Bosch shift detection - what does it do?

My Trek XM700 is equipped with the Bosch Performance Speed system, which features "shift detection". How does this work?

To reduce stress on the chain while shifting, I usually let up on my pedaling force before and during a shift. I'm wondering if this is unnecessary with a shift sensor.

Thanks to any and all who have some ideas about this.
 

Jeff Backes

Active Member
From all I can find on the internet, there may be some benefit with manual shifting, but I think the biggest win is with automatic systems like the Di2 and Nuvinci.

I don't feel and difference when I pedal.

jeff
 

pxpaulx

Well-Known Member
My Trek XM700 is equipped with the Bosch Performance Speed system, which features "shift detection". How does this work?

To reduce stress on the chain while shifting, I usually let up on my pedaling force before and during a shift. I'm wondering if this is unnecessary with a shift sensor.

Thanks to any and all who have some ideas about this.

You are correct, no need to let up the bike will sense the shift and lay off the power when the shift occurs. No harm in laying off though either.
 

Ravi Kempaiah

Well-Known Member
Shift sensing on the Bosch system had me intrigued me quite a bit.
On certain bikes like Kalkhoff, you have a physical device that is connected to the shifter cable and any movement of the shifter cable triggers the shift sensing.

On the Bosch system, it's more like a G-spot... no body knows whether they exist or not. Some think it does exist and works but I have ridden Bosch bikes (both Haibike Super race and Full Seven S Rx) for over 500 miles and did not feel the shift sensing mechanism. You can have clunky shifts under load.

From all my "internet" research and riding experience, all I could gather was ... the controller algorithm notices the change in crank rpm and the load and ensures smooth ramp up of the power. Since there is no device running along the shifter cable, once you have changed the gears, the motor doesn't put out the same torque it was operating at before the shift but rather rev up the motor smoothly.
And that's why Bosch system can feel under powered if you are shifting a lot because the system has to adjust itself for different gearing ratios.

I hope I made sense.
 

Chris Nolte

Well-Known Member
The Bosch Shift sensing actually detects the difference of the load on the chain via the torque sensor. This is not an easy thing to do, but they do it exceptionally well. This does not work with internally geared hubs though, but they do include a way for the motor to overcome this. In the most recent software the motor actually leaves small gaps in the assistance to allow for IGH shifts. It's not something you would notice but if you focus in on it you can feel the difference.

Keep in mind sensors made by Bosch can be found in most modern devices including the iPhone. No other system on the market senses as well as the Bosch in my opinion.
 

Don12

New Member
The Bosch Shift sensing actually detects the difference of the load on the chain via the torque sensor. This is not an easy thing to do, but they do it exceptionally well. This does not work with internally geared hubs though, but they do include a way for the motor to overcome this. In the most recent software the motor actually leaves small gaps in the assistance to allow for IGH shifts. It's not something you would notice but if you focus in on it you can feel the difference.

Keep in mind sensors made by Bosch can be found in most modern devices including the iPhone. No other system on the market senses as well as the Bosch in my opinion.
Hello does shifting sensing have to be enabled by the end user or is it an automatically enabled feature? Thanks for your help
 

TrevorB

Active Member
I've never noticed any shift sensing on Bosch CX drive, no real difference than Shimano Steps. For both drives I easy off or stop pedalling for shift especially when under high loads, both motor runs on for a second and complete shift..
 

Chris Nolte

Well-Known Member
I've never noticed any shift sensing on Bosch CX drive, no real difference than Shimano Steps. For both drives I easy off or stop pedalling for shift especially when under high loads, both motor runs on for a second and complete shift..
You can notice it if while pedaling normally you push the shifter and not actually shift. If you do that while paying attention to the power indicator on the right side of the display you’ll notice the power back off. This happens since the motor senses the difference in the amount of tension applied to the chain in this example.
 

tallpaul

Active Member
I have noticed the shift sensing on my Bosch Performance drive. it happens subtly and quickly.
I assume that backing off the power when shifting puts less strain on all drivetrain components, especially the chain.

Speaking of chains, is there a clear "best" chain that anyone knows of for our bikes?
I replaced the original Shimano at 1200 miles with an ebike specific chain by KMC but after another1200 or so miles can tell it is getting noisier.
To keep it quiet I have to lube it every ride of 25 miles or so, and that is mostly over asphalt and cement bikeways.
And the only lube I found that quieted it down, even for just one ride, was MucOff C3 Ceramic lube.
 

Ravi Kempaiah

Well-Known Member
With over 5K+ miles on Bosch powered bikes, I can say the Shift detection works quite well.
The pre-2016 version may have been slightly different but the ones coming out the last few years with smaller chainring, it sure does.
The motor detects sudden change in the torque levels because of the gearing and it smoothly ramps up the power after a very quick stop in power transmission. It's a nice feeling when your shifts are smooth.

Strangely, I tested the active line plus motor (the bigger chainring) and the shifts were still clunky. It was a Trek Verve+ and I went upto the Bosch rep and asked him about this. He didn't have any clue either.
 

Sweetwater

Active Member
Having recently upgraded to a 1 Gig Nyon, I can see the shift zones on the display very clearly.
However, my buddy has a new Yamaha on his Haibike and I've been very impressed with it.
Seems that the competition has improved products incrementally since my 2016 system.
Not yet time to trade up but that will be a consideration in another year or two.
 

sarantak

New Member
Region
Europe
A while ago I got some sand on my chain (cube compact hybrid sport) and then I went to my local service shop for the 1st service where he cleaned and re-lubricated the chain. After that the gear shifts were noticeable more noisy. I guess that there is no chance that the gear shift sensor is not working properly but this is due to the lesser or non-appropriate oil on my chain now. Correct ?
 

Alaskan

Well-Known Member
I find that the shift sensing works well on my Bosch powered bikes. However I find shifting works smoother, quieter and that my chains and the cogs on my cassettes last longer if I use the same shifting strategy I learned on the Rohloff. I take just a little bit of speed/pressure off the cranks as one foot is nearing the apex or 12 o'clock point, shifting and resume full effort when that foot is back on its way down. Our legs are applying the least torque when the pedals are in the 12 o'clock and 6 o'clock position. Just pulling a little bit of leg power at that moment makes a real difference over time.
 
Last edited:

Alaskan

Well-Known Member
You mean that you shift gear when the legs are at this position, right?
Exactly so. Shift at one foot high, one foot low with some pressure and speed reduced. You will hear the difference in shifting. It is possible to almost eliminate most shifting noise doing this. That quiet amounts to less wear on the drive train.
 

Art Deco

Well-Known Member
Region
USA
City
Selinsgrove
/offtopic/ Use the same pause at 6 and 12 oclock position to make tight turns without a pedal strike. 12 oclock on the inside of course./end offtopic/
This reminds me of what riding my 10 speed required when shifters were on the downtube, the front deraillier wouldn't shift successfully if the chain was even taunt. But you never forget and that's the way I ride on my Como w/o detection.
 
Last edited:

sarantak

New Member
Region
Europe
Screen Shot 2021-02-15 at 19.40.43.png


Is there any possibility that this will do more harm than good ? Am asking as I already have it for my other bicycles. MucOff C3 Ceramic lube is difficult to find here in Greece and I am planning to order it once W5 has finished or if it is unsuitable. Also, asking for confirmation, is applying every 25 miles a sensible think to do?

Product description​

W5 CARCARE chain spray
Forms a strong reliable lubrication and lubrication film
Increases the performance of the chain set
Synthetic, permanently can be Enschmier with a high solid content
Up to double performance and service life of the chain set
Recommended for use with O/RING
Suitable for motorbikes Entwickel and even for push bikes.
Capacity: approx. 200 ml
Quai nature made in Germany
 

Ravi Kempaiah

Well-Known Member
I have learned a thing or two about the Bosch shift sensing over the years. It is mostly software-driven and it certainly reduces the drive wear.
It works reasonably well, although there are rare occasions it could result in a hard shift due to user error.
For IGH systems, as @Alaskan mentioned, the system reduces the power for a millisecond when the cranks are in a certain position and complete the shift.
 

Johnny

Well-Known Member
It is at best hit and miss (a software driven shift sensor is mostly a gimmick, shifting under load it does very little). Also I don't see any evidence that supports this software sensing actually significantly increasing chain life, which is hard to test since you will need to be able to turn it on/off and ride same way for a fair comparison.

The best strategy is make it a habit to ease off slightly before shifting.