Russ Roth

I've got a pair of ride2 crank shorteners to begin with and fitted them to my cannondale today to try out, the result is that my 5yo would be able to ride with pedal blocks but they aren't quite long enough for him. Fitted to my gitane they will allow both my older kids to ride with no trouble (the C-dale has the shorter seat tube by 3") though I have to make an adapter plate so the arm is clamped from the back to the crank lengthener as they are too narrow to fit the wider arms on the gitane.

Worse case I might just buy some aluminum and make some of my own but I really don't want one more project.

unikid

Not sure I follow. Crank shorteners that need to be longer when using pedal blocks? Why not remove the blocks? Or maybe use thinner blocks? Or how about ultra-thin platform pedals?

Russ Roth

Longer crank shorteners would move the pedals further up the crank arm so shorter legs could reach them. With the ride2 version he can almost touch, if I installed pedal blocks he probably could but I don't think they're a great solution on top of using crank shorteners so I need to find or make a longer version. Id rather find them.

unikid

Sorry I got thrown by "longer". Ok so you need something that can reduce the length even more than the ride2 offers.

Googling the ride2 indicates it can reduce up to 76mm correct? How much shorter do you think you need?
Here's one that reduces up to 85mm: https://t-cycle.com/products/easy-knees-crank-shortener
Here's another that reduces up to 88mm: https://highpath.co.uk/cycle-crank-shorteners/

The same company offers to shorten existing cranks down to whatever length you want: https://highpath.co.uk/crank-shortening/
Here is somebody stateside who will do the same and more: BikeSmith Design and Fabrication

If you are feeling DIY you can tap a second hole farther up the crank. And then mount your existing shorteners from that point?
When the kids get bigger you can remove the shortener and mount their pedals in the second hole. Larger stokers can use the original hole.

Russ Roth

Thanks for the links, your first one thinks very highly of their product at 105.00 per side, seemed reasonable for a pair till I went to add it to the cart and discovered that wasn't per pair. I ended up finding these after more searching and looking at your links.
https://www.sjscycles.co.uk/componen...eners/?geoc=US
they claim to shorten 95mm and have a very reasonable price while also not being too chunky looking. I'm going to give them an order and see how they do.
I had considered shortening the cranks but I'll need shorteners for the other tandem so the other kids can ride either way, so easier to just get a longer version and have both set up.
Hoping to tour with the pair of them this summer if life permits it.

unikid

Hi Russ-

On reading this link: https://www.sjscycles.co.uk/componentstandem-specific-parts/thorn-crank-shorteners/?geoc=US it says "Fully adjustable from 98mm to 154mm (if fitted to 170mm cranks)."

I interpret that to mean if you install it on a 170mm crank, you can make it as small as a 98mm crank length. The pictures also give that impression.

So that means a maximum "reduction amount" of only 72mm (170-98 = 72). That's less than the ride2 you already own which provides a max reduction of 76mm. Probably need to keep looking. Or consider the DIY approach.

unikid

Hi Russ-

You should take a look at this item on the same web site: https://www.sjscycles.co.uk/chainset...-each/?geoc=US
It's infinitely adjustable up and down the length of the crank arm and has both right and left hand threads.

You should measure your crank to see how flat it is before it starts curving in toward the BB. If you have 3-4 inches of flat arm then you might be able to slide this down far enough to get the extra length you want.
Flip it around so the desired pedal thread is closer to the BB end of the mounting screws to give you even more drop.

Darth Lefty 

I think it was also SJS that had multi hole cranks that were shorter.
Edit: 110/145
https://www.sjscycles.co.uk/cranks/t...s-104/?geoc=US

Da Vinci also does but they are expensive. Theirs are 130/150/170 or 120/140/160
Components - da Vinci Designs

125 mm for a 3.5-5 yo is a hard ask, they really can’t reach nor do they have stand over to the ground. But a kidback puts them really high. Crank shorteners on the back of a tandem have a big Q factor too.

WheelsNT

If you get a straight post with a separate clamp like on inexpensive bikes, you can flip the clamp over so the clamp bolt and nuts are above the saddle rails. This will get the rails to around the top of the frame clamp. This can lower the seat by around an inch to 1.5 inches.

mibike

This is what I did when my grandkids were younger. I carried it a step farther and measured saddles from the rail to the top and got the thinnest one I could find. It’s fast to switch out the saddle and post depending on who was riding.

unikid

Those Thorn double drilled cranks look pretty sweet. Definitely worth bookmarking by anybody looking for small stoker cranks. If those aren't short enough as is, then adding the ride2 shortener onto those would give a really good reduction. Not sure if Russ is dealing with JIS square taper or if his BB might be Powerspline. However it's cheap / easy enough to swap the BB to JIS if not already.

unikid

These are all great ideas. Not sure if Russ also needed seat lower or just a shorter crank length to allow for proper pedaling. Either way all these solutions should help.

Russ Roth

The bike is square taper. I went to do the seat post idea but it wouldn't get the seat lower since it is almost to the top tube. Thanks for all the ideas. I hope to post my solution here soon.

wtandem

I’d give Mel a call at Tandem’s East. I think there is a reasonable chance he could get a longer set made or perhaps offer another solution. My memory is fading, but I might have used a child conversion when my kids were 5, switching to crank shorteners a little latter.