Me need losts of low end torque. Do you have any?

TerraPilot

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I hope I'm in the right place. I've just joined and I'll be putting a Robin 4 stroke from Golden Eagle on my bike soon. I just hope its not a big mistake to put a motor on my bike. I've just gotten back into biking I'm noticing I don't feel comfortable riding much above 15 miles per hour but I really want some help on the hills. My average speed seems to be around 7 to 10 miles per hour and at 250 lbs and a 41 lb bike, I just don't know if engines have any real power at those slow 10 miles per hour speeds. Am I in the right place for answers here?
That Robin 4 stroke is the closest I've seen to produce some slow speed torque.

Regards from
Bob Canada here in Memphis Tennessee.

Ps My bike is a new "Cruzbike" conversion version.
 

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I don't have a GEBE, but I think you will be impressed with torque performance at around 15mph and up. Below that there is still some torque, but that speed is where the motor rpms kick in with a lot of torque.
 
G'day Bob & welcome.
Personally i think u would be better with a larger capacity engine(around 50cc's)
 
low-end torque and small motor does not normally go together. I use a shift kit to get it up in the power band at slow speeds as well. I do not know much about GEBE, looks like a nice setup.
 
You are indeed in the right place for answers here and that is one fascinating recumbent you've got there. Front wheel drive, eh?

I too am new to this forum, however the help I've received here has been huge and quick. My wife and I also are older -- both 66 -- however, we are dedicated long distance self-contained bicycle tourists and have, for the last 15 years, ridden all over the world, including twice across America. Our most recent ride was San Diego to Jacksonville, Florida, last summer. We've also ridden across Australia, across Europe twice, and from Singapore to Yunnan Province, China, then to Tibet and Katmandu.

Even though I am a strong rider, my age is mitigating that strength and I find I now need help up the hills, at times, too. I also have a heart condition and had angioplasty about 10 years ago, hence the exercise pedaling affords is important. Most of the good folk on this site are more interested in developing motorbikes that go fast and hard. I am not and I suspect you are in that same frame of mind.

Happy Valley helped me immensely when he sent me a link to a 1999 posting by an engineer named Hugh Currin, who wrote: The idea of power assist for a bicycle is to add a motor while retaining the functionality of the bicycle. A power assist is for use on steep hills where it is most needed and turned off where pedal power alone is adequate. It differs from traditional mopeds which are small motorcycles and can't be reasonably pedaled without the motor.

Currin and his wife tour with two extremely heavily packed short wheel base (SWB) recumbents and according to his report, a 22cc Honda with a direct drive he engineered himself does the job to help him up some of those long climbs -- by two thirds, he said. In his case, that is reducing a three-hour climb to a mere one hour.

I have found the same to be true only I have a 35cc Robbins . . . the same as you are considering . . . and have found it to be extremely satisfactory and able to haul extremely heavy loads up very steep hills. I wanted the smaller 25 cc engine, but was talked into the larger one, even though it weighs a pound more. My rig was built by Stanton and I bought it from the factory on a cross-county auto trip this summer. I was able to install it at the RV park we were staying at. So far I have not had any trouble with undue tire wear, but then I don't use the engine that much, either . . . only when I need help or get over tired or get pressed for time.

My touring bike weighs about 38 pounds with fenders and racks, etc., then the loaded panniers add 50 - 65 additional pounds. I weigh 170 for a total weight of 270 pounds or so. On occasion I have a small dog in a trailer and she and the rig add another 35 pounds. I would say you will be quite happy with the motor you're planning on. You will have to replace the rear wheel with a stronger one that GEBE recommends. Both propulsion systems have their benefits and detractions.

As for your question about torque, Stanton offers several friction drive rollers. I bought the smallest diameter so that I might have the greatest amount of power with which to climb. Even then, it will propel me at nearly 25 mph on a flat -- again, fully loaded. If I can pedal only 3 or 4 mph up a hill (loaded), then with the motor, I can go 10 to 15. I can assist by pedaling or just let the motor do all the work. Pedaling picks up a few miles per hour.

I hope this helps you some and repays some of the fine help I've received here. Here is a link to the Currin site that Happy Valley gave me:

http://www.currin.us/bikes/assist/assist.shtml

And here are links to our China and trans-America rides, if you are interested:

http://www.crazyguyonabike.com/doc/wayneandkristina

http://www.crazyguyonabike.com/doc/racinglizards
 
I want to thank everyone for the response. I think backazimuth described my plight quite well. To coin a phrase I'm looking for "judicious dispensation of energy at a moderate speed while maintaining a level of petal quality with the engine off.

Regards
So far its the Robbin 33cc or the Tanaka 32 cc from GEBE.
 
I think your biggest issue will be freewheeling capability rather than torque. For that you should look at a friction kit or chain kit with a freewheel sprocket on the wheel.

Also get a lower geared bike if you want help up hills. Generally kits are sold to give you max speed on flat land, but you can get different gearing.
 
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