preventec47

I never used the new rims I bought when I first assembled my tandem. i ran across a used already laced up set of wheels and used them. i have been considering having a spare
set of wheels ready to mount with a different type tire when the situation called for it. I have casually looked around and did not see any 48 hole hubs to match my rims.

samkl 

I'd check eBay. You can often find some NOS or lightly used old Shimano tandem hubs for cheap.

Carbonfiberboy 

I built only a rear spare for our tandem - single wheels work OK for emergency use if they're decently sturdy and you're not too heavy. Rims aren't that expensive and they're the part that goes bad, long before the hub. Best to start with a hub for which it's easy to find rims. Even 36H rims are getting a bit scarce as the new model of building stronger rims and using fewer spokes continues to take hold in the industry. The nice new rims are now mostly 32H and less. We're still running 36H but I'm sure we'd be fine with the right 28H alu rims. 285 lb. team.

conspiratemus1

In my early days of wheel building, for practice I put a longer axle into a 32-spoke rear wheel that had given trouble on my randonee bike. Campag 8-sp. so quite asymmetric. I loosened all the spokes and re-tensioned them as if building from scratch. On the tandem it held up pretty well, didn’t break spokes but it was hard to keep the left side tight(-ish.). With more skill today from practice, I bet I could make it work in 32 spokes....but we’re well-supplied with 36-spoke wheels at the moment, so no pressing need to try.

And no, I can’t see buying a 48-spoke hub, and 48 double-butted spokes!, just to use a 48-hole rim, unless you were carrying trekking weight. Stuff is better now.

preventec47

Aside from carbon fiber, there have been no new improvements ( that I know of) in either the design or metalurgy regarding rims and spokes and hubs in the last 25 years so I dont really know why 40 and 48 spoke wheels are no longer in common use with tandems. I mean other than cost. It may just be that fewer spoked wheels were "good enough"
and it no longer made any sense to do the major overkill on component strength.

preventec47

After doing a good bit of googling and research, it appears that the price of the 48 hole front tandem hubs from the exotic tandem specialists cost about the
same as 48 hole hubs that have electric generators built into them. That could be kinda fun in the winter time to plug into my heated socks and gloves etc.
I probably will not be building up a spare front wheel setup that costs more than my bike might be worth.

conspiratemus1

Maybe not in 25 years. But the heyday of 48-spoke wheels for ordinary tandems was more like 40-45 years ago, the era of freewheels, narrow rear spacing, and a propensity to load up your bike with camping equipment for long arduous tours where a broken spoke would wreck your day if the wheel couldn't be trued enough to be useable. Time flies. Stuff, and skill/practice in wheelbuilding, is better today. 145 mm allows light teams to use single-bike wheels. And if something breaks, there is often Uber or CAA only a cell call away.

samkl 

Even in the past 25 years, rims have gotten wider and taller and stronger.

Carbonfiberboy 

Not true. There have been major advances in the design of rim extrusions and spokes. "Back in the day," box section rims were all there was. Now, almost all modern rims are deep and wide. They are stronger and stiffer, give better tire support, are more aerodynamic, require fewer spokes, and except for the brake track, last longer. Modern disc brakes get rid of the brake track wear issue, so now rims can last for the life of the bike - except even better rims will come along and offer yet another upgrade. Spoke design and manufacture have also changed. Our tandem runs deep alu rims with 18 gauge CX-Ray aero spokes. We use 36 of them because that's what our 2003 hubs have, but I'm sure we could run 28 with the right rim. Oh - we've never broken a spoke except for one which was damaged in an accident.

So that's another reason we don't see high spoke count tandem wheels anymore, and also why broken spokes are now very rare. I've never broken a spoke on any of my single bikes. My single now has 20 front and 24 rear, CX-Ray spokes also That works because of the modern alu rims I use. I build all my own wheels, so I get to choose the parts I want to use. One can also have wheels built at a local bike shop.

Modern wheels aren't just "good enough" - they're better.

conspiratemus1

I'm sure what you say is true; I just didn't want to be argumentative earlier. But don't short-change your own development as a wheelbuilder over the years, either -- if you are confident using CXRay spokes you are more skilled than I am. But even my tandem wheels stopped breaking spokes when I moved up to 145, and now I can build a reliable 140 mm wheel (for our old Santana) with 40 spokes on a modern deep-V section rim.

Last winter for the new tandem (145 mm) I built a front wheel with a used MAVIC MA-2 and a rear with a used inexpensive rim from my commuting days, the kind with eyelets only on the visible side, but it was wide enough to let a 32 mm tire through the brake without deflating it, both 36 spokes. The idea was to replace both rims with something better if they failed. Both have stood up to 250 km/week all summer with no adjustment needed at all ... used rims. Since getting a tension meter, I build with more tension than I used to -- I can see why the old timers said to stop only when you round the nipples off.


Everybody gets better at doing and making things with reflective practice. Big manufacturers and us humble enthusiasts turning nipples late at night in our basements to make wheels that our stokers will trust. You just have to want to.

Carbonfiberboy 

Yes, correct and even tension is the secret. I bought the meter before I built my first wheel. One has to sufficiently stretch the spoke. Thus lighter spokes can last longer than heavy spokes, the opposite of what was once recommended, plus they don't beat up the rim as much. Of course "correct" is a matter of debate. I settled on some tension numbers with which I wanted to experiment and though I don't know if there are better ones, they've worked on my equipment, not that they would work as well on other equipment . . . Experience is a very slow teacher. Maybe I'm lucky, maybe the builders I relied on for those numbers are correct. But my guess is that they'd work anywhere as long as they were within the rim manufacturers max tension spec.

I also hesitate and feel bad about the arguing. I try not to do it to no purpose. But I also feel a responsibility to history or if that seems too pretentious, to the readers who will follow us.

It is interesting to see how alu rims have evolved. Do you remember Helium rims, the red ones with a very flat box section? They were the lightest available and if you were a serious club climber, you'd want them. Turned out they made no discernable difference and were fussy. They disappeared off my buddies' bikes in 2 years. Now it's going the other way, heavier and more aero rims. IMO they're faster even considering time lost on the climbs - you'd get it back just on the descent. And conveniently for us, they work better on tandems if you can find the right hole count. Carbon of course would be faster, but having hit many a pothole at speed on the tandem and having rim brakes, I'll stick with alu. You know how it is, you're descending at 50 or so and the critical thing is to look far ahead and hold your line. So far, I've always seen the big stuff, but we go right over the 12" ones Tire pressure helps. Our team is only 285, which makes everything easier, though we've camp-toured using the same equipment but different tires, no problem.

LV2TNDM

Another reason to achieve high spoke tensions is to improve rim life. Cracked rims are an eventuality for anyone using a wheel long enough. Bill Mould presents a very good explanation on YouTube on how and why rims crack over time. His conclusion is high spoke tensions lengthen the life of aluminum rims. So high, even tensions are a good thing all the way around! (Pun intended!) And I'll add that if you're getting your spokes "just tight enough" to prevent NDS loosening, then your spoke tensions are most certainly too low.

120kgf is the ideal DS tension to shoot for (and just pray NDS is acceptable when the wheel's dished properly).