Bike shifter modification needed

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Bike shifter modification needed

Postby OutlawBiker » June 7th, 2013, 9:16 pm

I'm looking for some advice and help for my son's bike. He was born with a hand disability and does not have use of his left hand thumb. He's beginning to mountain bike with me, but cannot shift the front derailer as his thumb has no strength ( he was born without a thumb joint, muscle or tenden in his thumb). any suggestions for a shifter modification would be appreciated. thank you!
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Re: Bike shifter modification needed

Postby c0nsumer » June 7th, 2013, 10:15 pm

A twist shifter should do nicely. These are off the shelf parts and any bike shop can set you up with them.
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Re: Bike shifter modification needed

Postby barrybs » June 7th, 2013, 11:02 pm

Here's a link to a photo: http://brimages.bikeboardmedia.netdna-c ... ison03.jpg
The inboard portion of the grip rotates to actuate the front derailleur.
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Re: Bike shifter modification needed

Postby OutlawBiker » June 8th, 2013, 11:17 pm

Thank you all for your responses. He has a grip shifter on the left side and trigger shifter on the right. He can't turn the grip shifter as he can't grasp it tight enough without the thumb muscle. I will discuss with the bike shop though putting the grip and trigger shifters both on the right side. I never thought of that!
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Re: Bike shifter modification needed

Postby deuxdiesel » June 9th, 2013, 5:42 am

Another option is to use a "Thumbie" shifter, which is a road bar-end shifter set up on a flat bar mount. A little pricey, but very durable and can be shifted by pushing with the palm or heel of your hand and pulled back with finger tips.
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Re: Bike shifter modification needed

Postby Redstone Liger » June 9th, 2013, 5:51 am

Not sure what your budget is for this, but I have shimano dual control shifters with the hydro breaks and they worked great when I injured my thumb.

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Re: Bike shifter modification needed

Postby Roy » June 9th, 2013, 8:04 am

You could mount an old 10 speed friction lever. The Front shifters usually don't get much use.
Double grip shifts might require a longer right side brake handle.
If you go this route consider mounting the front shifter inside and increasing its diameter. Two diameters would make easier shift the inside shifter and not shift the out side shifter.
Check useable bar length.

Another option, rotate a left side click shifter so that the push direction could be done with the palm or the pad under the thumb or a push with the fingers. You might find that sweet spot.
Maybe a the push lever of a click shifter could be extended so that he could push it with a twist of his palm. (when mounted in normal position)
The Shimano dual control shifters (described above) have a removable lower lever. This would allow for a custom push lever to be designed. ( this system may not be made any more - mine is reverse pull and new reverse pull derailluers are not available )

I would be a little careful using grip shifters. The twisting action can strain the tendons over long term. I would consult a sports doctor before possible overloading the right hand. That right had will be doing double work for the next 70 or 80 years.
There are electric shifters made. It might take some looking to find one. The front would be fairly easy to make your self. A trip the the Radio Control store might yield the parts. How cool would a push button electric shift be?
Make contact with Shimano - they might want to help. It is worth a try.

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Re: Bike shifter modification needed

Postby TenSpeed » June 9th, 2013, 10:50 am

ibisman wrote:Or...eliminate the left shifter altogether and run 1x9

I would think that this would be the easiest modification to do. Currently running a 2x9 on my bike, and it might as well be a 1x9 because I never seem to use the granny gear.
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