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  1. #1
    Join Date
    Feb 2015
    Location
    Oz
    Posts
    528

    Default A trike build instead

    Well, that didn't go well, the bike proved too high for me to get a leg over so I bought a pair of 20" forks and swapped to a 20" wheel at front. Still no go, without the use of my hands balance is difficult, fell off twice trying to get on the thing, wacked my head on a pot plant first time, second time I put a nice gash in my leg. Was about ready for a third go but the wife convinced me to give up and make a trike instead.

    I've done a fair amount of work on the trike so far, welded up the frame, added a bottom bracket and front deraileur mount, fixed up the rear axle mount and derailleur mount, built up a couple of stubs with caliper mounts, turned up some bushes for the stubs from Delrin, turned up some chain idlers and mounted a bracket for them. The rims came yesterday so I laced one up last night. Calculations provided for 181/183mm spokes, I had a couple of 20" wheels with 185s so I tried them and they fit nicely. The rims I got off ebay for $67. They are caliper rims and look quite nice with anodised side walls. I'll lace the other one as soon as my hands recover, lacing wheels is very hand intensive. I've been busy making a filing machine the last few days so this is the first time I've worked on the trike for quite a few days..
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  3. #2
    Join Date
    Feb 2015
    Location
    Oz
    Posts
    528

    Default

    Added a couple of steering levers the other day. I spent the night before, pencil in hand, designing different systems. This system, they tell me is tank steering, so I spent the night re-inventing the wheel apparently.

    Two push pull levers each acting on the stubs in front of them and joined by a tie rod, push one forward, the other comes back the the wheels magically turn. The system allows a narrower gap between levers as the distance between outer thigh and lever remains static unlike the variable width of underseat steering.

    I have modified Ackerman so the inner wheel describes a tighter arc than the outerr - no tyre scrub. Caster and camber angles allow the wheels to lean into a turn and centrepoint geometry mean no bump steer, this trike should handle very well.

    Got sick of waiting for the Chinese tie rod ends to arrive so I ordered some from an Aussie seller. Twice the price for the same thing but I hope to have them by end of next week so I can move this stagnating build ahead.
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  4. #3
    Join Date
    Jul 2009
    Location
    Sanstone Point
    Posts
    296

    Default

    Can I ask what your problem is in not being able to mount a normal bike?

    What will be the running gear for the trike and where will you be doing most of your riding?

    To be making a trike from scratch, you must have some pretty good metal/welding skills to start with, so good onya for doing this.

    Foo

  5. #4
    Join Date
    Feb 2015
    Location
    Oz
    Posts
    528

    Default

    I have untreatable PsA which mainly affects my hands, wrists, fingers, thumbe, forearms, elbows, shoulders and neck. So much so my arms are withered and I have no strength in them. I can't place any pressure on them without immenxe pain. So If I fall, my bodt has to wear the brunt, usually my head. I've managed to fall over on almost every occasion I tried to mount the bike, despit it having a very low seat height.

    The trike has 15 degrees caster and 16 degrees cambers, toe is adjustable and steering is via push pull levers (a trial). Wheelbase is 110 cm and track is 710mm. Seat back angle is 44 degrees, front wheels are 20" and rear is 27. Brakes are Tektro hydraulics at the front, rear brakes don't work well on tadpoles so no rear brakes.

    Brake calipers are mounted forward of the right wheel and behind left wheel to account for both being lefties, righties are not available.

    Cycle componentry is all Deore except for front rims and disk hubs. All wheels are laced with stainless spokes. The rims are dual wall making punctures and changing tyres a very difficult job. They will be replaced with single walls as soon as I find a pair cheap enough.

    Frame is made from 30mm x 1.5mm square tube, seat is 3mm aluminium shaped to follow the curve of my back so no padding required.

    It also has Ackermam and centrepoint steering. Ackerman ensures the inner wheel turns in further than the outer wheel when turning so tyres don't scrub. Centrepoint eliminates bump steer.

    Seat height is 205mm and bottom bracket height is 380mm. The bike is custom made to fit me so I dispensed with an adjustable boom.

    To obtain measurements I set up a mock seat and foot block and got the wife to trace the curve of my back on a sheet of timber with a Texta, I also got her to measure from ball of foot to back of seat. Of course I got that wrong so I had to cut the boom and add 100mm in. At the same time I dropped the BB height so the difference between BB and seat base is around 150mm. This allowed my to mount the horizontal part of the boom so it was roughly the same angle as the rear forks - makes it look neater. I made the seat height about 50 mm higher than on previous builds to enable me to dismount a little easie. Dismounting can be difficult on tadpoles because the front crossmember is usually sited very close to under the bum so it's impossible to get feet directly under the rump.

    Today I hope to route hydraulics through the h/bars and assembly deraileurs so I can test. Once tested I can make any further changes I may need, weld and then paint.

    I bought a motor bike yesterday after being away for 18 years so I've made life difficult for myself: M/bikes are my home, I used to build show bikes so I've returned to my roots, so to speak. I posted a story on my last bike here a while back. It was a Bonneville and won best Triumph at the Darwin bike show back in 99. Time will tell if I can still use handlevers.


    Thanks for your interest, it's always nice to have someone appreciate your skills, no matter how ordinary they may seem.

  6. #5
    Join Date
    Jul 2009
    Location
    Sanstone Point
    Posts
    296

    Default

    Good stuff Sacc51.

    Foo

  7. #6
    Join Date
    Feb 2015
    Location
    Oz
    Posts
    528

    Default

    Not a lot of progress to date, too darn crook. I finish radio next week but I have a motor cycle coming tomorrow so probably still wont get much done. I did a bang up job of puckering the lever tubes for cable routing but with such a tight bend on the cables shifting is a little difficult so I'll have to re-design the levers I'm afraid. I've replaced the levers on the hubs with plastic thumb nuts, makes getting the wheels off a little easier. Chain idlers are on, although, I had to place an extra idler over top of the crossbar, still it all moves nicely. I cut through the boom and extended it 100mm, flattening out the last foot or so so it matches the rear forks, sort of. As far as the steering levers go I'm probably going to have to reverse the brake and gear levers levers and place them on the bottom section of the steering levers, something I didn't want, but!
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