First Build advice

[tgice]

Hi guys, I'm new to the community and am looking to build my first ebike for a 7 mile one way commute to work.

I'd like to be able to get a decent amount of exercise during the ride, but not so much that I'm heavily winded (or sweaty) when I arrive, so I'd like to be able to reasonably assist during the ride. I'd also like to possibly be able to get up to 25-30 mph during parts of the ride to make it nice and quick.

Desired max speed on level ground: 28mph
Desired max range at what cruising speed: 10 miles at 25mph
Preferred bike wheel size, or wheel size of bike you want to convert: 26", but flexible
Brake type of motor wheel: V brake on rear (motor), maybe disc on front (no motor)

I'm 6'2" and 155 lbs, and would normally not be carrying much of any extra weight with me.

I've read about how MTBs are generally best for a sturdier build in general, and you prefer steel framed bikes. The only one I currently have that could be a donor is an 20+ year old Huffy 26" 18 speed that's missing the front derailleur (it broke years ago and I just removed it, leave it on the middle of 3 gears) with some crappy caliper breaks that work, but I probably wouldn't want to rely on at speed. Naturally the cheapest option would be to start with that and later upgrade to a new bike, but I'm leaning towards buying a new cheap (Walmart) mountain bike, unless you guys can talk me out of it.

Most mountain bikes (even cheap Walmart ones) seem to have aluminum frames, even in the $125 - 150 range, e.g.:

http://www.walmart.com/ip/26-Genesis-V2100-Mountain-Bike-Dual-Suspension-Men-s-Bike/22899847

here's one w/ only front suspension, but apparently an all steel frame for the same price:

http://www.walmart.com/ip/26-Schwinn-Sidewinder-Men-s-Mountain-Bike-Matte-Black-Green/26999374

I think I'd prefer the paddle shifters on the first one to the Shimano Revos on the second (which also are more common the Walmart bikes).

In general it sounds like a *rear* wheel hub motor kit at 48V and 1000W would be the best bet for me. I'd get a Lithium pack of some sort, that initially I'd probably configure to carry in a backpack (save a bit on other mounting options up front, and might want to go indefinitely with it like that anyway, so it's easy to carry inside at the office and back at home to charge inside).

I think I'd prefer to have at least a front wheel disc brake to help with higher speed stopping, and in case I end up riding in rainy or snowy conditions (which is possible), even if these cheaper bikes have crappier setups, I suppose I could always upgrade them later, but at least I'd know the forks are wide enough to accommodate the disc, etc., right? Or should I go instead for the all steel Schwinn (or similar) with no disc brake, figuring I could just upgrade to a new wheel w/ disc and add the other part of a disc brake to the fork later?

I'm kind of leaning towards a Magic Pie (or Smart Pie) kit in the $400-450 range (shipped) vs the super cheap eBay kits in the $250 range, just thinking that maybe the quality is better there and I'd get at least some support if I have a problem, and it'd be more likely to last longer. I like the idea of an internal controller too.

Well, I think that covers most of the details I've been kicking around for awhile in my head in advance of putting out my first post. Let me know if I've missed something important.

I'd appreciate hearing general advice on a first kit where I'm trying to stay pretty cheap but at the same time be able to get built and on the road ASAP with something that could last me at least a 1 - 2 years so I can get a feel for how useful I'll find ebiking, for commuting primarily.

Thanks.

 

[wesnewell]

Unless they've changed, the Mongoose ledge has a steel swing arm with steel dropouts. I've got over 12K miles on mine running a 1000W motor up to 4KW with a 24s lipo pack. Any of these on it will give you ~30mph top speed witha 48V battery pack.
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=48v1000w%20rear&LH_PrefLoc=1&rt=nc&LH_FS=1
http://www.walmart.com/search/?query=mongoose%20ledge

 

[ColinB]

Hi,
Sounds like you have a nice commute lined up. Your top speed seems pretty reasonable for a "normal" bike, but I'd plan on averaging a bit lower. The extra speed is nice to zip through areas instead of holding up the cars. A few points:
- do you know about lipo safety? (Storage, charging, etc?)
- Size your components with a 20% margin, so you are not running your gear at 100% of rated capacity.
- Go for a wide, flat resistant tire. At least on your motor wheel.
- Torque arms are good. I welded mine to the frame. (But now I can't put a "normal" wheel on. Oh well.)
- Cycle Analyst is a nice item too. Great info display, and can limit power consumption to be nice to your motor and batteries.
- Will your bike have high enough gearing for your intended speeds?
- Will your motor accept the freewheel/cassette from your non-powered wheel? Will you have to bend (widen) the frame to accommodate it?
- Budget for some nice cycling gear; helmet, gloves, jacket, etc. Very bright lights are needed at that speed in the dark. (500 lumins at the minimum.)

If you are not sure how you will like it, I can see starting with the Walmart bike. How handy are you? Do you know how to adjust the bike? Wheel bearings, gears, etc? But if you are going to ride it a lot, I'd start with something better. But I know that I like it, so it is an easy choice for me.

One option is a pre-built bike. Some of those BIONX equipped bikes are pretty nice, and a person in my office has tens of thousands of kms on hers. Depends on what you want. Fixing one is harder though - basically have to take it back to the shop.

Colin

 

[tgice]

Thanks for the replies guys.

It seems that the cheap ~$225 kits (w/ free shipping) on eBay are fairly popular, at least for entry level builds.

Does anyone have any recommendation for how the Magic Pie kits compare to the $225 1000W kits? I don't want to pay a ton more if they're really pretty similar, but like the idea of an internal controller and also regenerative braking (which I assume the cheap kits must not have).

Also, the bluetooth option is an interesting later add on for me.

 

[wesnewell]

This is the same kit I bought in Feb. 2011 for $279 shipped to my door. I'm still running it today with over 16K miles on it. It did not come with regen enabled, but that was a simple matter of added a jumper for it on the supplied controller. Also had to enable cruise control, 3 speed switch, reverse, and speed limiter. Pretty much all controllers these days support those features even if they aren't enabled when you get them.
http://www.ebay.com/itm/48V1000W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/231520160623
The idea of an internal controller sounds good, but they had a lot of failures from heat buildup. Personally, I wouldn't touch one living where I do. You can spend a little or a lot for a motor and in the end there won't be much difference in them except what they cost you.

 

[dogman dan]

I think a decent quality bike without rear suspension would be a better choice than the cheapest possible FS bikes. I found when I rode a genesis bike, it's frame was too small for my body. I'm 5-11, but long in the legs. This is typical for walmart mtb's since the market is 90% 14 year olds, waiting to get a drivers license.

You might look at 7 speed beach cruisers at walmart, they are adult sized. Or better still, bikes in the $300-500 price range in bike shops. Once you identify some models, then look for much cheaper deals on the used market. Specialized rockhopper, Trek 820, Electra townie, are a few of the nicer bikes to convert. 26" bikes is what to hunt for.

While on the hunt, you could use that old bike, temporarily.

Remember, as a commuter, you will be on this bike daily. A shitty fit will be a shitty ride.

After that, your motor requirements are easy enough, just about any 48v kit will get you above 25 mph. Pick a rear motor, and a 48v 10 ah lithium battery.

 

[tgice]

wesnewell, I see that you've got a 48V lipo pack on yours, have you put all 12k miles on the original pack? What are the further details on that (like where did you buy it)?

Being in Illinois, I fortunately don't have to deal with the same kind of heat I'm sure you have in Texas, so I'd have less of that concern about the internal controller overheating, but then again, I don't want to spend extra money for no (or very little) real advantage.

Could you post a decent photo of your bike? I'm interested to see where you put the controller and battery and what it looks like on that Mongoose frame.

dogman dan, thanks for your advice as well. I hear you about getting a better bike before long. Whatever I do in the donor bike dept, I may just start w/ the Huffy and just focus on what to do about which kit to select and which battery, worrying about the rest later once I settle into how I use the bike.

 

[wesnewell]

I've never run a 48V pack on mine. For 3 months I ran a 14s 51.8V pack. Then with a new controller ran a 66.6v pack for a year. And have been running an 88.8V pack for over 3 years now. On 14s it topped out ~35 mph. This is with my 10ah 24s 88.8V pack on it.
View attachment 1
Here's a photo of the battery pack I slip over the top tube. Nothing fancy but very functional.

 

[tgice]

Thanks for posting the pics! I'm not sure I'm up to putting together my own battery packs like that at this point, I might just go with a already built one at a $100 - 150 premium or so.

 

[Jonathan in Hiram]

The battery even more than the motor is the heart of an ebike at this point in development, it's the single biggest expense and the limiting factor for range and maybe even speed. Of all the parts on a "commuter bike" that's not designed for ultimate performance the motor is probably the least important, having a good frame (one that at least somewhat fits you), brakes, tires and wheels is the most important, then battery, controller and finally motor. Don't get me wrong, motor choice definitely makes a difference but less difference to your actual everyday commuting experience than the other things.

You don't have to have the absolute best of everything but starting with decent quality will take you further, more comfortably, enjoyably and safely for less money in the long run. Craigslist is a great source for used bikes of all sorts, something like a Trek 820 is a good starting point. Beyond a certain point you run into diminishing returns spending money on bike stuff, a lot of it is ridiculously overpriced weight weenieism and you don't need that on an ebike.

Starting from scratch again at the point I am now with five systems under my belt to build a commuter bike with maximum safety and reliability and minimum cost I'd hit Craigslist for a good quality mountain bike that fits and is comfortable to ride for the max time you will be on the bike (my hands go numb from pressure on most mountain bikes for instance). For street commuting ditch the standard tires and put on a smooth tread or slick tire of the same or even fatter size. Consider that on a bike there are only two tiny patches of rubber between you and a crash, you want the best rubber you can find, rubber is cheaper than skin. Then buy your battery/motor/controller combination according to the speed and distance you want.

I have an early 90's rigid Trek MTB around here with a brushed direct drive front hub running on 36V and it would come close to what you want to do, other than the battery I have less than $150 in the whole thing, paid $100 for the motor in a cheap Walmart bicycle shaped object with lead acid cells on Craigslist, the Trek came from a yard sale.