‘74 commando rear wheel lacing.

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Looking to relace my rear wheel after L.A.B pointed out the terrible job that one of the previous owners did lacing it up. After thumbing through the parts catalog norton says there are 3 spoke types for the rear wheel, 10 LH inner, 10 RH inner and 20 outside. Does this sound correct and whats the difference, is it the length or head offsets or both? There is also a rim to hub offset of 3/16” toward the speedo side away from the drum? The rim and spokes are new only a couple hundred miles maybe but not sure if they used correct spoke kit. Sorry about all the questions just trying to wrap my head around the project. Thanks for any help.
 
Yes length and bend at the hub end. That they all went in at least the 20 outer are wrong.

This may be helpful: https://www.gregmarsh.com/MC/Norton/RearLacing.aspx I did not use stock spokes and recommend that you do and get them from AN or Buchanan. The spokes I bought for the wheel I documented were not all the right length.

I recently did another wheel and got the spokes from the rim manufacturer and had to re-bend 10 of them!

Originally there were two gauges used - not sure that's important, but using nipples that match the holes in the rim is very important - too small and they can pull through, too large and you can't get them in. So, measure any four holes in a row to see if they are the same - if not you'll need to get the different sized nipples that match the spokes. Buying a set from one place makes that easier.
 
Depends where you get your spokes. Most of the ones I re-lace come from Central Wheel in the UK, and they only provide 2 different spokes - inner and outers - all the same gauge. You then grind off the excess protruding through the nipple.

I can't speak for Buchanan spokes - they might use 3 different ones, but the difference in length is minimal.

What you do need to be careful with is using a Dunlop rim with new spokes from CW - I have run into a couple of cases where the rim hole angles were obviously not compatible - the Dunlop rim would have required shorter spokes to work properly.

Hope this helps.

Edit: Greg's wheel building pages are very helpful. Thanks @marshg246 for putting these together!!
 
The wheels are central would imagine the spokes were from there too being they are brand new.
 
After thumbing through the parts catalog norton says there are 3 spoke types for the rear wheel, 10 LH inner, 10 RH inner and 20 outside. Does this sound correct and whats the difference, is it the length or head offsets or both?
Yes, according to the 850 Mk1 parts book (original Mk2 rear spokes and rim can be different) there were three types but only two are listed in the factory manual.
AN also lists only two (8/10 SWG) spoke types (x2 sets of each required).

https://andover-norton.co.uk/en/shop-details/15870/spokes-per-10-outer-531-head-nm20063-06-7766-


There is also a rim to hub offset of 3/16” toward the speedo side away from the drum?

Yes, the rim needs to be offset toward the speedo drive by approximately 3/16".

The wheels are central would imagine the spokes were from there too being they are brand new.

If they are in good condition then there may be no need to replace them just change 20 to outers?
 
Longer spokes go to the outside. Look at the hook end as well, the inner spokes should have a shorter hook than the outer's. The hook angle might be slightly greater on the outer's as well.
 
Yes, according to the 850 Mk1 parts book (original Mk2 rear spokes and rim can be different) there were three types but only two are listed in the factory manual.
AN also lists only two (8/10 SWG) spoke types (x2 sets of each required).

https://andover-norton.co.uk/en/shop-details/15870/spokes-per-10-outer-531-head-nm20063-06-7766-




Yes, the rim needs to be offset toward the speedo drive by approximately 3/16".



If they are in good condition then there may be no need to replace them just change 20 to outers?
Going to try switching the incorrect inners to outer first. Are the outers the long offset heads? I currently have 20 short offset heads and 20 long offset.
 
Before I start trueing up this wheel does everything look the way it should?? Will need to true up and offset 3/16” toward spedo gear?
 

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Before I start trueing up this wheel does everything look the way it should?? Will need to true up and offset 3/16” toward spedo gear?
The pattern appears right. Do the nipples come out of the holes centered? Do the ends in the hub lay nicely? If the answer to both is then I think you are OK.
 
All the nipples seemed center nicely, there were a few heads that seemed a little unseated but everything is only about four turns tight. Decided to take a break for the day. If some of the heads dont lay flat can they be adjusted slightly?
 
Thanks for the write up on your website marshg246 it has been a huge help. Really got me motivated to try it being there are no wheel shops local to me.
 
All the nipples seemed center nicely, there were a few heads that seemed a little unseated but everything is only about four turns tight. Decided to take a break for the day. If some of the heads dont lay flat can they be adjusted slightly?
They can, but there's probably no need to. If you see one of them causing the spoke to bow then consider it, but usually a little cocked is fine.
 
I posted on here, when I was lacing a front wheel, a few months back. There's some useful info on there, even though a front wheel. See this, about how the factory approached building disc brake wheels, to get the spokes nicely settled and I think to start the offset, the factory would use a hammer: https://www.accessnorton.com/NortonCommando/front-wheel.34609/post-567462

It worked really well for me and got the spokes nice and straight ready for trueing.
 
I have read the 2nd paragraph of the sheet several times, but still don't understand it. I don't get the 1.4" offset point.
Because of the presence of the disc, obviously the hub itself is not exactly centered relative to the rim.. The center of the hub is moved (off set) in the non-disc direction 1.4". (35.56 mm)
 
Everything I've seen refers to half an inch offset. I laced my front with half an inch offset and it is central between the forks. 1.4" would be too much? Are we talking about the same thing?
 
Norman White's book gives offsets as:

Front disc: 0.563 inches, disc mounting flange to edge of rim
Rear drum: 0.25 inches, sprocket side edge to edge of rim
 
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