Bosch SX

[Jezrant]

Anyone tried an e-bike with the newish Bosch SX motor? Be interested to hear about any real experiences (rather than educated guesswork, speculation or regurgitating stuff read online).

[Vetus Ossa]

I’m interested as well.
Looking for a lighter bike with this motor and rigid forks for shorter rides.
I don’t expect the power and range I can get with my cx powered bike, but something lighter for shorter rides would be nice.
I do all of my riding on road and trails so brute power for off-road riding isn’t a requirement.
All of the reviews I have seen say to get the best out of them you need to pedal above 100 rpm and I ain’t going to be doing that.

[al_yrpal]

Not a lot different to the original Performance Line drive on my clunker 10 Nm more and weighs 0.3 kg less. More plastic parts I would guess.....

Al

[Jezrant]

FWIW, I very briefly tested a new Cube with this motor. They're now using it in a much-lightened CF version of the Kathmandu 'trekking' e-bike and a much less pricey 17kg alu 'e-Urban' type bike called Editor. Neither of those has suspension; they both use a CF fork. I have the impression the motor was originally intended for 'light' FS eMTBs, which use peak assistance in very short bursts. I'd seen stuff online about the 100rpm cadence business. I'm not sure how accurate that is, or whether it only applies to eMTBs, but Bosch motors, unlike say Shimano motors, do deliver peak power at high cadences. Shimano motors work in the opposite manner in my experience with power dropping off at high cadences. Bosch themselves say something like 70-90 rpms if I'm not mistaken. The thing I discovered quite quickly is it feels very different to the 85Nm CX. There's noticeably less power at normal cadences, and the gearing on the bike has to be low enough to keep the cadence high enough when riding uphill. If you've ever tried a bike with the Mahle X35 hub motor, the SX's assistance while riding on hilly roads doesn't feel markedly different, which was disappointing. It's possible Cube haven't quite got it set up right on the Editor. Unless there was a software fault or something wrong with the power settings, the gearing of that bike was also way too high (lowest gear is 33"!) to take full advantage of this motor on a road e-bike. BTW, that bike had 700x 50mm tyres as standard.

[Vetus Ossa]

FWIW, I very briefly tested a new Cube with this motor. They're now using it in a much-lightened CF version of the Kathmandu 'trekking' e-bike and a much less pricey 17kg alu 'e-Urban' type bike called Editor. Neither of those has suspension; they both use a CF fork. I have the impression the motor was originally intended for 'light' FS eMTBs, which use peak assistance in very short bursts. I'd seen stuff online about the 100rpm cadence business. I'm not sure how accurate that is, or whether it only applies to eMTBs, but Bosch motors, unlike say Shimano motors, do deliver peak power at high cadences. Shimano motors work in the opposite manner in my experience with power dropping off at high cadences. Bosch themselves say something like 70-90 rpms if I'm not mistaken. The thing I discovered quite quickly is it feels very different to the 85Nm CX. There's noticeably less power at normal cadences, and the gearing on the bike has to be low enough to keep the cadence high enough when riding uphill. If you've ever tried a bike with the Mahle X35 hub motor, the SX's assistance while riding on hilly roads doesn't feel markedly different, which was disappointing. It's possible Cube haven't quite got it set up right on the Editor. Unless there was a software fault or something wrong with the power settings, the gearing of that bike was also way too high (lowest gear is 33"!) to take full advantage of this motor on a road e-bike. BTW, that bike had 700x 50mm tyres as standard.

I have yet to try out a sx powered bike myself but have seen the editor online and it’s one I was considering.
I have been to my local cube dealer and they haven’t had any in yet to look at and try.
I will hang on till the spring though before buying and there should be more information available by then.
I think the editor is in the 16kg range which is a heck of a lot lighter than my Trek Powerfly.

[Jezrant]

I've hired a Trek PF5 a couple of times, and really enjoyed it off-road. The second or third time I tried it (this was over a few years' time), I deliberately took it up a long steep road in the Yorkshire Dales to see how it behaved. Like off-road, it was unflappable. But it's a beast. So I too have been hoping to find a much lighter e-bike mainly for tarmac and am also waiting til the spring. I'm pretty sure the Editor's gearing is wrong for that motor (it has a 44T chainring and 11-39 cassette). Seems a 38T chainring could be fitted, but not sure what then needs to be rejigged on the motor's software and whether you need Mr Bosch's approval to keep the warranty valid. I'm still keen to hear about peep's actual experiences of the SX, so if you're reading this and have tried it, don't be shy.

[Vetus Ossa]

I've hired a Trek PF5 a couple of times, and really enjoyed it off-road. The second or third time I tried it (this was over a few years' time), I deliberately took it up a long steep road in the Yorkshire Dales to see how it behaved. Like off-road, it was unflappable. But it's a beast. So I too have been hoping to find a much lighter e-bike mainly for tarmac and am also waiting til the spring. I'm pretty sure the Editor's gearing is wrong for that motor (it has a 44T chainring and 11-39 cassette). Seems a 38T chainring could be fitted, but not sure what then needs to be rejigged on the motor's software and whether you need Mr Bosch's approval to keep the warranty valid. I'm still keen to hear about peep's actual experiences of the SX, so if you're reading this and have tried it, don't be shy.

Interesting reading Jezrant, thanks for the info.
Yes, I have a PF5 too, great ride, but so heavy.
Like you I am interested in hearing from anyone with real world experience with the sx, I guess we will know a lot more by spring.

[Jezrant]

As a post-scriptum, I briefly tried Cube's new Kathmandu with same SX motor and 400wh battery. Sailed up the same steep hill that had defeated me and the Cube Editor with its ludicrously high gearing (33" lowest gear). Bike came with a Knox 500 display, so I could check power and cadence. I dropped down to 28" at around the same point where me and Editor ran out of puff, and then 24" to see how the motor works at higher cadences (lowest gear is 21”). It's true the motor peaks at 100+rpm, but you don't need peak power for steep hills if the bike has low enough gearing. It also has a slight on/off feel like a CX, not as natural feeling as a Shimano motor in my opinion, but it works well at normal cadences if the gearing is right. I didn't much take to the bike though. It was very comfy and nicely sorted but has the riding position of a Dutch-style bike, too upright for my liking. If Cube would sort out the dumb gearing of the Editor, it would be a Vado SL slayer IMHO.

[Jezrant]

Cube are on a roll. Seems they’ve just come out with another bike with this motor and battery, the Nulane, with a 40 x 46 lowest gear. No idea of prices but it’s another one with a CF frame.

[Vetus Ossa]

Cube are on a roll. Seems they’ve just come out with another bike with this motor and battery, the Nulane, with a 40 x 46 lowest gear. No idea of prices but it’s another one with a CF frame.

Looks lovely but it's going to be pretty expensive isn't it.
Edit.
Says £2,699 which surely can't be right.

[Jezrant]

That is the price I heard for the cheapest model (9sp Shimano Cues if I’m not mistaken) when I inquired yesterday, but I agree, it does sound inexpensive for a CF e-bike. I think I also saw it listed for 3k euros on Cube's website. They’re not expected to be available until late March. I’m not so keen on CF, but the claimed weight is under 15kg. I’d prefer the alu Editor with lower gearing like on the Nulane, but it sounds like Cube isn’t going to change it. There must be other companies planning on similar flat-bar e-bikes with this motor and battery. I’d also like to see Specialized up the motor on the Vado SL to the 1.2. Time will tell.