Tandem Cycling - Chain suck…and I dropped my stoker…literally…

OK, I will make a short story long….. My girlfriend/stoker has been gaining fitness, making our tandem rides longer and faster. Today we took a ride that ended up having some good things happen and some not-so-good things happen. We had a loose plan for the day - ride out to Oregon Ridge Park for a benefit pancake breakfast and continue on after that as we saw fit. On the way out, a long climb must be surmounted. Last time up this hill two months ago or so, we took it in low gear. Today, we managed 2 cogs higher! I was so impressed! The weather on the way out was not as favorable as predicted - cloudy and low forties. I had an extra wind shell stuffed in a back pocket which Nancy quickly put to use. The hall at the park was packed, but after a short wait we got our pancakes. We were the only cyclist out of several hundred folks but everyone was friendly and inquisitive. The breakfast was to benefit the Oregon Ridge Nature Center and of course, they had several raffles. We bought 6 tickets, depositing one in the box to win concert tickets at a local vineyard, and depositing the remaining five in a box to win a huge basket of cheer (is there a pattern here?). Soon enough, we had finished our food and were on our way north on Cuba Road. The temperature had risen a few degrees and the sun was out!

Clicking along at a nice pace up and down the rollers, standing to climb the shorter rises. We were doing just this - standing while climbing a short, steepish rise and hitting it pretty hard in the middle ring and low gear on the back when all of a sudden the drive train locked on the down stroke. We both freaked out for a second. We were quickly loosing speed. As we came to a stop part way up the hill, I got my left foot down, but very ungracefully. I was out of sync a bit I think because my right foot was still stuck half way down. My hard soled racing shoes and cleats slid out a little bit and the bike started to get away from me. I struggled to hold but failed. The bike and Nancy fell over! Luckily, there were not any cars behind us. She managed to get free of the pedal while laying in the road and I helped her up. She was unhurt, but a little shaken (she is new to cycling and had fallen over at a stop after losing her balance on her single not more than 2 weeks ago!). After getting out of the road and up the hill a bit, I checked everything over on the bike and could find nothing amiss. So, we got going again. It must have been chain suck. That is the only thing I can think of that would do that. If on a single, I could have looked down to check the chain and/or backpedaled to free the chain - hard to do on a tandem! On the rest of the ride, we climbed standing several more times without issue, but not climbing as hard, as we were now somewhat tentative.

I don’t have an odo, but there can’t be more than a 400 miles on the bike. The chain is always properly lubricated. But, I think I will buy a new chain anyway.

On the upside, while driving around later in the day, I got a call from Oregon Ridge folks - we won the basket of cheer!!!

Sorry 'bout the spill . . . but the basket o' cheer should soothe things over!
After 400 miles chain should not be ready for replacement; clean it, lube it and put it back is our suggestion!
Pedal on TWOgether!

We busted the timing chain on our tandem when we had one of those brief split second moments where one of us wanted to stop, and the other wanted to go. Bad news.

All I can think of to say about your chain mystery is that I'd much rather have SPD cleats when I have to step off the bike.

Just a couple thoughts...

1. Been there and done that busting drive chains while climbing the steep stuff off-road but -- knock on wood -- not on road. Debbie has been very forgiving of me in these instances and has proven to be pretty resilient which impresses the heck out of the grandkids.

2. Is your drive chain by chance a KMC model? A few of their OEM chains are notorious for inexplicable chain suck.

3. Double check (meausure) your chain wear to make sure it didn't wear-out prematurely which might be an indication that you need to check your middle and small chain rings as well as your cassette for excessive wear.

4. In regard to loss of footing, as Expat notes, this is why a lot of (but certainly not all) road tandem teams elect to leave the slick soled road shoes / exposed cleat at home and wear MTB shoes with recessed SPD or Frog cleat systems / pedals for non-race tandem rides.

I don't have any good explanations for what happened to you. If you really had chainsuck, the chain should have been found to be jammed between the chainstay and some part of the crankset, and it still should have been that way after you were stopped.

I am inclined to suspect some part of the chain is out of dimension owing to prior bending. I would look for a helically twisted or laterally offset link. I would also run all the chain backwards through the drivetrain, paying very close attention to the wrap of the chain around the bottom derailleur pulley and the movement of the jockey pulley cage. You are looking for a tight link, or a sticky link.

No gouges from the chain on the chainstay? If it was chainsuck, you have to have a mark. There's something funny about this.

Wheel still properly in the dropouts after you stopped? A full-power sprint on a single with a cheap QR, even with vertical dropouts, will rip the wheel out of the dropouts and cram it into the back of the seat tube, and that emphatically stops the bike, but the rear wheels skids, and you would know.

All of the people I ride with are apparently quite skilled compared to the national average. As soon as somebody drops a chain, everybody else opens up space to give them room to move. If they are on a hill, and they drop the chain, and they have been monitoring possible hazards with a mirror, as the speed drops they can do a U-turn and coast back downhill while they sort out the bug in the drivetrain without stopping. This would be very foolish unless they had been monitoring the traffic carefully prior to when they needed to know.

You can see that two-footed starts/stops (one captain foot, one stoker foot) could have been used to advantage here. It's hard to beat a Proper Method three-feet-clipped-in start for quick acceleration, but it isn't always the safest stop. I couldn't tell you where, but if you dig around, somewhere you will find I noted the increased hazard of slippery plastic-soled racing shoes (which is what I mostly use), and imperfect stops with the captain supporting the stoker.

After being sick all winter, I am just getting back on the bike. A few twenty milers convinced me that I could do the 68-mile-option FWBA Dill Road Adventure Ride last weekend, as long as I was prudent and rode with the slower riders.

I didn't do that, of course. Noooo...I rode with the lead pack, danced up all the hills, and motored along here and there. The result was I rode well for 35 miles, and not so good for 33 miles. I was still trailing along behind the lead pack, 2/3 mile behind the last rider, when I flatted just before the last big hill at about the 65 mile mark. When others heard about this later, they were sure I had made up the "story" about the flat tire....

All this is a long-winded way of saying it will be a little while before I get back on a tandem yet. FWBA had at least four tandems out (one Santana, two Treks, one Longbike), of which at least two did the 100-mile option.

I had a half step phantom shift that temporarily jammed our chain one time on a steep uphill while at very low speed. Neither of us a foot unclipped in time and over we went. Fortunantly there was no one around to see us. We had to look pretty stupid both laying on our sides clipped to the bike.

No gouges from the chain on the chainstay? If it was chainsuck, you have to have a mark. There's something funny about this.

Admittedly, on tandems that have oversized rear stays without dimples and fairly narrow Q / rear spindles, chain suck will cause the chain to jam between the chain ring and stay and rear stay.

Galen will need to weigh back in here, but IF the chain wrapped around the middle chainring (which is what I think I read) and the right chain stay is dimpled (which I believe KHS's are) you could end up with a "chain-suck-like" drivetrain jam without marring the frame or damaging the front derailleur.

Admittedly, on tandems that have oversized rear stays without dimples and fairly narrow Q / rear spindles, chain suck will cause the chain to jam between the chain ring and stay and rear stay.

Galen will need to weigh back in here, but IF the chain wrapped around the middle chainring (which is what I think I read) and the right chain stay is dimpled (which I believe KHS's are) you could end up with a "chain-suck-like" drivetrain jam without marring the frame or damaging the front derailleur.

There is a ton of clearance between the chainrings and the stays on the KHS. The bottom bracket spindles could be much narrower. However, there are some tell-tale marks on the chain stay paint, but they could be from a dropped shift to the granny cog at some earlier point in time. Since it was not a gear-shift induced chain suck, I think the chain just failed to disengage from the middle chainring because the chain may have been slightly dry or the amount of load and flexing of the spindle and/or crankarm or a combination of those factors. I have noticed spindle/crankarm flex before when standing and hammering a rise in a big gear.

But, to be on the safe side and having learned my lesson regarding footwear, I was at the Towson Performance store with new chain, a pair of touring SPD style shoes and pedals, all ready to buy when a wind-induced power blip knocked out the computer registers! ARGH!!!

But, to be on the safe side and having learned my lesson regarding footwear, I was at the Towson Performance store with new chain, a pair of touring SPD style shoes and pedals, all ready to buy when a wind-induced power blip knocked out the computer registers! ARGH!!!


Geez, that store must be staffed by a bunch of wusses :) I was at the Performance warehouse sale several years ago which was held the day after a hurricane. No power at all. They sold $549,000 writing the orders by hand and using flashlights and kerosene lanterns.

Doc