Niloc

Hey folks I was convinced to build my own wheels after posting about it on here. Funny I can't find that thread now... Anyways, I've started acquiring parts, I've got the hubs, now I'm looking into rims. I'm building a Campy 9-speed wheel and I understand that Campy hubs are more offset on the drive side than others - they have deeper freehub bodies. So I'm wondering how to handle the rather large difference in spoke tension that would result. On my current Campy wheels, I've had non-drive side spokes completely lose tension and put a wobble in the rim. I've had to true it a couple times this year already. Maybe the wheel wasn't build very well I don't know.

So there are asymmetric rims out there, and that seems like a good solution, but if so why aren't more people and companies using them? I read about problems with the spokes pulling out of the rim on the drive side and others have said well it does help even out the spoke tension but it's not really necessary in most cases. Another solution is to use a symmetric rim, but use lighter gauge spokes on the non-drive side, which will then have to carry more tension so that helps even things out. I read a complicated analysis, that I couldn't entirely follow to be honest, that said that only makes sense with stiff, deep profile rims with a low spoke count.

Any opinions out there I'm all ears. BTW here are my constraints:

-Rear hub is 32H, so a decent number of spokes these days. Planning on lacing 3x but open to suggestions.
-Planning on using round swaged (double butted) spokes. No need to go aero here.
-I want to use a wide (~23mm) tubeless ready alloy rim. I sometimes run wider tires and I like the concept even with 23-25mm tires. Like a HED Ardennes Plus. The Pacenti SL23 is one I'm considering. The only wide tubeless rim with off center drilling I could find is the Velocity A23 OC. I've read about quality problems with Velocity A23s and that they are not as stiff as some other deeper profile. However perhaps running it at 32H would mitigate that somewhat.
-The front hub is 24H and I'm planning on lacing it 2x. Perhaps I could run a Pacenti SL23 up front and a Velocity A23 OC in back. Or just two Pacentis.
-I weigh around 185lbs.

Thanks for your opinions.

fietsbob

I've got DIY 30+ year old wheels straight gage spokes, rims with on center ferrules , 36 spoke.. they still work fine.

if you want to use the various featured products as you describe, be my guest ..

Odd build: I have mid 70s <C> hi-lo F/W hubs high is 3X low is 4X .. so length differences are significant..


3X 32 hole is some what like 4X 36 .. 1st cross is the nearest spoke headed to the opposite rim side.

Have 2 disc brake Front hubs set up that way [rears are IGH so no analogs there] ..

Drew Eckhardt 

It's amusing to discuss the ideal bicycle wheel although in practice the fine details usually don't matter.

You'll be fine with 2.0/1.8mm spokes everywhere, 2.0/1.5 except 2.0/1.8 rear drive side (I rode those spokes on 1996 Campagnolo Chorus hubs updated to 9 cogs around 2000 for ~17 years at weights up to 215 pounds without issue, although neither rim is original due to object impact damage and I may be on the third rear rim), or even 2.0/1.5 everywhere (after thinking about it more I couldn't come up with a good reason not too - drive side and front tension is the same, many boutique wheels are running aerospokes which began life as 1.5mm round spokes without issue, etc - so I built the last few that way. With anti-seize windup is reasonable even at 120-130 kgf in deeper rims)..

Straight gauge spokes should be fine too, although as long as you're going through the effort you might as well spring for butted.

Non-drive-side tension is purely a function of the bracing angles on both sides of the wheel and unaffected by spoke gauge.

Differing spoke gauges allow for more similar stretch between the two sides, although that pseudo-science doesn't actually buy you anything.

Off-center rims give you more margin of error for under-tensioned wheels although you'll do well enough with a symmetric rear rim with suitable tension, especially as you move beyond shallow box profiles and their tension limits. Mechanically they're needed in fewer circumstances once you move to deeper rims where

1. The rim is stiffer (with stiffness proportional to the cube of depth) so the deflection from rider weight is spread across more of the rim making for less spoke length change.

2. The stiffer rim (with suitable spoke bed) will tolerate at least an extra 10-20 kgf of tension or 36-73 pounds of rider weight to get to a problematic deflection assuming a 60/40 weight split between front and rear wheel (in practice the real number should be much higher because rim deflection is less localized in the stiffer rim).

Theoretically a wheel built with lighter spokes will survive bigger impacts before collapsing which happens when the bottom spokes go slack, rim shifts off center, and the rim springs back when it's still off center after the bump passes.

In practice as long as you put enough (105-110 kgf front and rear drive side, with many deeper rims tolerating more) tension in there you'll be fine.

I recently decided I wanted to keep spare rims around which is easier when the front and rear are identical, although with your 24/32 spoke count that's not an option.

The Kinlin XC279 is another 23mm option (28mm deep).

Niloc

Thanks for all the analysis @Drew Eckhardt. So I assume a Pacenti or HED with a ~28mm depth is stiffer. I guess whatever spoke is thick enough for the 24H front should be enough for the offset 32H rear wheel. Do more spokes at the same tension equal a stronger wheel? But then this strength is reduced by deflection towards the drive side? Sounds like you think 2.0/1.5 would be enough. Got any preferred type/brand?

BTW I debated getting CXRays or other aero for the front but I decided that the rim isn't really aero and 24 spokes 2x isn't really aero so that would be a pointless waste of money.

Also neither the Pacenti SL23 or HED or I think many similar rims have eyelets. Is that b/c with the deeper profile or thickness of the material at the spoke bed they aren't needed?

Bill Kapaun

There's no reason you can't use an OC rim and different gauge spokes.
I did on my "grocery getter". (26" rim)
Velocity Synergy OC with straight 2.0mm on the DS and 2.0/1.8mm DB on the NDS.
I was going to use 2.3/2.0 on the DS, but availability became an issue at the time.
I basically wanted a wheel to carry extreme weight on relatively smooth roads.

San Rensho 

Get a hub with NDS offset that is less, that is, closer to the offset of the DS, Then the spoke tension will be closer DS to NDS

Niloc

Well I already have the hub (Campy 9spd) and can't be changing that. Don't think there are other much better options available anyways.

fietsbob

There are US made hubs .. but you got what you chose ..

you take in all the offset statistics? this talking differences less than 2mm?

Niloc

Yeah I wanted to run Campy - they are high quality hubs with cup-and-cone bearings which I prefer to cartridge. Besides with a Campy freehub and 130mm OLD how much better can anybody else make the offset? Not much is my guess. So this point is moot. After Drew's comments I'm pretty much convinced that I don't need to bother with an asymmetric rim considering that I'm interested in a deeper profile anyways. I need to do a few more calculations myself, but perhaps with my particulars using different gauge spokes DS/NDS doesn't make sense either.

Drew Eckhardt 

I like DT spokes because they have an aesthetic smooth taper between the narrow and full-sized sections, and if you're being honest bicycle parts are mostly about what looks best to you.

It's 1-2W @ 30 MPH depending on yaw angle which is not significant.

I'd guess all the material on the front side is bunched up into a narrow area so they're not needed.

As a side effect the nipples bear directly on the holes drilled in the aluminum rim during it's manufacture instead of smooth eyelets. Use a drill bit larger than the nipple holes (in your fingers) to debur them.

Also lubricate the insides of the nipple sockets with anti-seize to lessen friction and prevent galling. When it fits I like the same acid brush with half the bristle length cut off that I use for the spoke threads, although a q-tip will work in a pinch (but may leave behind greasy strands of cotton that offend the detail oriented).

Niloc

Thanks again for the tips. What's your preferred anti-seize? Do you use brass nipples?

Drew Eckhardt 

Zinc, which corrodes preferentially over aluminum like that in the nipple sockets (and perhaps nipples)

Amazon.com: Jet-Lube Zinc Dust Petrolatum Anti Seize Compound, 1/2 lbs Brush Top Can: Industrial & Scientific

Aluminum anti-seize seems to work fine and a small tube may be a lifetime supply when you're not working on motor vehicles, although after I finally contemplated the galvanic series I figured that I was putting a lot of effort into building wheels and as a craftsman should do the right thing.

Usually aluminum nipples (winter-only wheels with cyclocross tires mounted get brass). I'm detail oriented enough to measure my rims and get spokes which end between the slots and nipple tops so alloy nipples don't break. With proper lubrication I never had one seize up, even with 9 years of Colorado winters and road salt with aluminum anti-seize. Never stripped one either, although I made a couple trapezoidal making a bent rim rideable in an after-dark roadside repair via an incompletely seated spoke wrench. It's one of those craftsmanship things that's an intellectual aestheticism - I can so I do.

If you're a weight weenie (or commercial manufacturer selling to such people) alloy nipples are a very inexpensive way to shed grams - $0.13 per nipple / 0.7g savings = $0.19 a gram although 64 alloy nipples are only good for a speed increase of 0.05% up the steepest hills with a 165 pound bike+rider combination. Rotational inertia nearly doubling the impact on acceleration is still just 0.1% although so little energy goes into high-acceleration situations (criteriums) significant weight changes don't have an appreciable impact. Weight weenies ride wheels with fewer spokes where the benefits are even less pronounced.

Otherwise apart from lots of color choices there aren't good reasons to use alloy nipples (maybe internal nipples where that's all you can buy).

For my last wheels I used Velocity Fusion HALO retro-reflective rims, alloy nipples, DT Revolution 2.0/1.5 spokes, NOS Powertap hubs in silver with carbon accent, and NOS 1997-2006 Record skewers.

Valve stems are correctly aimed at hub labels, nipple sides all parallel to the rim side walls (90 degree increments are good enough on regular spoke count wheels), and I had to correct the spoke lines at the rim because I neglected to read my notes from the last PowerTap build saying I should use cross-2 next time not cross-3 (oops).