Power recommendation for climbing a long steep hill road everyday

[i2000s]

Hello there,

This is my first post here as I am excited to build an Ebike as many of you have done. My situation is that I have to bike on a long steep hill road (30-45 degrees or even steeper) quite often and mostly in windy days here. I am 160bls, and don't want to pedal too much on the road. How much power do you recommend for a front wheel driven motor kit? I am choosing a front wheel kit mainly for an easy setup and a full-wheel driven configuration. I understand that there is a 750W regulation for bikes on road.

Thanks,
i2000s

[Fred]

If the hills are truly that steep and with wind in your face. you may want a mid-drive BBSHD. You can use then the gears thru the derailleur or IGH to help with the ascent. Not as easy to install as a front-wheel hub, but really not that difficult at all.

[Rix Ryds]

I think Freds recommendation of the BBSHD is a good one. A mid-drive will far and away out perform hub motors on hills.

[Jon]

A 45 degree slope is about 100% grade, amazing! Can you tell the name of this road?

[Rix Ryds]

45 degree is 100% grade. The steepest road you will see anywhere is about 30% grade. The world record steepest is Baldwin street in New Zealand at 35% grade. There are four grades in North America over 30%, One in Los Angeles, one in Pittsburgh, one in Quebec and one in San Francisco.

[i2000s]

Thanks for pointing out the slops. My bad, I had overestimated the degrees. Turns out, it's only 4.4% grade with maximum 5%. See the map for a section of the road where I have to go day by day up the hill soon (moving there in Oct). See the map and grade estimation: http://veloroutes.org/hillgradecalcu...2C+USA&units=e

Should a 1000W front wheel drive enough for this case? Frankly speaking, the mid-drive scares me a little bit as a new builder. My Trek 800 has a 7-speed Shimano Biopace chainring (elliptical shaped) which I kind of like most. The place I plan to mount the battery is to the bottom of the frame as there are two screw spots. My locker mounter is also at the bottom part on the other side. I feel I need to buy a lot of parts if installing the mid-drive part. My bike looks like this one but not exactly: http://www.bikepedia.com/QuickBike/B...odel=800+Sport

No experience so far. All comments are welcome!

Thanks,
i2000s

[Rix Ryds]

I wouldn't let that mid-drive scare you. I see the bike you have has a standard 68mm bottom bracket. It's not a fat tire bike, so a BBSHD mid-drive will mount up with no problems. I would recommend the gear sensor for use with a derailleur. You could go with a hub motor, it will do those hills, but if you rode a BBSHD equipped bike and a hub motor bike side by side, you will want the mid-drive. The ability to use those rear drive gears should not be underestimated, it makes a big difference. Besides, whos to say you may find yourself climbing much bigger hills and then that mid drive would shine!

[Jon]

A front wheel hub motor would be fine for that type of hill. Does not require a lot of power. You are going to enjoy it!

[Alan B]

That web page fails to render properly in my browser. But it looks like that bike has a non suspension front fork, hubmotors in suspension front forks are difficult to make safe. Hubmotors in front forks require careful attention to detail due to various issues and the severity of an in-motion front wheel dropout failure.

5% is a fairly mild gradient, some of my rides get to 15+% which is a challenge.

A front wheel geared hubmotor should be fine. You can enter the data into the simulator on ebikes.ca website and see how the speed and power work out for various motors.

[i2000s]

I know you guys are wonderful in building DIY ebikes! I am grateful for all the comments above. That helps me evaluate my situation scientifically. I still have the following questions, if anyone can help answer them:

1. References: Any recommended ebike building references suitable for my type of bike? I would seriously consider both mid-drive and hub motors--more prefer on the hub motors so far while I haven't found suitable manuals for building my ebike. In fact, I haven't found any mid-drive building experience working for my derailleur case. I neither found proper guide on how to deal with the brake controller available in the hub motor conversion kit -- my bike has integrated brake and speed controller on both handles, and hence there seems no place to install another brake for power switch.

2. On the choice of battery voltage: The ebike.ca simulator is kind of strange. Can I use a 48V battery set for a 36V 500W motor? Based on the simulator, the performance seems better with a 48V battery than its standard 36V ones... But the controller I have read through seem only care about current.

3. Choice of motors: A 500W front wheel conversion kit (brushless gearless), from the simulation, seems to be almost equivalent to some 250-400W mid-drive motors. But there is a lot of different between even just hub motors with the same amount of power. I definitely want to be faster, but the 20mph speed limit should be fine with me for going up hill without pedaling. In terms of performance/cost, do you guys have any recommendations on where to buy those parts for a newbie?

I found some unbranded hub motors, like this one: http://www.ebay.com/itm/36-48V-500-1...sYcK0U-aMmVjdQ
Cheap but a lot of people buying it. I know you guys won't recommend it, but any bad stories?

4. The initial question: what power should I get? From 500W to 1000W, the motor may not make a big difference in terms of price, but the battery package will cost a lot more for high power. So, I guess I will need to find the proper power I need to my commuting tasks. Given my weight is only 160 bls, my guess is 500W may be sufficient for climbing the hill. Suggestions are appreciated!

[slickwheelie]

I would recommend that you stick with a US company- like luna cycles. you might find some better pricing but not sure exactly what you are getting- It seems to me that the guys at luna know their stuff and stand behind it. I am fairly new to ebikes as well and just converted an older bike with a bbshd for off road riding. It is a lot easier to learn stuff when you are using parts that you know already will work like they are suppossed to. Makes trouble shooting much easier- good luck - as for batteries and systems you need to match the controller to the battery size - ie 36v controller then 36v battery

[Rix Ryds]

I will second 'slickwheelie'. Buy from an American distributor. All this e-bike stuff is Chinese, the difference is the distributor. The first time you try to return something under warranty, the difference will be abundantly clear. With Chinese distributor, you will be lucky if they take your call, if they do give you a RMA, you will be responsible for postage to CHINA! The cost will floor you! And batteries, forget about it!
Now with Luna, you will get world class top notch customer service. You got an issue, open a service ticket and Eric's minions will be on it like a duck on a June bug! An example, my Luna charger went down, and I needed it replaced ASAP. So, thinking that Luna customer service might be too slow, I ordered another before opening the service ticket. They BOTH arrived in 5 days! You will never get that level of customer service from the Chinese! So if you buy that inexpensive hub motor and somethings not right, even right out of the box, well, you have no real warranty with the Chinese. You may pay more at Luna, but you are buying more than parts, your buying world class customer service. I'm tempted by those inexpensive drives as well, but having bought from Chinese before, I never will again. I'm Luna loyal! Deal with them for awhile, and you will be too!

[spinningmagnets]

For extra-steep uphills, you NEED a mid-drive. You can climb slowly in the lowest gear at 750W. Or you can climb faster in 3rd gear with 1500W.

You will never regret paying extra for more power.

[i2000s]

Thank you guys. I will look for more references to build up some confidence.

[FolsomRider]

I have a BBSHD and i live in the folsom area in Norcal with steep grades all around and i can climb any hills around on a specialized FSR. I am 6"2" and weigh 215 pounds as a reference. l noticed the bike you referenced has caliper style brakes. I would HIGHLY Recommend quality disc brakes. This is a life saver and should not be overlooked.

[i2000s]

So, I think 500W should be enough for me. And just ordered a 36V 12Ah battery on Aliexpress. Still waiting for my decision on motors.