Bicycle Mechanics - 24h rear lacing: 1x?

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thebeatcatcher
07-12-10, 08:39 AM
I'm going to build a 24h rear with a deep section rim (deep-V) and my searching on here has yielded mostly discussions between half radial lacing with 2x (pro/cons/NDS/DS/etc.). I was wondering why 1x seems to not be mentioned that much?
I was originally thinking radial DS and 2x NDS, but maybe 1xDS and 2xNDS? Or 2xDS and 3xNDS?
Are there benefits/drawbacks of 1x? It seems that 1x would be closer to radial lacing and therefore result in more of the DS tension balance benefits than 2x, without some of the drawbacks of DS radial.
I'm going to build a 24h rear with a deep section rim (deep-V) and my searching on here has yielded mostly discussions between half radial lacing with 2x (pro/cons/NDS/DS/etc.). I was wondering why 1x seems to not be mentioned that much?
..... It seems that 1x would be closer to radial lacing and therefore result in more of the DS tension balance benefits than 2x, without some of the drawbacks of DS radial.
No. The tension balance improvement you get from radial NDS is from the ability to lace heads-out, which basically does the same thing as moving that flange 1/2 with closer to the center of the axle. The tension balance improvement you could get by lacing the DS radial heads-in would basically be the same as moving that flange 1/2 of its width outwards.
I don't know if lacing 1X and all heads-in/out is doable w/o unhappy consequences due to the sharp bend in the spokes at the cross.
BCRider
07-12-10, 10:26 AM
Remember that the rear hub also needs to transfer power to the rim. 3x and 2x position the spokes at a more tangential line to the hub flange which makes the tension increase on the "pulling" spokes that much less. The closer your drive side spoke angle gets to radial the faster that force increases. And because it's a triginometic thing with sines and cosines involved the forces actually grow more rapidly as the angle gets closer to radial. At the extreme a radially laced rear would see such large spoke loads due to the drive forces that the spokes would fail. So you want to stick with a crossing pattern that keeps the spokes closer to tangential with the flange.
No. The tension balance improvement you get from radial NDS is from the ability to lace heads-out, which basically does the same thing as moving that flange 1/2 with closer to the center of the axle. The tension balance improvement you could get by lacing the DS radial heads-in would basically be the same as moving that flange 1/2 of its width outwards.
I don't know if lacing 1X and all heads-in/out is doable w/o unhappy consequences due to the sharp bend in the spokes at the cross.
you can lace 1x with the heads facing the same direction.
thebeatcatcher
07-12-10, 12:30 PM
you can lace 1x with the heads facing the same direction.
Would 1x with the heads out on the DS be better than 2x on DS? Would 1x heads in on DS be a problem?
While I'm at it, does anyone have a suggestion for the best lacing on a 24h rear? Should I just go with 2x/2x?
For a 24h 26" or 700c wheel, 2x is the best.
1x would give a fairly shallow spoke exit angle which would put more stress on the hub flange.
thebeatcatcher
07-12-10, 01:40 PM
Would you mix patterns or just go 2x on both sides?
Would you mix patterns or just go 2x on both sides?
Depends on the flange spacing. I've got an 24H XT hub, and that one has the NDS flange quite far in to the center. This give a surprisingly small amount of tension imbalance between DS/NDS even at a symmetric pattern. For a hub like that I'd probably go with 2X on both sides. But if I had a hub according to my old LX standard, I'd definitely consider heads-out radial NDS to get those spokes a little tighter.
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