Tangent Prototype

The Tangent is one of the most amazing displays of metalworking I've seen. As I understand this, it's a joint venture between Wendy Huebner, who owns a laser cutting outfit, and Pete Flaherty who owns a machine shop. As a display, to show off their capabilities at trade shows, it would be excellent. However they intend to produce and market it. The plan is for only 250 numbered units to be built. A scarry proposition for anyone needing any of it's many custom parts, a few years down the road.

They hired an "ergonomics expert" to design the seat. From sitting on it, I'll guess is that his specialty is office chairs. Sort of like hiring a really good diamond cutter to do your dental work. On a recumbent with a low BB and no backpitch on the seatbase, you move back and forth with each pedal stroke. Not enough to notice, but after 60 miles your glutes are on fire. Also, a steep seatback is known to be a major cause of "recumbutt", as all your weight is on your bottom. At least the base is adjustable in relation to the back. An important feature many production bents don't have. The BB/seat/bars relationship is good, as are the seat contours. If they rotated everything 15-20 degrees aft, they would have a very comfortable setup.

Wendy provided the following info and specifications, filling out a new questionaire that Luke created.
Name: Tangent
e-mail address: fulcrum@visi.com or wendylou@visi.com
Web Site? www.tangentcycles.com not uploaded yet
Occupation: Design Engineer
# Number of bikes built: three prototypes
Why did you start this project: To make a more comfortable and practical bicycle for recreation and transportation.
Is there a commercial intention: Yes
Original Design Goal: Comfort & aesthetics
Intended use: Touring and commuting
Biggest difference between design goal and project to date: None
Cost of parts on project: N/A
Type of steering: Ergonomic (proprioceptive) arms at sides
Seat construction: tube, foam and fabric
Favorite design feature: Comfort & L.A.D. Low Aerodynamic Drag
Most difficult part of build: Seat
What you'd do differently if done again: N/A

Specs:
Wheelbase: 59"
Weight: 43 lbs.
Frame: laser cut space frame
Frame material: 304 Stainless Steel
Steering: cable
Wheel sizes: 26” Kenda Kross Plus (nite glo)
Brakes: Shimano hydraulic disc F& R
Drive: enclosed drive train.
Hub: Sram Dual drive internal 3-speed hub
Speeds: (3 x 8) 24

This info may be what is proposed for the production bike. This frame wasn't stainless steel, and everyone who picked it up was skeptical about the claimed weight. They brought it to a WISIL meeting, where Warren Beauchamp estimated the weight at 100lbs. I'm sure it's well under 60, maybe even under 50.

Their claim for "Low Aerodynamic Drag" illustrates one of 'bentdom's most pervasive myths, ie "Any recumbent has less drag than any wedgie". There are certain 'bent design decisions that are well known to reduce or increase drag.
Low Drag High Drag
More reclined seatback More vertical seatback
Above seat steering Under seat steering
High BB in relation to seat Low BB in relation to seat
Low rider position High rider position
Small front wheel/Few spokes Large front wheel/Many spokes
Shallow head angle/Narrow Fork blades Steep head angle/Fat fork blades
If there has ever been a recumbent with more drag inducing features than this one, I'm not aware of it. When you add a frame that has this many edges, surface interruptions and airflow tripping planes, it's possible this has more drag than any bicycle since the Ordinaries.



When you add the power losses of a sliding chain tensioner, mid-drive and an internally geared hub, to the weight and frontal area, anyone who goes fast on this must be very strong indeed.

It does have one nice innovation. As the seat is moved, the handlebars move with it, without the need to make any adjustments. Several people commented on the play in the sheathed cable steering, but I think that is not likely to be that big a problem with the machine in motion.


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