NC29 wheels into a NC23... but it's not going as expected.

[LancasterTony]

Hello, all

I thought I might post this in here as enough of the members have done this particular swap in the past, and will have informed opinions.
I've read through the other posts on this particular subject and few of them mention what I found... so I thought I'd check.

Firstly, the NC29 wheel with spacers is a few mm's wider than the NC23's and I also have an issue with the bolt hole of the chainguard being in the way of the nuts holding the NC29's sprocket in place. I don't have the rear brake hanger on this swinging arm because it's not on a bike and secondly the 29's wheel wouldn't arrive to let me take these sort of measurements anyway.

Anyway, I thought this would come in handy as a visual reference for anyone attempting this conversion.



First the NC23 setup and measurements.




NC29 initially with the wheel able to turn (clearing the swinging arm)
it's 3-5 mm narrower which is a lot when dealing with steel... as it doesn't bend.


And playing with getting the left spacer flush with the swinging arm's inner surface.



Chain alignment and clearance comparison (seems ok once the chain guard mount is shaved flat - but would also benefit from the sprocket carriers bolts being a couple of mm shorter to avoid any interference.



Thinking around the problem I briefly entertained swapping the sprocket carrier over as the cushes fit... but that is all.



Any suggestions as to how to best go about solving this issue very welcome.

[LancasterTony]

This addresses some of the width issues... viewtopic.php?f=28&t=52929&p=377604
However reducing the left spacer would make the interference an even greater issue.

[CB1pod70]

I've done this on a few race bikes and while everything is close, it does all fit with just 1mm shaved off the larger diameter end of the L/H spacer. I have always run my race bikes with no chainguard (just the sharks fin underneath) so usually cut the rear chainguard mount off the swingarm for clearance however you should be ok to just shave the back of it off.

Sometimes the sprocket carrier can sit a bit proud of the wheel and not fully seat until the spindle is tightened so check that as well

Another option to gain some clearance would be to completely remove the studs for the rear sprocket and use m10 x 1.25mm bolts fitted from the sprocket side. I would guess they would need to be around 30mm long but check this

[LancasterTony]

I've done this on a few race bikes and while everything is close, it does all fit with just 1mm shaved off the larger diameter end of the L/H spacer. I have always run my race bikes with no chainguard (just the sharks fin underneath) so usually cut the rear chainguard mount off the swingarm for clearance however you should be ok to just shave the back of it off.

Excellent, good to know while very close there's no chaffing.
interesting that you shave the thickness from the flange end of the spacer, as there looks to be about 3mm between the flange bit of and the wheel, but perhaps this the part where you mention it not sitting properly.