Author Topic: Bicycle freewheel replacement  (Read 2423 times)

Jack

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Bicycle freewheel replacement
« on: October 19, 2015, 05:41:29 PM »
My cycling route home has a short segment where I cross the Interstate on a six-lane highway, which (as you may guess) I try to do as quickly as possible. Today, I managed to hit the depressed area of lane where a manhole cover was at the same time as I was pedaling hard trying to accelerate, felt a snap, and realized my bike wasn't quite working right anymore. I limped the bike home (luckily, only about a mile, and mostly downhill), and here's what I found...

It turns out that my freewheel sheared itself apart, and when I took the wheel off the bike the ball bearings fell out. Does it look like I need a whole new wheel (and maybe other stuff), or can I get away with just replacing the freewheel? If the latter, where do I find a replacement part? And how do I get the remains of the old one off?

(If it helps to know, the bike in question is a circa-1991 Specialized Hard Rock 21-speed, 26" mountain bike.)

Syonyk

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Re: Bicycle freewheel replacement
« Reply #1 on: October 19, 2015, 06:12:53 PM »
If the threaded bit is still on the wheel hub, you should be able to use a freewheel remover tool to pull that off and put a new freewheel on.

kendallf

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Re: Bicycle freewheel replacement
« Reply #2 on: October 19, 2015, 07:49:19 PM »
So you have a 7 speed freewheel, looks like.  Or the remains of one.  Take a look here so you can see what the hub looks like without a freewheel installed; it also will show you what a cassette hub looks like (so you can be less confusing when giving others advice..  :-)  ).

http://www.sheldonbrown.com/free-k7.html

I can't tell from your picture if the remnants of the freewheel still have the inner portion intact for the freewheel removal tool to work on it.  Look at the various types of freewheels shown on the page above; yours should have notches or splines and you'll need to find someone with the corresponding removal tool. 

Then go and buy a replacement 7 speed freewheel; something like this:

http://www.sheldonbrown.com/harris/freewheels.html



andyp2010

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Re: Bicycle freewheel replacement
« Reply #3 on: October 19, 2015, 10:24:09 PM »
If you can't get it off with a freewheel tool, which can happen if they're that knackered, especially this awful old type they had with just the 2 prongs on, just stick the remainders of it in a vice and twist. Plus, then you don't need to buy the tool as the new one screws on by hand/by pedaling.

It's definitely a freewheel. Also, don't go for a 'Shimano Megarange', one of the most common types, unless your old one was a Megarange, which I doubt being that old. Long story but just don't or you might not have your lowest gear to use. 11-28 or 11-30 ratios are a good bet. Any non-poncy bike shop will carry them.

Jack

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Re: Bicycle freewheel replacement
« Reply #4 on: October 20, 2015, 02:26:25 AM »
Lucky for me, I remembered that my mountain bike is also a 26" wheel with a 7-speed gearset. So I pulled the rear wheel off, swapped the knobby tire for the slick from the broken wheel, shoved the replacement on (which took a little effort as the mountain bike axle was a couple of mm wider) and should be good to go for my commute in the morning. I might have to switch my shifter from indexed to friction, but hopefully it'll work well enough to tide me over until I can take the broken wheel to the co-op (which isn't open until tomorrow evening) to get it fixed.

I have too many bikes, but it came in handy today! (Actually as I write that I realize that maybe I should have grabbed the wheel off my wife's crappy mountain bike instead of my good one... Oh well; too late now.)

Jack

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Re: Bicycle freewheel replacement
« Reply #5 on: October 22, 2015, 07:39:49 PM »
So I went to the co-op on Tuesday and tried to remove the remains of the freewheel, but it wouldn't budge. The little prongs broke off when I tried to use a freewheel removal tool, and I couldn't even get it off by clamping it in a vice and twisting against the rim, even after applying a liberal dose of PB Blaster. Worse, they didn't have a suitable replacement wheel.

(On the bright(?) side, the guy helping me noticed that my rim was worn and probably needed to be replaced anyway, so it was no big loss.)

Today I went back to the co-op and found a suitable wheel (which must have been donated yesterday). It has an extra gear, but the ones that my shifter can shift to are aligned correctly, so that's nice (and I couldn't be bothered to swap it out). Maybe one day when I'm not busy I'll go back and scrounge a nice set of 8x3-speed trigger shifters...

andyp2010

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Re: Bicycle freewheel replacement
« Reply #6 on: October 23, 2015, 01:01:53 AM »
Sounds like that's gone ok. A good trick in future is to use the wheel nuts or quick release skewer to clamp the freewheel tool in, this way it cant move and is much harder to become stripped.

It's unusual for a 7 speed shifter to work with the first 7 gears on an 8 speed. Have seen it sometimes though. As long as the set screws are set correctly so your chain doesn't come off into your wheel/frame.

Do be aware if you change the shifter to an 8 speed, your derailleur may only be able to do 7 speed judging by the age of the bike.