Bicycle Mechanics - Don't want to look stupid...

...well, except here ;)

OK, I'm not too sure about terminoligy here (although I've got Bicycling magazine's - Bicycle Maintenance and Repair manual in front of me.)

First off the problem:

When I stop pedaling, sometimes the freewheel doesn't coast. Instead, it tries to drive the pedals around like a fixed-single speed bike. I hear a crunching noise and the rear derailleur cage moves towards the pedals. It then gives a final crunch and I'm then able to coast again (OK, I could just stop coasting, but I'm lazy :D )

Also when I come to a stop, moving the pedal upwards will sometimes cause the same problem, it's similar to what happens if you suddenly stop whilst in the middle of shifting a gear and then try to 'reverse pedal'. The chain goes all slack.


So the specs.

It's a 2002 Klien Quantum Pro. With Shimano Ultegra components.

The wheels are (F) Bontrager Race Lite 20 hole, alloy rim
(R) Bontrager Race Lite 24 hole, OSB alloy rim

Rear cassette is Shimano Ultegra 12-25, 9-speed


OK, I've tried to see what the problem was (and fix it), I removed/cleaned the chain (even though it was pretty clean and lubed)

I gave the rear derailleur a good clean and ensured that there was no crud around the jockeys.

I then tried moving the pedals and it was still happening. I then removed the rear wheel and examined the rear cogs.

It spun ok (the cassette). I then pushed it, as if the chain was applying pressure to it and then tried to move it backwards (like I was coasting) Aha! It was stuck, so I then moved it the other way (like pressure was being applied again) and then moved it back (coasting) and it spun ok.

So, it seems to be something to do with the rear hub (bontrager).
I looked at the manual I've got and it said spray in some degreaser and then apply oil. This I done. Now it rides slightly better but it still happens. I think I need a new freewheel/cassette.

Now this is where I'm confused, this manual seems to chop and change between talking about a freewheel (which I think is 'older tech.) and a cassette.

So I browse the web and cassettes seems to be the cogs themselves?!?

So then I looked up hub and it seems like I'd have to replace the whole of the hub in order to change the cassette thingy (nice techy term...) that contains the rachet mechanism. This doesn't sound right as I'd then have to rebuild the whole wheel.

OK, (Hmm, sorry, this is starting to be a bit long winded but I wanted to place as much information as possible.) So in brief terms:

1. I think I need to replace the rear cassette (possible rust inside?) that contains the coasting mechanism. What is this called? Just so I don't look an idiot at the LBS (or confuse them). And is it replaceable?

2. If it is replaceable (woo hoo!) What tools to I need to remove apply it. i.e. Take off the lockring etc.

3. OK, I could just take it to the LBS and ask them (nicely) to fix it, but I want to try it (and learn) myself.


Free (virtual) beers all round if anyone can help me.



:beer:

I think you are talking about replacing the freehub body. The freehub body is that part of the hub that contains the pawls which allow a bike to freewheel. The cassette slides onto to the freehub body and is held in place with a lockring. On most hubs, thte freehub can be replaced, though the expense, effort and parts availability may dictate against it. Most freehub bodies can be removed with a large (10 or 11 mm) allen wrench. If the freehub body is not too far gone, you may be able to clean it out and lube it.

To remove the cassette you will need a chain whip, a lockring tool, and a big old wrench.

Check out Park Tool's (http://www.parktool.com/repair_help/howfix_freehub.shtml) website for some pretty good instructions.

EDIT: You'll want some cone wrenches, maybe an axle vise and a bench vise, too. Be aware that it takes some serious torque to remove the freehub body. You will be rebuilding the hub, too, a job that takes some mechanical skill. Better replace the bearings while you're in there, and be sure you have grease on hand. Ah, heck, go read the Park Tool website! Good luck!

Your freehub pawls are either junked-up, or they are shot. Unless you know how to repair it yourself (trust me, you don't..), take it to the bike repairman.

That sounds like very premature mechanical failure. Perhaps a small foreign (or even domestic) object has worked its way into your freehub body.

i'm stumped. is the chain an ultegra 9-speed or compatable?!

does this only happen under load or is it replicated on a repair stand? sounds like it doesn't matter if it is under load or not.

the dishing of the rear wheel is good?!

i've got ultegra and have never experienced this quandry.

I had a simular prob. only witha screw on f/wheel I had to take it to bits & fit an exra thin spacer/shim as it kept tighting it self up when free-wheeling , exactly the same symtoms.! Fine now tho. Cassettes, sorry Ive had no experiance with them
cheers.

Sounds to me like a freehub body issue, as was mentioned above. Best bet is to take this one to your LBS and let them sort it out. It's not terribly fun.

Hi, thanks for all your help, esp. Regular Guy.

I stripped down to the cassette hub and then soaked it in Kerosene and let it dry. Applied lubricant several times and then put it all back together.

It now seems fine :D No sticking and it also seems to be running a lot smoother. I tried to jar it by stopping pedalling and then quickly reappliying pressure but it worked fine.

However, I only went on a short test run (about 3 miles) the proof will be longer term use over this week (about 100 miles).

How many miles do you have on this bike? I know Bontrager is Very Good about warranty replacement. If your bike is relatively new, I'd take it back to the shop. If you've logged many miles, then your Freehub is most likely shot.

Your LBS, may have this tool called a "Freehub Buddy" is specifically designed to inject grease into the freehub. I have one, it costs about $50, and not worth buying unless you have a lot of bikes.

Also, you will need a 12mm allen wrench for a Bontrager freehub body, not a standard 10 mm. I had to go out and get one from Sears!

The thing to do is to remove the freehub, soak it in degreaser or paint thinner, rinse it well, let it dry overnight, and use the "freehub buddy" to fill it with grease! If that doesn't work, it's shot and you'll need a new one!

L8R

Thanks a2psyklnut, I've done about 2,500 miles on it. However, this was through the winter, so plenty of rain and salt was around to attack it!

It's still going fine, I'm planning on taking it to the LBS when I'm next on holiday (as I use this bike to commute on) so that I don't have to resort to using a car to get to work (hey, I've got the bike commute bug ;) ).

Either that or buy a spare rear wheel so that I can leave my current one at the LBS for them to sort it out.