Da mini stretch combo

deacon

deacon

minor bike philosopher
Like any good combo plate you get some from column a some from column b... The bike has the motor from the gary fisher bike...the trailer from the hub motor bike...The electronics were spare parts from other builds...The bike itself is a combination of a 26" mountain bike, and spare parts from previous builds.

I have only bench tested it and rode it without power so my observations are preliminary. The brakes seem to work okay even thought I moved them around. The chain stays on now that the rusty dérailleur is gone , it is a one speed now with the chain set on the biggest sprocket in the front and the smallest one in the rear. In my last configuration, that combination gave me the best speed assist for the motor.

The bike frame is longer but not any higher than the 20" frames. It might be a little lower even. It gives me a lot more room to mount the motor. it also gives me a lot more knee clearance since the seat is much farther back. So far it seems superior to the twenty inch frame. I will give it a power test tomorrow when the weather is better.
 
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This was the first shot.. Handle bars are different and not it has the motor but it's a start
 
its the sunny (er freezing right now) south...It was like 16 degrees last night,
 
this is the test version. I think it will do okay. I have the brakes too tight but I think once I loosen them it will be fine.
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I have been under the weather for a couple of days but I did get the bike adjusted and rode it today. I think I am going to do some welding later if the weather stays nice. i am still trying to decide what I want to do about my trailers and power supplies.

The stretch bike after I loosened the motor runs pretty good. The ones with the 24v controllers have more pep than the 36v controller both run 36v. I'm toying hard with the idea of putting 48v on the stretch. Thirty six volts does everything I want with just a small amount of pedal assist on the largest of hills. That is just to keep the speed up, but I think it would be more gutsy with that extra 12v.

I also think I would be happier with a coaster brake rear wheel. I have messed with gears enough. I think I like the security of that extra brake more than any imagined use of the gears, I probably will redo the big bike before long.
 
I managed to find the strength to switch the big trailer to the new bigger bike. I plan to convert it to 48v today and test ride it.I am looking forward to having a more powerful bike just to see what it will do.I have decided to weld the nut onto the trailer bolt as well as put a chain on as safety features. I can use my cutoff grinder to remove the bolt just about as easy as unscrewing one with lock tight on it.

I should get to ride it today sometime.
 
I reconfigured the bike today. I now have a 24v motor, a 36v controller, and a 48v battery supply. It runs really nice. I could take the chain and pedals off, If I had a much larger power supply. I think the bike is running at about 1200 watts configured like this. I rode it two miles and ran the old set of 12ah batteries, I cobbled together, flat after a 1 3/4 miles. Of course the motor didn't stop it just no longer had the same guts. I could still get it home just fine, though I did have to pedal a bit.

I think I might go with eight 12ah batteries in parrallel and series to make 48v 24ah. First of course I am going to rebuild my 36v bikes with better trailers. They sing along just fine with the smaller power supply and I have one of those already.

Something else I have to take into consideration is what I call the rest effect of the batteries. If I ride them a mile and stop for an hour then ride them another mile they seem to do much better than to ride them two miles straight. scientific explaination: HowStuffWorks "Why do batteries come back to life if you let them rest?"
 
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I might have to rename this caravan. It has to be as long as some of the new cars.
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This should be the configuration for a while at least.
 
The boiler problem got taken care of early, and since they want to mail a bill, probably so the repairman doesn't get any BS, I went riding this afternoon. I really just wanted to try a mileage test. Ride it easy and see how the batteries held up. I took it two miles nice and slow, which I can't really do with the 36v configuration. The bike feels like it wants to stall out but with the 48 I could crawl even uphill. It seems to be a nice powerful combo.

With this combo, I came home with 51.4 volts still in the pack. I know it's amps I should worry about but I don't have an amp meter. Since it was non stop, I should get anywhere I need to go without any problem. It is only a 12ah pack at that.
 
Nothing is ever perfect, darn it. It is forty eight degrees and he bike has had a day of tweaking and ready for a test ride. I am also ready for a walk in the great outdoors on the bike trail for a change. but it rained all night last night again and the roads are soaked. I can ride on a damp road, it's those roads with standing water that make the motor on my bike useless. I tried to ride out this morning but got about half a block when I realized it was counter productive.

Since the idea of the bikes was to let me get some independence, the exact timing of the ride isn't important. I can easily wait an hour to ride. It is just that I want to go now, now darn it. Some days I wouldn't mind having that chain drive bike after all. I swore I would not build another bike and I mean it, but then there are all those bike parts up for grab from the dealer I have been buy scooter parts from.

A rear wheel and motor for under fifty bucks and I have everything else. But no I will carry on now that the road is dryer. Just a momentary thought.
 
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It turned into a beautiful day. I even got a lot done. I waited an hour for the road to dry a bit then I rode to the mall. When I got there the drive was hanging by a thread. It was still bolted to the bike but had slipped off to the side somehow. I spent the rest of the day redoing the bike to make the trailer hitch and the motor drive system independent of the rear axle. You can weld a axle in place but I can now weld the drive supports. I like to think of this as continuing education. I am learning the best way to build this drive system. Hopefully one day I will be able to write a how to pamphlet and let all the old guys build there own green ebike.

Anyway I tested the new configuration and it works fine. Actually I tossed some of the newer ideas in favor of ones I have used before. For one thing I went back to a coaster wheel. It works much better than the mountain bike wheel and is easier to find as well.

So you can either build one of these bikes on a kids coaster bike or but a kids coaster bike and an old mountain bike at the thrift store and combine them. Either way you get an easy to build fairly easy to maintain DIY ebike.
 
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