Impressions on using BadassBox with Bosch Performance mid drive
 

I have a new Electra Townie Commute, which is basically enhanced beach cruiser with Bosch Performance mid drive, 700c wheels, hydraulic disk breaks, and 8 speed Shimano Nexus hub. It weights in at just under 60lbs. Practical speed limit on it is 19MPH, as you approach 20MPH putting more effort on pedals does not affect your speed but prolongs battery charge instead. So with factory settings the bike trains you to ease off and find the right cadence to maintain 19MPH, this results in using speed 7 on flat surface.

Putting BadassBox on it does not make it into rocket rod, you can comfortably cruise at 21-22MPH, and you can maintain 25MPH with decent effort using maximum speed 8 (maintaining 25MPH will significantly decrease your range though, so I prefer to only use it at certain stretches and not all the time). Sprinting at speed up to 30MPH is possible for short durations at maximum effort, and you need to drop real low on that cruiser handlebar, that really drains your battery too. All this essentially makes it into class 3 e-bike that is still street legal where I ride it.

What I really like about it, is that it sort of behaves like factory speed limited bike at Turbo assist level when you put it into Sport assist with BadassBox. With very compatible speed and battery range, but now you can get speed boost when you need to make that traffic light and (my favorite) you no longer run into speed wall at 20MPH and the entire experience becomes a whole lot more comfortable.

Depending on the laws in your state, the solution is technically usable.
In Europe or especially germany (where Bosch is located too), an S-Pedelec would be the safer solution because of the vehicle insurance needed for Pedelcs faster than 25kph.

I was tempted by Biktrix's 35 mph Ultra-mid fat bike on Cyber Monday, but fought off the urge to purchase one.

Which s-ped bikes did you test that didn't allow you to cruise at 28mph? I've ridden quite a few s-ped Bosch bikes and almost all were comfortably able to cruise at 28mph, and some would easily have kept going past that mark if not restricted.

Dunbar, I've ridden a couple of Juiced bikes for short intervals and thought they achieved 28 mph (sometimes test bikes may be "juiced'); surprised to hear yours didn't achieve 28 mph. I'll probably order a "dongle" for my Yamaha Haibike one of these days now that its warranty has expired, but don't now what to expect (I've heard everything from 26 - 35 mph). My "1500w" (30 amp controller, 52V - $600 kit + battery) Frankenbike does 33 mph easily (on Cyber Monday they were selling the rear hub kits for $157 delivered).

Where did you get the information about reaching the cruising speed of 28mph with Bosch Performance Speed?
With just 350W the Bosch Motor reaches 28mph.
bosch-ebike.com/en/products/performance-line/

Since its a Pedelec and not a ebike, you also have to Pedal. So it also depends on overal weight, your used force/energy and other factors.

And yet my first hand experience riding many s-ped Bosch bikes contradicts this. So bringing up the old "basic physics" is all well and good, but if that doesn't reflect real world use, then clearly it's not really that basic, with many other factors at play.

I'm not debating watts with you. I'm refuting this exact claim you made: "Yeah, the Bosch systems top out around 500-550W which is not enough to cruise at 28mph." And I'm refuting it with first hand experience riding many different models of Bosch S-Ped bikes, that were easily able to "cruise" at 28mph. How many of your 10K miles are on Bosch S-Ped bikes? And which of those models were not able to cruise at 28mph? It sounds like you're trying to make a theoretical argument around watts performance that clearly does not translate to the subject matter of Bosch S-Ped bikes in real world use.

The issue of watts is murky; the rating is supposed to signify the maximum power that an electric motor can produce indefinitely, but at times it seems as though manufacturers designate a rating that suits their needs. My friend had a 2016 Bosch-equipped Felt (with a "350w" motor) that he modified by moving the magnet and sensor to the crank area and the bike was capable of 30+ mph. I've ridden two "500w" Stromers and both were capable of 30 mph for extended periods.