Thinking about going all belt ..

Discussion in 'Hubs, Gearboxes, Sprockets and Chains' started by Jcs1989, Aug 14, 2016.

  1. Jcs1989

    Jcs1989 New Member

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    Thinking about changing out my chain sprockets. To an all belt bike. Anyone tried this ? I'm thinking the belt drive would be more reliable. . .
     
  2. curtisfox

    curtisfox Well-Known Member

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    #2 curtisfox, Aug 14, 2016
    Last edited: Aug 14, 2016
  3. Jcs1989

    Jcs1989 New Member

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    Interesting. I figured it would work. I'm thinking it will be much quieter than the noisy chain drive. Not to mention if a belt pops loose I'm sure the damage will be far less than if the chain pops loose. I'm not sure which pulley sizes to go with. I'm thinking an 8" for the rear an 2-3 inch up front with a belt tensioner will do the trick. Anyway got the idea from Harley sportster set ups. My bike already has the 4stroke huasheng engine and Xhd gear reduction. Only question is what gears will run about the same as the chain gearing I have ? . . Bike runs fast enough.
     
  4. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    I used all belts with extra low gearing (high ratio 20:1) on a 26 inch rear wheel drive.

    Problem is that smaller 2 inch V-belt will have trouble with a lot of torque applied and would slip. I removed belt and used chain on one of the three pulley pairs and went with gear and chain. Smaller gears like a 9 tooth I have are compact but unlike small pulleys will not slip. Cogged V-belts the AX type allow to go around smaller pulleys, but I've had problem with 2 inch diameter pulley and would not go smaller than 2.5 to 3 inch. Note the clogged belt is not a toothed synchronous belt. It just bends tighter radius without as much friction and heat.

    Major reason I used belt was I started out with a home made sheave out of a washing machine pulley. Problem is now unlike 25 years ago washing machine pulleys are made of aluminum alloy much weaker than pressed stamped steel of the past. I bought a Whizzer Clone Sheave when my home made shave broke.

    Other is when wet a belt slips more easy chain does not.

    If you want quiet and go with belt and can find affordable in a synchronous belt and pulley set up, that I would think best, if not chain in my opinion.

    Gearing down is just each pair of connections (gear or pulley). So I have in the past used a belt clutch with for example 2.5 inch diameter on engine crankshaft. Then to 10 inch diameter pulley on jack-shaft. 10 / 2.5 = 4 That is a ratio 4:1

    Jack-shaft with 3 inch diameter pulley and rear wheel sheave pulley diameter of 15 inch.
    15 / 3 = 5 That is ratio of 5:1

    Multiplying all ratios (in this case just two) 4 * 5 = 20 That is overall ratio 20:1

    Remember 20:1 ratio in my set up connects to a 26 inch wheel. A smaller wheel would go slower and have more torque. Theoretically using speed calculator given rpm ratio and wheel diameter (with tire height added for accuracy), I would have 13.5 mph at 3500 rpm engine speed maxed out. This is good for trail riding with my 3hp 4 stroke Briggs engine.

    Depending on your engine rpm and torque (horsepower) it has and what speed range you want you can adjust the ratio.

    There is a thread on this site: http://motorbicycling.com/showthread.php?t=4820

    It has Motorized Bicycle Gear Calculator information and links. Some don't work and some need to down load so beware. I have my virus and internet protection software stop some sites when trying to access them.

    My hand drawn out method on my thread shows all the math and gets the same results of the calculators out there.

    Page 4 post #39

    http://motorbicycling.com/showthread.php?t=29678&page=4

    MT

    http://motorbicycling.com/showthread.php?t=54926 Trail Riding
     
    #4 MEASURE TWICE, Aug 14, 2016
    Last edited: Aug 14, 2016
  5. curtisfox

    curtisfox Well-Known Member

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    8" not quite big enough 15" is Whizzer then to about 2.5 , 6" next to it then 2" on engine, check out msrfan another briggs build..........Curt
     
  6. Jcs1989

    Jcs1989 New Member

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    Well I'd done my research using simple ratios. The 10/44 chain an gear ratio on my MB is 4.40 gearing. So to get about the same with a pulley set up I figured if I went with a 2.5 on the jackshaft an 11" on the wheel I'd get the same 4.40 gearing. And I'll have a strong spring tensioner to keep pressure on the belt. I've found a few pulleys. But not sure which I'm gona use. Next weekend im gona take a trip to the local salvage yard. They have a old lawnmower graveyard which I can sift thru. Maybe I can find the pulleys I need. I've got 27.5 " wheels which is much faster then my 26". The Schwinn is also a little heavier. Which makes climbing hills a little harder. But surprisingly still does. I've finally got the chain to stay on the bike but I'd still like try out the belts. I'd rather hear my engine rev vs the loud chain. Here's the bike tho jus built this weekend. Schwinn swindler 275 Huasheng 4stroke kit from gas bike.net has the xhd change drive trans. . Had the kit on one other bike. Over all kit has about 120-40 miles on it.
     

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  7. curtisfox

    curtisfox Well-Known Member

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    I see now you have a trans on there already, it also has a reduction. But you might run into belt slipping with the smaller wheel pulley, time will tell. .....Curt
     
  8. MEASURE TWICE

    MEASURE TWICE Well-Known Member

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    From the outside cover it looks like the engine trans has probably 2:1. Then the combination of ratio as is now is the 4.4:1 * 2:1 = 8.8:1 ratio.

    If you are going to put a pulley on the rear wheel it is difficult as I tried. Don't as I did by mistake use weak aluminum, best to use steel. So anyway already made up are the Whizzer and Whizzer Clone Sheaves and yes they are 15 inch diameter. But check all items first to be sure before buying anything.

    If you are leaving the trans at the 2:1 which it probably is, then to get the same 8.8:1 ratio, the pulley belt section needs to be 8.8 / 2 = 4.4

    The 15 inch sheave pulley of a Whizzer type would the need to be matched with a pulley to get 4.4:1

    15 / 4.4 = 3.41 Maybe use some thing close to a 3 inch pulley and a 15 inch Whizzer type pulley.

    15 / 3 = 5 (3 inch pulley has more surface contact area less likely to slip)

    5 * 2 = 10 A ratio of 10:1

    10:1 is close to 8.8:1

    If you increase the gearimng down to a ratio of 10:1 will have slightly more torque for up hill, but less top speed. Theoretical 27.1 mph from the calculator with 10:1.

    Since I saw roughly a 4 inch to 2 inch diameter ratio I sort of see in the cover of the trans, that is why in the calculator I use 4 and 2. Even if it has a chain an gears under the cover so it could by 18 teeth and 9 teeth same ratio 2:1.

    As it is now the speed calculator with 8.8:1 and if you get 3500 rpm and have 26 inch wheel it said speed of 30.8 mph so that is loosing 3.7 mph just about 10%.
     

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  9. Jcs1989

    Jcs1989 New Member

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    Thanks guys for all the help. I believe I'm gonna check around an find pulleys. I may use the whizzer sheave. But I'm a fitter fabricator an have some skills that could help me fab up a great sheave. I may go with a bigger drive wheel to help keep slippage at a minimum. If I decide to go with a 3.5 " sheave. I believe it has a contact area of about 2.95. Which is close to 3" and to get the same 4.40 gearing I'll have to go with about a 13.5" hub sheave. To get close to the 12.95 contact area needed to get 4.40 or 4.4/1 . . I'll check an see what the Xhd trans gear ratio is. It is chain an I have taken it apart to grease the poo out of it. But never counted the teeth on the gears.
     
    #9 Jcs1989, Aug 15, 2016
    Last edited: Aug 15, 2016

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