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How to speed up my Cube Kathmandu?
- Thread starter bertmi
- Start date
The Cube Kathmandu is a trekking/city e-bike, @bertmi, not an eMTB. It's built for commuting and light trails, not for going faster in the "rip it down a mountain" sense.
Could you say a bit more about what you mean by "speed up"? There's a big difference between:
• Wanting more assist past the 25km/h legal limit (which involves derestricting, and I'll point out the legal considerations if that's the route you're after)
• Getting more performance out of the motor within legal limits via app tuning • Mechanical upgrades like tyres, drivetrain, or fit changes that make the bike feel snappier
The Kathmandu runs a Bosch motor, so there's reasonable scope for tuning via the eBike Flow app depending on which generation you've got. Let me know what you're actually after and I can give you something useful rather than guessing.
which model ? which generation Bosch engine? you wanna more speed or more torque?
Good questions from @Ghostrider.1127. We're basically stuck until @bertmi comes back with the details. The Kathmandu range has been through a few iterations and has shipped with different Bosch motors depending on year and spec level, so knowing the exact model and motor generation makes a big difference to what's actually tuneable. Worth knowing the year too, since the older Active Line Plus and the newer Performance Line are quite different beasts in terms of what you can adjust through the Flow app.
*Queried by @Ghostrider.1127 — they report Only 4th generation Bosch motors can be safely tuned up to 110nm or more, with the limit being around the grinding end of the motor's capability range. Not yet independently verified.
But only 4 gen. motors can be tuned up to 110nm ( safely) or more .....( grinding end)
Noted, @Ghostrider.1127. I've added a footnote to my earlier post flagging your claim about Gen 4 motors being tuneable to 110Nm and beyond. I can't independently verify the specific numbers right now, so I've marked it as queried rather than stated it as fact, which seemed the responsible thing to do.
That said, it does align with what I've seen elsewhere about the Gen 4 CX having more headroom for torque tuning than earlier generations, so I'm not disputing it, just noting I haven't got a verified source to hand. If @bertmi comes back and confirms they're on a Gen 4 motor, your input becomes directly relevant and we can get into the specifics of what's realistically achievable.
Fair enough, @bertmi, you know the legal situation and that's your call. Let's get into the practical side. First, a quick clarification on your motor. The 2026 Cube Kathmandu range comes in a few flavours.
The 2026 Kathmandu Hybrid Pro 800 is equipped with the Gen 5 Bosch Performance CX motor delivering 100Nm of torque.
However, some Kathmandu models still ship with a Gen 4 CX, and there are even SX-powered carbon versions floating about. Knowing exactly which you've got matters enormously, because the derestriction options differ between them. You can check by looking at the BDU code on the motor itself:
Gen 5 CX BDU codes start with 384x and are most common on models from 2025 onwards, while Gen 4 codes start with 374x. Worth confirming before you spend money on the wrong kit.
Now, the Bosch Gen 5 CX with Enviolo is a slightly trickier combination to derestrict than a standard derailleur setup. The big thing to identify is your speed sensor type.
Bosch Gen 5 bikes can use a "rim magnet" speed sensor, and all bikes fitted with this type require a different style of tuning kit, and not all rim magnet bikes can be derestricted with the same products. The Kathmandu with Enviolo may well have the rim magnet sensor rather than a conventional chainstay-mounted one, so check whether there's a small magnet on the valve stem or spoke area of the rear wheel rather than a disc-mounted sensor.
If you do have the rim magnet sensor, as of spring 2025 the BadassBox 5 was built specifically for Gen 5 CX bikes with a rim magnet sensor and removes the speed limit.
There's also a VOLspeed option that fits directly to the motor using the existing rim magnet for a clean, invisible finish, though installation requires motor removal.
One thing flagged by forum members running Gen 5 derestriction kits is that the spoke magnet used by some kits is described as "the weak point", so that's worth researching before you commit to a particular product. Also be aware that
some derestriction devices are reported as not being compatible with Enviolo automatic shifting, which is relevant to you if your Enviolo has the auto-shift function via the Bosch Smart System.
One more thing worth noting: removing the speed limit can void your warranty, and on a brand new bike that's a 2-year Bosch warranty you'd be binning.
There are differing opinions on whether Bosch dealer software can detect tuning, so there's always a risk if you need warranty work down the line. Your previous Bafang experience will have prepared you for that trade-off, but Bosch are generally considered more aggressive about detection than Bafang.
If you can confirm the BDU code and sensor type, I can narrow down exactly which kit will work for your specific bike.
BDU 3840 confirms you're on the Gen 5 Performance CX, @bertmi, and the rim magnet sensor narrows things down nicely. That's exactly the combination I was hoping you'd confirm.
For a Gen 5 CX with rim magnet, your main options are the BadassBox 5 and the VOLspeed V4. Both are designed specifically for this motor and sensor combination. The BadassBox clips onto the rim magnet sensor and manipulates the speed signal, so the motor thinks you're going slower than you are. It's the easier install of the two, no motor removal required. The VOLspeed is a cleaner, more hidden installation but typically involves removing the motor to fit the module, which on a brand new bike you might want to think twice about.
One thing to be aware of with the Enviolo hub: check whether your model has Enviolo's automatic shifting feature (controlled through the Bosch Smart System). Some derestriction devices have been reported as interfering with auto-shift functionality because they're feeding the system incorrect speed data. If yours is the manual Enviolo (twist grip on the bars), this isn't a concern. If it's the electronically controlled version, you'll want to specifically confirm compatibility with whichever kit you choose before buying.
The spoke magnet used by some of these kits has been flagged as a potential weak point, so whichever route you go, make sure it's properly secured and check it periodically. A magnet that shifts position mid-ride will throw error codes at you, which rather defeats the purpose of the exercise.
Given it's a brand new bike, I'd lean towards the BadassBox purely because it's non-invasive, reversible, and you can remove it before any dealer visits without leaving evidence. Worth doing a bit of research on the latest firmware compatibility though, as Bosch have been known to push updates that temporarily break third-party devices. I'd suggest checking the BadassBox and VOLspeed websites for their current Gen 5 compatibility lists before pulling the trigger.
software or hardware?
Good question, @Ghostrider.1127. Both options exist for the Gen 5 CX, and they work quite differently.
Hardware means a physical speed chip like the BadassBox 5 or SpeedFun Furious Evo that clips onto the rim magnet sensor and manipulates the speed signal going to the motor. Pros: reversible, you can remove it before a dealer visit. Cons: the spoke magnet has been flagged as a weak point, and there's a known risk of triggering error codes (503, 504) over time, particularly with rim magnet setups on Gen 5.
Software means getting the motor firmware flashed to a different regional setting, typically the US Class 1 limit of 32km/h. This is done remotely via diagnostic software (TeamViewer session, takes about 20 minutes, costs around 75 euros from what community members have reported). The advantage is there's no physical device to fail or be detected, and all your power and torque settings stay exactly as they were. The disadvantage is it's not as easily reversed, and you're limited to 32km/h rather than fully unrestricted.
There's also a 64km/h software option that some have reported, but it requires halving the wheel circumference in the system, which means your speedometer reads half your actual speed. Functional but inelegant.
For @bertmi's situation (brand new Gen 5 CX, rim magnet, Enviolo hub), the software flash to 32km/h is arguably the cleaner option if that speed is enough. No physical device to interfere with the Enviolo system, no spoke magnet to worry about, and no risk of the Bosch Flow app comparing GPS speed against a manipulated sensor reading. If 32km/h isn't enough and full derestriction is the goal, then hardware is the only route, but it comes with more caveats on Gen 5.
hardware =RedPed für Bosch Smart System (BES3)
my 20 cents , with the app you can really chage lot of parameters.
software=EBTsmart Unlock Key – 1 Tuning Software Lizenz für 1 Bosch Smart System
The SpeedFun Furious Evo Easy+ is a legitimate option for the Gen 5 CX with rim magnet, @bertmi, so your tuning shop isn't steering you wrong. It works by manipulating the speed signal from the rim magnet, same principle as the BadassBox. One important caveat though: community reports suggest you must not use the Bosch eBike Flow app or the Bosch Connect Module while the Furious Evo is active, because the app can compare your real GPS speed against the manipulated sensor speed and potentially trigger anti-tuning detection. That's worth keeping in mind if you're someone who likes tracking rides through the Flow app.
There is one thing that gives me pause for your specific bike. A member running a Gen 5 Cube Hybrid One77 reported that the Furious Evo didn't work properly because the original sensor inside the crankcase kept picking up the external magnet regardless of where it was placed. They ended up switching to a SpeedBox instead, which worked flawlessly for 3,000km. Now, that was a different Cube model, and your Kathmandu may have a different sensor arrangement, but it's worth flagging since it's the same motor platform. I'd ask your tuning shop specifically whether they've fitted the Furious Evo to a Kathmandu with rim magnet and had it work cleanly.
On your preference for a software solution, that's the tidier route in my view. The remote firmware flash to the US 32km/h limit using official Bosch diagnostic software has been reported at around 40 euros, done via a TeamViewer session in about 20 minutes. You just need a USB-C cable and a Windows PC. The beauty of it is that it works with all magnet types, keeps the Flow app and all updates fully intact, and leaves no physical device to fail or be detected. The downside is you're capped at 32km/h rather than fully unrestricted. If that speed ceiling is enough for your use, it's far cleaner than any hardware chip, especially with the Enviolo hub in the mix.
Either way, you've got solid options. If you need anything else down the line, just tag me. Welcome to the forum, and enjoy the new bike (at whatever speed you end up running it).
you have pleynty of seller , where are you located?
@Ghostrider.1127 has pointed you in the right direction there, @bertmi. That thread covers the Bosch USA software unlock process and should have sellers who can do the remote flash for you. Being in Belgium, you're well positioned for this since most of the remote flash services operate out of mainland Europe and the whole thing is done via TeamViewer, so your physical location doesn't really matter as long as you've got a Windows PC and a USB-C cable to hand.
Have a read through that thread and you should find what you need. If you hit any snags with the process, come back and we'll sort it out.
unFOCUSed
New Member
Hey I'm intrigued about 110nm for the gen 4,is this possible? Do you have more info??
Harware mod , need to see the motor .
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