Symox

I got bit by the wheel lacing bug. I did a rim brake rear 28Hole with 3X lacing both sides and its great. Now I'm addicted to doing other patterns. I'm thinking of trying a radial non drive side pattern with 3X drive side. Other than the small weight savings due to the radial spokes, are there other benefits? According to Sheldon Brown it appears it will make the tension of the spokes more equal if the heads of the spokes go "out" for the radial spokes.

Also, I'm thinking of using butted spokes for weight, potentially more shock absorption (is this a myth?) and better fatigue life of the spokes. Again, this is for a RIM brake bike with 28 holes (mavic open pro) and Bitex RAR12 hub. Probably Sapim spokes and nipples (brass).

I'm NOT a racer but appreciate a high performance machine.

Thoughts?
Thanks for your insight

Kimmo 

Butted spokes all the way, especially on the NDS of a rear.

Only real issue with radial is hub flange has to be up to it, shouldn't be an issue for the low tension of NDS, pretty much just applies to front hubs. There's less metal in the way of a radial spoke wanting to pull through the flange; recent hub flanges are beefier than older ones.

AlmostTrick

Coolness factor / looks. Please post pics when you get it done.

JohnDThompson 

Thee's really no functional benefit to radial spoking. And as mentioned above, if your hub isn't designed for radial spoking, there's a chance the hub flange may fail.

HillRider

As disc brakes become more prevalent on road bikes, the radial spoked wheel is going to be less and less common.

Symox

Why do you recommend butted spokes, especially for the NDS rear?

Kimmo 

They stretch more for the same tension. The NDS spokes are quite loose, and are usually the first to suffer fatigue failures from going completely slack as they go past the ground. Butted spokes, being more elastic, are less likely to lose all tension when the wheel's loaded.

If you want to learn all about wheels, it's possible find a free copy of Jobst Brandt's book on wheelbuilding with a bit of digging. There's a lot of bunk out there about wheels, but Jobst knew his stuff and wrote the bible on it (although he wasn't around for the advent of low-spoke count wheels, so they're not covered).

AeroGut

To the question of benefits of half-radial spoking, occasionally you will see radial on the drive side and crossed on the non-drive side which I think is supposed to reduce the asymmetry of the tension due to the dishing, but it requires a beefy hub to transmit the torque to the nondrive side and not stress the drive side spokes too much. Shimano's 105 R561 wheels are an example. I have no idea if it actually makes any difference in performance. I got more annoyed by the fact that the shimano linear pull spokes on those wheels used an odd size nipple that needed a special spoke wrench, and you had to take the cassette off to get at the nipples on the drive side, but that's an aside.

oldbobcat

What he said.

Symox

Well radial spoking does reduce spoke length and hence weight. So, there is always that.

Symox

Got a copy of Jobst Brandt's book. Very well written.

He seems to really like the butted ("swaged" in Brandt's terminology) spokes. He isn't a fan of radial spoking which is interesting.

Symox

According to Sheldon Brown:



"Radial front wheels offer mainly esthetic benefits, but half-radial rear wheels can be substantially more durable than conventional ones, if the wheel is highly dished. The high amount of dishing with more and more sprockets has caused an increase in spoke breakage on the left side of rear wheels. This is caused by metal fatigue. Just as you can break a paperclip by bending it back and forth a few times, you can break spokes by flexing them back and forth by a much smaller amount, millions of times -- even if they don't flex enough to take a permanent set."



"With half-radial spoking, the amount of dish is very slightly less to begin with if you run the radial spokes up along the inside of the flange ("heads out.") In addition, since there are no left-side "leading" spokes, no amount of torque on the hub can reduce the tension on any of the left-side spokes. In fact, if you have an old wheel that has been breaking left-side spokes, "half rebuilding" the wheel into a half radial will solve the problem once and for all."



https://sheldonbrown.com/wheelbuild.html#half-radial

Bill Kapaun

Obviously you had your mind made up before you posted.
Why not do a 1X NDS with a thinner spoke?

oldbobcat

Jobst Brandt always chose strength and durability over, erm, other considerations. At the time he wrote that book, all serious riding and racing was done on hand-built wheels. Only a handful of race mechanics built radially spoked wheels, and then only the front, and only for time trialing, climbing, and track for the lightest riders. It's presumable that these wheels did not last long.

Radial spokes pull raidially from the spoke hole in the flange. To prevent the flange from eventually cracking, it needs more material in the direction of pull--either by drilling fewer holes closer to the center, or by forging a higher flange.

A buddy of mine once built a rear wheel with a radial spokes straddled by a pair of tangential spokes on the non-drive side. It looked cool but was rather pointless.

Mackers

How is this supposed to work? Surely NDS tension as a function of DS tension and hub geometry will be identical for whatever butting and gauge spoke you use? And a spoke will go slack at the same moment regardless of butting or gauge. It will just have elongated more while under tension.

Bike Gremlin

My thinking out loud - haven't been able to measure this:
Downwards, or sideways force pushing the rim towards the NDS can both effectively shorten the distance from the NDS flange to the rim of certain NDS spokes.
Similar goes for the leading ("pushing") spokes when the drive torque is applied.

The more elongated spokes are when the wheel is built, the less likely they are to become completely slack from such temporary rim deflections and very slight rotations relative to the hub.

Of course, without having measured this, it is just theory. The other advantage of swagged spokes: the thinned down mid-section effectively acting as a spoke-shock-absorber, unloading the more stressed spoke ends, hence making the spokes a lot more durable, is what I would consider to be tried and tested - and confirmed.

Symox

because you are obviously trolling

cpach

Go for it if you want, it's fun and almost entirely harmless. My personal road bike has a radial/2x 28h rear wheel, mostly because it looks neat and it was fun. It has held up fine, despite the very low weight of the wheelset (~1300g, all aluminum) and my voluptuous butt. NDS radial lets you choose putting the heads in our out: heads in will increase triangulation and thus lateral stiffness slightly, heads out will decrease triangulation and increase NDS tension/longevity slightly. Also, if you lace radial NDS if the hub shell tries to transfer torque to the NDS all the spokes will just wind up and increase tension--if they're crossed, half the spokes will loose tension. Given that the NDS is under less tension, this slightly decreases the chances that a spoke might be at lowered tension due to load and due to torque, and thus theoretically increase fatigue life on the NDS very slightly. As you mentioned, it will extremely slightly reduce weight. If your hub shell doesn't accommodate radial lacing well, it places more stress on the hub flange and can lead to hub flange failure. On a crossed wheel the opposing spokes compress sections of the hub shell, rather than pull out on it.

Butted spokes save weight and reduce fatigue failure of the spokes. That wheels absorb shock meaningfully is mostly BS--Jobst Brandst explains this pretty well in his book. The greatest deflection of wheels measured is orders of magnitude smaller than several other parts of the bike. As the spokes on the bottom of the wheel lose tension, they shorten to an incredibly small degree until they entirely lose tension. Note that very thin butted sections are more prone to wind up and require more active wind up management/skill to build well.

Bill Kapaun

And you're not?
Ignore List

Symox

Looks like Campagnolo rear wheels are regularly built half radially. I think I'll give it a go!

oldbobcat

If the wheel is highly dished. With the prevalence of 130 and 135 mm road hubs, 140 mm and wider MTB hubs, and disk brake rotors on the non-drive side, dishing on non-boutique wheels has actually decreased since the days of 126 mm.

Some boutique wheel manufacturers do build rear wheels with radial patterns. Mavic actually puts the radial pattern on the drive side of their Ksyrium wheels, with a wider flange. Even with a rim offset to the non-drive side, non-drive side spokes are significantly longer. I'll probably never know Mavic's rationale for this. I do know Lance Armstrong's US Postal team raced on tubular Ksyriums one year, and my 14 year-old Ksyrium SLs are still going strong with routine freehub servicing and minor occasional rim truing. I can't kill these wheels. But these are boutique wheels. Trust that the manufacturer knows what they're doing, and if you try it at home and it breaks, hey, you're on your own.

Symox

I'm sure Mavic knows what they are doing, but everything I've read says the radial should be on the non drive side.
Glad to hear your Ksyriums are doing great!

Symox

FYI I've decided to build 3X drive side and radial NDS using butted spokes (Sapim Race) and brass nipples (Sapim Polyax) after reading Jobst Brandt's excellent book and heeding (most) of his advice.

I'll keep you posted

Symox

It looks like radial NDS is more common than I thought. Here's another from Mercury wheels:
wheel
and from
trimax
Profile Designs

Surprisingly (to me at least), Vision wheels uses radial NDS on a DISC brake wheel

cpach

The Ksyrium thing was mostly to bring the DS flange out a little farther without hitting the cassette, particularly with the stupid zircal spokes. It relies on the hub shell to transmit torque. They're honestly pretty underwhelming wheels, but they were some of the first system integrated wheelsystems popular on the market.

A lot of the Campy stuff is actually triplet laced, with twice as many spokes on the DS as the NDS to increase NDS tension. There are advantages and disadvantages to this, as you might imagine.

The one thing to ignore on Brandt is his advise on bringing tension up until the rim starts deforming in waves when stress relieving. Lightweight road rims in the 80s would do this, modern rims will be on the verge of spoke hole failure before this happens. Use a tensiometer.