5 Feb 2016

5th February 2016 Moving the cassette over.

Friday 5th 36F, 2C, heavy overcast, light breeze. Rain forecast with possible sleet or snow this morning. The 36tooth sprocket is causing the chain to rub against the top reinforcing loop. This only occurs during actual gear changes on the bottom gear sprocket. The chain rides up before settling into the sprocket teeth. The clearance is so close that the side plates are cutting a tiny slot in the underside of the axle loop.

It has been suggested that I remove the 11tooth top gear and this will move the cassette to the right. Giving me more chain clearance during bottom gear changes. A similar situation exists on the rear facing axle loop. The frame builder can hardly be blamed for the new trend towards huge rear sprockets. It is only my insistence on using a double chainset, rather than a triple, with a 36t sprocket which has caused this problem.

Naturally I don't want to risk the structural integrity of my beautiful trike. So something must be done before more damage is caused. Unfortunately there is no 11 speed option with a 34 or 35 tooth sprocket. These are only available in ten speed which would have the wrong sprocket pitch.[Lateral spacing.] Removing the smallest sprocket should move the whole cassette further away from the trike's framework. I still retain the 11 speed sprocket spacing but lose a gear I rarely need. Except on steep descents with a following gale.

I started the day with my usual walk. I never tire of the the approach to the woods with its undulating rise from the amphitheater floor. There was a thin skin of ice on the puddles and ponds. The ground in the woods was still lightly frozen too. Allowing better progress than on previous occasions. I saw several birds of prey and a woodpecker. The grey sky started spitting as I exited the woods and gently increased as I walked home along the road.

It didn't take long to remove the rear wheels, withdraw the axles and drop the cassette on the Trykit 2WD freehub. Then all I had to do was remove the 11t top gear sprocket and refit the locking ring.  The BB lock ring was screwed the 1/4" along the freehub to tighten the cassette firmly in place. Finally I used the chain wrench/whip and the toothed cassette fastening tool again to re-tighten the lock ring.

The image shows how far the cassette moved along to the right. Leaving plenty of chain clearance. Naturally I shall keep an eye on the spot to ensure the chain isn't still cutting into the frame loop during gear changes. There was, and still is, no problem at all once the chain has settled onto the 36t bottom gear sprocket. It is only during the chain's ride-up onto the sprocket phase of the gear change that the chain needs much more room. This problem is only ever likely to occur on a trike with its complex, axle supporting loops.

I'm still hoping the weather will clear up later, as promised, so I can get a ride in today. It never did clear up and remained wet, dark, windy and miserable.

Click on any image for an enlargement.


No comments:

Post a Comment