Levo Gen4 derestriction with PLANET3

May 27, 2025 by Alex the Engineer

High Priority

Technical

12 min read

I’ve been waiting until I got my personal bike (Gen4 Comp Carbon) to test and make a post regarding the PLANET3 and Levo Gen4. After testing this weekend, here are some findings in order of importance:

Specialized has finally gone the route of Giant/Shimano/Bosch – they’re being bastards

The new system is now paying attention to gear ratios—i.e. the cadence vs. speed “map.” This means the days of fully derestricting a Specialized e-bike via a mechanical planetary gearset with a 3:1 ratio are basically gone. 🙁

It’s not that it doesn’t work at all, and for some use cases, it’s perfectly fine, but with a 3:1 ratio, you’ll get an error in anything lower than 8th or 9th gear.

With a dual-planet set, the ratio of PLANET3 is halved to ~1.5:1, but even with this configuration, the Gen4 Levo will cut your power in the first 3 gears (i.e., the largest cogs on the cassette). The rest works fine, and the speed limit is raises by about 50% (for EU/UK, this is from 26–27 km/h to ~40 km/h, and for the US, from 20 mph to 30 mph).

More Speed, Less Power: The Hidden Trade-off of Class 3 Mode Switch

Yes, some of you will say that this is unnecessary, as the US-spec bikes come with the selectable option to go from Class 1 to Class 3 (28 mph), BUT what most people forget is that this option also halves the power output of the bike – from 666 W to Levo SL levels of power – and good luck reaching 28 mph on flat asphalt with that power.

I don’t know about you, but I’ve personally never used the lowest gears (even on a Gen2 Levo with a much smaller cassette). That said, I might not be a good representation of the “population average,” since I mostly use my bike as a personal shuttle for relatively low-inclination fire road climbs due to my hip flexion problems (I can’t really bend forward and put pressure on the pedals without pain).

Still, even when I chose a really steep incline and put the bike in a down-tuned Trail mode, it’s not really necessary to use the first two gears. In my opinion, they’re mostly there for situations when you’re in OFF mode or climbing with some “acoustic” bike people. However, potential users should be aware of this limitation.

How Specialized’s Cadence-Speed Checks Affect Derestriction

The way Specialized is currently checking this cadence vs. speed map is by sampling ~25 seconds of continuous pedaling. The bike cuts your power if you’re in an “impossible gear” for a given cadence/speed combination for this period of time. However, if you stop pedaling for just 1 second every 20 seconds, everything works – but that’s a really stupid way to ride.

That being said, if you’re doing bike park downhill runs and don’t need to pedal for more than 20 seconds at a time i.e. you’re just throwing in some pedal strokes before jumps and want to make sure you’ve got power – a single planet configuration works wonderfully, and the speed limit goes to 3x the regional speed limit.

What actually happens when Levo Gen4 cuts your power?

When the bike cuts your power, nothing happens visibly – no error messages on the screen, none in the Specialized app. I’ll check if anything shows up in Turbo Studio (the dealer app) in a few days, but so far, it seems the power cut is the only consequence – and it goes away as soon as you restart the bike.

That doesn’t mean Specialized won’t “upgrade” this in the future to something more aggressive that might void your warranty, but previously the error just said something like:

“It looks like you’ve got a smaller or larger front chainring than is mechanically allowed in our system. Please visit the bike shop for a list of allowed ratios and change it back.”

Of course, if you’re using a 3:1 ratio device that adds 300% to the cassette, and you’re in 1st gear (e.g., 51T), the bike expects ~6 km/h at a given cadence, but the sensor reads 2 km/h… then yeah, they could say:

“Hey, there’s no 150T cog on ANY cassette, so cut that shit out!”

But in my experience across more than 10,000 PLANET3 units installed on Specialized e-bikes – this hasn’t happened.

Anticipating the Firmware Lockdown – And Staying Ahead of It

I’ve been delivering devices with a dual-planet config by default for more than two years because I expected this moment to come, even for Gen1/2/3 Levo (i.e., Brose S-Mag motors), but it never did. Those bikes can still be fully derestricted with PLANET3 and it warms my cold dead heart!

For those motors, we’re safe. When I found out about the potential firmware error (“gear ratios outside the allowed range”), I didn’t just ship dual-planet mechanical units – I invested time and effort to develop the PLANET3-E chip, which handles this issue more effectively and is more future-proof.

Next up: I’m cutting apart my Gen4 Levo connectors.

Just like previous Brose generations, they’re not available in the connector industry. Gen1–Gen3 used Brose connectors, Gen4 uses a mix of Higo and Chogori. Even though these are usually available via Alibaba, the exact variants used here are OEM-specific and not for sale to the gen-pop. So, I’m going ahead with tooling and injection molding, just like I did with the Brose connectors in earlier generations.

This will take time, as it’ll take us months to finish PLANET3-E for Gen4, not just a few weeks.

TL;DR:

Gen4 Levo can be derestricted to ~40 km/h (EU/UK) or 30 mph (US) using a dual-planet PLANET3, if you’re OK with not using the first 3 gears.
For high-speed bike park runs, a single-planet (3:1) device still works – just avoid continuous pedaling in gears lower than 8th or 9th for more than 25 seconds.

Compatibility notes:

All Gen4 bikes are supported: Levo Gen4 – PLANET3

Comp Carbon and lower models require a replacement axle/end cap due to an incompatible concave profile. Which we include in the kit; installation takes <1 min by hand.

S-Works: Needs a replacement end cap for the DT Swiss 240 DEG hub (OEM conical shape can’t be gripped via press fit). I’ve machined compatible end caps based on DT 350S tool-free profile, with a straight 19 mm profile.

Pro and Expert: Use straight 19 mm hubs – fully compatible, installs like previous generations.

Questions from customers

“Have you been able to determine if Specialized has added any measures to combat the use of speed chip solutions? Previous gens were easier than Bosch, Shimano, etc. Is Gen4 any different?”

Answer: For Gen4 the answer is – I don’t know yet.

On Gen2/Gen3 they’re all pretty much the same – if you can get access to CAN messages between the display/motor/speed sensor and simply modify the value of speed given to the motor to stay below the limit (~80% of the speed limit is what most chip makers use) then no manufacturer uses the rest of the available hardware to fight derestriction that actively.

For example, some displays/TCUs have barometers i.e. altitude sensors, Giant e-bikes have an inclination/tilt sensor. However, even though an algorithm could be written to detect potential cases of tampering i.e. power being drawn like you’re climbing while the bike is still horizontal and the tilt sensor is not saying you’re going up – they’re not doing any of this because either they don’t want to and recognize there are potential scenarios where it’s perfectly plausible (say you’ve got a monstrously obese wife or you’re so goddamn fertile that you’ve managed to reproduce an army of little minions, and you’re towing your clan behind your e-bike on the flat) OR they are willing to look the other way and make my job easier (which I don’t buy for a second).

Bosch is cheating!

Bosch is cheating and know this for a fact because they’ve built their algorithm for tampering detection to basically say “if you’ve never hit the speed limit and kept pedaling without power, you’re cheating” so, we just make sure to hit the speed limit occasionally – just like all the manufacturers circumvent the 250 W nominal power rule of law (we know all the motors continuously provide 600W+), but if you put them on a dyno or log the CAN bus you’ll see that every 30 seconds the power will drop back to 250W for a few milliseconds. You don’t feel this but the rule of law is satisfied and you can surely pedal for 15 min in Turbo mode without ever feeling any power drop.

Specialized Doesn’t Snitch—Unless You Help Them

Specialized, for example, since day one of Gen2 Levo had the Mission Control draw a map of your ride using the GPS data but exclusively used the speed sensor data for distance and speed. It’d be ridiculously easy for them to simply compare the two and say “Hey, you’re being a naughty boy!” but they don’t. Also, don’t be a twɑːt and use the official app that will provide the manufacturer with data that is direct evidence against you.. Main advantage of Specialized e-bikes was a lack of any screen bullshit.

Speed Without a Sensor: How Gen4 Could Ditch the Magnet

On the Gen4, they could without ANY issue do what Shimano /kʌnts/ do with Di2 derailleurs. Since all the bike Gen4 Levos (for now) come with AXS derailleurs which know exactly in which gear they are, they can use this information along with the motor cadence and the wheel circumference to calculate speed very accurately. You don’t even need a speed sensor any more. And I believe they already do this because that’s the math behind the smooth power delivery and less wheel slippage when climbing on loose terrain. Same as DJI Avinox, which will display ON SCREEN in which gear your bike is even though you have a mechanical rear derailleur and no sensor for position of said derailleur. This can all be done and maybe it will be in the future, but for now they’re leaving it alone.

As things progress in the future, manufacturers might simply lowjack your bike with GPS and you will agree to it via a standard EULA when you buy the bike or register for the app and then they can use this info against you.

Final advice: