Hand cycles ?

[fatjel]

A cycling friend of mine has a disabled adult son. This week she bought from ebay a hand cycle.
Its a wheelchair with a front fork, wheel , hub gears and hand pedals attached
It looks really good but as soon as a slight gradient appears the front wheel loses all traction
They are both hugely dissapointed and asked if I had any ideas
Maybe a better tyre ? I shall take the front tyre off my bent to see if that's better
Other than that I'm pretty clueless
Living in Wales this renders it pretty unusable

Any suggestions as to how / if the problem can be solved
Or what is a good workable alternative
As I understand it he has limited use of his feet , so walking or pedaling any distance is no good

 

[Ming the Merciless]

1. More weight needed over front wheel. A Brompton block and bag on the front?
2. Lower pressure in front tyre for larger contact patch
3. Slick and softer rubber for better grip.

What size is front wheel?

 

[HMS_Dave]

Im no expert but there will be a lot of weight over the back wheels and not much on the front, so its pulling the entire weight pretty much. Wonder if there is a way to increase the weight load over the front wheel a bit?

 

[byegad]

Wot Yukonboy sed.
Also think about a lowrider front rack with a couple of small panniers.

 

[fatjel]

Hiya
The front wheel is a 406 and the tyre is a sort of semi knobly with a very small contact area but is already quite soft. I checked
I have a 406 marathon on the front of my bent which is worth a try but it is so traction free on the mildest of slopes I dunno
I don't have it here but will try that asap They arn't keen to spend more money on it.
I bought a brompton block and bag once and I suspect adding gold bullion to the front wheel might be a cheaper alternative lol
It does have hub gears cogs etc on the front which would add a good bit of weight already

 

[fatjel]

The problem is most likely weight distribution, he's no lightweight since the lockdown swimming pool closure

 

[Illaveago]

I don't know if it is possible with that particular wheelchair but I looked on my daughter's wheelchair and found that the rear axle could be changed to be behind the rear frame . Is it possible to move the axle backwards slightly .
A larger cushion at the back might bring the centre of gravity forwards a bit as well .

 

[fatjel]

That is worth looking into @Illaveago . Thanks

 

[classic33]

Are the front wheelchair wheels on the ground during use!

The two I've seen locally both have the front wheelchair wheels off the ground. It's then three point contact with the wheels, not five.

Rear axle clamp, on the one pictured, allows the axle to move back about an inch only.

 

[fatjel]

The front wheels are off the ground which is a shame as that would have been a quick fix

 

[Milkfloat]

Looks like there is some kind of fixing here that would allow the rear axle to move back an inch. I don't know if it is possible, but can increasing the padding behind his back (cushion), move him forward to compensate and move the COG even further forward?

 

[handcrank]

Hi i have one of these , its called a "Speedy bike" originaly supplied by https://www.bromakin.co.uk/index.php/products/handcycles/leisure-handcycles/speedy-bike .You are right about the rear axle, get it as far back as you can. And right about a spare seat cushion behind the back . The front casters Must be off the ground by about three cm when attached to the chair I would recomend talking to rob at bromakin though
I have a second axle set behind the front one, HTH

 

[mickle]

Move the front wheel backwards (if possible - though looks unlikely on that set up). The limit being how close you can get the back of the front wheel to the rider's toes without interference. And/or the limits of adjustment in the handcrank itself unit and/or the range of available adjustment in the connecting point where the crank unit attached to the frame of the chair.

And/or: Move rear wheels rearward, which will require additional/secondary mounting blocks to be fitted for this purpose (do they can be swapped between) or will render the wheelchair useless as a wheelchair.

And/or: as has been mentioned upthread, larger footprint tyre, softer compound (good luck) or fine tune the air pressure.

This manufacturer makes a version with a 16" front wheel in an effort to overcome this very problem, which is inherent in the design. And why electric assist versions of these things hang all the batteries over the front axle.

 

[fatjel]

Thanks all so grateful for your time and input am meeting them this evening to have a proper look at it. Have a marathon to try and will look into moving the wheel back . The wheelchair came with the bike so can be modified without worry

 

[davidphilips]

Off subject and hope you dont mind the suggestion but a recumbent flag and rear lights might make the bike more visible?