I think the Bosch Performance CX Race has been doing okay, I haven’t seen a huge rush of people reporting bent cogs and broken chains. But I suspect that’s because this limited-edition motor has only been sold on expensive bikes with top-of-the line drivetrains. It seems the Sram Transmission for instance will handle the motor power.
But what about the Shimano EP801? This motor can be found on bikes running 12-speed Shimano Deore, Sram SX and such. With the 4.3.0 motor update, the Shimano EP801 can have lots of motor overrun. This is done by setting the “Assist Carryover” to “Long”. The result is overrun comparable to the Bosch CX Race.
Riding undulating forest trails, there is a lot of variation in speed. We’re suddenly surprised by a corner and have to brake hard. Or we’re going around a tree just to find a very steep incline. In situations like these, it’s easy finding oneself in the wrong gear. We stop pedaling, but the motor is powering on. So, do we wait for the motor to deactivate before shifting? It’s the same when accelerating hard, do we stop pedaling and wait before upshifting and continuing to increase the pace?
Of course we don’t wait! In some situations that would leave us standing still in too high of a gear. We shift under load. Sure, we can ease off the pedals, but there could still be several hundred watts going through the chain. Holding back the rear wheel with the brake could help, but I’d rather not brake when accelerating and I’d prefer not coming to a stop. What definitely helps is reducing the assistance. Riding Eco mode will make your drivetrain last longer.
Okay, I’m riding a demo bike, and I’ve got no idea how it’s been treated before I got it. Perhaps the chainring had been smashed into rocks? Regardless. I managed to snap the chain! I tore an outer plate off the pin.
After having fixed the chain, we kept riding and shifting under load. The drivetrain worked fine and still does. But it was a reminder; how hard are these motors pushing the drivetrain? How will the cheaper 12-speed drivetrains cope? Or how about the older 10 and 11-speed systems that aren’t designed to shift under load?
I really like the long Assist Carryover, but will it be too much for an older drivetrain? The "middle" setting could be kinder and there should be little problems when riding the default "low" setting. ANd as mentioned, stepping down the assistance from Boost mode will help.
But what about the Shimano EP801? This motor can be found on bikes running 12-speed Shimano Deore, Sram SX and such. With the 4.3.0 motor update, the Shimano EP801 can have lots of motor overrun. This is done by setting the “Assist Carryover” to “Long”. The result is overrun comparable to the Bosch CX Race.
Riding with maximum overrun and assistance
There are rules for how long the motor overrun can last, and these two motors are very likely right at the limit. That’s why I’m calling them out.Riding undulating forest trails, there is a lot of variation in speed. We’re suddenly surprised by a corner and have to brake hard. Or we’re going around a tree just to find a very steep incline. In situations like these, it’s easy finding oneself in the wrong gear. We stop pedaling, but the motor is powering on. So, do we wait for the motor to deactivate before shifting? It’s the same when accelerating hard, do we stop pedaling and wait before upshifting and continuing to increase the pace?
Of course we don’t wait! In some situations that would leave us standing still in too high of a gear. We shift under load. Sure, we can ease off the pedals, but there could still be several hundred watts going through the chain. Holding back the rear wheel with the brake could help, but I’d rather not brake when accelerating and I’d prefer not coming to a stop. What definitely helps is reducing the assistance. Riding Eco mode will make your drivetrain last longer.
Will the drivetrain handle it?
We have been testing the new EP801 motor settings on a brand-new Merida eOne-Sixty 675 with the Deore Linkglide drivetrain. And I’ve been very happy with the shifting. I’ve managed to suppress my mechanical sympathy and just shifting whenever. This 10-speed drivetrain seems a great fit for riding Boost mode with maximum overrun. But …Okay, I’m riding a demo bike, and I’ve got no idea how it’s been treated before I got it. Perhaps the chainring had been smashed into rocks? Regardless. I managed to snap the chain! I tore an outer plate off the pin.
After having fixed the chain, we kept riding and shifting under load. The drivetrain worked fine and still does. But it was a reminder; how hard are these motors pushing the drivetrain? How will the cheaper 12-speed drivetrains cope? Or how about the older 10 and 11-speed systems that aren’t designed to shift under load?
I really like the long Assist Carryover, but will it be too much for an older drivetrain? The "middle" setting could be kinder and there should be little problems when riding the default "low" setting. ANd as mentioned, stepping down the assistance from Boost mode will help.
