I was feeling quite uninspired today and still bothered a bit by yesterdays speed ride. So I decided I needed some perspective - a reference point for which to judge TCR's stability issues. So I unlatched the old Kettweisel delta trike from my floating bike rig and took her out for a neighborhood spin.
If this commercially available trike is an acceptable standard for trike stability, it's far LESS stable than my lean steer. I found I could lift a wheel at 20 to 22 kph - not 25 that it takes to lift TCR's wheel. 20 kph isn't bad considering how much higher you sit in a Kett, but the rear wheels are much tighter - both in width and in relation to your center of gravity. Also the rears are canted which puts the Kett at a very distinct speed disadvantage. The Kett was very sluggish - of course. Took more effort than I was prepared to invest just to get it to 25 kph. I guess I've been spoiled.
The turning radius of the Kett is amazing - about as good as it gets, but TCR isn't designed for that. I can do a U-turn in 30 feet with TC, doing 25 kph and that's more than I would ever need for a cross country trek. More importantly, at 150 watts I can cruise along at over 30 kph and the kett would be doing 20.
Two years ago I did a long cross country tour in the Kett - 800 miles to the inaugural Ironman Utah where a man drown in a freak wind storm. I took a read through my journal to see if I could find any reference to speed and stability. Basically, I had the Kett up to a high speed of 50 kph going down a mountain pass once - that's it. I can easily get TC up to 50 on a flat with a bit of a headwind! So I can't really use the Kett as any acceptable reference point.
Also - I set up a 2x4 on the road and ramped TCR up to 30kph and hit the 2x4 with one rear wheel intentionally causing a bump steer. The trike always resumed it's original bearing upon all three wheel returning to earth. I tested the effect of a full steering brake compression as I hit the bump and it does help mitigate the bump steer effect. So - I'm thinking about changing my steering to a worm gear. Worm gears have a unique feature that limits action to ONE direction. Ie: You can turn a worm gear which turns a gear which turns the bike, but the bike cannot back turn the worm gear. It's like having a full-time steering lock - when you aren't turning the steering bar, everything is locked into place and the lean steer acts like a regular delta trike.
2 Dew LIST:
1. Buy and install right brake (FINALLY ordered it!)
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 tensioners 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 (starting now)
9. Invent steering stiffener10. Add larger chain ring
and modify chain stays12. Fabricate new steering bar (aluminum or composite?) or rework existing
11. Make clamp-on out riggers and try to flip it (changed to#25)
13. Lathe an aluminum collar for .5" hub axles (
Ben E. said he'd do it for me) (That didn't work - I'll get someone else to machine it).
14. Design and build a trainer to fit mag trainer (donated by Michael Hoenig).
15. Replace steel cables with Kevlar (maybe not - I think the flex of steel is good....)
16. Crotch guard / fender
17. Narrow chain stays to allow foot to clear
18. fix derailleur
19. crank hitting chain stay
20. chain stay frame flex?
21. Narrow, high density foam for seat
22. Make front quick release safety23. Change steer cable sheaves to Pete Heals idea
24. Add missing and new webs26. Firm up relationship with a charity (Helen???)
25. Add a g-meter and quantify turning g's at flippage threshold. (add outriggers)
27. Find a PR person
|TOTAL distance on TCR1|
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