Rocky Mountain Altitude C50 Review


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Jul 26, 2020
The Rocky Mountain C50 Altitudes eMTB is very capable.. The geometry and stance are completely standard to their other bikes, that is, sub 430 chainstays, normal reach and stack numbers. A fun bike, with or without the motor. The motor, from in house DYNAME was built to fit the bike, rather than the bike built to fit the motor. First brand doing this, and it is a difference.

There is a pretty innovative torque sensor, that truly measures rider input in real time. Having plenty of miles on Brose, Bosch, Shimano and Yamaha, I can confidently say that the reaction time, and amplification of the Dyname is superior. No lag, and no over/under reaction. The motor is truly assisting the rider's efforts. Other motors feel a little like the rider is supporting the motor.

I own a bike shop, we sell Giant, Focus, Kona, Rocky Mountain, and I've been riding eMTB pretty much exclusively for shy of 2 seasons.

I must admit, I still love all the eMTBs I've had the chance to ride, even some pretty dodgy conversion bikes! I'd really say the PowerPlay is a benchmark in eMTB evolution.

Try one out if you get a chance.
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The chain line required for that innovative torque sensor reminds me of an old-timey threshing machine.

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USA models start at $5300 for alloy Altitude PowerPlay, on up to stratosphere. Same motor and technology on all models. 500wh battery on base, 632wh on higher models. Parts spec varies by price, as you'd expect.
Looking across the spectrum of eBikes, from conversions to Bosch/Brose/Shimano/Yamaha/Panasonic integrated eMTB, Rocky Mountain's set up is no more "threshing machine" than the others. Once you've seen the belts, nylon gears and other reduction going on inside all the motors. Just a form follows function sort of thing. But certainly understand your impression!
All this to avoid a strain gauge in favor of using mechanical motion for torque sensing. It’s likely much more sensitive at low torque with the trade-off of that serpentine chain path. Probably it’s most beneficial at high assist levels; it would be interesting to ride an A-B-A test with a conventional setup to see whether it’s actually a worthwhile improvement or just done that way because of the eccentricity of one particular engineer.
And you could say the Bosch/Yamaha/Brose/Shimano motors use nylon reducers, composite belts and a strain gauges to avoid having a serpentine chain routing! It's the only motor system designed around the existing trail bike geometry, pivot placements, etc. The other units are a motor handed to the bike company to work around. Crack open one of the other motor units and there is a lot of stuff going on inside, here the non-intuitive chain route is visible once you pull off the cover.

The Hall-field torque sensor system is very sensitive as you surmised. Smooth/intuitive power application, no lag.

Yah, riding back to back is a fine plan on any of these newfangled contraptions. I like the Shimano motor a lot as well, even though most of my riding has been on a Focus with sorta short front end with a sort of tall stack (far from what I like). The RM Altitude Powerplay definitely is more fun than the Focus once the motor shuts off and things get rugged down the hill!
Curious how well those short chainstays work going uphill with e-assist. I’d think it would be difficult to keep the front wheel down on seated climbs.
Suppose you got really really fit overnight, would you climb better if you put 60mm longer stays on your existing bike?!

The reaction of this motor is sensitive and instant. Plus as with any eMTB, lower level power on slow techy climbs is proper motor use. Save turbo for the wide open.
"No lag, and no over/under reaction. The motor is truly assisting the rider's efforts."

Sounds like the way I use my throttle assist on my BBSHD conversions, I find my thumb more sensitive and responsive then any torque sensing system so far. WH's used per mile back that up.
I’d buy that. The BBSHD throttle is definitely able to be a very re-active assist, run through the human brain. Pretty hard to beat torque sensor. Well, even there variables exist!
I know we (Laramie, Wy and Rapid City, SD locations) will have our demos mid-February. PowerPlays to sell end of February. Not all Rocky Mountain Bike Dealers can get them, only 30 or so PowerPlay trained dealers nationwide.
Just like non ebike, it improves technical riding, makes it easier to manual, and makes the bike more playful.

Long chainstays are fine for riders who aren’t riding technical single track.

That said, a chainstaybof 442mm is not short by any stretch of the imagination.

One look at that bike and it’s obvious someone didn’t do their homework, what a frogging mess! Aesthetics aside, the chain run is nuts and wholly unnecessary, reinventing the wheel without paying attention to what came before, and this is what you get.

Good luck selling that bike to anyone but an RM fanboy.

Wanna see the future of ebikes, check out the Shuttle and the Wiki Peak.
Chainstays certainly do not define the ride in totality. Look at RM Altitude geometry, and Instinct/Pipeline geometry. The Powerplay versions are the same (6mm increase on 29/27+ stays for PowerPlay), and you’ll find normal reach and stack as well. Great riding bikes.

Put some time in on all the motor systems and you’ll find Shimano or Brose sitting on top. This new Dyname PowerPlay approaches several things in novel ways, hope you get s chance to ride one soon. You’ll see the chain run mess has a specific function, as do the nylon gears and belts that spin hidden within the drive units from the biggies.

Brose, Shimano, Yamaha, Panasonic, Fauza offer motors any brand can work around for bike design, Rocky went another way, evolutionary steps that drive competition give us all new options.

The USA market is rising, giddy times. More to come at Sea Otter I’d expect.
I get through Laramie from time to time, flying, but I'm always packing my Montague folder ebike, I'll stop by the shop, sounds interesting.
Rocky Mountain should be applauded for thinking out of the box.
As I see it, all the current major assist motor builders include the bottom bracket in the motor assembly which tends to increase the chainstay length.
Fezzari has broken that trend with a reasonably short chainstay using the Shimano motor.
RM appears to use a standard in the frame BB and the motor is totally independent which require the additional sprockets to get enough chain wrap around the traditional chainring.
I ride a Haibike with a BoschCX motor that uses a non traditional chainring and an additional sprocket.
Electric motors for the most part need gear reduction one way or another to develop torque