Cycling UK Forum

I currently use a bike trailer (Adventure AT5) to ferry my 5.5 year old around. However she is getting quite tall for it so have been thinking about another solution. (She is a pretty good cyclist for her age, but we've only just started riding on the roads near our house, and wouldn't want to rely on her cycling on her own bike for anything other than the shortest distances).

One thought we had, is that I have an old "California Barracuda" tandem bike that has been gathering dust in the garage for years, and whether adapting the stoker seat at the back for her might be the best solution? After some googling it looks like what I need is a "kiddy crank". (I would get my local bike shop to fit it all)

I have been in touch with SJS cycles, who have advised me that what I need is:
- this kiddy crank https://www.sjscycles.co.uk/componentst ... -mm-black/
- this chainring https://www.sjscycles.co.uk/chainsets/s ... mm-cranks/
- these pedals https://www.sjscycles.co.uk/pedals-clea ... ch-thread/

I just wanted to sense-check this with others? Presumably I likely need to get a child saddle as well - as the adult one will be too big? Anything else I am likely to need? Thanks in advance!

Welcome

We have two tandems and two kiddy cranks: one an aluminium block and the other the Thorn/SJS (bought through this forum).

It's been a brilliant solution for us. And it's now working with the grandchildren. They can put in as much or as little effort as they want... we shout "Turbo" when they're needed. The day isn't limited by their stamina. And they're rigidly attached to us.

We start with a bar on the frame tube and no pedalling, then the kiddy crank and the seat steadily ascends until they're ready to drop down to the crank shorteners alone.

It can take a bit of tweaking to get the lateral spacing of the chains and sprockets just right.

Our children and grandchildren prefer plastic toe clips without straps. And you may need crank shorteners at some point. The adult saddles have been fine. The rear dropped handlebars are rotated to bring the drops to the top, and bar end extensions are fitted according to taste. Bells and speedometers are optional.

Have fun

Jonathan

I used a pair of crank shorteners similar to these https://www.avonvalleycyclery.co.uk/fol ... ers__74396

For them to work correctly you have to be able to set the rear saddle low enough so the child can reach, this will be limited by the frame of the tandem. The alternative is to use the device in the original post to raise the pedals.

You will also need a way to join up the kids pedals to the existing drive train somewhere along the line!

Reading the stuff on SJSC website, I’m still not sure if the cranks are for half inch or nine sixteenths pedal thread. This may matter for Jonathan’s toe clips; which I agree with.

I used “normal” ie chain on the right chainset reversed ie chain on the left for my kids, the pedals didn’t fall off with a bit of threadlock.
You can probably scrounge a perfectly sound chainset from a kids bike, which will be fine; and maybe even cotterless!

Not every bike shop will be familiar with all this!

Thank you all very much for your responses! I must admit though some of this has gone over my head (I am not the most mechanically-minded!) so please forgive my follow-up questions.

Mr.Benton I have had a look at my tandem and compared it to my daughter's bike, and even with the seat at its lowest it's quite a distance to the pedals still, so I don't think I have an alternative to the Kiddy Crank?

1 - Crank shorteners

I would have presumed that this part - which SJS recommend is bought in conjunction with the Kiddie Crank - would do away with the need for crank shorteners? https://www.sjscycles.co.uk/chainsets/s ... mm-cranks/

As I presume this is sized for children? Unless I have misunderstood the purpose of the crank shorteners.

2 - Cranks

In answer to your question 531colin, SJS have said the cranks are half-inch. Could you show me an example of plastic toe clips that might fit? Do these attach to the pedals, or do they replace the pedals?

3 - "You will also need a way to join up the kids pedals to the existing drive train somewhere along the line!"

When I e-mailed SJS they said that in addition to the Kiddie Crank, and the chainring linked above, "you will also need a second chainring for the front chainset to take drive from the front chainset up to the stoker position and new chainring bolts to match", is this what that is?

Google “ toe clip pedals “
You know what pedals are, obviously; the toe clips bolt to the pedals, so solid plastic pedals won’t work with toe clips, you need bolt holes on the pedals.
SJSC ‘s chainset has cranks about 100 mm long, four inches in old money: these are child length. The pedal holes in the cranks are half inch diameter, so if you buy this crankset you will need pedals with half inch thread which will also take toe clips. (As before, I think you can scrounge a kids crankset and pedals from a scrap outgrown bike; not just cheap ( free?) but you can see chainset and pedals together, and wether or not torclips will fit)
How you connect up the kids chainset with the existing drive will depend on the layout of the drive, and is best left to whoever will do the fitting.

r6mile wrote: ↑2 Apr 2024, 8:24pm ...
3 - "You will also need a way to join up the kids pedals to the existing drive train somewhere along the line!"

When I e-mailed SJS they said that in addition to the Kiddie Crank, and the chainring linked above, "you will also need a second chainring for the front chainset to take drive from the front chainset up to the stoker position and new chainring bolts to match", is this what that is?

r6mile wrote: ↑2 Apr 2024, 8:24pm How you connect up the kids chainset with the existing drive will depend on the layout of the drive, and is best left to whoever will do the fitting.

On both of our tandems the chain from the kiddy crank runs down to the rear bottom bracket. And the new chainring is fitted inboard of the original rear chainring of the front to rear drive.

Other layouts might be preferable on other tandems, as above.

Jonathan

r6mile wrote: ↑2 Apr 2024, 8:24pm ...
1 - Crank shorteners

I would have presumed that this part - which SJS recommend is bought in conjunction with the Kiddie Crank - would do away with the need for crank shorteners? https://www.sjscycles.co.uk/chainsets/s ... mm-cranks/

As I presume this is sized for children? Unless I have misunderstood the purpose of the crank shorteners.
...

531colin wrote: ↑2 Apr 2024, 10:11pm ...
SJSC ‘s chainset has cranks about 100 mm long, four inches in old money: these are child length.
...

I can't remember if we've ever used crank shorteners on the kiddy cranks. We've always used them at the next stage where the kiddy crank is removed, the saddle goes down to its lowest, and the child pedals on the original rear cranks.

Jonathan

We're in South Oxfordshire. You're welcome to come and have a look.

Jonathan

Thanks all for your really helpful replies!

I have now purchased the kiddy crank, the recommended chai set from SJS, as well as these pedals I found with a pair of compatible toe clips as advised - https://kidsracing.co.uk/collections/cl ... ids-pedals

I will let you know how I get on! I also want to fit a bipod stand on the bike, as I imagine you need to lift the child on and off the seat.

Thanks all again.

I didn’t use a stand.
It’s all very well putting the tandem on the stand and lifting the 5 1/2 year old onto the saddle, but then you have to get the tandem with the child on board off the stand and get on it yourself, without kicking the child in the teeth.
I used to get on the tandem and hold it secure while the child climbed on board. Getting off was the reverse, the child climbed off first while I sat on the bike.
If you need a stand to get on the bike, how do you get off?

How did everyone else do it, in the days before the internet?

What Colin says. I would strongly advise against allowing a child to get on a tandem held up by a stand or leaning against a wall or similar.

Pilot gets on first, stands astride with both feet on the ground, then child climbs on. Reverse to dismount.

Jonathan

PS: And similar for child seats on bikes: the child should never be in the seat unless an adult is holding the bike.

I found kids in seats more difficult.
Stand astride bike facing backwards, lift child into seat.
Then turn round!
Dismounting is reverse

531colin wrote: ↑3 Apr 2024, 5:24pm I found kids in seats more difficult.
Stand astride bike facing backwards, lift child into seat.
Then turn round!
Dismounting is reverse

Agreed.

Jonathan

Tandem 001 by 531colin, on Flickr

Gratuitous photo!