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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 05-22-11, 05:52 AM   #1
Machka 
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Timing Chain Incident

Have you ever had your timing chain "fall" off during a ride?


We did a rather difficult century on Saturday, described in the link below, and just as the sun went down, we rode over something which neatly removed the timing chain. We have no idea what we rode over, although by the way it sounded and the way it hit my foot, my impression was that it was a branch. Next thing we knew, the chain was dragging.

I was afraid, at first, that the chain was broken. But it was all right, and after a couple tries, Rowan was able to get it back on again so that we were reasonably close to in-sync again and we finished the ride.

http://www.bikeforums.net/showthread...1#post12673219
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Old 05-22-11, 06:34 AM   #2
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It was probably just too loose and the stick was either coincidence or the last straw. Probably no harm done, but you'll need to adjust your eccentric.
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Old 05-22-11, 09:15 AM   #3
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Yup, it's happened once. The chain was just a little loose (my fault, of course) and the right combination of bumps in the road threw it. I got it back on without much problem, but the bike felt like the frame had cracked as it was so "whippy." It hadn't even occurred to me to line up the pedals when putting the chain back on and we were completely out of sync. The kid stoker was polite and didn't say anything until I brought it up, and then she made me stop and fix it. :-)
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Old 05-22-11, 09:33 AM   #4
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I've never had our timing chain come off, but I generally take a 4/5/6mm hex tool with me in addition to the multi-tool just because it's so much easier to use. I also carry quick links for timing and drive changes, but your post has me thinking that my timing chain is 8 spd while the link I'm carrying is 9 spd!
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Old 05-22-11, 03:11 PM   #5
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Yes, it was fine in this case as the chain was intact, and it went back on without needing to undo the elliptical BB... which in itself probablly indicates I need to tighten the chain a tad now we are home.

I couldn't identify the item that was thrown up by the front wheel because it was after dark, and despite using an IQ Fly, we were bussing along at a good clip. I suspect it was a more solid item than a branch or stick, and it did clatter along the bottom tube before doing its dastardly deed on the chain.

When thinking about it later, we might have been in a spot of bother had the chain actually broken. I am not certain what speed the chain is meant for, and I didn't have joiner links in my little kit. However, I could probably have jemmied something together, taking a link out of the drive chain and shortening that, and transferring it over to the timing chain without too many dramas.

It was quite the eventful century for us -- some extremely tough climbs that put us out of time on the event were riding, some painful cramps for me, and then the timing chain incident.
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Old 05-23-11, 07:58 AM   #6
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We had a strange incident happen last year. We were a group of 2 tandems and 4 singles riding around Manhatten on the Greenway trail, which is, especially on the East side, quite an adventure. We were travelling west through Spanish Harlem, when our left side stoker crank loosened and spun around its bottom bracket's square shaft, accompanied by the dropping of the timing chain. We had nothing resembling a 14 mm socket wrench to tighten it back up with; I had forgotten that I gave away my trusty old Campy wrench with the sale of our old Burley with its 14 mm rear axle nuts! Here we were, stuck in this very busy and colorful neighborhood on a Sunday morning, asking, in broken Spanish, for a bike shop or hardware store, when all of a sudden, a gentleman appeared pulling along the bottom half of a wheeled office chair, with a bunch of stuff on it. He reached down to me with the only tool that he had with him; a 9/16 socket with a ratchet handle and said: Maybe you can use this? Of course, it was a loose fit, but I was able to draw the arm back onto its taper and get it just tight enough to complete the ride and get home! We exchanged grateful hugs and handshakes and he soon disappeared into the crowd. This story has spread through our club and has become sort of a legend!
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Old 05-23-11, 04:08 PM   #7
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Just read Machka's report. Out of curiosity, what are the grades on the short hill that made you walk?
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Old 05-23-11, 09:04 PM   #8
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We walked sections on the longest of the hills (7-8 km). We were told it would be 6-9%, and I'm sure there were sections of 6-9% because it did become more gradual in places, but we've been measuring the grade of lots of the hills around where we live lately with a device Rowan built, and now having an idea of what various grades really look like, I'd have to say that the first time we were off and walking, we were on a 12% section ... same with each of the other times we had to get off and walk on the way up that hill.

And we were told that the hills to come were even steeper.

Our tandem is just not set up for climbing ... and neither are my lungs.
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Old 05-23-11, 09:19 PM   #9
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Quote:
Originally Posted by Machka View Post
We walked sections on the longest of the hills (7-8 km). We were told it would be 6-9%, and I'm sure there were sections of 6-9% because it did become more gradual in places, but we've been measuring the grade of lots of the hills around where we live lately with a device Rowan built, and now having an idea of what various grades really look like, I'd have to say that the first time we were off and walking, we were on a 12% section ... same with each of the other times we had to get off and walk on the way up that hill.

And we were told that the hills to come were even steeper.

Our tandem is just not set up for climbing ... and neither are my lungs.
Ah thanks! Actually I'm glad you answered. We've tried climbing on our tandem, seems ok up to 7% average, maybe short 10-12% for a few yards. Far from fast but we make it.

We had trained for a few rides in the past. We'd train climbing on singles then some on the tandem. Love your comment about the lungs. We did a long climb and I was bushed and Gina looked rather fresh. I told her that I could feel her lagging and that we needed to get her more climbing on her single (constructive criticism). She got cocky, said it was me and that she was in better shape and that maybe it was me that was lagging.

So we hit the climbs on the singles. She learned that day it was her, tough love style. She never made that statement again.

When I read Rowan's claim of cramps, I wondered if it was that he was picking up some of the slack while climbing as I do on the tandem. I know when we climb on the tandem, I'm sweating like a dog, huffing and puffing with salty helmet straps while Gina clilmbs with a smile. It can be tough but hey, when you're in love.....................


BTW, we've got a 28/28 gearing on our tandem. I have no idea what is considered a good climbing gear for a tandem.

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Old 05-24-11, 02:46 AM   #10
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One of the routes out of town here is a little over 1 km (right from our doorstep) and at least half of that is 8%. We handle that just fine on the tandem, and we've done other similar climbs as well. But much more than that is really tough.

Our low gear is 30:32.


I have EIA (Exercise Induced Asthma) and climbing is a killer for my lungs. I end up wheezing and puffing like a steam engine when the hills get steep ... I'm panting so hard that I can go a bit dizzy. On the hill this weekend, I was doing that ... and my quads and calves were burning ... and I hit 187 for a max HR. I don't think I could have put much more into it at my current fitness level.
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Old 05-24-11, 03:02 AM   #11
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As to the gearing for climbing, there are undoubtedly others here who can chime in.

But the climb that got us on Saturday was up around the 15-18% mark. As Machka says, up to around 10% for relatively short distances, we have been reasonably OK.

At the checkpoint where we pulled out of the ride, another rider took great interest in the Santana. He owns a tandem of Italian heritage. We got to discussing gearing for climbs. He figured a 24 or 26T chainring might be a solution with the 32T cog on the rear. I do already have a 26T 5-bolt ring, so I might give it a try. But I also am thinking of leaving the 30T on there and trying a cassette with the big 36T cog on it.

I have to sit down and do the calcs on the gear ratios just to see what I really am dealing with and what the realistic possibilities are.

I figure that I can keep the bike reasonably straight and upright at around 4.5km/h or a smidge under 3mph. When on the tandem, Machka and I have a reasonable cadence, but she doesn't particularly like mashing, so keeping a moderate cadence with a quite low gear-inch at 3mph is feasible.

Now, where's that calculator.
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Old 05-24-11, 10:22 AM   #12
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Ah thanks! I see our 28/28 is 27 GI and the 30/32 is 25 so we are close enough in gearing. I did forget about Machka's condition, that would make a difference. I'm not trying to compare climbing ability etc, just wondering how our gearing ranks. Heck, having friends like member JohnR and his tandem partner that ride The Everst Challenge, I know we aint climbers. (Gina and I )

I do want to do more climbing on our tandem but Gina won't climb unless she does some singles training first. She feels that she's slowing me down but hey, I don't mind, Riding a tandem is a different experience!

With us and our gearing, I think more training and less Ben and Jerry's will work since we are both healthy.
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Old 05-24-11, 01:27 PM   #13
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We went to a 26 Salsa ring in front, so we're 26-39-52. In the back, we're 12-34, a much better cassette than the 11-34. We run 9-speed Shimano. 26 X 34 is the real deal. Even lower would be good, but the shifting from 26-39 is a little slow already. 13T difference is supposed to be the limit, though I know some folks exceed it. We have a chain stop inside our 26, and wouldn't ride that combo without it. We are reasonably fast (for us) with this gearing, and spend the majority of our time in the big ring, even touring, because the middle ring doesn't work with the outer two cogs in back on this FSA crankset.

We've managed 19% for about 100 yds., loaded, with that gear combo, but were at our absolute limit. An odd thing is that with that low gearing, it's useless to stand since we're IP. The bike completely stops at the end of each downstroke. The only way we can manage the really steep stuff is to sit and pedal circles, including the much-maligned pull up on the backstroke, which we've trained ourselves to do in unison. We try to keep our upper bodies still and move the bike forward at a very even pace.

Our team's wattage difference is such that in effect this captain is riding a touring bike with an all-up weight of about 90 lbs. When one looks at it that way, these gears make a lot of sense, are about what others use, and are in no way unusual. I have no problem with any of this. I prefer to tandem with my wife and frankly don't care if singles go by us on the climbs. Now, other tandems, that's a different matter . . .

My asthmatic wife has gotten much better over the past few years with the use of the Advair diskus. Highly recommended.
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Old 05-26-11, 11:30 PM   #14
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We ride a 29 front 36 rear on our CoMotion 700c. I am 51 and tour with a ten year old stoker and a six year old behind us on a TAB. Total weight with gear bikes and people loaded is 470 pounds. We have made it up a 10 - 11% mile long hill with maybe just a little bit to spare, but not much. Kids do help some but are not fully pulling their weight. We use a sky-mounti to measure grade. We live in Pittsburgh and if you ride more than a few miles here you have to ride hills like this. The back side of our hills is good to evaporate the sweat you just generated!
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Old 05-27-11, 04:42 PM   #15
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Never dropped a crossover chain; but did break one a couple times.
First time we were just leaving a motel while on a tour and that was an easy fix.
Second time was less than a mile from home. Stopped, picked up the chain and stoker Kay pedaled us back home while the captain coasted and steered.
BTW Kay has 75% lung capacity and has ridden/climbed at over 9,000 ft. elevation in our 'younger' (read under age 65) days.
Keep the eccentric properly adjusted to avoid chain drop.
Pedal on TWOgether!
Rudy and Kay/zonatandem
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