Found: HXR Easy Shift Drivetrain Hints Fixed Gear is the New Enduro

Shimano had exactly the same system in the early 80’s with their FF (Front Freewheel) system.

It never caught on and one real problem was that the chain was moving whenever the rear wheel was turning. Working on the drivetrain could cause serious injury if you turned the crank and then touched the chain while the rear wheel was still turning but the crank was stopped.

This would only work if the rear hub had an emergency clutch that would disengage with enough force to prevent disaster when a stick hops into your derailleur.

Psi Squared – Of all the video streaming services available Vimeo streams the worst on both of my computers. – C

Drew Diller, I am like 90% sure that’s how Positron worked. I remember being in awe of some seriously sticky freewheels at the shop, and an old mechanic enlightened me that they were for a front freewheel system.

The video looks like a ROSS bike, they had that system like 30 years ago.

My kids Early Rider Belter 16 has this. It’s actually not a good idea.

I like the use of the term “unsprung weight”. I have really been worried about that 100grams of weight in my free hub. The fact that I am 30 lbs over weight and eating Oreos for breakfast has no impact on my total weight of me and bike.

@Alan US and international patents last 17 years, so something from 1980 would be long out of patent protection…

I like the idea. But I am curious as to how it works in rough terrain.
The tension on the top run of chain helps keep the chain aligned and seated on the teeth. When this thing is freewheeling when descending there is no tension on the chain. You may need some additional derailleur tension to keep things on line.

SRAM tried this in the late 90’s with a DH front freewheel crank. I remember seeing HB testing it out at Mt. St. Anne if memory serves. Same idea in terms of allowing shifting while coasting, and same problems in that HB said that they had been having a tough time dialing in adequate chain retention. His was running some variation of a MRP two roller two plate system. 15yrs later they are obviously not using it anymore, so I guess it didn’t really work out for them either.

As ChaseJJ points out, with a system like this the bottom run of chain will drive the system when coasting, with only the derailleur clutch and spring to keep it tensioned. Neither of those mechanisms were designed for loads of that size, so it seems that they would need to be reworked too, hopefully without messing with shifting function.

@Terry—It’s a solution to a huge problem. Rear derailieurs are road bike tech, same with 9mm quick-release and rim brakes. None of that stuff has ever had any business on a mountain bike, yet mountain bikers have fought tooth and nail to keep them. The transmission should be in the frame, and the rear sprocket fixed. It’s a no-brainer. All of our bikes are compromised because we’re unwilling to break old habits. We’d have been riding stiffer, better performing full suspension bikes a long time ago, with less unsprung weight, more centralized mass, with vastly stronger and stiffer rear hubs, less pedal feedback, and yes, the capability to shift while coasting (probably the least significant advantage). Last I checked, having a fixed rear sprocket doesn’t seem to cause motocross bikes to blow up too often. I’d say the fears are of a runaway chain are totally unfounded. In 10 years enduro bikes will all be running fixed rear sprockets with a 7-10 speed transmission in the frame, guaranteed. We’re already seeing the progression with mountain bikers ditching the triple and double ring crankset (road bike tech) overnight.

You could do the same with the old hammersmit cranks. I have been talking about this idea for years. I’d be interested in getting those cranks. Shifting while coasting would make for smoother transitions from downhill to sudden uphill especially when pedalling might cause your pedals to hit something!

Interesting… but I’m a bit disappointed it’s not e improved version of the hammerschmidt as iI expected from the picture

For the record the Shimano FFS system has pawls on each individual rear cog allowing it to disengage when enough reverse load was applied.