Kidback mismatch
09-30-18, 10:36 PM
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Kidback mismatch
Just came here to vent, really. Today I started putting the kidback on my Burley. Initial problem, the shell's clamp was too big and the insert it came with was too small. I made a shim out of a milk jug and got it mounted. The kid tried spinning it and after overcoming his initial fear of climbing on, he really loved it. So I proceeded to take the timing ring off to put the kid ring on, and discovered that my stoker crank is 130bcd/39t and the kid timing ring is 110/36t. The actual kid crank has a swaged-on 36. So basically in summary, nothing fits and I need to buy a lot of stuff... or give up. I guess I could buy a bunch of chains and do the alternative setup where the stoker crankset moves to the front and the timing chain goes to the kid crank.
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Last edited by Darth Lefty; 09-30-18 at 10:44 PM.
10-01-18, 12:22 PM
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I'm going to buy an Origin8 130/110 ring and see if I can use it like a triplizer
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10-08-18, 12:27 AM
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That worked but not well enough. Would need extra long chain ring bolts to get the 36 to clear the spider, chain line would be awful. Instead, found an ancient NOS Exage right side crank on eBay, I'm going to put it on the left and that will let me just install it like a normal 110 double. If I'm extra lucky it will be in phase with the Truvativ on the right
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Last edited by Darth Lefty; 10-08-18 at 12:41 AM.
10-12-18, 01:32 AM
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The saga continues. The Exage crank was shipped to my old address. I realized after I bought it that its square was 45 degrees out of phase with the Truvativ, which has them straight with the crank arm... which I guess, looking around, is kind of unusual. I found an SR Suntour tandem stoker crankset on eBay and it was supposed to arrive today. It didn't. I bought a Tiagra 34t ring thinking to go 1x on the right side. That order was canceled without explanation. I bought a 38t Race Face NW ring instead. Ironically, since it's the last thing I bought, it's the one that has actually been delivered. Once it is all together the tandem will have front cranks that are early 2000's satin black, stoker cranks that are early 1990's soap bar polish, with a black timing ring and silver kidback ring on the left, and a laser etched black NW ring on the right, and kidback cranks that are 1980's fluted. Avert your eyes!
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10-12-18, 04:50 AM
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Years ago when I set up our tandem as a kid-back for our daughter I also used a variety of scrounged/free parts. As a result the chain ring on the child's crank was a slightly different size from the timing ring on my crank. Not really a problem in practice although the different cadence made our pedaling look weird to others. Another issue was that the child's crank was turned around so the pedal on the left side was right-hand threaded so the pedals tended to come loose. A little lock-tite kept them secure.
10-12-18, 11:34 PM
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Cranks arrived. They are a set - in a sense - both left side timing cranks! I thought they were the stoker pair. Hahaha. At least I can use them with the kidback. And now I have everything I need to get moving again.
10-13-18, 02:35 PM
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New ground in chain ring matching
10-13-18, 07:40 PM
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I got the 4 yo to ride it but only got a photo of the 2yo twin girl taking a test sit.
Chain line was a problem but solved by undoing the kidback’s clamp. The BB within is a smooth sealed cartridge so I could just scoot it over.
Chain line was a problem but solved by undoing the kidback’s clamp. The BB within is a smooth sealed cartridge so I could just scoot it over.
10-13-18, 10:58 PM
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Also, I never really took a close look at the front end of this drivetrain since I bought the thing a couple years ago. The eccentric is sitting like a quarter inch off to the left of where it should be. I’ve got the appropriate tool on order.
10-21-18, 07:31 PM
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We’ve got it going great now. 38-32 is too high for anything serious but we’re not doing anything serious so it’s ok.
10-27-18, 04:24 PM
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Some photos courtesy of SWMBO!
10-29-18, 11:11 AM
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@darth_lefty My son and i rode one at the bike shop a month or so ago. it was fun but he complained about not being able to see where we were going and his feet did not reach pedals for the full stroke but it was pretty fun. i am amazed we did not wreck.
10-30-18, 04:37 AM
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Great photo's, so nice to see the family out for a ride. Enjoy!
My granddaughter will be 1 yr this April, I am so looking forward to rides such like this.
My granddaughter will be 1 yr this April, I am so looking forward to rides such like this.
10-30-18, 08:33 AM
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Yes, he mentions the view sometimes. But he’s been in a kid seat 2 years already so he’s used to it
10-30-18, 09:16 AM
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10-31-18, 10:33 AM
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I am curious, what length cranks are being used by the child? At first glance it appears that the pedal circle may be as much as 3.5" too large for the leg length, which could seriously over work his developing growing legs/knees, depending.
11-01-18, 12:25 AM
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Kids' bikes often, maybe usually, have the wrong crank length and the wrong seat height to match. The cranks on his 16er are 4" and would fit him better right now but so far I haven't snuck the seat height up on him so he's folded up even worse there.
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