childback backtandem vs kiddi cranks

[annies]

Does anyone have any experience of using kiddi cranks vs a childback tandem. We have a trailerbike which we currently use with our 7 year old daughter, however is is quite wobbly as the fixing is not great on it and she is also quite happy not to pedal. We would like to do some longer rides with her and possible some touring next year. I've been looking on ebay and most of the childback tandems go for quite a bit of money and wondered if a standard size tandem with additional cranks is a good alternative. If so where would I go about sourcing these and would they be easy to fit?

[531colin]

At 7 years old I would go for a child back tandem, or even a small two adult bike, fitted with crank shorteners.
You dont want the "stoker" to put her foot down, anyway, so you can use the old trick of wooden blocks on the pedals to reduce the effective "size" of the bike. Crank shorteners will stop her knees having to go through extreme angles of bending.(as seen with small children on BMX bikes with adult length cranks)

[AndyB]

I've no experience of childback tandems, but our five-year old sits on the back of a double-adult tandem (size small) with kiddycranks. He has no problems mounting and dismounting and enjoys being up with me (some childback tandems seem to leave the child with its face at the adults saddle or lower-back level. It also means that my wife and I can comfortably ride together, which is pretty rare (e.g., Bishop's Castle Tandem Triathlon). It seems like a more versatile solution to me, with little (anything?) against it.

[AndyB]

If so where would I go about sourcing these and would they be easy to fit?

Santana do them, but they're not cheap (there's a surprise!). Easy to fit though - they just clamp around the seat tube, and the chain links to the inner chainring on the timing chain. Try speaking to JD Cycles in Ilkley.

[gaz]

Kiddycranks are fairly straightforward to fit but it can involve a considerable faff factor.

KiddyCrank1.jpg

First step is to attach the BB unit to the stokers downtube. Sounds easy doesn't it and the clamp is extremely straightforward. However it does need a bit of fine tuning to keep the cranks in time and have reasonable tension in the timing chain. The timing ring must be the same size as the chainring on the child's crank. Most clamps are for a 28.6mm diameter tube but other sizes are available.

KiddyCrank2.jpg

I've put the timing chain to the stokers left hand chainset. This means that the crank arms are wrong way around. There wasn't sufficient frame clearance to run the child-stoker timing ring in the inner position so it sits on the official outer position of the stoker's left hand chainset with the stoker-captain timing ring set even further out.

Additionally the kiddycrank BB unit is upside down with the fixed and adjustable cups on the wrong side to allow the child's cranks to clear the front derailleur without being even further up the seat tube.

This means the bottom bracket and pedal threads are on the wrong side and have the potential to undo whilst riding. In practice it's unlikely to be a problem as kid's don't pedal hard enough to make it happen.

Finding out and solving all of the above involved a lot of faffing about.

An alternative option for the timing chain is to run it to the captain's right hand crank. You'll need a suitable crank for the captain and a longer timing chain but the child's pedal threads will be correct.

I went down the kiddycrank route when mini-me was nearly 5. He's always enjoyed his trailer-bike more whilst I've always found the tandem more stable. He's almost nine now, too heavy for the trailer bike and would much rather ride his own Islabike now.

I chose kiddycranks as we already had the tandem. Whilst I've no personal experience I think a childback tandem would be much better.

[531colin]

A lot comes down to how long the kids legs are. Andy B. and Gaz both say kiddie cranks at 5, and I'd agree with that. At 7 , you may be able to miss out the expense and faff of kiddie cranks and go straight to a small/kiddieback tandem.
(tandems are enough expense and/or faff anyway!)

Edit annies....where are you? theres no people on earth friendlier than folk who take their kids tandeming, you could get a go on somebodys rig by asking here, or the tandem club, I would think.

[nicholasgrundy]

We have four children and bought a Thorn Voyager Kiddy Back tandem when the eldest, now 15, was 5 years old. The youngest, curently 6, is now the stoker, all of the children have enjoyed being a stoker. It was reasonably expensive but the stokers cranks have holes drilled in them so that the pedals can be set for a small child say up to a 10 or 11 year old. The stoker's seat post also extends sufficiently high for a ten or elven yera old. At the time we bought it ew lived in London and didn't have a car. The fact that it was shorter than a convetional tandem (the wheels are 26") and the top tube is shortehr because it rakes doiwn towards the back wheel made it feel safter than a normal tandem as did the wrap around bars. Also the child's weight is low so that if they wriggle it does not affect the bike's balance too much. Finally, the Thorn Tandem was able to take a child seat for any baby.

My experience was that we were able to go pretty much the same speed on the Kiddyback tandem as I was on my solo; and with our eldest son (no 11 years) I was able to go significantly faster as he was pretty strng aned weighed nothing.

I would recommend the Kiddy back whole heartedly.

Nicholas Grundy