Spinning Crank and pedalsb when pushing

[georgeidf50]

Why oh why does the crank spin when I push my Catalyst with Speedhub14

By the way I am on South american ripio ( gravel and mud) roads in the Andes with a 45 kg BOB Ibex trailer, so I push quite a bit and the cranks keep spinning.
 The pedals go into the back of my knees and cripple me

why oh why

george

[Ratty]

This happens to me too.

The back of the knee or the ankle blows are particularly painful.

The Rohloff manual says to try dropping some Rohloff cleaning fluid into the hub and Thorn told me to hit the axle with a rubber mallet but neither of these things have worked for me.

I hope one of these might work for you.

Does anyone have any other ideas for me?

Anthony

[jgrgilbert]

So I guess this is a problem with the freewheel mechanism?

Interesting. This isn't a problem with the hub I have read about before.

Does it help if you put it into a different gear?

[Ratty]

Changing gears only changes the rate at which the pedals spin.

[PH]

What age are your hubs?
Mine did this till I'd done around 3,000 miles then it stopped doing it.  Nothing else has changed.

[Ratty]

mine is 11 months and more than 3000 miles old but the problem persists

Anthony

[TonySmith]

Come to think of it mine did this once or twice in its first year but hasn't happened for a long time now.

[graham]

I have two Rohloff hubs and both do it.
The one currently in the Raven tour has about 4800 miles on it, but it did most of those in the tandem.

The new hub in the tandem is about 2000 miles old.

Personally I'd previously put it down to an apparently robust nature of the freewheel creating more drag than you'd see on a derailleur equipped bike.
But thinking about it as I write this, I suspect it's probably mostly because there's no chain tensioner arm with a Raven. The drag caused by that on a conventional bike is probably greater than the drag caused by the freewheel, so the chain doesn't move. On a Raven, the bottom bracket may well spin easier than the freewheel, so that's the bit that moves. For those of you who don't see the effect, maybe your B/B is a bit stiffer than some.

I'd confirm that the rate varies with the gear you're in. I'm not sure how that fits with the above theory, but I don't think it necessarily invalidates it.
Personally, I walk with the bike leaning a bit or at arms length so the pedals can't get me, and don't see it as much of an issue.

[Ratty]

Everyone here seems to be talking about new hubs (all under 5000 miles old).

The first oil change happens after 5000 miles or 1 year so I wonder - because of the lack of postings from people with older bikes - if this might solve the issue for us.

BTW Thorn has some new advice on Rohloff oil changes. Check:

http://www.sjscycles.com/thornwebsite/rohloffhuboil.html

Anthony

[graham]

quote:The first oil change happens after 5000 miles or 1 year so I wonder - because of the lack of postings from people with older bikes - if this might solve the issue for us.

No, 5000 Km. 3100 miles.

My hub with 4800 miles on it had the oil change some time ago now.

Actually, we rode the tandem again today and on the small bit of pushing the cranks did not go round. Probably because of the extra chain and two sets of rings and two bottom brackets overcoming the slight drag from the gearbox. This hub now has just under 2100 miles on it. And hasn't had the oil change yet.

[jawj]

Just dug up this ancient thread and it attracted my attention as it appears some people's cranks stopped spinning after their hubs had done  such and such number of miles. I've done two oil changes (both were slightly overdue...) and my cranks still spin as robustly as ever when pushing the bike.

Anybody's hub bedded in in such a way that this phenomenon has stopped for them?

[pdamm]

After 21,000 km on my Raven Tour it comes and goes.  It is possibly a little bit reduced from when the bike was new.

Peter

[freddered]

After 21,000 km on my Raven Tour it comes and goes.  It is possibly a little bit reduced from when the bike was new.

Peter

Similar here, I think (because I don't really notice it any more)

[ALMEIDA]

To all guys with spinning crank: does your bike own achain tensioner or not?
If yes - the crank may not spin
If no - the crank may spin in some gears. Important is the correct chain tension.

[jawj]

To all guys with spinning crank: does your bike own achain tensioner or not?

I think we're mostly talking about various Thorn Ravens here so no chain tensioners.

I, for one, like to believe that my chain tension is perfect  but even when it has been less-than-perfect (lazy days...) the cranks have spun so I don't reckon that's a factor, though I can see how having the tension too tight would mean they don't spin.

The cranks spin in all gears when pushing. Have you noticed a difference between gears, Almeida?