Cassette spins freely in both directions

[abchandler]

I have a Trek 1400 fitted with Shimano 105. On my ride home last night I was suddenly able to pedal freely with no drive going to the rear wheel. When I stopped, I found that the rear cassette could spin freely in both directions.

As the ride is generally downhill I started scooting along and rolling down the slopes. Playing with the gears, I then found that changing up to a higher gear/smaller cog I re-engaged the cassette and it was fine this morning.

Is it likely that the freewheel just needs a good clean? Or is it likely that I'm going to need a replacement cassette?

 

[fossyant]

I'd bank on a replacement cassette soon.

Best remove said freehub (remove axel and 10mm allen key into freehub) and give it a good soaking with WD40. Let it dry, squirt maybe some light oil in, dry bearing races, refit, regrease races and refit axel.

 

[Landslide]

You shouldn't need to replace the cassette at all.

You may need to service or replace the freehub body. Advice on this can be found here.
This problem tends to rear its ugly head more often in cold weather as the temperatures affect the grease/lube in the freehub.

 

[jay clock]

if very cold it could just be that causing the problem....

 

[Fab Foodie]

You shouldn't need to replace the cassette at all.

You may need to service or replace the freehub body. Advice on this can be found here.
This problem tends to rear its ugly head more often in cold weather as the temperatures affect the grease/lube in the freehub.

Agreed.

Not too difficult, a few tools required. All kinds of crap and water can get into the pawls and eventually they clog, stiffen-up and fail to engage. Cold can stiffen any remaining claggy grease too.
Dismantle, clean, re-grease (Vaseline works a treat for this, whack-it in) and all should be well.

 

[MadoneRider1991]

You shouldn't need to replace the cassette at all.

You may need to service or replace the freehub body. Advice on this can be found here.
This problem tends to rear its ugly head more often in cold weather as the temperatures affect the grease/lube in the freehub.

+1

it will have nothing at all to do with the cassette!

 

[abchandler]

Thanks all. Looks like my evening will be busy then!

 

[jpembroke]

Sometimes the pawls seize but I'm willing to bet it's a knackered freehub. Quite easy to replace but can be expensive depending on make (Shimano freehubs are usually fairly inexpensive though). Hope you get it fixed soon.

 

[abchandler]

I'm willing to bet it's a knackered freehub.

I thought that until it re-engaged and is currently working. I hope that a good clean sorts it out properly

 

[jpembroke]

I thought that until it re-engaged and is currently working. I hope that a good clean sorts it out properly

Actually, come to think of it, that happened to a Centaur freehub a few years back: started spinning and then re-engaged. Hopefully then it's just a case of sticky pawls.

 

[llllllll]

I thought that until it re-engaged and is currently working. I hope that a good clean sorts it out properly

Wouldn't risk it, I had the same problem with a Sora hub. It was fine most of the time, but would suddenly 'let go' with out any warning. I tried cleaning and greasing the freehub and it seemed fine for a while, but eventually it let go just as I was out the saddle and it threw me across the road. For the sake of the price of a freehub it's just not worth it.

 

[abchandler]

Well it's had a good clean, but I couldn't get past the bearing cup - no tools for that bit of the job. Anyway gave it a generous lubing while spinning the freewheel, so we'll see how it fares in the morning. It's nice to learn a new bit of your bike every now and again. Suspect the bottom bracket should become my next acquaintance.

 

[andy_wrx]

Well it's had a good clean, but I couldn't get past the bearing cup - no tools for that bit of the job. Anyway gave it a generous lubing while spinning the freewheel, so we'll see how it fares in the morning.

Yes, without the special impossible-to-get Shimano tool, or making one as described in that IceBike link (good to see someone else linking to that as well, it's the one I always use), you won't get into the freehub body itself.

I guess the freehub body is supposed to have grease in it, you've had to wash that out along with the gunk with your lubing, so have to see how it works with lube inside it rather than grease - it might be fine, it might go again or get noisy.

You can get replacement Shimano freehub bodies, but they're £20-odd+ and you have to be careful to get the right one.
I actually got myself a replacement by looking on the exploded parts diagrams on the Shimano website, getting the part number I needed for my hub and noticing that the same part number was also used on the old-model Tiagra hubs, managed to find one of those for £8 and take the freehub off that...

 

[abchandler]

So how is the freehub itself attached to the wheel? If I wanted to replace it rather than keep it clean would I need the special tool?

 

[Sam Kennedy]

Definitely not the cassette! My bike is starting to develop the exact same problem, I took it to someone I know who used to work in a bike shop, and they took the cassette off, and they said it is a problem with the freehub body, not the cassette or bearings. Sadly my freehub body is machined and there are no notches for an allen key to remove it

New Wheels!