Yesterday I fabricated new cable tensioners for the cable steering and they work quite nice. I bored out a 1/4 inch threaded rod then added a plastic thumb knob to the end and threaded the cable through the whole thing to a washer. Then I welded a small fastener to a nut, bolted it to the steering bar and screwed the hollow threaded rod into it. Like this:
Works great! To increase or decrease cable tension, or to adjust steering trim I just turn the thumb knobs on the steering bar. Now I've got a full steering radius. This is one more item I would like to eventually redesign and have CAD CAM milled out of aluminum to clamp onto the steering bar. I'll put some miles on this setup first to make sure it's exactly the way I want it before investing the time and money into the CAM.
Today I spent most of the day working on a steering brake. What I did basically was add a Deore brake caliper to the rear frame and a curved strip of metal to the tube that the steering cables connect to. When a brake lever is activated on the steering bar, the brake caliper grabs the curved strip and locks the pivot. The test ride confirmed that it worked GREAT! I could keep the steering cables quite loose and simply lock out the steering which turned out to be a surprising 90% of the time. This machine is intended for fast and efficient cross country travel, not spirited track racing. The only problem was my hand getting tired from compressing the brake lever - I'll have to think about how to make that easier, but I'll leave it for now to get some more experience with it.
Peddle induced wobble is a problem for any front wheel drive pivot bike like a lean steer or a flevo-type recumbent. Each stroke of the crank produces a body weight transfer to the opposite side and the weight shift causes a steering reaction. The only way to eliminate it is to lock the pivot out with a brake, dampener or very stiff steering controls.
I received my McMaster-Carr order today - two very heavy 20mm shoulder bolts to replace my 1/2 inch axle bolts with. NOT! They are WAY too heavy! In my opinion (Paul from Greenspeed agrees with this), 20mm bolts are overkill for trike hubs. My flanges and frame tubes would give way before that half inch axle does. So, what I'll do instead is keep the 1/2 inch bolts but add aluminum sleeves to the hubs to fill in the gap.
I came to the realization today that I may need to make a new steering bar - the brake levers and shifters don't fit properly onto the bar I'm currently using and the curves don't feel perfectly right. To tell the truth, I'd really rather not, as the steering bar that I am using is from my first touring bike from about 20 some odd years ago. I think it would be good carma or something to have a bit of history built into the TCR1. I cycled from Vancouver to LosAngeles down highway 101 with my cousin Tim on those bars - great memories.
Also added to the todo list is to replace the steel cables with Kevlar - a suggestion from John Tetz who commutes to work everyday in his human powered streamliner Check it out here.
In other news, the World Human Powered Speed Challenge 2004 at Battle Mountain, Nevada started today! This is the 5th consecutive year of this prestigious event. This competition pits man, technology, and sheer determination against the seemingly insurmountable forces of air resistance and friction to determine the absolute boundaries of man powered speed over a 200 meter distance. The use of high level aerodynamics and maximum athletic power result in shockingly fast speeds. I follow this event very closely, as the technology involved directly relates to my own goals with the cross Canada project.
In 2002, Sam Whittingham broke the world speed record for the third year in a row by going 81.00 MPH! Yep - you read it right. 81 miles per hour - on a straight, flat road.In 2003, Damjan Zabovnik broke the European speed record by going 68.21 MPH facing backwards!
The .deciMach prize for human powered speed of over $23,000 will be offered this year to the first racer to go 82MPH at this event! Good luck to Canadian Sam Whittingham!!!
Check out the results as they happen at the WHPSC 2004 web site!
For tomorrow I think I'll spend some time riding! I'm becomming concerned about the discomfort I feel from riding this bike - sore butt, sore quads. I'm pretty sure it will get better with conditioning - at least that's what everybody who has a lot of recumbent experience tells me. In April of 2002 I started training for a 800 mile tour to Ironman Utah with my Kett trike and I do not recall having such a difficult time adjusting to the recumbent position. If it's not windy I'll repeat the Watts test and see if I can verify those blistering speeds from Sunday.
TO DO LIST:
1. Buy and install right brake
2. Invent new cable tensioner to allow more steering bar turn radius3. Add front derailleur
4. Order 20mm axle bolts for the rear wheels (I'm using 1/2 inch now which isn't right)5. Design and machine 2 seat mounts out of aluminum to replace current steel ones (e-machineshop.com) LATER.
6. Design and machine 2 steering tensionsers out of alum to replace LATER
7. Order a new front wheel! (Helen is kind of upset that I am user her Zipp race wheel!)
8. Start work on the first fairing
9. Invent steering stiffener10. Add larger chain ring and modify chain stays
11. Make clamp-on out riggers and try to flip it
12. Fabricate new steering bar (aluminum or composite?) or rework existing
13. Lathe an aluminum collar for .5" hub axles.
14. Design and build a trainer to fit mag trainer.
15. Replace steel cables with Kevlar
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