HIGHPATH ENGINEERING

 

 

EGG

Swing Cranks

for riders with limited knee movement

 

How to check if a Swing Crank is suitable for you
Long Swing Crank for more severe disability
Price-list and order-form
Spare parts and repairs
Fitting instructions
Is there a cheaper option?
What if I have 2 damaged knees?

 

Swing Crank pedal path path of foot with
normal crank
 
 
 
 
path of foot with
Swing Crank

Use a Pulse Swing Crank when one of your knees doesn't bend as much as it should. It enables your leg to contribute as much effort as it can without being lifted so high.

  • For use on upright bicycles and tricycles
  • No need to raise your saddle or alter your riding position
  • Uses your existing crank and pedal (suitable for all adult pedals)
  • Includes a Pulse Crank Shortener which may also be used on its own
  • A Swing Crank will keep your leg straight at its lowest position (unlike a shorter crank)
  • A Swing Crank won't bend your knee so much at its highest position
  • Not recommended for use on recumbents unless you are particularly fit (see note)

 

Adjustable for different degrees of disability

A standard Swing Crank and Crank Shortener each have three pedal holes. These allow you to adjust the effect to suit your particular needs. You can even reduce the effect in stages as you recover from a leg injury:

 

  Standard Swing Crank
  normal setup:
  If you need to bend
your leg less:
If you can bend
your leg more:
  Crank Shortener: middle position
  Swing Crank: middle position
Crank Shortener: short position
Swing Crank: long position
Crank Shortener: long position
Swing Crank: short position
middle position short position long position

 

There are other possibilities if you have difficulty straightening your leg completely at the bottom of the pedal stroke. For example, you can use just the Crank Shortener on its own:

Crank Shortener: middle position   Crank Shortener: short position   Crank Shortener: long position
alternate position alternate position alternate position

 

Or you can use one of these intermediate setups:

Crank Shortener: middle position
Swing Crank: short position
  Crank Shortener: short position
Swing Crank: middle position
  Crank Shortener: short position
Swing Crank: short position
alternate position alternate position alternate position

 

(These lengths assume your cranks are 170mm long. Increase them by
10mm for 175mm cranks and reduce them by 10mm for 165mm cranks.)

 

 

How to check if a Swing Crank is suitable for you

Ask a friend to measure how high you can raise your foot, as follows:

1)

Raise your saddle so your leg is almost straight at the bottom. Measure height A.

2)

Lift your pedal and foot as high as you can. Measure height B.

3)

The height you can raise your foot is B - A.

 
 
measure A measure B

Choose a Standard Swing Crank if you can raise your foot 200mm (8") or more.

(or 190mm if you use 165mm cranks,
 or 210mm if you use 175mm cranks)

 

Choose a Long Swing Crank if you can only manage 164mm (6½") or more - see below.

(or 154mm if you use 165mm cranks,
 or 174mm if you use 175mm cranks)

 

 
 

 

Long Swing Crank for riders with a more severe disability

Long Swing Cranks are only recommended for riders who can't raise their foot 200mm (8") but can still manage at least 164mm (6½"). They are available in 2 different types and offer the following possibilities, plus various intermediate setups:

 

  Long Swing Crank
  normal setup:
    If you need to bend
  your leg less:
    If you can bend
  your leg more:
  Crank Shortener: middle position
  Swing Crank: middle position
  Crank Shortener: short position
  Swing Crank: long position
  Crank Shortener: long position
  Swing Crank: short position
middle position short position long position

 

3-hole Long Swing Crank for bicycles

The Swing Crank and the Crank Shortener each have 3 pedal holes, allowing the 3 basic setups illustrated above (164mm, 200mm and 240mm). This is suitable for all types of cycle including bicycles, tricycles and exercise bikes.

 

4-hole Long Swing Crank for exercise bikes

The Swing Crank and the Crank Shortener each have 4 pedal holes, allowing 4 basic setups (164mm, 200mm, 240mm and 286mm). This is suitable for tricycles and exercise bikes. It is unsuitable for bicycles as there would be a danger of grounding your pedal as you lean to turn corners.

 

(These lengths assume your cranks are 170mm long. Increase them by
10mm for 175mm cranks and reduce them by 10mm for 165mm cranks.)

 

 

Please note

Pulse Swing Cranks can be used on most upright bicycles and tricycles, but are not recommended for use on recumbents unless you are particularly fit (you will need to use clips on a recumbent to overcome gravity).

A Pulse Swing Crank is machined from high grade aluminium alloy and incorporates sealed bearings and stainless fasteners. It is supplied with a selection of fittings, allowing it to be fitted to most cycles:

  • Left cranks up to 41mm wide (*)
  • Right cranks up to 41mm wide (*), with removeable chainrings
  • All standard adult pedals (you can re-use your exising one)

      (*) please request 'fat cams' if your cranks are VERY narrow (less than 21mm)

 

Prices and how to order

Click here for other ways to order your Pulse Swing Cranks.

 

 
MSF
 
 
 
 
 
JustGiving

 
Autumn 2014
3000 km from Wales to Gibraltar

I'm currently attempting to ride solo from Wales to the Straits of Gibraltar to raise money for Médecins Sans Frontières (Doctors Without Borders - MSF).

This humanitarian organisation provides medical-aid where it's most needed, regardless of race, religion, politics or gender. MSF has already won the Nobel Peace Prize for raising awareness of the plight of the people it helps and for fighting the vested interests of the giant pharmaceutical companies. It's an independent, impartial organisation for which I have huge respect.

Blog:  You can follow my weekly progress and donate money by visiting my JustGiving website.  And please ask your friends to support me by...

  • spreading the word on Facebook
  • spreading the word on Twitter
  • downloading a sponsor form       --->
pdf
 

 

  Pulse Swing Cranks
    complete with Crank Shortener
  GB
pounds
   
 
  Standard 3-hole Swing Crank  (for all cycles)   £ 230.00
 left   right no order
 
  Standard 3-hole Swing Crank, polished  (for all cycles)   £ 300.00
 left   right no order
 
  Long 3-hole Swing Crank  (for bicycles)   £ 260.00
 left   right no order
 
  Long 3-hole Swing Crank, polished  (for bicycles)   £ 330.00
 left   right no order
 
  Long 4-hole Swing Crank  (for trikes + exercise bikes)   £ 260.00
 left   right no order
 
  Long 4-hole Swing Crank, polished  (trikes + ex. bikes)   £ 330.00
 left   right no order
 
 
  Spare parts
 
      Click here to order Swing Cranks without Crank Shorteners,
    and other spare parts
 
  Post + packing:   £ 5.00 to any part of the World.  Free on orders over £150.00
 

plastic cards

 

no checkout

 

Delivery

I aim to despatch these items within 7 days, but there may be delays at certain times of the year (eg. busy periods and holidays) - please contact Chris if you need to be certain. Click here for full delivery information.

7 day trial period

If you are unsure whether a Swing Crank will suit you or not, please order one anyway and try it out on your own bike. If it turns out to be unsuitable, just return it within 7 days, at your expense, for either an exchange or a refund.

Free fitting
pdf
standard
pdf
long
Printed instructions are enclosed with every Swing Crank, or you can download copies here.
 
Important : Your safety depends on the correct fitting of this item. SEEK PROFESSIONAL HELP IF NECESSARY.
Alternately i will fit your Swing Crank for you if you send your crank(s) to me.

 

Is there a cheaper option?

If price is a concern, you could try a single Crank Shortener instead. Then, if this didn't work out, you could upgrade to a full Swing Crank (see Spare parts). However if you read the following explanation, you will see why a Swing Crank is probably the best solution:
 

Using one Crank Shortener (or one short crank)
  • This would require a different saddle height for each leg - which, of course, is impossible!  (This is the only way that each leg could straighten at the bottom of its pedal stroke.)
  • Leaving the saddle at the right height for your good leg would mean that your damaged knee would always be bent, even at the bottom of its pedal stroke. This is shown in the diagram on the left below.
     
Using 2 Crank Shorteners (or 2 short cranks)
  • Your saddle would need to be higher. This might make it difficult, and possibly dangerous, to put a foot down when you stop.
     
Using a Swing Crank
  • This allows your saddle to be at the correct height for each leg.
  • Both legs straighten at the bottom of their pedal strokes, without your damaged knee having to bend so much at the top. This is shown in the diagram on the right below.
  One Crank Shortener
 
its pedal is raised at the bottom, so your damaged knee remains bent all the time
Short crank pedal path   Swing Crank
 
both pedals reach the bottom, so both legs straighten at the bottom
Swing Crank pedal path

 

What if I have 2 damaged knees?
Bicycles
  The best solution A custom-made bike with a much lower bottom-bracket and 2 short cranks. This would, of course, be very expensive.
  2nd best 2 Swing Cranks.
  Cheapest but dangerous 2 Crank Shorteners (or 2 short cranks). You would need to raise your saddle - too high to be able to reach the ground with your feet. This would be very dangerous!
 
Tricycles
  2 Crank Shorteners (or 2 short cranks). You CAN raise your saddle because a tricycle doesn't fall over when you stop!

 

 

 

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Chris Bell
HIGHPATH ENGINEERING
Cornant, Cribyn, Lampeter, Ceredigion, SA48 7QW, Wales, UK
Wales
©  Chris Bell