Input requested on newbie build with Trek 820

First of all, I'm so glad I found this site instead of just buying some crappy kit on eBay! I've been reading the FAQ links, doing searches, and reading lots of threads. It really has me excited about converting my bike. I have some general direction, but I could use some more guidance.

My bike:
I have a stock 2007 Trek 820 that I like a lot for general riding. Nothing fancy, but it fits me well and I'm comfortable with it. From reading on here, it sounds like it's actually a good candidate for conversion since it's a steel frame and all. One drawback is that the shifters and brakes are all one unit, so it would not be simple to swap to e-brakes. I don't know if this is a big deal or not.

My route/goals:
I'd like to use this bike for commuting to work. My route is 17 miles one way, so it's a bit lengthy, but I can charge at work no problem. I live in Denver, and most of my route follows the S. Platte River, so I have nice wide, flat bike paths for 90% of it. There is only one steep hill at one end by my office, but I can truck up it at low speed with minimal power assist. It's only about 200' long. From the river trail to my house I have to ride up a long, steady incline of less than 5% for about 3 miles.

I'd like to be able to go 20-25 mph continuously so that I can make the trip in under 1 hour. I'd also like to pedal along with the motor for exercise. I'd like to keep the weight of the bike down because I will sometimes take it on the light rail, and I don't want to have to lift a 100 lb bike onto the train. I want to save on gas $$/light rail fare and get some exercise.

My build ideas:
I really like the idea of the MAC motors from Cell_man rather than a DD motor due to the weight savings. I'm not sure if the 6T or 8T would be better for my application.

LiPo batteries sound like they need more babysitting than I want to provide, so I'm thinking Ping batteries or similar. I don't want to spend too much, but I don't want to be disappointed and have to buy a bigger battery later. Should I go 36V or 48V? Would 15ah be enough to go 17 miles on relatively flat terrain while pedaling? The 820 has a nice triangle to put the battery in to offset the weight of the motor in back. I don't want to overdo the battery and make it heavier than needed because I'll probably lug the bike on the train sometimes too.

About me:
I'm 35, 6' tall, 210 pounds, in okay shape. Right now I use the light rail to get to work most of the time. It's about 4 miles from my house to the station, then a 30 minute train ride, then a 1-3 mile ride to work (depending on which station I get off at). I usually drive from home to the station and then ride a bike from the other end to the office. I've had a membership in the Bcycle bike sharing program for the last two years, and that works great but the bikes are heavy and slow.

For one summer I tried riding my Trek from home and locking it up at the light rail station. This was a piece of cake in the morning since the ride was all downhill, and it only took like 5 minutes longer than driving. Getting home was another story. It was much hotter by then and I had to slog uphill the whole way. It took me about 30 minutes to do the ride, or longer if I had a headwind too, ugh. I would get home at least 20 minutes later than if I drove. Not a big difference, but that's 20 minutes less each night that I have to see my kids before they go to bed.

Last year I decided that an e-bike might be just the thing to speed up my commute. Before I spent a lot of money to convert my bike, I decided to get my feet wet with a starter bike. I found a nearly new Currie eZip Trailz bike on craigslist for a little over $200. I did a test ride from my house to the station and back, and I made it downhill in 17 minutes and uphill in 19 minutes - much better than 30+ minutes on my Trek and I didn't break a sweat! The other day I decided to cut out the Bcycle and try taking the eZip with me on the train and then riding it the rest of the way to work. Screw that! This thing weighs like 100 lbs with the SLA on it, and it was a beast to maneuver up the steps onto the train. At the end of the day I decided to ride the whole way home instead of dragging the bike on the train again. I really liked the ride along the river, but that bike is s-l-o-w. It took me an hour and a half to get home, and the battery was on its last legs. I was getting passed by lycras the whole time. With a faster bike, that would be a really enjoyable ride and I could make the trip door-to-door in about the same time as my car-train-bike combo right now.

Thanks for any input and for reading that whole thing if you made it this far!

48v 15 ah pingbattrery will take you about 22 miles, at 25 mph. 36v will be a bit slow, so a faster 48v might be best for a longer ride. So that's the size for you. 48v 20 ah is too big and hard to carry.

8t Mac will work, but a muxus dd motor from Emissions free, or any similar dd motor kit will also do fine. The mac is not that much lighter than a dd motor, but it is a smaller diameter. Some really prefer the quicker take off of a Mac, others like the reliablitly of the simpler dd motor. Rear motor best, but you could use a front motor if you have the steel bottoms suspension forks.

Carry the battery in the frame triangle, FOR SURE. The bike will be ridable if you put it on the rack, but just barely. It will handle sweet if you put it in the frame.

You'll love your ebike,

If you REALLY pedal along (as opposed to fake pedaling), a 36V 15Ah battery is more than sufficient to cover 17 miles at your desired speed. But every single newbie wants more speed and longer range after the first week. So a 48V 15Ah battery is probably a better choice, financially speaking.

As for e-brake, I have to have at least one. For me it's not an option, it's a necessity (safety). Good luck and have fun with your first build. The Trek 820 is a good choice in my view.

Really, for you I would recommend a "crappy Ebay kit " :lol:

Wesnewell, another guru and avocate of DD motors[as Dogman is], really likes these kits,

http://www.ebay.com/itm/48V-1000W-26-Rear-Electric-Bicycle-Engine-Kit-Bike-Hub-Conversion-Scooter-Motor-/290694031625

They really are a lot of "kit" for the money.

To me, except for the lifting part, your ride goals say direct drive. Yes, they are heavier than a geared, but you want some upper body work-out, right?

Balance is as important as overall weight, so think about a frame bag for the battery[Falcon EV].

Speaking of weight, while the Ping is a great commuter battery, it's a serious chunk. Some here are trying out LiMgCo[Li-on] battery packs from BMS Battery for a considerable weight savings. They look promising, but the jury is still out on longetivity.

36v 15 ah would be too small on that wonderful day that you have to ride 17 miles into 25 mph wind. However, if your had said you wanted to crawl along down that trail at 15-20 mph, that would be a good size to get.

I listened to the part where you said you wanted to ride faster, so i recomended a 48v battery of the correct size. I'm the guy that did do a daily 15 mile one way commute for about 4 years. Plenty of days my 48v 15 ah pack shut off just a few blocks from home. Enough wind will screw you. You need 48v 15 ah, or similar watthours in any case. Enough size to make it with only about 80% discharged on the nice days, which makes your battery last much longer than draining it 95-100% twice a day. You should get 3-4 years from a properly sized ping.

The 48v 15 ah pingbattery fits into the frame triangle of a Trek 820, so size is a moot point. Weight is a tolerable 15 pounds. What you do want, really want, is Li Ping's exemplary customer service. None of that ship the battery back to china and we'll help you out crap from Ping.

But you do have the option of hopping the train when it's nasty. I have a similar option, a bus ride. But the bus ride took one full hour longer than riding the bike, so I just took the bike home in all weather. I'd slow down to 20 mph for part of the ride if facing that much headwind, and still beat the bus by 45 min. Most of the problem with the bus was it came by only once an hour. So you always add a 30 min wait or longer for a bus in my town.

If you do want to shave a buck, and get an ebay kit, then that link is the guy to buy from. Any problem, and you ship it back to California, vs dealing with CS from china. But nothing wrong with the quality of those kits from that vendor. Any good kit will do, and that vendor is gaining a decent reputation. If you want the ultimate customer service, you go to Grin Cyclery.

If you have integrated brakes and want to keep them, it;s no problem to make brake switches. That's all they are: switches that switch on when you brake. There's several solutions depending on how much work you want to do. Here's two simple methods:

Method 1: tape a reed switch to your frame cross-tube; fix a speedo/cyclecomputer magnet to the bare inner cable along the cross tube. When you brake, the magnet moves over the reed switch and switches it. You have to experiment a bit with the position of the magnet to get it to switch at the right point. This method is not so easy for the front brake because you need to make a bracket to hold the reed switch.


Method 2: Buy two of these light/horn/indicator things; cut off the little switches that clamps on a cable. They operate the brake light that you don't need, so cut off the connector from your kit's e-brakes and join the wires. Fix it to your cable and that's it. If you hunt round on Ebay, you can find them a bit cheaper than this
http://www.ebay.co.uk/itm/3-1-Bicycle-Bike-Turn-Signal-Brake-7-LED-Light-Horn-/150672362164?pt=UK_SportsLeisure_Cycling_Bike_Lights&hash=item2314c5cab4

I went with a 36/20 ping for my grin kit and in retrospect, I would
most defiantly have gone with the 48/15. That 3 or so extra mph would
be welcome keeping up with town traffic, shorter commute time, etc.

Wow, lots of great feedback and info to chew on here, thanks!

1. Everybody pretty much confirmed my thought that I want a 48V 15ah battery from Ping for my application. I think that and a Falcon EV bag are pretty much settled.

2. Motomech, that eBay kit actually looks pretty good - especially the price! For $100 less I could probably handle the extra 6 lbs from the DD motor instead of the geared motor. I'm not really concerned about stealth. I see that this kit comes with a 6 gear freewheel though as opposed to the 7 gears I have now. Will my stock derailleur be compatible? Will I be able to pedal at 20 mph or higher, or would I have to change the crank gears to keep up? I don't have much experience with bike gearing and maintenance. I've worked on cars a lot, but not so much with bikes.

3. d8veh, the brake switch options look interesting. I'll look into that and consider whether to do switches or change to separate shifters/brakes. If I get the eBay kit and use those brakes, how much do you think it would cost to get some separate shifters? My Trek has Shimano gear and is a 21 speed.

1. 15ah for sure, but I'm a lipo fan. You could get 20ah of 12s lipo in the triangle easy. Bulk charge at work, Balance charge at home when needed. 15ah of 15s would also work well for more power and speed with close to the same wh as 20ah of 12s.

2. You likely won't use but 1 gear anyway. That's all I use 99.9% of the time. Shouldn't be a problem using your derailleur. I've never had a problem with several different bikes. I've got 42T chain ring and 14T rear gear and it's hard for me to keep up at 20mph, but I'm 65 and in lousy shape. It was easier with 48T/14T gearing, but I really don't even try to pedal over about 18mph either way. This old body just isn't what it used to be. If you have at least a 48T front gear, you should be able to assist to a little over 20mph.

3. New shifter set can be had for $15.

Do I really need the motor cutoff on both brake levers? I never brake with just the front, so it seems like I could leave the combo shifter/brake alone on the left, put the e-brake lever on the right and just buy 1 new shifter.

I wonder if the eBay kit would work with a different freewheel, like this 7 speed:
http://www.methtek.com/2011/11/12/7-speed-11-32-freewheel-21/
With the 11 tooth gear I should be able to pedal faster and get more range/exercise.

anarce said:

Wow, lots of great feedback and info to chew on here, thanks!

1. Everybody pretty much confirmed my thought that I want a 48V 15ah battery from Ping for my application. I think that and a Falcon EV bag are pretty much settled.

2. Motomech, that eBay kit actually looks pretty good - especially the price! For $100 less I could probably handle the extra 6 lbs from the DD motor instead of the geared motor. I'm not really concerned about stealth. I see that this kit comes with a 6 gear freewheel though as opposed to the 7 gears I have now. Will my stock derailleur be compatible? Will I be able to pedal at 20 mph or higher, or would I have to change the crank gears to keep up? I don't have much experience with bike gearing and maintenance. I've worked on cars a lot, but not so much with bikes.

3. d8veh, the brake switch options look interesting. I'll look into that and consider whether to do switches or change to separate shifters/brakes. If I get the eBay kit and use those brakes, how much do you think it would cost to get some separate shifters? My Trek has Shimano gear and is a 21 speed.

Click to expand...

Pedaling @ 30 mph would be a challenge. You wouldn't use the kit 6-speed, but would need a DNP 11T 7-speed from Cycle 9 or one of the Ebike stores.
11/44 is good to around 25 mph and going to a 48 chain ring[if you have enough clearance from the chain stay]will add a couple of MPH.
But according to Dogman, one can't add much at 30 mph[I've never been there ], even with the necessary gearing.
The good thing is, the DNP will match your derailleur and shifter.

anarce said:

Do I really need the motor cutoff on both brake levers? I never brake with just the front, so it seems like I could leave the combo shifter/brake alone on the left, put the e-brake lever on the right and just buy 1 new shifter.

Click to expand...

Frankly, at these relatively low power levels and speeds I saw no need for them at all. You will be carrying
plenty of juice in your ping so regen. isn't a factor and at sub 30 mph speeds, a good set of regular bike brakes
will stop you just fine. I didn't hook mine up when I got the kit and 2000 miles later I still don't feel a need to go
and install them.

d8veh said:

If you have integrated brakes and want to keep them, it;s no problem to make brake switches. That's all they are: switches that switch on when you brake. There's several solutions depending on how much work you want to do. Here's two simple methods:

Method 1: tape a reed switch to your frame cross-tube; fix a speedo/cyclecomputer magnet to the bare inner cable along the cross tube. When you brake, the magnet moves over the reed switch and switches it. You have to experiment a bit with the position of the magnet to get it to switch at the right point. This method is not so easy for the front brake because you need to make a bracket to hold the reed switch.

Method 2: Buy two of these light/horn/indicator things; cut off the little switches that clamps on a cable. They operate the brake light that you don't need, so cut off the connector from your kit's e-brakes and join the wires. Fix it to your cable and that's it. If you hunt round on Ebay, you can find them a bit cheaper than this
http://www.ebay.co.uk/itm/3-1-Bicycle-Bike-Turn-Signal-Brake-7-LED-Light-Horn-/150672362164?pt=UK_SportsLeisure_Cycling_Bike_Lights&hash=item2314c5cab4

Click to expand...

that looks pretty good but to add to them there are couple more options, checkthis out
they are very sensitive and so far mine hasnt failed me at all!

I don't mean any disrespect here, however the paths you're referring to, from Chatfield all the way downtown are multi-use, including runners, and AFAIK, all are posted 15mph. I've been using them constantly and see injuries, many from excessive speed. I remember one, a nice person with half her face ripped off. All she could say was "it all happened so fast..." Good thing she was just a block from DGH where I'm sure they stitched her up for all her $$$$$$$.

HAROX said:

I don't mean any disrespect here, however the paths you're referring to, from Chatfield all the way downtown are multi-use, including runners, and AFAIK, all are posted 15mph. I've been using them constantly and see injuries, many from excessive speed. I remember one, a nice person with half her face ripped off. All she could say was "it all happened so fast..." Good thing she was just a block from DGH where I'm sure they stitched her up for all her $$$$$$$.

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if the road really is 15mph speed limit then going 25 is not a good idea. However, if the cars are going at 25mph then going slower will increase the chance of accident since more cars will by pass you. (personally being able to go fast is a good thing, but speeding around the town/city while cars aren’t going fast can be dangerous

And here's a double ++. Denver has sharrows almost everywhere. The bike map I got in 2005, 300 miles of shared or other great paths, mapped out, so this town is almost a natural for a wheelman.

Nice. But do be a gentelman, and obey a speed limit if the paths have one. Don't be the guy that turns Denver into Fr Collins. You'll find lots of back routes on streets you prefer anyway I bet, where you can cruise at 25 mph through residential areas.

Empty bike path is a joy, but the oblivious walkers four abreast are no joy if it's crowded.

Ebrakes are not needed. Chances are you are smart enough to let go of the throttle when braking. Wiring the ebrake circuit to a convenient located kill switch can be smart though. I just make the battery main power plug easy to quick disconnect myself.

dogman said:

Ebrakes are not needed. Chances are you are smart enough to let go of the throttle when braking.

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Another irresponsible advice. Ever heard of cruise control? How do you let go of something you're NOT holding?

Brushed controllers are notorius for failing in wot mode. that's another case where you'd want cutoffs on the brakes, or a easily reached kill switch.

Let me make this moronicly clear.... yes you do need some kind of way to kill the bike... Yes you really do, but it does not HAVE to be in the form of brake cutoffs.

Sorry if poor choice of words made it sound like nothing that kills the bike is needed. I mentioned two alternatives to ebrakes, but wasn't very emphatic that a way to kill the bike is mandatory. It seemed fairly obvious. Throttles can stick, or short into wot, so do have a way to kill the bike.

My method is just pretty simple, easily reached and unplugged battery wire. One swipe with a hand at my seatpost and it's not just off, but disconnected from power.

dogman said:

Let me make this moronicly clear.... yes you do need some kind of way to kill the bike... Yes you really do, but it does not HAVE to be in the form of brake cutoffs.

Sorry if poor choice of words made it sound like nothing that kills the bike is needed. I mentioned two alternatives to ebrakes, but wasn't very emphatic that a way to kill the bike is mandatory. It seemed fairly obvious. Throttles can stick, or short into wot, so do have a way to kill the bike.

My method is just pretty simple, easily reached and unplugged battery wire. One swipe with a hand at my seatpost and it's not just off, but disconnected from power.

Click to expand...

Moronic, yes.

Real life scenario: You are cruising along at 18 to 20mph, you are ON CRUISE CONTROL. A child steps into your path. You have a fraction of a second to react. What does a normal person do? May be a moron would first reach for the kill switch and then the brakes. But the rest of us simply grab the brakes. The rest of us would most likely avoid hurting the child. The "smart" moron would most likely hurts the child because he spent the invaluable fraction of a second to reach the kill switch before he braked, very smart!

About riding the TRAIN. "NO motorized bicycles allowed." Reason, well, start with LIPO and proceed to errant switching, etc. They don't allow any such conveyances b/c, they're dangerous on a train.
In 2007, I wrote for a variance to the powers that be, and they gave me one to use my Ebike. That works fine if your rig has a removable battery.
Still, with all the inconveniences of a bicycle, 8-15 mph adds up to saving money and time. If you look at the freeway at rush hour you'll see the whole vision of an efficient bustling America going right down the tubes. Progress has fallen in on itself, anytime the whole traffic mass is below 8mph.

moronic would be riding in cruise controll where a child, or a dumptruck is very likely to pop into your path.

But I will grant you, that ebrakes would be a good idea for a bike with cruise.

Cruise is another feature I've got no interest in on my bikes. Hammer swinging carpenters paws I have don't exactly get tired holding a tool. I suppose a child could pop into my path at the exact instant that my throttle that doesn't have pack voltage in it shorts. If it's raining, in a place it never rains. I'll take those odds.

Reading back, the original poster never asked about or even mentioned ebrakes anyway. Another thread highjacked.

dogman said:

Reading back, the original poster never asked about or even mentioned ebrakes anyway. Another thread highjacked.

Click to expand...

anarce said:

My bike:
I have a stock 2007 Trek 820 that I like a lot for general riding. Nothing fancy, but it fits me well and I'm comfortable with it. From reading on here, it sounds like it's actually a good candidate for conversion since it's a steel frame and all. One drawback is that the shifters and brakes are all one unit, so it would not be simple to swap to e-brakes. I don't know if this is a big deal or not.

Click to expand...

This thread, not jacked. (Dealing w/ all criteria. Let me be the one to lay the point. Your city is where you could USE an Ebike, and right now the vote is split whether they're safe- anywhere! You have to almost dismount to "ride" in NYC, so safety criteria is up 4 grabs. Back on track..shifter...N.P., already solved. Buy a shifter set only, and might as well get something that will DOITNO matter what. Same time buy an extra set of cheap grips to slide on the bar ahead of all your controls, to have a center on human power. There's time's the battery won't, when you have to, or you're flat, or chain broke, or whatever. Your best asset is your seat, your grip and the transmission. On that, the whole world turns. Everything else is gravy. Learn how to enjoy that 3% climb around Highlands, without power. Then you'll know what you got when you get it.
As for power management, I want the new CAV3, but that's a different thread.

Ok you win. I missed that on the re read.