A Frankenstein Shimano CS-M5100/7000 Cassette :)

[Stefan Mikes]

My Vado SL 4.0 Gen 1 came with a 10-speed Shimano Deore drivetrain. As there were big jumps between some gears, and I also needed a wide range cassette, I replaced the drivetrain with a 11-speed Shimano M5100 drivetrain with a 11-51T cassette, a new long cage derailleur, and an appropriate shifter. A new high quality shifter cable had completed the upgrade. Combined with a 42T Garbaruk chainring, the upgrade met my expectations. Why M5100? It was because the drivetrain was relatively inexpensive and had a wide gearing range.

A wide gearing range at the number of gears limited to eleven is a trade-off. There still will be gaps/jumps between some gears! Unfortunately to me, there was a pretty big gap between the 7th and 8th gear, and there's where I ride the most! So my cadence in the 7th gear could be in 70s but it jumped to 90s in the 6th!

Having available spare compatible sprockets, I built this cassette:

Yes, now there is a big jump between the Flatland and Mountain gearing range!

Now, I consider swapping the chainring for a 38T. It would give me five equally spaced high gears for a constant cadence...

 

[Base]

aha a mega-range cassette. Should work

 

[fooferdoggie]

We use the 11-50 and a 38 chairing on our tandem, we can climb about anything with that combo. You can get to 20 if you can pedal about 110 rpm. We don't use those may gears on the tandem, so the spacing is not an issue, but I would not want it on my regular bike.

 

[Stefan Mikes]

You can get to 20 if you can pedal about 110 rpm.

You can get to 26 if you can pedal 90 rpm.

See the graphical results for the Frankenstein cassette and a 38T chainring.

 

[Stefan Mikes]

To anyone interested: The Frankenstein cassette works perfectly in all gears. The shifting from 7th to 6th has a big gearing gap. I will use that gear to initiate any climb.
On a regular ride on the flat, the constant cadence is pleasantly kept, which was the whole goal!

 

[Jeremy McCreary]

On a regular ride on the flat, the constant cadence is pleasantly kept, which was the whole goal!

A fellow constant-cadence rider here. Gear and assist choices are almost always about staying close to preferred cadence (currently ~88 rpm). Happily, I have the gearing for it, and my motor prefers that, too

 

[Stefan Mikes]

A fellow constant-cadence rider here. Gear and assist choices are almost always about staying close to preferred cadence (currently ~88 rpm). Happily, I have the gearing for it, and my motor prefers that, too

You are lucky Jeremy to own an e-bike with the stock 12-speed drivetrain. I keep my Vado and Vado SL both at 11-speed as it makes the maintenance easier. There are more trade-offs with 11s than with the 12s of course. I'm waiting for a 38T chainring for my Vado SL. Having it, the chain will almost exclusively work between the five equally spaced cassette sprockets. Only climbing will take the gears 1 to 6.

Giant Trance E+ is 12-speed, and riding at a constant high cadence there is easy!

 

[Jeremy McCreary]

You are lucky Jeremy to own an e-bike with the stock 12-speed drivetrain.

Absolutely, and between my bird legs and mix of local hills and flats, they all get used.

 

[Stefan Mikes]

Just to inform you I have completed the upgrade process. Now, the custom cassette is accompanied by a 38T 104 BCD Round Garbaruk chainring and a 120 link Shimano chain. (I put a lot of attention to find out the correct chain length).

I will be able to pedal at a constant cadence in five top gears at a constant cadence of 80 from 21 to 37 km/h, which totally meets my expectations! The remaining 6 low gears are for climbing, with the granny gearing of 20.8 gear-inches, that is, just the MTB range.

 

[Stefan Mikes]

I have standardized on Garbaruk chainrings. These are unbelievably good and reliable! You simply are not able to place your chain in a wrong pattern there! Pictured: A Garbaruk 38T 104 BCD Round chainring.

The five smallest sprockets are geared equally by 2 teeth. Combined with the 38T chainring it ensures me I can ride just in these five gears on the flat. When a climb comes (a flyover/overpass), I'm getting into the climbing gearing range where the jumps between the cogs are significant. It does not matter on the climbs where you just stop at the convenient gear for your cadence!

I could have calculated the necessary chain length by comparing the length of the old chain to the new chainring size. This time, I was very careful to do it right. An online chain length calculator read 116 links. I knew, however, I needed 4 extra links for a mega-range cassette. I tried the "largest cassette cog" method next. It requires placing the new chain on both the chainring and the largest sprocket, and joining the chain ends together. Then you need to add 4 links for a mega-range cassette. I was careful so I chose 122 links for the start. Turned out, it was two links too many, so I removed them, ending at the proper 120 links (116 + 4).

Now, the ride on my Vado SL is just a pleasure. Constant cadence, no jumps between the gears, easy climbing!