trekker pete

I am an infrequent bike commuter. 12 hour work days mixed with a 12+ mile (one way) somewhat hilly commute is just a little more than I want to do very often. I have been lurking here in the e-bike forum on and off for a few years and was thinking that a little e assist would likely get me on the bike a lot more often.

My commuter, a trek 1200 is out of the question. It is a nice road bike and I would just as soon keep it that way. Also, the ride of that aluminum frame sucks. The idea here is to get comfy and sweat a bit less.

The other candidates are an old Nishiki sport with straight bars. A 5 dollar tag sale find. Awesome old bike with a fairly large frame that rides like an old caddy. I think this would make a great ebike. Next candidate is a Giant ATX 970. Old school full suspension mtb. Cromoly frame and pretty sturdy suspension should hold up nicely to the bumps and extra weight. I bought this recently as I am getting into mtbing, but, am starting to think that for my style of riding, a newer hardtail is probably the way to go.

Any suggestions appreciated.

Pete

chas58

Really need to figure out your requirements before picking a bike.

Do you know what motor you will put on, how much power you want? What size battery do you need? Going RWD?

You can between 10 lbs to 30lbs or more for a conversion. A light weight slow build is easier than making a fast electric motorcycle.

In general a 90’s era steel bike is good – inexpensive, strong, and durable. The giant sounds good – the only problem with the full suspension bikes (assuming everything is working) is that the suspension limits your mounting options for batteries in the frame. Frame bags are a popular route to get the weight centered and low.

As for the Nishiki, I think the general minimum tire size for an ebike should be about 35mm, although for most people 50mm or bigger is the popular choice.

Personally with tires over 2.0”, I don’t think a frame can be too stiff. Most people just put way too much air in the tires. Even with an ultra stiff frame, the tires should be absorbing a lot of the harshness. With the Pro mountain bike races I go to, they are racing on bikes with no suspension and soft 29” wheels.

Try putting together the Giant, getting a feel for what you want/need, and then go from there.

trekker pete

Thanks for the response. I have pertty much the same thoughts as you.

I think the Nishiki would work well, assuming I can get big enough tires for it. It currently has old 27" rims with thin, I think 1 1/4, tires. It has Dia Compe side pulls. Getting a fat tire past them could be tough. Another possibility is an old trek 520 with canti brakes. I am hesitant as this is a great bike as it sits and the frame is a bit small. I am trying to get the wife interested in biking and have her use this. The cantis will allow for huge tires though. A longer seat post and a set of flat bars would probably make this more comfy for me.

I have the same concerns with the Giant. But, being an older FS, all the suspension stuff inside the diamond is up high, so there should be ample room down low, just above the BB.

As for power, nothing to crazy, probably 300-500 watts, tops. I still plan on providing a good bit of the wattage, just looking to make those 12 miles a little shorter. As to FD or RWD, I don't know. Does handling get sketchy with fwd at speed?

trekker pete

A question about mid drives, which I am leaning towards, given their hill climbing ability. Is it possibly to use one of the front rings of a triple as the e drive sprocket? I was thinking that using the big one would be best as I would only lose a little high speed down hill propulsion. Also, it allows for more torque that using the little ring. Seems like this would save a fair bit of expense, work and a bit of weight.

I would like to hear from anyone that has tried this.

chas58

Try reading this article (part 1 and part 2)

https://www.electricbike.com/diy-mid-drive/

and:
https://www.electricbike.com/2013-mid-drives/

chas58

Pete,

How are you going to mount the battery in the frame down low? Most people use frame bags to go inside the frame. You could use a “bottle battery” but every one of those I have seen is 1C or less, meaning that a 36v10ah battery struggles to put out 10 amps of power. 10 amps isn’t nearly enough (and is going to give you a very short battery life).
On my E road bike I have 32mm tires (gatorskin) on the motor. It’s pretty snug with calipers – I have to back off all of the adjustments to get the wheel off. It’s happy at 80-90 PSI, so that is better than running a 120psi 23mm tire.

My dilemma was what bike to build – 26” wheel or 700c/29” wheel. So I built both. The second motor was only $79 with no shipping cost (that is huge), and I had that built into a wheel locally. The motor and the throttle/PAS are the only things that need to be mounted to the bike so building a second ebike (sharing the battery) wasn’t very expensive.

Check out my bike builds for some more ideas and thoughts (a mountain bike and a road bike):

https://www.bikeforums.net/showthread...highlight=q100