Is it still worth to buy an e-bike with Bosh Performance CX gen4?
Posted by R0dod3ndron@reddit | ebikes | View on Reddit | 14 comments
What do you think? There is usually a huge price difference between new e-bikes with gen5 and gen4 and I'm wondering if it's any advantage of spending much more money on gen5 for casual rider as me?
unseenmover@reddit
compare..
https://www.youtube.com/watch?v=8KdQWUKILO8&t=27
Vinceinva@reddit
I’m in my researching phase before my first e-bike so as a retired IT person, I still spend way too much time in front of computer. This is a distillation of info I’ve gathered in my journey with the help of Claude. Hope it helps 🙏🏽
Short answer: Yes, Gen 4 is still very much worth buying in 2026, and for a casual rider it’s often the smarter choice.
What Gen 4 (BDU374Y) gets you right now:
• 85 Nm torque, 600W peak, 2.9 kg
• A partial Performance Update 2.0 — specifically, support boosted from 400% to 600% in Race/Turbo/eMTB+/Cargo/Auto modes (free OTA via the Flow app, rolled out May 4, 2026). This makes the motor feel noticeably punchier off the line.
• Mature, proven motor with years of real-world reliability data
• Fully Smart System compatible (Flow app, Kiox 300, all connected features)
The hard limit: Bosch is explicit that Gen 4 torque cannot be raised beyond 85 Nm. That ceiling is permanent — no future firmware will change it.
What Gen 5 (BDU384Y) adds that Gen 4 cannot get:
• 120 Nm torque (vs. 85 Nm), 750W peak, 2.8 kg
• Redesigned 3-stage gearbox that eliminates the “clack/rattle” Gen 4 makes on descents
• Decoupled drivetrain for crisper engagement
• 2-bolt pivot mount (cleaner integration, though some frames have had a floating-bushing creak issue)
• Customizable Extended Boost, Drivetrain Tensioner, Trick Check, Garmin Edge live data — none of these come to Gen 4
For a casual rider on pavement, paths, and light hills:
85 Nm is plenty. You won’t feel torque-limited. The freewheel “clack” Gen 4 is criticized for is mostly a mountain biker complaint — on a city or trekking bike you’ll rarely notice it. The 600% support boost from PU 2.0 closes a real chunk of the perceived gap with Gen 5 in everyday riding.
Where Gen 5 actually justifies the premium:
• Aggressive eMTB use (steep technical climbs, fast technical descents)
• Heavy hauling under load
• You want the latest platform for long-term resale value
• You’re a strong rider who wants maximum assist available
The price gap:
Brands typically charge $800–$2,000+ more for an otherwise comparable Gen 5 build. For casual riding, that money goes further on a bigger battery, nicer contact points, or just staying in your pocket.
Bottom line: Gen 4 with the free 600% support update is a genuinely smart buy in 2026. The hardware ceiling is real but it’s not a ceiling casual riders ever bump into.
BoringBob84@reddit
This is the 'show-stopper' for me. Bosch motors require special frames with proprietary mechanical interfaces. When the motor goes obsolete (like when Bosch decides to stop supporting 'older' motors) and fails, the bike will be useless.
For much less money, I can get a Bafang or Tongsheng mid-drive motor that I can install on a standard bottom bracket.
SadisticPawz@reddit
Important detail: for less money, you can get something that ALSO is repairable by you for cheap.
BoringBob84@reddit
I would consider a Bosch motor if they made a version that would install on a standard bicycle frame without permanent modifications (as Bafang and Tongsheng do).
SadisticPawz@reddit
I would consider a bosch motor for it if I could buy the parts and download the software for it.
R0dod3ndron@reddit (OP)
Where did you find the information about 600% update for gen 4?
Vinceinva@reddit
Straight from Bosch — three primary sources confirm Gen 4 (BDU374Y) gets the 600% support boost but stays capped at 85 Nm torque:
1. Bosch Performance Upgrade page (https://www.bosch-ebike.com/en/performance-upgrade)
The eligibility list explicitly includes:
• Performance Line CX (BDU384Y) → up to 120 Nm + 600% support
• Performance Line CX (BDU374Y) → up to 600% support (no torque increase)
• Performance Line CX-R (BDU386Y) → 120 Nm + 600%
• Performance Line CX Race Limited Edition (BDU376Y) → 600% only
• Cargo Line (BDU384Y) → 120 Nm + 600%
• Cargo Line (BDU374Y) → 600% only
• Performance Line PX (BDU347Y) → 600% only
That same page states the BDU374Y has a maximum torque of 85 Nm that cannot be increased further.
2. Bosch Help Center (https://help.bosch-ebike.com/en/help-center/performance-line-cx-for-the-smart-system/asset-ast-00284)
Lists the BDU374Y in the Performance Upgrade 2.0 eligibility section, requires Flow app v1.35 or later, and confirms the 600% support is unlocked at speeds up to 15 km/h in Race, Turbo, eMTB+, Cargo, and Auto modes.
3. Bosch May 2026 features announcement (https://www.bosch-ebike.com/en/news/newfeatures-2026-05)
The footnote on the 600% support feature lists BDU374Y as an eligible drive unit, with the rollout date of May 4, 2026.
So the full picture for Gen 4 CX owners:
• ✅ 600% support (up from 400%) in 5 riding modes, below 15 km/h
• ❌ No torque increase (locked at 85 Nm)
• ❌ No customizable Extended Boost
• ❌ No Drivetrain Tensioner
• ❌ No Garmin live data integration
Push-back from Gen 4 owners on Bosch forums (and a change.org petition) has been arguing the hardware is capable of more, but Bosch has not budged on the 85 Nm cap.
The Bosch performance-upgrade URL is the cleanest single link but you have to dig into it.
getmethehorizon@reddit
You can de limit the Gen 4. Not so much the Gen 5.
sticky-fingered@reddit
I’ve been using gen4 for 2-3years. Love it!
specialsymbol@reddit
Yes. It's a fine motor.
InvestigatorSenior@reddit
there's already plenty of gen5 exclusive features (torque, power, traction control) and more are coming this year (extended boost and possibly chain tensioner).
IMO gen4 is at maintenance mode now which is fair for 5 year old design and Bosch will use lack of updates as a way to convince us to buy new bikes. I wouldn't be surprised if Sram eShift integration that was strongly hinted at May 2nd press demo will be gen 5 exclusive.
blackhawk00001@reddit
Not that it matters, but I have several untouched koms on uphill segments with a gen 4 cx rail in a fairly active area. I got it on close out price and have no plans of upgrading. Go for the cheaper gen 4.
Excellent_Poetry_718@reddit
For casual riding Gen 4 is enough 👍 Gen 5 is nicer but not worth the extra cost unless you really want the smoother feel.