New Nomad build

[Andyb1]

Hi
I am just in the process of building up a Nomad with a new MkIII frame and some existing parts I had.
I am using a Shimano 3 x 9 gear system and a couple of things I would welcome comments on:

1. The chain is VERY close to the stay when on the smallest rear sprocket.   The only solution I can see if to adjust the mech so I can not use it - ie limit the bike to 3 x 8 speeds not 3 x 9.  Not the greatest hardship.
2.  Ground clearance with 170 cranks is about 1” less than on my existing bikes (with 26 x 1.75 tyres).  This is with the BB in the highest position in the eccentric.
3.  Chain line is a bit too far to the right with a 126mm BB axle but if I use a shorter axle (118) then I think the small chainwheel will foul the eccentric BB holder.

This is the first time I have built up a bike and it has been interesting setting things up.

Andyb1

[PH]

Hi Andy, welcome to the forum. 
I don't have much to add I'm afraid, just didn't want you to think you were being ignored!
On point 3 - You can space the driveside of the BB out a little, though there's not much consensus on how much is acceptable, as long as the non - driveside cup goes in far enough it should be fine.  I've used 3mm of spacers to get a perfect Rohloff chainline, I don't notice it being asymmetric. 
Also BB lengths can be deceptive, they're not all symmetrical, I can't remember the models but I've had two different lengths with the same chainline!  I've seen a list somewhere, but can't remember where.  The 73mm shell does make finding the perfect match harder.
How far off complete is the build?  Don't forget the photos

[B cereus]

On point 1.

You don't  say what your smallest sprocket is but I have a bike where the chain clears the seatstay at the dropout with an 11T sprocket but which is uncomfortably close with a 12T  sprocket.
 
You could try re-spacing the the rear axle. Whatever you add to the drive side you should subtract from the non drive side to maintain OLD. You will also need to centralise the axle.

If it isn't possible to loose spacers on the non drive side just increasing the OLD by 1 or 2mm with a washer between the drive side cone and locknut might gain you enough clearance. If you do this make sure that you have enough axle protruding each side to secure the wheel in the dropouts. It should still be easy enough to spring the dropouts to fit the wheel. Ideally you should also re-dish the wheel but I wouldn't bother.

[John Saxby]

I have a bike where the chain clears the seatstay at the dropout with an 11T sprocket but which is uncomfortably close with a 12T  sprocket.

Pursuing B cereus' comment:  Until recently I had a light touring bike (700c wheels) with a Shim 3 x 9 at the front, and over time, various rear Shim cogsets.

The arrangement I finally ended up with was:

Front:  22 - 34 - 46  (low ring was a Race Face, the two larger ones Stronglight, via XXcycle in France)
Rear:   11 - 34 (mated to a Shadow long-cage RD)

That set up allowed adequate clearance for rear seatstays, and sufficiently low gearing to let me manage 14%-plus hills.

Hope that's useful -- good luck.

[Andyb1]

Thanks for the replies.  Much appreciated.

The frame has now gone back to Thorn as there were other issues, so I am now looking at an alternative make of bike.

Andyb1