh Nov 16 '15 at 20:30
  • Thank you very much for the images. If you have any other "gentler" explanations / images of "pawls" and how freehubs work, please send them my way. With my limited understanding, I have to say that it seems an amazing invention! – Dave Nov 23 '15 at 18:42
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    A simple mind view for a pawl/spline is as follows: Imagine a child holding a stick running alongside a picket fence. If they let the stick trail behind and then hold it against the fence, it makes a clicking noise (to annoy the neighbors) as it slides past the fence. If they let the stick poke ahead instead, then they come to a rapid halt as the stick wedges into the pickets and stops dead. The pawl/spline is just like that - clicks in one direction and allows wheel to rotate relative to chain-ring in one direction, catches so chain-ring and wheel rotate as one in the other direction. – Penguino Oct 18 '17 at 23:24

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