15 speed Cambiogear Bicycle Transmission

15 speeds on front chainring (at the crank) made of Dupont Zytel (nylon strengthened with chopped fiberglass). Invented and designed by prolific engineer Royce Husted near Chicago for the Excel corporation. 6 segments expand and contract to produce 15 sizes of hexagonal chainring between two plates. Only 2 of the segments have teeth; the other 4 are just place holders. The fixed outer plate has radial grooves to lock the segments into place. The inside plate has 6 spirals (which act as inclined planes) with distinct indents for exact gear position. This plate can be stopped temporarily with a brake that acts on its outer edge. You pedal normally to upshift and backpedal to downshift. A complete (or partial) downshift to any gear only takes a second or less. Mr. Husted also designed the world's best bicycle brake (not shown in this video) consisting of an additional groove external to the main rim in which a loop of Kevlar string loosely rides. The "cambio" in Cambiogear means "change" in Spanish. There was another 50 speed transmission called the Biocam and these two devices are not related. The Biocam was a cam-following kidney bean shaped chainring which drove both sides of the rear wheel with dual chains. Its advantage was the ability to easily pedal a 150 inch gear due to power curve modification. You could pedal effortlessly VERY slowly in extremely high gear.

[nightowl]

I'm from Australia, and in the early 90's there was a small bike shop in the town I lived that had boxes of these in their back store room. Haven't seen them since then, now I stumble across this video!

[ianthompson]

One of the very few really original small-step transmissions I've ever seen. Almost everything else you see when you google CVT is a variant of the age-old expanding pulley or toroidal systems, with their reliance on adhesion, but this Cambiogear is something fresh.

[PaulDriverPlus]

I had a Nordic Track tricycle that I bought in a garage sale, it had one of these front gearing setups instead of a front derailer.

Didn't have the clamp for the break, but a brazed on post the brake mounted to

It was very old when I got it, but it cleaned up nicely and worked well, had been int he elements like 20 years and survived fine

[whitepawrolls]

Had one of these years ago, and I really miss it. Would love to see them make a comeback, or to find another one in good shape that don't cost a small fortune.

[jobfromdayone]

Thank you very much for introducing me to this device, Pop. I do appreciate.  This could be something I wish I had on my bike. :)

[TOGIever]

Thanks for the video. Very interesting concept. I immediately thought of using a torque arm for automatic shifting in concert with a separate brushless motor and pedal assembly for power input. It is a shame that the unit was not manufactured with widely accepted materials such as aluminum alloy. Consumer perception is a big part of capturing market share. I think it could be a hit if properly configured (and properly marketed).

[johnsmith]

Very interesting. THx for sharing. Sure seems like that could of been great, especially if made of metal, a very elegant design and does not require lateral flexion of the chain.

[danovskibear]

bravo, this is the kind of stuff im looking for. great ide, still needs polishing before it could be perfect

[gdsandkes]

Hello Pop, thanks for the video. I tried to make an auto bike transmission like this, but with 2 spiral plates, back to back, but set so the spirals ran in opposite directions. Where the spirals intersected, I had 6 small dia. bike chain derailleur gears between the plates that would follow the opposed spirals as one plate turned in opposition to the other. There was a recoil spring in the center which made one plate turn in opposition to the other, forcing the gear set to a higher gear. My thinking was as the load increased, say going uphill, the torque exerted by the rider would overcome the recoil spring and cause the crank side plate to force the derailleur gears (which were not free wheeling) to a lower gear. I see from your video that I should have used only 2 or perhaps 3 of the derailleur gears with the others smooth "dummies", to allow for the change in effective radius of the gear set. Maybe I will revisit this idea.

[rjwse]

It upshifts by means of (1) pulling the lever and (2) pedal forward and (3) listen and feel the number of clicks. You can actually, intuitively feel and hear what gear you are in. To downshift you (1) pull the lever and (2) briefly backpedal a fraction of a circle. Again, you can feel and hear (more or less) what gear you are in.

[FNIX]

Maybe the reason for it lack of success in the market is the way you change the gear? You have to stop the motion of your feet and rotate backwards to gear up and then rotate forward again to continue. Luckily when going uphill you can just tap that gear-handle to get into a lower gear, that way you don't loose any momentum while going up. But you probably could not put very hard force into it while changing gear as it would probably skip a lot of gears while doing that.
If the way you change the gear was done by some sort mechanics or pistons instead of the outer brake ring it would have been a lot better?

[bbglas]

Amazing! So much potential, i wonder why it failed? Too bad, however it would be great if someone invented this in 2015 as production and distribution is relatively largely covered by today's internet consumer culture. It would have no problem sustaining itself on a niche. I love shit like this!

[jimmym]

It’s a brilliant idea, market fail maybe becos of its reliability & material use. What if the spiral is a smooth and add another locking mechanism. 🤔

[hemiforever]

Maybe if you tried it on the bike you would have found out why it failed in the test market?

[rjwse]

I never mounted it. It came with French rather than English sizing on the bottom bracket. I heard the plates brake after time under heavy load.

[GoldenSim]

is there a patent number on the box ? i think i know how to make this work better

[jibrilchannel]

Why they use plastic instead of metal?

[MrRodeobike]

why no more on the market??? too good to sale???

[alexeggler]

Hi
Hwru
Could you put out detailed pictures more of that there works?
Thank uou

[ahchoooo]

If the inventor can modify the design such that as the force applied on the pedel increases, the 6 segments will move inward automatically. The critical force that will trigger the down shifting could be set up by the rider, depending on his/her strength. This will make this design completely automatic to operate! I have thought of a similar design for years, but I never got my design to work.