165mm Crank length through the Bosch Dive unit option !?

[NETTA17]

Hello,

Bosch offers to select two Crank through the SW update :
The new Performance Line CX Package

>=170mm <=165mm

I just changed the cranks to 165mm on my Rail 2021.
Did someone do the same AND update it in the software?
Is it any different? For good or bad?

Cheers,

 

[Bomble]

I had 155‘s fitted to a couple of previous bikes, had the Bosch update but couldn’t tell that it changed anything but then maybe that is the point?

 

[Paulquattro]

I have 155mm cranks
No difference with no software change that i could tell.

 

[Mikerb]

Hello,

Bosch offers to select two Crank through the SW update :
The new Performance Line CX Package

>=170mm <=165mm

I just changed the cranks to 165mm on my Rail 2021.
Did someone do the same AND update it in the software?
Is it any different? For good or bad?

Cheers,

most EMTBs are supplied with 165mm cranks so the software is already tuned to 165 or smaller ( <=165 ). The SW update is therefore only applicable if you change to a crank longer than 165

 

[NETTA17]

You are correct, Mikerb, But I'm on the Trek rail, which comes equipped with 170mm.
The motor adds torque by sensing the rider torque on the crank (as far as I know, anyway)
So, the 165mm rider input is lower than 170mm, and the Software adds less supporting power...

 

[Shark58]

@NETTA17
In case you are still interested in the short crank option, here is what I know about it.

In 2017, when there still was the CX Gen2 motor, Bosch introduced their first dynamic mode and called it eMTB. This mode was developed to dynamically change support level based on rider torque input. At the same time manufacturers started to put shorter cranks on electric mtbs to reduce pedal strike. Soon smaller/lighter riders started complaining that they couldn’t reach the higher support levels in eMTB mode or sustain it for long.

Some months later Bosch introduced a second variant of the eMTB mode for „short cranks“ which they defined as being 165mm or shorter. We are now in 2018 and still have the CX Gen2 with max 75Nm power. The new application, as Bosch calles it, raised the progression curve of the eMTB mode and at the same time raised the fixed support for the Tour mode from 120% to 140%. Now lighter riders could get the full benefit of eMTB mode.

When introducing the CX Gen4 it started with 75Nm max power and was later updated to 85Nm max power. The 85Nm update raised the support levels for all modes and gave us what we have today: 140% for Tour and 340% for Turbo with eMTB dynamically moving between 140% and 340%. There where still the two applications for eMTB with short or long cranks. Any dealer can choose which version to install, hopefully after asking the customer what he wants.

Fast forward to early 2021 and Bosch introduced the second dynamic mode called Tour+. That mode in general works like eMTB but dynamically moves between Eco (60%) and Turbo (340%) support. The rider also needs to input more force to reach the higher support levels. Now comes the caveat: If one wants Tour+ installed, you are forced to install eMTB for long (regular) cranks. Bosch hast dropped support for the eMTB short crank version with the installation of Tour+.

Now with the CX Gen4 smart system there is no short crank version anymore. But you can now install Tour+ without being forced to also install eMTB. In fact you can have any combination of four modes you like with the smart system. And you even have a third dynamic mode called Auto, but this mode doesn’t react to rider torque. Instead it changes support based on outside factors like wind or steepness of the road to maintain the speed.

Easy, isn’t it?

 

[NETTA17]

Thanks, I figured out why I felt something was not as before ... It wasn't!
The shop update the software to the standard "Tour = Toure +" Instade off "Tour =eMTB lite"
This is a "TREK specific" option - But it can apply to any Bosch Gen4 (If you can use a Trek dealer to do so...)
This is much superior and has the most powerful & "natural" feel - with minor (if any)
battery consuming!
You wouldn't disappoint - Guarantee

 

[Shark58]

The Trek eMTB lite was the Trek specific predecessor of Bosch‘s more general Tour+. The Trek mode changes support between Eco (60%) and Sport (240%) whereas Tour+ can move all the way up to Turbo (340%).

I didn’t know a Trek dealer could still install eMTB lite. Thanks for sharing.

BTW, Moustache also had their own Tour+ version before Bosch and called it Magic Tour. That mode could move support from Eco to Turbo, just like the Bosch Tour+.

 

[TommyC]

Now with the CX Gen4 smart system there is no short crank version anymore.

I had my smart system bike in for diagnostics today and the report says one of my active modes is ‘emtb-short crank’.

I didn’t ask for them to change it. Bike came with 165mm and I’ve put 155mm on it about a month ago. Bought it in March 22.

 

[Shark58]

I had my smart system bike in for diagnostics today and the report says one of my active modes is ‘emtb-short crank’.

That is great news. Thanks for sharing.

When Bosch introduced the smart system they omitted the short crank version of eMTB. I had contacted Bosch support and asked when it will be available as I’m using 160mm cranks on my non smart bike. They answered there was no plan in place to bring it back.

Good to hear that they changed their mind. I could now consider a smart system if I need a new bike.

 

[TommyC]

I’m not sure if it’s been there from the start or it was part of an update, like tour+ replacing tour. Would bosch have considered the original 165mm a short crank anyway?

 

[Shark58]

Would bosch have considered the original 165mm a short crank anyway?

Yes, Bosch defined smart cranks as being 165mm or less.

The smart system and Tour+ where introduced together. Prerequisite for having Tour+ was an active eMTB mode.