[Project Share] 72V Sportbike Platform (CMEM-SR55) - 3kW Hub Motor with High Capacity Battery - Seeking Feedback

[WUXI CMOTO INTERNATIONAL]

CMOTO
Hi everyone,

I'm posting from Wuxi, China. Our team (Cmotos) has been developing a new electric sportbike chassis, and I wanted to share the specs with the ES community to get some technical feedback before we finalize the production configuration.

We are trying to build a solid full-sized commuter that looks like a sportbike but offers practical range and decent speed for city riding.

The Project (Model: CMEM-SR55)Unlike many small-frame electric bikes, we are using a full-size 17-inch wheel platform with a trellis-style frame.

Here are the raw specs from our current prototype:

• Motor: 3000W Hub Motor (QS style). We chose a hub motor for efficiency and simplicity in this price bracket.
• Battery: Lithium 72V 120Ah.
  • Note: We are aiming for maximum range here. I know 120Ah is massive for a 3kW bike, but we managed to fit it in the fairing.
• Controller: Configured for high phase current to help with acceleration off the line.
• Top Speed: Testing shows stable 80-100 km/h (GPS), which handles most urban highways.
• Wheels/Tires: Front 110/70-17, Rear 140/70-17.
• Brakes: Dual disc front, single disc rear.
• Dimensions: 1405mm Wheelbase, 180mm Ground Clearance.

My Questions for the Community:

1. Battery Weight vs. Range: With the 72V 120Ah setup, the bike is heavier (approx 130kg+ gross weight). Do you think the trade-off for the massive range is worth it for a daily commuter? Or would you prefer a lighter 60Ah swappable setup?
2. Hub Motor Heat: For those running 3kW hub motors at 100km/h for sustained periods, have you run into overheating issues? We are considering adding ferrofluid or hub sinks (cooling fins) as a factory option.
3. Tire Choice: We are currently using standard street compounds. For a hub motor build, do you recommend going wider on the rear (e.g., 150) for looks, or sticking to 140 for efficiency?

We want to be transparent about the build. It's not a Zero SR/S, but we think it fills a gap for an affordable, long-range electric sportbike.

Attached are the photos of the bike and the spec sheet.