If Pushkar can put Gates/Rohloff/Fenders & Rack on this he will have a very unique Ebike in the industry, the lightest one that's is for sure, and the ultimate hybrid.
I like that it also comes with the slightly beefier 3" tires.
The reviews on this bike from even people that own many Ebikes is fantastic, there is a guy who owns 6 high end Ebikes, he says it's the very best of the bunch.
German video of it
Something like this?Pushkar, could this new bike be turned into an all-purpose bike? By all-purpose could fenders be added. Where I live, on Vancouver Island, better know as the wet coast, fenders are really important for at least 6 months of the year. If fenders could be added I'd be interested in this bike.
If there was an innovator award for ebikes you'd surely be the winner. Well done!
You are right that R&M is doing it. There are a couple others that are as well.
Here is my understanding of why this is hard on the Bafang ultra in particular.
- Gates updated tension requirements here - https://www.gatescarbondrive.com/~/...arbon-drive-tension-recommendations.pdf?la=en
- Using the Bafang ultra with that much torque puts us in the "Punching rough pedaling style" category. (We tension our belts at ~43lbs as a reference)
- With FS and belt, we need to be atleast at 45lbs nominal (sitting down on the bike) position to account for belt slack. The drive train will routinely blow through the highest recommended tension with the incredible rear suspension travel.
- If we choose to have a lower tension to begin with, we risk the belt falling off and will need a belt guide and other contraptions.
With a smaller motor, like with R&M, we can be in the 35lb-50lb range, and not breach belt tension ceiling. So R&M full suspension will work because it is a smaller motor.
There are 2 ways of making this happen on the ultra.
IMO, In both these Ultra-related options, we can get a close enough / reasonable ride experience with the Kinekt seatpost - the standard setup as it stands right now on the UC Pro. I am not super comfortable about breaching limits regularly. I have spoken with Gates to see what options we have, and I will keep looking at designs to be in the sweet spot.
- Have a smaller travel for the rear suspension.
- Have a soft tail suspension (another way of limiting travel with rear suspension).
Also as for the belt, Bridgestone has done 12mm wide belt, which I believe is same as some lighter weight motorcycles.
Goodyear and Continental also make belts too, do you absolutely need to stay with Gates?
I'm not a entrepreneur so I don't know.. I know you have to think about parts availability for customers and all that.
So are you saying you need higher tension from the tensioner if you were to go Bafang Ultra?
I'm not an engineer so I may have missed something.
Let's say you have two pulleys, one on wheel and one of crank (or whatever power source) and maybe think about pulling something heavy like cars.
The tension will stay on the top part of belt, not the bottom part.
Unless you use the tensioner on top part of the belt to push down the belt, I don't know if you need to add much tension on the tensioner?
For example, without tensioner, the bottom part of belt will be floppy and may come off, but all tensioner has to do is to keep the belt in place.
It's not like motorcycle where you use downshifting (in this case, all the tension comes to the bottom part of belt).
In addition, bicycle's cadence is only like 100rpm or so... it's not like motorcycle revving up to 14,000rpm.
Because motorcycle tensioners need to push down the belt pretty hard, otherwise the belt will come off because of centrifugal force.
However, I don't know if bicycle belts are exposed to much g-force at 100rpm (centrifugal force in this case)
I know simple rpm calculation doesn't say much, because bicycle chain rings and motorcycle sprockets have different sizes and all that, but I still don't know if bicycle belts will expand to outside due to centrifugal force like how motorcycles do on the dyno at full rev.
You said that belt drive will be hard because of the rear suspension travel.
Both of your proposed solutions were to reduce the suspension travel.
Do you think the suspension travel (the travel of, the center of rear wheel) was the problem? or is it the distance from chain ring to rear wheel?
For example, what would be more problematic? 1) rear suspension with 50mm travel, but has 10mm change in rear stay, or 2) 140mm travel with 5mm change in rear stay?
The change in rearstay length will depend on the suspension geometry.
For example, I've seen a several MTBs with no change in chainstay length.
Now, even if you look at more modern MTBs, some of them clearly have more change in chainstays travel than other.
Depending on the design / geometry of suspension, the travel of chainstays differ drastically.