Freewheel not freewheeling

larkim

Son reported last night that his chain ended up mangled and slack, and when I observed him riding around the garden I could see that when he was freewheeling the chain was being driven forwards slightly as if the cassette / freewheel was rotating with the wheel a little.

Where do I start?

dgunthor

sounds like you need a new freewheel for the hub - probably a £15 to £30 part, local bike shop should be able to sort it easily

larkim

Cheers - presume much the same advice as viewtopic.php?f=10004&t=12888697&p=17973440&hilit=freewheel+forward#p17973440

Probably not the parts that are expensive, its the tools to get the cassette off and then the freewheel hub etc?

I'm getting OK at DIY - done a bottom bracket recently, shifters for both sides, as well as serviced the bearings on my roadie. And degunked forks and adjusted brakes. Neighbour has plenty of tools, might be worth going down that route if I can identify the right part.

Would there be any benefit to a massive dose of some lubricant or other in the right place, or am I likely to damage bearings or something else in there?

larkim

Also, any hints on likely part number - bike is Specialized Hardrock Sport Disc 2011, if I could get the part ordered today I could get it down to the LBS this weekend and see what they say, or have a go with the friendly neighbour.

cooldad

So same as tghe thread linked. Is it a freewheel or freehub?
What is the hub?
If a freehub, try removing the cassette and cleaning/lubing the freehub first.

larkim

Freehub I think, based on no information other than that the cassette on the bike is a SRAM pg830 which I assume means it sits on a freehub body, rather than being a cassette which includes a freewheel? Or is that a complete misunderstanding on my part.

The Spesh spec says:-
Rear Hub:Forged alloy, mid flange, double sealed, ground race, machined disc mount and flanges, cassette, Quick Release, 32 hole
Cassette:SRAM PG-820, 8-speed, 11-32

Which I expect is little help!

cooldad

Not much. Take it to bits and see what's wrong. Likely just gunk.

larkim

Cheers. So I need a chain whip, a cassette tool, cone spanners etc

Remove cassette from drive side.
Remove lock nut / cone / bearings from non-drive side
Remove axel, bearings from drive side
Remove freehub from wheel
Clean, grease, replace new etc in reverse.

Sounds do-able, all I need to be able to get my hands on is a cassette removal tool and a chain whip. I've got the rest covered.

I presume there isn't much to be gained in trying to service the inside of a freehub, assuming that its a bog standard £15 freehub - e.g. likely to be http://www.wiggle.co.uk/shimano-c201rm4 ... ehub-body/

Thanks for the help as ever.

larkim

Of course, I've now read this - http://www.cyclechat.net/threads/cannot ... it.126318/ - which implies that i might discover a non-standard freehub when I get the cassette off etc.

I've e-mailed Spesh to see if they can confirm the part before I go ahead and order.

cooldad

Just take it off first and see if the pawls etc are gunked up.

larkim

Cheers - sounds like that's my Saturday afternoon sorted ;-)

njee20

You won't get at the pawls, it's just a sealed cartridge unit. Flush it through with GT85 or similar, or just replace. Probably have to go through a Spesh dealer to get the part, won't be a stock part.

larkim

Feel free to call me stupid (!), but if it is a SRAM standard cassette, presumably any 8-speed standard freehub would fit inside that. Therefore, even if it is a spesh own brand part, what part will not likely be compatible with the rest of the wheel? Is there something on the hub which would likely be non-standard sized?

njee20

Not stupid, but you're wrong.

Freehub bodies are hub specific (the cassette spline is standard as you say). There is no "standard" freehub body.

Your cassette would fit any of these, but obviously they won't all fit your hub:









Yours will likely look like the latter, but won't be identical.

larkim

Excellent explanation, thanks. Here's hoping its a bog standard one, if it needs replacement.

I wouldn't normally flush with WD-40 / GT-85 if I was concerned that there were greased parts in the internals. Any risk of damaging by flushing such non-oil products through when I get the old one off? e.g. I'd never spray either of those two (or degreaser for that matter) near my hub bearings "just to clean things" as I know they would interfere with the grease if they penetrated the bearing race. Any risks with my potential cleaning options?

larkim

I'm currently sounding the idiot alarm...

Got home tonight prepared to strip off the cassette etc, and took a look at the bike hanging up in the garage - don't know why I hadn't spotted it sooner, but the plastic disc between the largest cog and the spokes had cracked and wedged itself in between the cassette and the spokes, and that was what was causing the chain to drag forwards whilst rotating.

That's a much cheaper and easier fix than I was expecting!

Thanks to all anyway - when the freehub goes, I'll know exactly what to do!!

njee20

larkim wrote:

I'm currently sounding the idiot alarm...

Got home tonight prepared to strip off the cassette etc, and took a look at the bike hanging up in the garage - don't know why I hadn't spotted it sooner, but the plastic disc between the largest cog and the spokes had cracked and wedged itself in between the cassette and the spokes, and that was what was causing the chain to drag forwards whilst rotating.

That's a much cheaper and easier fix than I was expecting!

Thanks to all anyway - when the freehub goes, I'll know exactly what to do!!

Happy days!

As for degreasing a freehub body, obviously it's an inherently bad idea, but at the point at which it's gummed up and not freewheeling I'd flush it through to get rid of any contaminants as a potential short term fix.

Chunkers1980

cyd190468 wrote:

It's always the pie dish I don't know why they continue to put them on new bikes :?

Because if the gears are not set right the chain can easily go over the top. Carry on pedalling and ram it right down the back and sometimes you can't get the chain unstuck without taking the cassette off.

njee20

Of course the gears should be set right, but there's a tendency for folk to drop bikes and bend mech hangers, or to fiddle and suddenly they cease to be set right and you're asking for a load of broken spokes and a trashed mech.

larkim

This is what I am fearful of. I'm sure some 14 year old lads are excellent at bike maintenance and not in the slightest bit careless. But I've got one of the "normal" ones who assumes that cleaning and maintenance is something that the midnight cleaning and maintenance fairies do for him. I'm working on him, honest!!

For now it's working - perhaps I'll get my chance to take the cassette off in the near future due to a stuck chain, instead!!

The Rookie

Or just adjust the stops properly, of you van fit the Rookie ring properly you can surely set the stop properly rendering it unnecesary.

njee20

And that's the crux innit - as I said, many people will either neglect their bikes, so mech hangers get bent and a shift into the spokes is more likely, or they'll twiddle screws when their gears don't work properly and send the chain into the spokes themselves.

You need to protect people from themselves.

cooldad

My old Rockhopper (1987) has a metal pie dish, properly mounted. Never bothered to take it off as it doesn't bug me one way or another.
New ones are plastic held on with plastic clips - rubbish.