YT Video about 5 new geared hubs - sime stronger than Rohloff

MitchJi

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5 Incredible New Bicycle Gearbox Drivetrains for 2023 // Revolute Hub1, 3X3 Nine Hub, Intradrive
[youtube]pyeMBKJLtWI[/youtube]

The Hub 1 and 3x3 are rated for 250nm vs 143nm for Rohloff! Fewer speeds is another plus.

At the end he also talks about a 2 speed unit to replace front derailers. I'm not sure if it can be driven by a mid-motor? Interested if possible ebike applications.
 
When the riding becomes rough off trail riding, the rear derailleur gets bent and non functioning. Navigating to keep it from bumping the many close obstacles and through or around all their projections is a task not do able 100% of the time. A minimal watt motor keeps the bike weigh low but the low wattage motors just about needs gears to keep crawling in these conditions.

The geared hubs and transmissions have shells that can protect them from harmful encounters with the surrounding.

But so many hubs, so little time. And $$$? I am holding back for now. I do have a nu Vinci 360 hooked to the pedal side not the motor. But with these higher torque gear boxes there will be some fun builds.

Maybe soon we can do a shift under load without concern about...
 
[Youtube]gcHrE8SvnbM[/youtube]
 
Two high torque geared hubs looking [marginally?} suitable for an off-trail ebike are the 3x3NINE and the Revolute Hub1 which has 6 speeds. Both list max torque at 250Nm. The 3x3NINE though could not be found for sale yet (cost is ??), the Hub1 costs about $1100.

A means of calculating hub suitability for max torque needed is to look at how much torque would be needed to climb a 45 degree slope. Never mind the traction issue. Your Big Ass aside, let's choose a weight of 100kg for bike, motor, battery and rider. Approximately, we find...

The force downward is 9.9 x 100kg = 1000N,

Resolving the needed traction force at 45 deg is 1000N x sin 45 deg = 700N

The torque input for a 29" wheel (say 15 inch tire radius) becomes 700N x 15/39 = 270 Nm

So 270Nm is > than 250 Nm. Safety factor = .92. I prefer designs with a S.F. = 2.

Spikes in torque [shock loading] arise when hiting a headwall(vertical walls or rock etc). Depending on the local traction these torque spikes can exceed the typical hill climbing torque needs. I once tore a Lightning Rods Gates belt apart headwalling.

My QS 3000 edirtbike and I may just barely exceed 100 kg. The wrench torque needed to remove the White Industries Ultimate free hub is about 300Nm. The hub removal torque for the the QS 2000 edirtbike is say 200Nm. Both these builds get difficult climbs with headwalls never a continuous 45 deg slope.

The bottom line as to the suitability of these new hubs for off trail use based on the above data is that for a light rider and bike with not to strong of a motor (3000 watts) you are likely okay to marginal. I may try the Hub1, who needs 9 speeddds with a motor?

One test for off trail use is whether your bike setup can do a full weight burnout from a throttle twist begining at zero. My Cyclone 3k that is one speed geared to go 30+ mph cannot. It is not fully suitable to off trail starts, but likely with one of these geared hubs the torque would be sufficient?
 
After some thought on the above analysis done for riding up a 45 degree slope it seems that slope requirements is a quite stringent design criteria. You get maximum traction when hill climbing when you are doing a wheelie as all the weight is on the rear wheel. Maintaining wheelie position while climbing at 45 degrees is quite a skill. We are talking start and go while on the 45 deg slope, not getting a run for the uphill coast.

A more reasonable slope angle to employ is 30 degrees. From our previous calculation of 270Nm we can back out the sine 45 and employ sin 30 degrees.

270Nm x (sin 30 / sin 45) = 270 x 0.5 / 0.7 = 193 Nm.

Safety Factor = 250 / 193 = 1.2953

It should be noted that using a smaller rear wheel than 29" reduces the torque effort because needed traction torque-arm is shorter.

For a 26" wheel( say radius is 13.75".

193 Nm x 13.75 / 15 = 177Nm

S.F. = 250/ 177= 1.41

I use 24" rim on the QS 2000 Big Hit ( r = 11.75" with tire)

Torque needed = 151Nm

S. F. = 250 / 151 = 1.65

These two hubs are looking like they might hold up! Just don't let your 300 lb friends ride your 3x3 NINE up a 30 deg slope unless you are using a 6" tire.
 
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