CapTandem

Hi all. Bought our first tandem a year ago. 2007 C'dale with 40 count Mavic A719 rims and DT Swiss 540 tandem disc hubs. We have put approx. 1800 miles on it in the last 12 months and our team weight is 400#.

Monday night as we left for our club ride, for the first time, I heard the distinct musical sound of spokes being 'plucked' against each other on the front wheel. After reading some threads this morning about tandem wheels being sensitive to spoke tension, I went out and checked by squeezing the overlapping spokes. Most 'twanged' as I squeezed them. A few were noticeably not as 'taunt' as the rest. On my single bike, I just kept on riding until a spoke broke. I'm not sure about doing the same on our tandem.

What are some 'rules of thumb' I should observe? First, how often should I be checking the spoke tension? Second, how critical is it to get the bike into the shop? The end of season century is less than two weeks away, and I'm tempted to chance it for two more weeks. HemiGirl may put me into the dog house if she can't get her tandem fix... Well, you know what I mean.

Thanks in advance. Hope to see y'all on the road sometime!

stapfam

I would say ones years riding and 1800 miles is time enough to put the wheels into the builder for a retension and true. I ride hand built wheels and get mine checked out after 100 miles from new.

I check the tension on the spokes fairly regularly- and if there is a great difference on the tone when twanging the spokes- then you would probably find the wheel out of true aswell. And if the spokes feel as though they are slack- then the spokes do need retensioning.

And if you do get to the stage of breaking a spoke on a 400lbs team- It could be a call for recovery- and an expensive rebuild.

jgg3

I build my own wheels (at least, so far). If there is any significant difference in tension, you have a wobbly wheel, or a damaged one. A wheel builder's most prized tool is a tensiometer, and the goal is to have them all the same. We have about 4000 miles on our CoMotion right now, and the wheels are still good and true (they came with, I didn't build them, but I trued them a bit).

When a wheel is damaged, you can sometimes get it straight by some radically differing tensions -- but that should be considered a temporary thing, as over time, those uneven tensions make things worse and cause spoke failure.

TandemGeek

Once, on the day you take delivery of the wheels.

Seriously, properly tensioned wheels won't need to be checked again unless you damage them or wear out the rims and need to lace new ones to the old hubs and spokes. Even a little out of true condition should only require a tweak (always tighten, never loosen)

If your wheels are going out of true, out of round or seem like they have loose spokes, get them back to your bike shop so that: 1) they're put on notice that they seemed to have been built with too little spoke tension and, 2) to get them retensioned because, well... that's about all you can do at this point. If in the event you experience a spoke break down the line, you'll want to go back to your dealer and remind them that they had to retension the wheels to correct an original out of spec condition.

zonatandem

20,000+ miles on our Zona tandem wheels (King hubs, Velocity Aerohead rims, DT Revolution spokes; 32H front, 36H rear). Couple minor trues and 2 broken front wheel alloy nipples.
A good wheelbuilder is a huge +!

CapTandem

A big thank you to everyone for sharing your knowledge!

Read your comments, slept on it, and decided that I needed to find someone with a tensiometer to at least take a reading on the spokes. Shop told me that the readings were all over the place on the front wheel -anywhere from 11 to 16. Told me that it would take a little while to fix and to do it right. The rim, by the way, had only the slightest wobble that was barely discernable on the truing stand only with the rim gauge in place.

Now that I think about it, road hazards are common in this area. Narrow or non-existent shoulders with crumbling asphalt, pot holes, debris, and grade level rail road tracks which I will drive over faster than I want because of close cars or at night with lights that illuminate most, but not all hazards. All things considered, it was not improper wheel building, but my driving and riding habits, and these wheels have proved themselves to be pretty ‘bomb-proof’.

I’ll take quality and durability any day. Thanks again to all.

TandemGeek

Unless you nailed a pot hole and deformed the rim, it's not your fault.... Chances are, the wheel was not evenly tensioned or properly distressed when you took delivery and the uneven tension has allowed what uneven tension will allow... spokes to loosen.

If it was the back wheel I'd be more inclined to buy into the notion that normal wear and tear from a 400# team perhaps with a stoker who likes to bounce would begin to fall out of true; however, not so with the front wheel. Even if it's a disc-equipped model with a dished front wheel, the tension on each side should be fairly uniform, the disc side being higher than the non-disc side.

Bear in mind, there are a number of folks like us who ride tandems off-road who beat the heck out of well-built wheels with no ill effect short of bashing one into a rock or getting one crossways and turning it into a taco-shaped-object.

CapTandem

Thank you.

Your point is well taken. It was a little of a shock to find this on a nearly new tandem and my 'knee-jerk' reaction was to blame myself. Thank you for pointing out that it's not me. I will be discussing this with the shop I bought it from.