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Swinging crank /pedal shorteners?

 
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MarkS



Joined: 08 Nov 2015
Posts: 440
Location: Telford, Shropshire

PostPosted: Mon Nov 09, 2015 1:09 am    Post subject: Swinging crank /pedal shorteners?  Reply with quote

Hi,

Has anyone any experience of using either of the above?

Further down the line, after I've painted and rebuilt my trike, I may, due to being an amputee, need such items.

And if anyone has come across them, any leads on a cheapish supplier?
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LWaB



Joined: 14 Nov 2013
Posts: 65

PostPosted: Mon Nov 09, 2015 11:46 am    Post subject: Reply with quote

I am not an amputee but I raced a tandem bike with the Aussie Paralympian team and worked in an Aussie bike shop for a few years which modified bikes and trikes for 'Technical Aid for the Disabled'. None of the amputee racers used crank shorteners.

Crank shorteners are typically used when a rider has a limited range of motion of one or both legs, generally because of hip or knee restrictions. Is this a problem you have?
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MarkS



Joined: 08 Nov 2015
Posts: 440
Location: Telford, Shropshire

PostPosted: Mon Nov 09, 2015 12:19 pm    Post subject: Reply with quote

LWaB wrote:
I am not an amputee but I raced a tandem bike with the Aussie Paralympian team and worked in an Aussie bike shop for a few years which modified bikes and trikes for 'Technical Aid for the Disabled'. None of the amputee racers used crank shorteners.

Crank shorteners are typically used when a rider has a limited range of motion of one or both legs, generally because of hip or knee restrictions. Is this a problem you have?


Due to the level of my amputation, my prosthetic side won't provide any power at all. All propulsion will come from my good side. The range of movement isn't as great with my prosthesis, it cannot bend as far back as a normal leg. To raise the saddle so as to get maximum thrust on the downstroke with my good leg, means that the prosthesis cannot come up as far as it should.

By using crank shorteners, the range of movement in my prosthesis is reduced, which also negates any additional stresses on my stump.

Hope you can understand what I mean by that!
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Gaz from Cas



Joined: 28 Apr 2014
Posts: 1287
Location: Castleford (clotted) Cream of Yorkshire

PostPosted: Mon Nov 09, 2015 12:37 pm    Post subject: Reply with quote

In my favoured bike shop, Sally Hurst is a regular and she will be (hopefully) competing in Brazil at the Paralympics, The shop do the mods on her bike if you would like I could ask for some info or get a few photo's of the adaptions.
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MarkS



Joined: 08 Nov 2015
Posts: 440
Location: Telford, Shropshire

PostPosted: Mon Nov 09, 2015 1:07 pm    Post subject: Reply with quote

If you could Gaz, that would be very helpful!!
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merseytrikus



Joined: 30 Jul 2015
Posts: 59

PostPosted: Tue Nov 08, 2016 1:56 pm    Post subject: Reply with quote

I have seen tandems/triplets for children on the rear saddle with an additional chainset half way up the rear seat tube with crank shorteners to enable the child to pedal in smaller circles for their little legs.   Tandem Club may be able to help.
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MarkS



Joined: 08 Nov 2015
Posts: 440
Location: Telford, Shropshire

PostPosted: Tue Nov 08, 2016 2:13 pm    Post subject: Reply with quote

What a coincidence! I followed a link from the Tandem Club last night, and found some crank shorten era at a cracking price!

When I originally looked, a company was manufacturing a shortened come swinging crank at £300, which was way out of my budget.

I have sourced some now though for just £60, following the link I found last night.

I am going to experiment with a shorter crank, but if that fails, might invest in some if these.

Ultimately, I might need a bracket fabricating, similar to the one on the photo a Gaz attached. It may be that despite whatever adaptation I try, I need to remove my prosthesis to ride.

Thanks for thinking about he though - much appreciated  positive
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"It doesn't matter what equipment is on your bike. You've still got one pair of legs to turn the pedals". Or one leg, in my case!!
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9494arnold



Joined: 29 Apr 2014
Posts: 763
Location: West Midlands

PostPosted: Tue Nov 08, 2016 2:54 pm    Post subject: Crank Shorteners Reply with quote

Type crank shorteners into e bay there's a few.

And I am sure SJS do a crank with three pedal holes for a "growing juvenile" application

And if you type item 361773282764 there's a "bolt on " bottom braket, the type you'd generally use on a Tandem with a child on the back, you run a lay chain from kiddicranks mounted to them into the main drive train . (I think that's what merseytrykus is talking about)

(A want ad in the CTC might elicit one at a more advantageous price . )

Be careful if you go down this route, I had one on a tandem years ago and I had to have it on a lateral tube rather than the seat tube because it had a curved  seat tube and I don't think the lateral tube was quite man enough for the job and deformed. If you use a butted 531 frame the tube is thinner away from the lugs/bottom bracket.

And not quite a prosthesis,but, I used to ride with Percy Stallard in his latter years , he was on his third Hip replacement (one each side and one worn out by cycling !!) and rode with straight bars and a walking stick strapped to them for when he had to walk. positive


Last edited by 9494arnold on Tue Nov 08, 2016 6:51 pm; edited 1 time in total
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MarkS



Joined: 08 Nov 2015
Posts: 440
Location: Telford, Shropshire

PostPosted: Tue Nov 08, 2016 6:45 pm    Post subject: Reply with quote

Hi Paul

It is SJS product that is £60

Never used the CTC; I've advertised stuff on retrobike, and put a wanted ad on there previously

The great Percy Stallard!! A legend in West Mids cycling!
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"It doesn't matter what equipment is on your bike. You've still got one pair of legs to turn the pedals". Or one leg, in my case!!
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Barry



Joined: 10 Jun 2012
Posts: 258
Location: Yorkshire

PostPosted: Tue Nov 08, 2016 9:52 pm    Post subject: Reply with quote

You need to speak to the people at Get Cycling in York. http://www.getcycling.org.uk/  These people are one of the UK's leading disability cycling shops. To them, there is no impediment too disabling, nor no disability so severe, that they wouldn't have a cycle, product or suggestion. There are products that do shorten cranks and there also reasons, that I don't remember off the top of my head, why they may not be suitable. Get Cycling will be able to tell you exactly what they are for and who they will benefit. They will also be able to advise on crank pendulums and explain why they may be more suitable

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