Chain goes slack when pedalling backwards...

courtmed

Went out this morning and my gears seemed a bit off. After a bit of preparation (and trepidation!) I decided to index them. Before I did this I noticed that I soon as I move my pedals backwards, the chain goes slack. If I force it a bit (eek) the chain moves a little bit before the rear derailleur clicks a bit. I thought post-indexing this might go away.

Indexing went fairly well and they seem fine but it still hasn't gone away. I decided to take my back wheel off & clean the cassette/jockey wheels to see if that would make a difference - it didn't. The cassette spun backwards freely when I did it by hand, so I think something must be getting stuck.

Any suggestions you wonderful lot? I mean, being able to pedal backwards is hardly a necessity, but something must be off so I'd like to find out why.

Edit - Just in case it's relevant, the bike in question is a 2016 Cube Attain GTC Pro Disc with Shimano 105.

benws1

I'm due to pick one of them up on Saturday. Hope I don't have the same issue.

The only time I've ever noticed the chain not going backwards properly was when I was using dry lube on the hybrid last summer. I'd ride the bike a few times, the chain would get noisy and wouldn't spin backwards, so I'd lube it and it would work again. I finally fixed it by using a wet lube which seems to make it quieter and better running.

Have you lubed the chain at all? Anything catching on the derailleur jockey wheels? Have you given them a quick spray of something like WD40 to lube the moving parts?

courtmed

Hopefully yours is fine! I've had this for a months now so wouldn't be too surprised if it's something to do with cables stretching or similar. Yeah I lubed the chain/jockey wheels after degreasing it.

Something I've just noticed, which does make my feel a little better, is it's only happen in the small chainring biggest sprocket. As soon I shift through the gears I'm able to spin backwards with the chain pretty much keeping the same tension as going forwards. Having said it makes me feel better, it also seems weirder

fat daddy

stiff chain or gunked up jockey wheels or dirty hub or bad chain line give the chain set and derailleur a good clean and try again

k-dog

Yeah, stuff link most likely followed by bent hanger.

courtmed

If it was the jockey wheels/hanger would it only happen in that one gear?

andy9964

Mine did this after I serviced it. Turned out I'd been too generous with the grease inside the freehub. Stripped it down again, cleaned the pawls and springs, leaving a light coating of grease, and it's now running perfectly

Matthewfalle

Knackered freehub. Does it before they Jeff up completely.

A strip down, good clean, soak in light oil, rebuild may do the job.

courtmed

Sounds a bit more serious than I'd hoped :shock: is that a big job to do at home or not? May have to make my first journey to the LBS with this bike.

Cheers all!

pippi_langsamer-2

Could be drag in the freehub caused by sticky pawls. Could be gunk.....could be someone's greased them. Are the wheels old?

Not sure about Fulcrum (assuming you're running the stock wheels?), but most freehubs require light, sewing machine type oil on the pawls. Any form of grease makes them stick and drag. I know this is certainly true for Mavic anyway, as I've serviced many hubs over the years using sewing machine or hair clipper light oil on the pawls and inside the freehub body.

courtmed

They are the Fulcrum wheels yeah. Not old at all - only since November. It's the fact that it's only happening in the one gear that's throwing me... :?

Matthewfalle

courtmed wrote:

Sounds a bit more serious than I'd hoped :shock: is that a big job to do at home or not? May have to make my first journey to the LBS with this bike.

Cheers all!

Not sure on Fulcrum but normally it's remove cassette, one 5mm Allen key in each side, undo, clean out, do up again.

It's not that difficult - none of this bi-cycle stuff is. But peopl like to try and make it sound difficult!

rolf_f

Matthewfalle wrote:

courtmed wrote:

Sounds a bit more serious than I'd hoped :shock: is that a big job to do at home or not? May have to make my first journey to the LBS with this bike.

Cheers all!

Not sure on Fulcrum but normally it's remove cassette, one 5mm Allen key in each side, undo, clean out, do up again.

It's not that difficult - none of this bi-cycle stuff is. But peopl like to try and make it sound difficult!

In this case probably a couple of spanners to do the same. You can draw the freehub out on the axle taking care not to lose the spacer in the back of the hub. If the pawls are gunked up it is probably worth tapping the axle out of the freehub and cleaning and regreasing the outer face of the outer freehub bearing as well = another spacer to lose!

When putting the freehub back, some very complicated advice is sometimes given about tying thread around the pawls to close them or using a special tool. None of this is at all necessary. Just slowly spin the free hub as you press it in away from the drive direction. The drag of the pawls on the edge of the hub body will close them up and the freehub will pop in. This probably won't make any sense until you actually try it!

It really is straightforward - one of those tasks that anyone can do if they are capable of undoing a bolt and doing it back up again!

Alex99

Pippi Langsamer wrote:

Could be drag in the freehub caused by sticky pawls. Could be gunk.....could be someone's greased them. Are the wheels old?

Not sure about Fulcrum (assuming you're running the stock wheels?), but most freehubs require light, sewing machine type oil on the pawls. Any form of grease makes them stick and drag. I know this is certainly true for Mavic anyway, as I've serviced many hubs over the years using sewing machine or hair clipper light oil on the pawls and inside the freehub body.

Can also be caused by the derailleur chain tensioning pivot getting stiff with salt and crud (probably working in tandem with a less than perfectly free-flowing freehub). Happened to me last week in fact. Stripped the derailleur down and greased stuff which sorted it.

k-dog

This time of year those external type things are further up my list - it doesn't take much to gum them up.

Sutton_Rider

I use car engine oil (5 30) on the pawls, but maybe that's too thick. Seems to work OK though.

keef66

Sutton Rider wrote:

I use car engine oil (5 30) on the pawls, but maybe that's too thick. Seems to work OK though.

I've used exactly that, and some gearbox oil, (history of owning and servicing Fords) to drizzle into the internals of my Shimano freehubs on an annual basis; seems to be about the right viscocity and keeps them working through the winter.

No experience of other makes of rear wheel, but I understand Fulcrum / Campag / Mavic have simple, accessible freehub pawls / replaceable parts, but that the ease of access means they are less well sealed against the elements?

arthur_scrimshaw

Yeah my money is on the free hub, if it's a cold day and the lubrication of the pawls is grease this could lead to the symptoms you describe. Shimano mineral oil (for hydraulic brakes) is best for Mavic freehubs apparently.