Retrorockit
1 kW
This mod is so simple, cheap and easy to try, I would like to ask you to try it before posting here.
There have been threads about using the front freewheel that most mid drives have instead of the rear one that bicycles already have. So this would apply mostly to converted bikes with mid drive kits, and not factory made ones.
There were a lot of negative comments mostly fear, panic, and rumors about the chain pulling you off the bike or removing body parts.
So of course I had to try it for myself.
1- Bikes were made in the 1970s with Shimano Front Freewheel System (FFS). So this is actually nothing new. The freewheel was in the crank.
2- They used a special cassette/freewheel with a fiction drive for each cog so it would partially disengage and "coast" to a stop if the chain got caught up in the front.
The functionality of the locked freewheel can be duplicated by simply tying the hub/spokes to the inner cog of the cassette with a nylon wire tie. "Zip Tie" in US terminology. The smallest commonly available ones are 14#/6kg rating. I can put one around my finger and with a pair of pliers break it. So it performs a breakaway function if the chain gets hung up. It doesn't drive the bike it just carries the chain/cassettte around when coasting. I've used 2 at once so far with good results and am going to test with just one. I carry a few spares and some tweezers in my tire repair kit in case I need them.
That is the entire modification. Easily reversible.
I've tested this on a 1500W BBSHD street bike used for intercity cruising. Speeds from 0-32mph. In EU this would be a 50kph pedelec.
This bike does already have a twist shifter, and Rapid Rise low normal derailer installed for better downshifting. Gearing is 50tx11-40t 8 speed on a 26" bike with speed rated balloon tires.
It works great. Upshift or downshift any number of gears as long as the bike is moving. This can be tested/demonstaraed on the center stand any time. The only difference is you stop pedaling to shift. This cuts power, and releases the front freewheel.
if this is hard to learn, a quick back pedal motion works even better.
This produces a conventional Motor-Clutch-Transmission layout like normal cars and motorcycles use. You drive it the same way.
One question that was asked was what about a shift sensor switch?
I had one and took it off the bike before this mod was even considered for 2 reasons based on it's own function.
The fixed delay it provided was too long for fast acceleration in traffic. The fast-slow- fast - slow acceleration confused drivers behind me.
The delay was also too short for multiple gear downshifts when braking from speed, and would send power to the chain when between gears. With a BBSHD that can be lot of power.
With this mod the delay is whatever I need because it's determined by me. The sensor is totally unnecessary.
The other question which remains unanswered is how it works off road. I'm 69 years old and it's flat where I live, so someone else while have to answer that one. Modern clutch type derailers and chain guides may have a lot to do with the results.
This rides very much like an IGH bike. It's better than the Low Normal derailer solution ( although I can still downshift when stopped). The Gripshifter is still a big plus.
The notion that E bikes can only shift one gear at a time is total nonsense. If I throttle the BBSHD I need at least 2 gears up for cadence to catch up.
This mod is so simple, cheap and easy to try, I would like to ask you to try it before posting here.
If you are motorizing your own bike, you are responsible for understanding what you are doing, and the risks involved.
There have been threads about using the front freewheel that most mid drives have instead of the rear one that bicycles already have. So this would apply mostly to converted bikes with mid drive kits, and not factory made ones.
There were a lot of negative comments mostly fear, panic, and rumors about the chain pulling you off the bike or removing body parts.
So of course I had to try it for myself.
1- Bikes were made in the 1970s with Shimano Front Freewheel System (FFS). So this is actually nothing new. The freewheel was in the crank.
2- They used a special cassette/freewheel with a fiction drive for each cog so it would partially disengage and "coast" to a stop if the chain got caught up in the front.
The functionality of the locked freewheel can be duplicated by simply tying the hub/spokes to the inner cog of the cassette with a nylon wire tie. "Zip Tie" in US terminology. The smallest commonly available ones are 14#/6kg rating. I can put one around my finger and with a pair of pliers break it. So it performs a breakaway function if the chain gets hung up. It doesn't drive the bike it just carries the chain/cassettte around when coasting. I've used 2 at once so far with good results and am going to test with just one. I carry a few spares and some tweezers in my tire repair kit in case I need them.
That is the entire modification. Easily reversible.
I've tested this on a 1500W BBSHD street bike used for intercity cruising. Speeds from 0-32mph. In EU this would be a 50kph pedelec.
This bike does already have a twist shifter, and Rapid Rise low normal derailer installed for better downshifting. Gearing is 50tx11-40t 8 speed on a 26" bike with speed rated balloon tires.
It works great. Upshift or downshift any number of gears as long as the bike is moving. This can be tested/demonstaraed on the center stand any time. The only difference is you stop pedaling to shift. This cuts power, and releases the front freewheel.
if this is hard to learn, a quick back pedal motion works even better.
This produces a conventional Motor-Clutch-Transmission layout like normal cars and motorcycles use. You drive it the same way.
One question that was asked was what about a shift sensor switch?
I had one and took it off the bike before this mod was even considered for 2 reasons based on it's own function.
The fixed delay it provided was too long for fast acceleration in traffic. The fast-slow- fast - slow acceleration confused drivers behind me.
The delay was also too short for multiple gear downshifts when braking from speed, and would send power to the chain when between gears. With a BBSHD that can be lot of power.
With this mod the delay is whatever I need because it's determined by me. The sensor is totally unnecessary.
The other question which remains unanswered is how it works off road. I'm 69 years old and it's flat where I live, so someone else while have to answer that one. Modern clutch type derailers and chain guides may have a lot to do with the results.
This rides very much like an IGH bike. It's better than the Low Normal derailer solution ( although I can still downshift when stopped). The Gripshifter is still a big plus.
The notion that E bikes can only shift one gear at a time is total nonsense. If I throttle the BBSHD I need at least 2 gears up for cadence to catch up.
This mod is so simple, cheap and easy to try, I would like to ask you to try it before posting here.
If you are motorizing your own bike, you are responsible for understanding what you are doing, and the risks involved.