Bosch Class III pedelecs cut out at 26.5 mph
- Thread starter rudymsmith
- Start date
This is reasonable. Assistance up to 26.8 is quite reasonable.
@Over50 from your graph looks like the ramp down / transition to over 28 is quite smooth. Awesome.
The big improvements in Gen4 are that you can maintain higher speed,and it is much easier to go over 28 on human power .. pretty great!
I think testing this is somewhat easy.
Nyon and new kiox displays both have gauges that show you how much the motor is putting out(the darker blue bar around the odometer is motor power and light part is the rider's). So if you can mount a camera while riding and pushing to 28mph we can all see how the support behaves.
For gen 2 CX which cuts out at 20mph on Nyon I could easily see that once I pass 18.5-19 the assistance percentage was going to 0 fast. For gen 2 speed motor I have good reason to believe that the cut began before 26mph.
For the new gen 4 speed motor I didn't have the opportunity to test its limits so I can not comment on it. But here are a couple of thoughts.
Bosch will keep it legal and to keep it smooth it has to start cutting before 28mph. I am unsure about the law since Stromers seem to cut out a few miles over 28mph so if that is ok then maybe Bosch also took that approach.
Even if it starts to cut before 28mph it is still possible to hit 28mph for two reasons:
1. The speedometer has a lag and if the rider is accelerating fast enough she/he can keep the full assist and hit 28mph until the speedometer catches up and the assist completely gets to 0 (On the flats it is also possible for the fit rider to hit 28mph after the assist goes to 0 but I think most people here does not have that kind of fitness, when I did this on flats I was seeing 500+W on my part which I wouldn't call sustainable).
2. The speedometer may be off by 1-2 miles hence it gives the illusion of hitting 28mph while real speed is still 26-27mph.
On a gen 2 Bosch motor once the speed limiter is bypassed I have no problem keeping 26-28 on flats (it is with a bit of an effort) at %100 percentage assist level(I don't go beyond %100 since I cap the motor even at that level) and my personal experience mirror Ravi's.
Nyon and new kiox displays both have gauges that show you how much the motor is putting out(the darker blue bar around the odometer is motor power and light part is the rider's). So if you can mount a camera while riding and pushing to 28mph we can all see how the support behaves.
For gen 2 CX which cuts out at 20mph on Nyon I could easily see that once I pass 18.5-19 the assistance percentage was going to 0 fast. For gen 2 speed motor I have good reason to believe that the cut began before 26mph.
For the new gen 4 speed motor I didn't have the opportunity to test its limits so I can not comment on it. But here are a couple of thoughts.
Bosch will keep it legal and to keep it smooth it has to start cutting before 28mph. I am unsure about the law since Stromers seem to cut out a few miles over 28mph so if that is ok then maybe Bosch also took that approach.
Even if it starts to cut before 28mph it is still possible to hit 28mph for two reasons:
1. The speedometer has a lag and if the rider is accelerating fast enough she/he can keep the full assist and hit 28mph until the speedometer catches up and the assist completely gets to 0 (On the flats it is also possible for the fit rider to hit 28mph after the assist goes to 0 but I think most people here does not have that kind of fitness, when I did this on flats I was seeing 500+W on my part which I wouldn't call sustainable).
2. The speedometer may be off by 1-2 miles hence it gives the illusion of hitting 28mph while real speed is still 26-27mph.
On a gen 2 Bosch motor once the speed limiter is bypassed I have no problem keeping 26-28 on flats (it is with a bit of an effort) at %100 percentage assist level(I don't go beyond %100 since I cap the motor even at that level) and my personal experience mirror Ravi's.
Aha! A man with the fine print answer. For all us Yankees out there, that's 26.7mph..
dblhelix
Well-Known Member
That’s not full power to 28mph. I will post the Riese and Müller advertising this weekend. I believe you on yor description of Trek.
dblhelix
Well-Known Member
Posted specs are posted specs. Do you own a Riese and Müller? Why are you so anxious to defend their practices?
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
To keep the matters simple.
Bosch is German, and Germany is a EU country. Switzerland is only associated with EU and has own laws.
The EU law reads any Pedelec (45 km/h or 25 km/h) shall gradually reduce its PAS until it drops to zero at the restriction speed. Bosch follow that requirement down to a iota. However, Swiss laws (which are far more relaxed) put no such demand on e-bikes. Therefore, there is nothing wrong with Stromer to cut off the assistance "a few miles" past 28 mph: Stromer e-bikes are legal in Switzerland but illegal in the EU. Any brand making an S-Pedelec for EU makes sure the motor cut-off happens at 45 km/h sharp. Is it R&M, Specialized, Trek, Bulls or Haibike. The only matter is how early the assistance starts to be reduced.
Personally, I wouldn't have minded if it were 26.7, 27, 27.5 or 28 mph. It might matter to those who think the advertisement shall tell us the truth. Do advertisements say truth at all?
Specialized EU-Certificate of Conformity for a 45 km/h Turbo Vado.
Last edited:
dblhelix
Well-Known Member
Coukd have been an apples and oranges comparison.
When we purchased our Charger NuVincis, they were advertised as full power to 28mph by Riese&Muller. Full stop. People had a lot of trouble with this. The Nuvinci hub was blamed. Recommendations were made to upgrade to Rohloff. Most of this was mid-2018.
For MY19, Bosch changed the motor parameters to start cutting out at a higher speed. If your Rohloff bike had the MY19 firmware, your comparison would not be valid. This could have been applied via a firmware update prior to your receiving the bike — apparently by accident, if @Chris Nolte is to believed - he says he didn’t know anything about the engine tuning MY17-18-19 Gen2.
And that’s really the point. The posted specs are not necessarily true, and you don’t really know, and even your dealer is in the dark. Certain people are trying to obscure this, but if I’d been honestly told the engine specs in the first place, I wouldn’t have been jumping around from bike to bike based on misinformation And various blame games.
dblhelix
Well-Known Member
When performance did not match expectations, a number of us were told to explore other model options based largely on misinformation.
J.R.
Well-Known Member
- Region
- USA
- City
- Piedmont Highlands
Several years ago people complained most ebikes felt like it was hitting a wall at the cutoff speed. It would seem Bosch and others heard this criticism and programmed the motors to gradually drop assistance as they approached the max speed. Ebike manufactures try to make ebikes feel as natural as unassisted pedal bikes. Maybe the next generation will allow the user to choose between a gradual drop and hitting a wall.
dblhelix
Well-Known Member
I will publish a detailed post this weekend in the R&M subforum. My original response was to the OP’s concerns.
Whether or not Bosch is required to draw down just below 28mph is not my primary concern as will be clear. I am very happy with my Tern and feel it was honestly represented by reviews here, the manufacturer, etc. It is a Bosch bike.
The Riese and Müller experience has been something entirely different. People can offer up cynical views regarding advertising, but when their own dealers are left in the dark, there’s a problem and everyone‘s time is getting wasted.
Stefan Mikes
Gravel e-biker
- Region
- Europe
- City
- Mazovia, PL
I hear you, of course. I can only re-iterate that all brands making speed-ebikes for EU must follow the law, and the EU market is huge. The confusion has arisen from the R&M attempt to compete with Stromer, where Bosch-based bikes were at the battle lost from the beginning. (Stromer is illegal according to the U.S. Federal law but who cares).
A good example are the Specialized SL e-bikes equipped with the Mahle motor. The power cut off happens when it should but the bikes are designed the way you can't feel the "wall hitting" and just pedal stronger if you can ride faster on pedals only.
Interestingly, Giant SyncDrive motors (EU regular e-bike) cut off past 25 km/h, I think the real cut off speed is some 16 mph.
Luv2ride
Active Member
I solved the cutoff issue by installing bikespeed rs from day one to de-restrict my Trek Super Commuter.
I now have 32,000 miles with no motor problems.
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I now have 32,000 miles with no motor problems.
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Over50
Well-Known Member
Yes, I will confess I did chalk it up to the gear ratio of the Nuvinci hub. And then learned that @Ravi Kempaiah replaced the hub so I then chalked it up to gear ratio and/or defective hub. I did hear later that the Bosch software was probably tuned to the hub but it still seemed like a hub issue to me in that the programming had to match the capabilities of the hub and it just wasn't cutout for use on a speed pedelec. And it left me thinking that I wouldn't want a Nuvinci/Enviolo again on a class 3 bike. But willing to be convinced otherwise based on experience with more recent bike models.
Akrotiri
Well-Known Member
- Region
- Europe
I reach 28mph with my gen 4 Bosch speed motor with only moderate effort. Sometimes higher if I’m well-rested. High speeds aren’t for me though, I like to cruise around 12-15 mph. But I like the fact my ebike can reach 28mph when I want or need it to, and it does.
I started riding an e-bike with a Bosch motor a couple months ago after decades of non bike e-bike cycling. The one issue I cannot figure out how to resolve is the cutoff of the motor @ 28mph. My rides start and end in a suburban area with highways, stoplights, no road shoulder and a lot of vehicle traffic. On one particular section I get a .25 mile lead from vehicles after series of stoplights. I need that advantage of being ahead of vehicle traffic to exit the highway and return home. On traditional non e-bkes I use to sprint this section above 33mph. With the Bosch motor I am getting so much resistance turning over the cranks above 28 that I am loosing the distance advantage with vehicles approaching in the rear.
I also have other sections on the route that require a 30+ mph pace with traffic to get in the left turn lane at a stop light. No different than any other vehicles on the road. I saw some tuning devices made for Bosch motors to eliminate the 28 mph cut off and fellow e-bike riders have advised not to do that as it may damage the motor and end the warranty. I can get a bit more speed if I change tires , handlebars and lower my riding position just a bit. I luv everything with e-bikes and really enjoy the experience. Just wondering if anyone else has figured out a solution to not have the e-assist with Bosch shut off 28 mph. My motor is from 2019, not Gen4. Wondering if the Gen4 Bosch motors are the same with crank resistance above 28. Anyone have any practical solutions or is this 28mph limit the norm with most class 3 Bosch equipped ebikes?
I also have other sections on the route that require a 30+ mph pace with traffic to get in the left turn lane at a stop light. No different than any other vehicles on the road. I saw some tuning devices made for Bosch motors to eliminate the 28 mph cut off and fellow e-bike riders have advised not to do that as it may damage the motor and end the warranty. I can get a bit more speed if I change tires , handlebars and lower my riding position just a bit. I luv everything with e-bikes and really enjoy the experience. Just wondering if anyone else has figured out a solution to not have the e-assist with Bosch shut off 28 mph. My motor is from 2019, not Gen4. Wondering if the Gen4 Bosch motors are the same with crank resistance above 28. Anyone have any practical solutions or is this 28mph limit the norm with most class 3 Bosch equipped ebikes?
dblhelix
Well-Known Member
At 28mph, you are getting no assistance. It starts cutting out at 27mph with drop to zero at 28mph. This assumes you have recent vintage firmware as the cutoff was earlier for pre-MY2019.
I feel your pain. I was on a bike-legal hwy in CA that required merging to one lane w/no shoulder with traffic at 50mph+. CHP pulled me over pre-merge to warn me and to drive behind me so that I could make it through. They looked at the bike and said “28mph, good bc we need you to do 30mph+.” I tried not to laugh.
My impression is that the resistance is really the bike’s inertia, due to its weight, rather than resistance due to the reduction gear/Gen2. If someone with reasonably similar Gen2/Gen4 models would share their experience, it’d be helpful. Has anyone found new life at 30-32mph, say, for a quarter mile, after moving to Gen4?
So true.I don't think the difference between gen 2 and 4 is drastic since it is only a couple of additional gears that are turning not the motor itself (there is already a clutch for that).
The only reason why people are faster at lower assistance levels with gen 4 is because gen4 assistance percentages are bumped up. I rode gen 4 then back to my gen 2 with custom modes and my average speed was almost the same(I need to do a prolonged test but I have no plans of buying a gen4). Also these motors don't have the power output to sustain anywhere close to 28mph(28mph is actually 26-27mph without speedo inflation.) unless the rider puts a very significant amount of effort. It is simply a matter of continuous power which these motors don't have.
@Alanzo I don't know what your fitness level is but as dblhelix said keeping this bike 30mph+ without assistance is significantly harder than a regular, light road bike. I don't think gen4 will be any better. However since you have a gen 2 you can use a dongle like badassbox which will eliminate the speed limit. Can not talk about warranty but it can not damage the motor.
Alaskan
Well-Known Member
Unlike gen 4 motors, Bosch gen 2 motors do not have software that puts the motor into walk mode if derestriction is detected. Instead, gen 2 motors in one of the firmware updates started to record the derestriction, which showed up in the diagnostic report if the bike is put on a Bosch maintenance system. It is my understanding that can be used to void the warranty but the motor is not rendered useless. Given that your bike is likely more that two years old and therefor past warranty, this should not be of concern.
When I bought my 2018 Delite Mountain with the gen 2 CX motor, used in early 2019, I immediately put a Bikespeed RX dongle on the motor, underneath the motor housing. I figured it was worth the risk. And of course now, there is no risk as the warranty has expired anyway. What I got was a CX motor with no top assist limit, i.e. CX torque and power, EMTB option and a bike that I could pedal at higher speed. In order to access that speed in a meaningful way, I had to replace the 15 tooth front chainring with an 18 tooth one. The put made higher speeds attainable using a sustainable cadence. In order to recapture lost climbing ability due to the larger chainring I changed out the cassette from the stock, 11-42 to an 11-46. At one point, going down a long hill with a 3-4% downgrade, I spun up the cranks as fast as I could to see what kind of speed I could attain. Result: at a cadence of 115, I was going 42 miles per hour.
Finally, I did have concerns about possibly damaging the motor. That bike now has over 5,000 miles on it, I have gone through at least four chains and two cassettes and replaced the chain ring twice as well. The motor has not missed a beat and still provides all the power it always has without any hiccups, odd noises or problems.
Luv2ride
Active Member
I ride a Trek Super Commuter with a Bosch gen 2 motor . My bike has been derestricted with the Bikespeed RS dongle from day one and as of today has 36,736 problem free miles.
I also changed my front chainring to a 22 that I got from a third party vendor and an 11-46 cassette.
I can maintain pretty high speeds with the right assist level and the assist is there as long as I can pedal.
I also changed my front chainring to a 22 that I got from a third party vendor and an 11-46 cassette.
I can maintain pretty high speeds with the right assist level and the assist is there as long as I can pedal.
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