Tandem Cycling - # of spokes and tire size

Looking at replacing my straight handlebar comfort tandem with a road tandem.

Tandem I'm looking at, Cannondale Road Tandem 3, comes with 40 spoke, Sun ME14A w/eyelet and machined sidewall, 40 hole, and 700x28 tires.

For a 210 lb and a 225 lb rider, is 40 spoke enough? Should we be riding on 32 tires? Or at least a 32 for the rear?

Well, I'll take a shot at it. 420g rim is pretty light. Might be OK for front rim, but a Velocity Deep V would be better in the back. You'll find out.

40H is plenty. 36 would be fine, too. I don't see 40H offered for that rim, but mebbe so.

Depends on the tires. I'd want a 28c with 120 lb. rated pressure. If you don't pinch flat, fine. If you do, get more tire. Except that rim is spec'ed as a 19mm rim, which means really about 14mm inside, which is probably too narrow for tires wider than 28c. Deep V is about the same width. Folks here who want to run wider tires like Velocity Dyad rims.

I'd try it as is and then see where you want to go with it when you have some experience with the bike.

Well, I'll take a shot at it. 420g rim is pretty light. Might be OK for front rim, but a Velocity Deep V would be better in the back. You'll find out.

40H is plenty. 36 would be fine, too. I don't see 40H offered for that rim, but mebbe so.

Depends on the tires. I'd want a 28c with 120 lb. rated pressure. If you don't pinch flat, fine. If you do, get more tire. Except that rim is spec'ed as a 19mm rim, which means really about 14mm inside, which is probably too narrow for tires wider than 28c. Deep V is about the same width. Folks here who want to run wider tires like Velocity Dyad rims.

I'd try it as is and then see where you want to go with it when you have some experience with the bike.

FWIW, we run 32's on a Deep V wheel without any problems (Panaracer Pasela 700x32).

As to spoke count, I can't imagine running 500 pounds of bike+rider+gear on 36-spoke wheels. Our team weight is closer to 400 pounds with bike+rider+gear and Peter White would not guarantee a 40-spoke wheel for us, only a 48 spoke. Possibly he is being somewhat overly conservative, but I'd rather err on the side of caution than have a wheel fail at 50mph in a downhill turn. The wheel Peter sold me has a White "Daisy" hub and Dyad rim. The Deep V is on a Hugi hub and has "only" 40 spokes. It's probably fine but doesn't feel quite as rock-solid as the Dyad wheel, so it is a "backup".

Nick

The daVinci V-22 rims seem to have a good reputation for strength/weight. We're a 350 lb. team, at least 400 lbs full-up and have had not problems with the 40h wheels that came on our daVinci. I don't know the width offhand, but Todd at DV said we could run up to 38mm tires, but that may exceed to standard rule of thumb. We've had no pinch flat issues running our 28mm Conti GP 4 Seasons at 115 front/120 rear.

As to spoke count, I can't imagine running 500 pounds of bike+rider+gear on 36-spoke wheels. Our team weight is closer to 400 pounds with bike+rider+gear and Peter White would not guarantee a 40-spoke wheel for us, only a 48 spoke. Possibly he is being somewhat overly conservative, but I'd rather err on the side of caution than have a wheel fail at 50mph in a downhill turn.
Nick

40 spoke wheels don't typically fail like that. It's not like they're a R-Sys. If a conventionally spoked wheel isn't up to the task, spokes will break prematurely, the spokes won't stay properly tensioned,and the wheel in true, and rim eyelets may crack. But the odds a 40 spoke wheel, made of decent components and properly assembled is just going to fold up on you are diminimis.

It's more of a durabilty, maintenance, and cost of replacement issue than a safety issue

On the triplet we run 700X28 tires with no probelms (500 to 550 lbs total wt.) We use 48h wheels.

28 spokes with Velocity deep V's and 25's. 450lbs with bike, no problems.

48 spokes would build a stronger and more durable wheel for you. But 40 spokes seems to be the new standard as they are on most new tandems and the choice in 48 spoked rims is narrowing. The quality of the wheel build is also a major factor in what will or won't work.

I think that the number of spokes, taken by itself, is meaningless. You have to consider the wheel as a whole.

The past six years we (320# team) have used 16-spoke Campag Vento in front, 36-spoke Deep V in back, 20-spoke Rolf in front, 32-spoke 14mm normal clincher rim in front, and Bontrager 24-spoke tandem wheels front and rear. No problems, other than wearing out rims from braking. But the tandem is never loaded; no racks or panniers, just small seat bags to hold spare tubes, snacks, etc. So there's one more sampling point.

L.