Suspension

• http://www.cs.chalmers.se/~olahe/Bike/menu.html
• Electric Trike
  
  
• http://www.outsideconnection.com/gallant/hpv/sprung/4_7_2001/
  
  
• Check out USA patent 5326121
  
  
• Swingarm suspensionfork for recumbents
  
  
• Rear suspension to a rigid MTB frame
  
  
• Malcolm Steck's HPV'S
  

• Converting a bike to rear suspension. (Not a recumbent but has the same relevance)

• 'Woody'

• Fully Suspended P-38

• WYMS LLC

• IHPVA

• A BMX Delta

• See Andrew Wagner's Trike

• A.S. Engineering S-327 "Sputnik" trike

• How to make a recumbent bicycle yourself

• From: Frank Bokhorst BOKKIE@psipsy.uct.ac.za
  Date: Tue, 13 Jul 1999 10:08:22 SAST-2
  Just recently I built a parallel link front suspension for my trusty old upright commuting bike. It also includes a disk brake. At first it seemed scary to attempt such a seemingly high-tech project, especially for the FRONT of an UPRIGHT bike! However, it was successful, and now in daily use, and I am very happy with it. Can do low-tech!
  A detailed description of the suspension/disk brake is at: http://www.uct.ac.za/depts/psychology/bok/fork.html

• FWD Fully Suspended SWB Recumbent

• How to make an In-head front suspension

• http://www2.bitstream.net/~mstonich/MNbikes/pix/brick11s.jpg & http://www2.bitstream.net/~mstonich/MNbikes/pix/brick05.jpg
  
  
• From: Rick Horwitz
  Subject: [trikes] Rear suspension/pogo chain line
  I have read this thread with much amusement. Currently, I'm making last minute changes on a rear suspension system I am building for a trike. I've experimented with a couple of prototypes and have recorded some raw data concerning the tension of the chain in relationship to the vertical wheel force. However, this data is not at my disposal at the moment, but I do have some conclusions that may be of interest.
  As many people have noted, the active chain line should intersect the pivot axis of the swing arm. Ideally this is true, as any chain line deviation from the pivot axis produces a non-linear vertical force to the rear wheel.
  The good news is that the chain can wander off this intersection by a few degrees with minimal consequence. Having a large or small tooth count on the rear cluster does not affect the suspension as long as the chain intersects the pivot axis.
  Recumbent rear suspension is not as critical as a mountain bike suspension. Remember that on a mountain bike, the bottom bracket and cranks are placed generally below and in close proximity to the swing arm pivot axis.
  Consequently, when pedaling is applied, the bike has a tendency to pogo. A recumbent has the bottom bracket out forward and away from the pivot axis. Therefore, the pogo effect is minimized. However, there is always exceptions. let's say we want 15 cm(6 inches)of travel on our trike . Well, the deflection rate is simply Kg per cm. On an undampened, linear steel spring suspension system the back-end is going to pogo regardless of the conditions. However, if we restrict the amount of suspension travel to 7.5 cm (3 inches), have an axle deflection rate of 80 Kg per 2.5 cm of travel (175Lb. per 1") and use some type of viscous dampening, the rear end becomes increasingly stable, hence no pogo.
  Another question I noticed was why would the pulley or mid drive be mounted on the swing arm pivot axis. Using the swing arm pivot axle is a practical approach. If the pulley (or mid drive)were placed in an optimum location, the cost and weight of the vehicle would increase. The increase in weight and cost may not justify the minimal improvement in suspension performance. Of course the conclusion is left to the designer.
  
  

From: Carey Chen

Guzman wrote:
'How can I attach a aluminum hub, probably with compound curves to a cro-mo hub?'

Bolt it to the frame, on the first big WHIRL ride in 1998, there was a home build that used such a setup. It used a rear hub which also had the intermediate drive as part of it.

'Better yet, how can I reproduce the necessary structure to support the bearings for the arm?'

This bike had the hub bolted to the frame by drilling out the spoke holes, for I guess 5mm bolts.

And maybe, how to make the rear arm rigid, since its hinge end is "open" like forks. This is probably not an issue, just make it long enough and run some cross pieces.

On Alan's Outlander 22 the rear swing arm pivot is the rear axle assembly from a Suntour Grease Guard hub. This has a 10mm axle with sealed cartridge bearings. The cartridge bearings are held in the frame by a tube that looks like a BB shell. The swing arm is adjustable in the horizontal axis and the longitudinal axis. The horizontal axis is done with what looks like forward facing track drop outs. The other is done with shims and set screws. The swingarm it self is made of 1" square steel tube with 2 cross members, plus a plate on which the elastomer pushes on. It is very rigid.

• At first thought the normal bike bottom bracket would be the obvious choice for a suspension pivot. The difficulty I have with it is I haven't found an easy way to make it so the bearings can be serviced and the rear forks removed. Here is a simple to build suspension joint that can easily be removed for bearing adjustment and is made with normal bike steering head parts. To get a symetrical joint 2 threaded fork stems will need to be butt welded together if you can't thread the tubing. 2 bike steering head stems are cut down so both sides can fit inside the pivot. A washer is welded to the end of the head stems for the bolt to pass through.

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Thursday, 29 January 2009