My goal is to use an ebike for my 2-3x/week, 32 mile (each way) work commute in the DC area-- a mix of flats and rollers. Nearly the whole route is paved, in good condition, and 80% is on bike lanes or paths. On my current road bike, the commute is 2:05 one-way and I'm looking for the ebike to get it down to 1:30 or below, which the Stromer proved was possible.
I'm 6', 180 lb, and I want to cruise 28-30 mph on flats with moderate pedaling. I’d like to use max 70% of the battery's charge range for my 32 mile commute, which means about 32/0.7 = 43 mi total range from the battery. Bike weight goal is mid 40s lb with battery, mostly so I can lift the bike without throwing my back out but also to help with efficiency. A little heavier is OK if need be.
The http://kreuzotter.de/english/espeed.htm tool estimates I put out about 180 W average on my current roadbike, and that I’d need 580 W average on my ebike to hit the 90 minute goal. So the motor needs to make up the 400W difference, requiring 600 Wh over 90 mins, which seems achievable with a 48V 17.5 Ah battery.
I'm expecting to spend about $2.6k (total-- new bike, motor kit, battery, lights, rear rack, etc.) but can afford a little more. I can assemble, crimp, and solder, but no heavy DIY customization.
I’ve got a couple old bikes, but I want hydraulic brakes, so I'm going with modern models. I found nothing on Craigslist in my area so I'm starting with a new bike.
My basic design so far is:
- $600- $1k for an Al road bike or hybrid with 700mm x 32 - 38 tires + hydraulic discs + threaded BB.
- will add torque arms if needed.
- Internally routed cables sound appealing so I don't have to re-route them across the bottom bracket during motor install.
- Some of these bikes come with carbon forks which I assume is OK since Luna's own KHS Grit 220 bike comes with them?
- 11T smallest rear gear so I can go fast-ish on downhills
- BBSHD kit with standard 750W programming, optional chainring, 48V 17.5 Ah Panasonic GA hard case battery on the downtube, charger. Should total ~$1400
- Chainring: Luna Eclipse 48T. I think a 52T would work better for flats/rollers if they're available.
- Charger with selectable 80/90/100% limit
- Other stuff: gear sensor=yes, PAS only=yes, throttle=no, display=DPC-18
- I plan to look into a Thudbuster after the build is complete.
First, appreciate any comments and suggestion on the above design.
For the bike purchase, any suggestions for things to look for, apart from riding comfort, bigger brake rotors, torque arms if Al dropouts, and fender/rack mounts?
Is a lightweight steel bike (e.g., Jamis Coda Elite) better than Al, assuming they both are mid-20s lbs?
I haven’t seen much in ES about PAS lag/response time of the BBSHD. I've test ridden some commercial ebikes that had huge (felt like forever but probably ~1 sec) motor cut-in/cut-out lag, which sucked. What's the BBSHD like?
The hydraulic discs on these bikes are almost all 160mm. Is that sufficient? I'm thinking of starting with them and upgrading if they don't feel strong enough.
Is suspended fork worth the weight and "maintenance" for comfort and to reduce impact on an Al frame? I'm thinking it's not needed for road-only riding with mid-30s tires.
Has anyone with a road ebike tried aero bars? It seems that would help with efficiency in the flats, at least while on dedicated bike trails.
I'm super excited to nail down my design and put in my order, so thanks in advance!