Freehub nightmare
 

Hello everyone,

please go easy me as it is my first post!

this is link to the bike model (there a tab for the tech specs)
http://www.specialized.com/us/en/bc/...45856&eid=4352

CASSETTE
Shimano HG-50, 8-speed, 12-25t

REAR HUB
Forged alloy, double-sealed, cassette, QR, 32h

I have been riding a road bike for the last six months and clocked up about 2500 miles doing so, when a few days ago I noticed occasionally when coasting at a slow speed my freehub isn't freewheeling.

Obviously this is an issue with the freehub, I don't want to take it to the LBS as I like to know how things such as this work, so the problem lies in where to purchase a replacement and compatible freehub body as I don't really understand the relating acronyms. So could anyone recommend what model type I should purchase and where from?

Also the freehub presently on my bike seems to take a 11mm Hex key which seems odd as I assume it to be a Shimano freehub and from what i have read it is usual for all shimano freehubs to fit a 10mm hex key?

Cheers

Harry

http://www.harrysewell.co.uk

The easiest way to do it is to take it off, then go down to your LBS with it and tell them you want "one of these"

If it needs an 11mm hex key that's what it needs. Usually when a freehub becomes less free it's because either thick grease buildup, and/or dirt binding the mechanism. Obviously remove the cassette from the body, then remove the body from the hub, and give it a long soak in mineral spirits.

Once it's soaked a while see if it can be worked free in your hands. If so keep working it and rinsing until it's free and the rinse solvent runs clear. If it comes back to life, it needs to be shaken free of excess solvent, dried in a warm place, and re-lubricated using a heavy oil such as Phil Tenacious or this other chain lube which I won't mention but the label looks like a perfume label.

Some freehubs have an oil port in the splined area, others require that you work it in past the bearing clearance. If you have one without a oil port, it helps the oil flow in faster if you warm both the freehub and oil. Don't get carried away, about 125-130 (the temperature of hot tap water) is plenty.

From the specs, Rear Hub- Forged alloy, double-sealed, cassette, QR, 32h Most likely not Shimano. (If it was, it would say so.)You're right,most Shimano freehubs are removed with a 10mm hex, but some require a 14mm. Never seen one that takes an 11mm. Probably made for Specialized by Formula or some such company.
Finding a replacement freehub body may be a problem. If the bike is fairly new, I'd try warranty.

+1 on cleaning and re-lubing before replacing.

If the bike is fairly new then the shop should be doing this work or replacing the wheel or whatever.

However if you're doing this to learn more about bike work then fine and good on ya!

Do a search on this mechanics forum with the key words "cassete flush" or "cassette cleaning" and it should turn up more than a few threads where there's descriptions of some dunk, spin and flush methods of cleaning and re-oiling.

Check the Park Tool website, they have a section on freehub overhaul.
http://parktool.com/

If you have one, sometimes the plastic spoke protector can get loose from the spokes and cause the cassette cogs to drag across it, causing friction.

Specifically: http://parktool.com/repair/readhowto.asp?id=45 , but I agree with VO: check to make sure something isn't dragging on the cogs. I've unwound string and bits of vegetation from cassettes that played havoc with coasting.

It's a formula hub. Remove it and take the seal off of the back side and flush it with solvent. If that loosens it up drip a heavy oil into it and put it back together.
If this doesn't fix it get a new free hub body.

Hey guys, I'm tempted to make a new thread, but since this is quite similar, i will just post here.

Yesterday, My freewheel was having problems, where they freehub would turn along with the rear wheel at low speeds (like the op). I Commuted to work today using the same wheel and arrived fine, though i did have some mechanical difficulties.

For one, when pedaling, the freehub would feel as if it loosened, allowing my foot to pedal with no resistance. This did not stop me from arriving at work as the wheel would reengage. After work, after getting ready to head home, i get on my bike and attempt to pedal, when my freewheel just completely loosens, and im just spinning on my pedals. absolutely no resistance, freewheeling while pedaling forward...

I hadnt maintained this wheel at all for the past year and now im concerned that my neglect has indeed caused failure.

So, exactly what damage has been done and what can i do most budget wise, to get this freewheel back up and running. Fortunately i have another set of wheels i can use, but its still a bummer.

anyway, any help would be appreciated thanks!!

Shimano freehubs can be taken apart with moderate effort and trepidation, and, given the state of contamination/corrosion, may or may not be possible to resurrect. If you don't succeed, the're not that expensive to replace.
I've only managed to get a freewheel open with improvised tools once, so unless a flush is sufficient I usually bin them.

How cold is it where you ride? This can happen if grease in the hub is too thick for the cold weather. The pawls inside the hub are stuck and don't engage so the cassette spins freely every which way. Temp fix is to bring the bike inside to let it warm, but if this is a recurring problem, you should apply thinner lubricant. See this Icebike article for details.

I'm not sure that can cause the other problem you described though, where your bike essentially becomes a multispeed fixie. I've had that happen to me once, but that was because one of the bungee chords caught rear wheel and jammed between cassette and hub. Pretty much what Jeff Wills described above.

--J

11mm is VERY COMMON for generic freehubs on generic loose ball hubs Dan. Typically you loosen the nut on the non-drive side - leave it sitting in the hub shell. Then loosen and remove the freehub itself.

The 11mm allen is clamped into a vise long side up...

Typically the generics in question have the following profile/layout/dimensions:

http://www.mrrabbit.net/images/a5012.jpg

=8-)

'
Hi, thanks for the reply. I have a feeling that this is exactly what is going on, as ive inspected the rear cassette, and it seems so gunky and grimed up that the cassette wont spin at all without some decent pressure. I havent maintained this wheel AT ALL for the entire winter, and lately its been especially snowy. Hopefully its just gunked up and not a devastation, as i happen to like these shimano 105 mavic cp22's.

I need to find a cassette remover now.

Thanks!

The shimano 105 freehub is removed with a 10mm allen wrench. Park makes an excelent cassette lock-ring tool. http://www.biketoolsetc.com/index.cg...em_id=PA-FR5GC