I've just put in new rear inner tube on my Agattu. Slightly awkward with the Shimano Nexus cable stay, I wouldn't want to do it on the road.
In fact, I'm going to fit a pair of Schwalbe tyres as Flecc suggests to avoid the need if possible.
My question - it's so many years since I took a hub geared rear wheel off, I'd forgotten the need to line it up in the forks. I've had derailleurs for years, of course.
I've judged it by finger width as I used to but I'm wondering if this will be accurate enough for a rear wheel carrying so much more power than a non pedelec. It's quite awkward on the Agattu because of the mudguards, chainguard and weather skirt. How critical is the wheel alignment?
Any thoughts?
Lemmy
"Finger width" between wheel and chainstay, plus a good eye from the back of the bike is fine. You might be able to get a little more accuracy by finding a socket on an extension that just passes through the gaps on each side when they are equal.
Just as important is to set the forward/backward position to the same as before to bring the brake blocks neatly to the centre of the rim.
The non-rotation washers (grey on the left side, black on the right side) are deeply grooved. After tightening the hub nuts to their full torque, you will leave a clear impression of the position in the aluminium dropouts, and will be able to match up to the same position next time.
The "full torque" of the hub nuts is important - the correct figure is 390 inch pounds. How long is your hub nut spanner or socket wrench ? Perhaps 9 or 10 inches. Divide the length into 390 giving between 39 and 43 lbs (17 - 20 kg)to be pushed down on the spanner.
The hub nuts need checking quite frequently to avoid the wheel shifting in the dropout slots.
If you don't have them already, it is worth printing off these two sheets from Shimano.
Agattu with 7 speed gears and rotary shifter
a) Service Instruction for
Adjusting the Gear Cable
b) Service Instruction for the
7 Speed Hub
Tasman with 8 speed gears and rotary shifter
a) Service Instruction for
Adjusting the Gear Cable
b) Service Instruction for the
8 Speed Hub
Pro Connect with 8 speed gears and lever shifter
a) Service Instruction for
Adjusting the Gear Cable
b) Service Instruction for the
8 Speed Hub
If the gears are very graunchy after refitting the wheel, it is possible that the wheel is sitting deeper into the dropout slot (further from the pedals).
This causes the gear cable to pull away from the bottom of the socket in the cassette joint, because there is a rubber grommet gripping it to the chainstay.
Release the rubber grommet from the clasp on the frame, and pull a little more cable through, towards the hub.
This will correct the alignment of the yellow marks in 4th gear as described on the Shimano sheet.
James
