How do I maximize top speed

[MancaveAle]

Greetings, just built my first one. BBSHD on fat bike. I seem to get a top speed of roughly 40-41 km/h. Anyway to increase that?

[commuter ebikes]

Greetings, just built my first one. BBSHD on fat bike. I seem to get a top speed of roughly 40-41 km/h. Anyway to increase that?

The best way would be to increase the voltage or increase the tire diameter.

What is the voltage of your battery and your actual tire diameter?

Also, like paxtana said in another thread, a larger chainring in front.

Finally, maybe you could try a freewheel (or freehub, cassette) with less teeth on the smallest cog.

How many teeth are on your chain ring and smallest cog now?

[MancaveAle]

I put it on the Schwinn Biggity which has 26" tires but I set the DPC-14 to 29" as that was closer to the diameter with the fat tires. I have the 52 v shark battery and stock chainring Luna sells with kit. Luna programmed it for "hot rod" but I'm just wondering if I should adjust things in the DPC-14 to get a better top speed? As far as the chainring it is the stock 46T.

[ykick]

I posted a response in your other thread - https://electricbike.com/forum/forum...speed-question

I may attempt to merge the 2 threads but I need to be careful since I'm relatively new to the board utilities and I don't wanna nuke your posts? No big deal if we don't merge them but it might better help future folks who follow the bread crumbs?

[ncmired]

Unfortunately, there's no motor armature RPM indication via the display, other than the watt meter - at top speed are you pegging or maxing the watts ("max" being all of the red dots, or > 1000 watts)? And top speed is via throttle only, on level ground, still wind? If I remember correctly, the Hamilton area is pretty flat.

Presuming sticking with the stock BBSHD and controller and a max 52 volt battery, I'll venture the guess that you could increase your gearing if your watt indicator is not maxed out (instead, in the 40-70% range) on throttle only, which implies that the motor could pull a higher gear. No / low cost speed improvements could be gained by reducing rolling resistance, weight, and air drag.

On the indicated speed, have you cross-checked it against a GPS device?

As an aside, I wish we had a "under like conditions" max speed database for the BBS02 and BBSHD - I'll look into creating one, online somewhere.

[jakethe5nake]

If they're using programming similar to "karls special sauce" speed might be limited to 40km/hr. To get around this you can use the throttle.
If you have the USB cable you can try re-programming or even check the current programming

https://electricbike-blog.com/2015/06/26/a-hackers-guide-to-programming-the-bbs02/

[calfee20]

I have often thought that the 30 mph figures that everyone bandies about is wishful thinking. My top speed is similar to yours. Then again I am 6'4" 280# and I have an upright riding style so I am about as aerodynamic as a sheet of plywood.

[ncmired]

Hi Calfee - over 30MPH is possible.

For comparison, my bike can consistently roll a GPS-verified 32MPH (throttle only, no wind, flat ground), with a 1:1 (64 gear-inch) gear - that's with narrow tires and a total package weight of about 370lbs-380lbs (with/without groceries). Going up one (slightly overdrive, 78 gear-inch) gear hurts the speed. In both cases I'm pulling over 1200 watts per the display. I've tried to minimize the rolling resistance as much I can (drivetrain and tires), and hope PAS-only riding lowers the weight over time.

I too have a upright (high drag) riding position which hurts the speeds.

Honestly, I'm real happy with the results ... other than that I somehow killed one motor. There's only so much one can wring out of, what, 1.5HP?

[calfee20]

Well I finally went to Sheldon Brown's gear calculator and I mapped my bike in gear inches. My cadence is to low to allow the motor to wind up. I am over geared. I will have to try again sometime with throttle only and your suggested gear.

[MacGyver_Season1]

Gearing, it's all about gearing. With the factory chainring and ideal rear cassette you could either climb stairs or go 100+ Kmph. For the record, I don't recommend either :). The "Cadence" at 52v for the BBSHD is about 189 rpm.

http://www.bikecalc.com/gear_speed

https://www.sram.com/sram/mountain/products/xg-1299-eagle-cassette

[MacGyver_Season1]

or Kph? I dunno, I'm American and used to MPH, sorry

[Gr8fun]

I have 4000 miles on my bbs02 in less than a year. Finally upgrade battery to a 20ah 52volt and a batt man dashboard. I have found with the wattmeter my efficiency follows bicycle efficiency modeling programs very closely. Only complaint is flat tires and chain wear.
Thete are many of these on line. Just specify the parameters of your bike and change wheels, driving position etc.. I now have a 52 (36) tooth in front and an 11 (32) in the back. 26" touring tires on mtb. With this my cadence can keep up easily with 34 mph.but to achieve this speed i had to tuck into arms and body forward position at 750 watts. Sitting up like a sheet of plywood, i could only reach about 28. As i go forward into an aero position, it is like stepping on the accelerator.
I intend on going to a sturmey archer 3 speed igh with 8 speed cassette. Should even increase the abilty to add power by pedali g at even higher speeds and get a range of .8 to 1 at lowest, and above 6 to 1 at highest.
for higher speeds without sacrificing range , i need to go recumbenant with streamlined body (with solar cells). Ten watts permile at 30 mph is the holy grail. In my dreams.

[Gr8fun]

With my bike set up and sitting upright, the wind at 30 mph is a brick wall with 750 watts. Pushes well over. 30 watt per mile.
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[calfee20]

I have that Sturmey-Archer IGH and I think you will love it. I rarely need to use the derailleur. One of the nice things about it is it is compatible the front 3spd shifter. I have a Luna 42 tooth chain ring and most of my riding is spent on the 15 tooth cassette sprocket.

[Gr8fun]

That 42 to 15 combination sounds very close to what is needed for reliability. These 11 tooth are just not holding up. More chain on the cog. The igh sounds a lot more durable than wearing derailleurs chains etc. By shifting.
Thanks for the feedback.