https://i.pinimg.com/736x/87/e5/4d/8...etro-bikes.jpg

https://i.redd.it/4sx3ekw4eugz.jpg

Yes but I guess the challenge presented by a measuring device which is a) priced for consumer application and b) used while in motion was too steep a hill to climb (pun intended, we will never know *how* steep, not with that gadget)

The fixtures 1/2 way up the fork legs are foot pegs. You'd place your feet on them when going down steeer hills, when the crank rpm exceeded you maximum leg cadence. Remember, these were fixed gears, so there was no coasting downhill, unless you put your feet on the pegs.

Thats actually a rear brake linkage. The rod extends from the brake lever to a bell crank at the base of the head tube. Another rod extends from the bell crank to the spoon brake behind the bottom bracket.

Thanks again! Didn't know that was a fixed setup, so the pegs make sense. And yeah, I thought it was likely that was a brake linkage but my photo didn't seem to show enough detail about the wheel end of the braking system for me to make a definitive determination.

DD

The Slingshot used a sprung cable instead of a down tube, and had some sort of fiberglass hinge at the rear of the top tube. It seems like it should have been far too flexible to be useful, but I've heard of some folks who really liked it.
I'm not sure how there is enough torsional stiffness in that frame to work, and the marketplace seems to have decided that it wasn't a good idea, but some folks liked it. I'd love to hear from any BF folks who have experience with it.
... of course, I have a friend who loves his Schwinn Varsity too, so I guess you can never tell what someone might like. :)

Steve in Peoria

I suspect that it was intended to compete with the Avocet 50, which had a barometric altimeter and could calculate total feet of climbing (with a reasonable degree of accuracy, I guess).

For measuring the steepness of a road, I've used the Sky Mounti inclinometer. It's just a bubble level, with all of the sensitivities of such a gravity based sensor. It is definitely sensitive to fore & aft acceleration, so you do need to keep a steady pedaling rate. This isn't always easy to do when grunting up a steep hill, but I thought it worked well enough.

The marketing material:


https://cimg3.ibsrv.net/gimg/bikefor...90f1ef8334.jpg


https://cimg9.ibsrv.net/gimg/bikefor...2faef5a868.jpg


and a photo while stopped on Bouquet road, southwest of St. Louis, which indicates a 19% grade. Normally you'd just glance at it while riding, but I was trying to record key features of the ride route. I think I slipped and almost fell over when I tried to get started after taking the photo. :)


https://cimg7.ibsrv.net/gimg/bikefor...d8ad63770d.jpg

I think I've got a spare Sky Mounti, if anyone is interested.

Steve in Peoria

Any votes for "Suicycle"?

Museeuw threw his suspension Bianchi away in disgust in P-R 1994. Chasing Tchmil, he had just lost 10 seconds on a bridge over the freeway.

yep that tiny level gauge or what you want to call it was around, I remember :) I had an avocet wrist watch altimeter, in fact several of them, and loved them. Very intuitive menu design, unlike my Suunto or *shudder* any polar, for that matter. The Avocets were very precise. I remember having read somewhere that the Jobst Brandt was involved in the design, but I don't know if that's true.

While freewheels were availble in 1890, my underatanding is that they were used primarily on adult tricycles and rarely on safety bicycles. They didn't become common on safety bicycles until around the turn of the century. By that time, the increasing popularity of pneumatic tyres had virtually eliminated the spoon brake, giving way to coaster and stirrup brakes.

Perhaps the attached photos will help will your understanding of the braking system.
https://cimg3.ibsrv.net/gimg/bikefor...82ffdbfc8c.jpg
https://cimg4.ibsrv.net/gimg/bikefor...19f988c62a.jpg
https://cimg5.ibsrv.net/gimg/bikefor...40ca9afbe9.jpg

It would be interesting (to me, at least) to learn about how the Avocet computer/speedometer was developed. I suspect Jobst might have been involved in the mechanical design a bit, but my guess is that the design was done by a contract engineering firm. Maybe Jobst had engineer friends who cobbled together a prototype of some sort? The final design had a custom semiconductor designed, so this required working with a design group with this specific expertise.

Some time ago, I was in contact with a fellow at Specialized who was working on their bike computers. I must have met him on the Bikecurrent list or the iBob list?? He did end up sending me a computer to play with and evaluate, which was interesting. I think it died an early death, which isn't a surprise for a product in development. I think it must have been typical of a lot of consumer electronics, where some company wants some particular device designed, but the company doesn't know how to design the item. The company puts together a specification of what the device should be and should do, and then manages the development process with the electronics design company. I've done similar things with electronics for earthmoving equipment.

Steve in Peoria

Yikes! That's pretty bad. Thanks for the explanation. I only knew the story about how suspension forks won Roubaix for 2 or 3 years in a row.

Litigation Limiters
 

My daughter's 1987 Schwinn Sierra has clips in place of lawyer lips:

https://cimg6.ibsrv.net/gimg/bikefor...3600ba9e52.jpg
Clip.

https://cimg5.ibsrv.net/gimg/bikefor...e694772e67.jpg
Clip snaps over an eyelet on the fork.

I always forget this bike is different and end up unscrewing more than I need to.

Not at all surprised that this is a BSA design, as BSA motorcycles up thru the 1970 model year had a setup when removing the rear wheel left the chain and sprocket in place and, quite frankly, was an easier to change system than Triumph's which was the traditional knock the axle out, drop the wheel and sprocket, and disengage the chain to remove the wheel.

Just wait for Absolute Black to see these pictures

For those interested in this sort of thing I recommend Sharp's book; one of his own contributions in this vein was a hub with helical grooves, as many as and each the width of the spokes; said spokes being a single wire for a pair, the middle of the wire being wrapped partially around the hub in its own groove.

https://archive.org/details/bicycles...ge/n8/mode/2up

Published in 1896, 550-ish pages of text and diagrams/drawings, and I bet Jobst would have agreed with every word.

There was a recumbent trike kit sold by a guy who built them out of aluminium box tubing, not a good trike at all except at the time is was the cheapest option by far; but actually dangerous - at the front braking was two side-pulls each mounted on a arm that extended from its hub. The braking torque was taken by

a: the friction between the (unkeyed) axle axle nuts and the frame; and
b: a small machine screw bolted through a hole connecting the two parts that should NOT rotate relative to each other (the brake mounting arm and the frame), said hole about an inch or so from the axle.

Of course the torque was enough to break the bolt, it was only about 4mm dia, and when that happens the arm rotates forward; the rider is then pulled forward out of the seat; if lucky their nether regions missing the chainring as they are launched out of the trike and into the path of whatever they were trying to avoid.

After this happened I contacted the inventor/seller, got a reply saying essentially nothing other than he wasn't in business anymore. I see a relative is making a similar trike, with the same torque-arm system - the screw looks a bigger diameter but if that's all there is I wouldn't trust it.

I did tell the inventor how I modified the trike I had so it was safe; a strip of aluminium triangulating the end of the brake mounting arm, a hole in each end, two matching holes on the trike, two screws and it looks the same as the rest of the machine. He didn't seem interested, probably thought he was litigation-proof.

Mountain Tamer Quad and Mountain Tamer Quad Plus.
https://cimg6.ibsrv.net/gimg/bikefor...9b1f5e6e98.jpg
https://cimg7.ibsrv.net/gimg/bikefor...e0ac5fb784.jpg

I don’t have 10 posts yet so imagine the slingshot pics from a few posts earlier.


Back in about 1984 I had a 20” slingshot BMX bike. Dual tension cable “down tube”. It was a pretty cool bike. I still remember the serial # after all these years. It was A0022 so I assume it was a very early frame. Wish I had it now.

https://cimg3.ibsrv.net/gimg/bikefor...ddcea34a32.png
Maybe not CV, but weird.....META-VERSE?
:lol:

Curious ... what's the Q-factor on those things? Looks suitable for a pregnant hippopotamus...
Also, the two middle chainrings on the Quad (is that a 1/2 step + uncle + granny?) -- are the missing/worn-down teeth in line with the crankarm really intentional?\

Folding bicycle shipping crate:


https://cimg1.ibsrv.net/gimg/bikefor...3d3d71e69c.jpg

Kellog three-stage pump:


https://cimg7.ibsrv.net/gimg/bikefor...96cc36b625.png

The first commercially successful folding bike, the 'Captain Gerard':


https://cimg3.ibsrv.net/gimg/bikefor...65b9ab229a.png

Peugeot began production of these in the late 1890s. The French military adopted these and commercial fabrication was killed off by ~1920 with the glut of war surplus machines on the market. Prevent theft; carry it into your flat or workplace:


https://cimg2.ibsrv.net/gimg/bikefor...b58681c3d1.png

Accept a lift in Le Auto:


https://cimg3.ibsrv.net/gimg/bikefor...a59af604c2.png

Before .gpx files we had 'Dan Henrys':


https://cimg8.ibsrv.net/gimg/bikefor...942906a5fb.jpg