Need lower gearing, but which gears ??

Discussion in 'Rack Mounted Engines' started by Bill P, Dec 17, 2014.

  1. Bill P

    Bill P Member

    I have a Staton crank-shift kit up and running on a 21- speed MB. kit runs good but I need lower gearing and am not sure what the best approach would be. It came with a 12-tooth sprocket for the drive shaft, I changed that too a 10- tooth which helped a little, but not much. Now, I am not sure if a cassette change would do it or if a front crank set would be the way to go, seems a bit pricey really. In the advert for the kit he claims this will "go up any hill" , so I thought the lower gears ( largest front sprocket,smallest rear ) would be "granny low like ) but not even close. Any help appreciated..........:grin5:

    The stock cassette is 7-speed, 14- 28 tooth
     

  2. Bonefish

    Bonefish Member

    You have it backwards. You want to run the staton gearbox to the SMALLEST FRONT SPROCKET(chainring) Then switch gears so your cassette is in the LARGEST GRANNY GEAR in the back. That will give you the lowest gear ratio. Have you used the automatic gear-ratio calculator?
     
  3. Bonefish

    Bonefish Member

    Opps. You run the staton gearbox to the largest chainring, then run your running chain from the smallest front sprocket to the largest cassette gear to give you the lowest gear ratio. Try using the automatic gear ratio calculator provided by this website. I have used it and it is interesting to find out what ratio you are running.
     
  4. Bill P

    Bill P Member

    Bone, The crankset provided by Staton has a seperate 44 t chainring then 3 others for the bike chain. The lowest gearing ie producing the most torque for hill climbing would be largest front, smallest rear, I have tried what you are suggesting, thats a high gear for top speed.
     
  5. Bonefish

    Bonefish Member

  6. Bill P

    Bill P Member

    It's a very simple thing to get on and shift 3 gears to determine which is lowest, no need for calculators. I wonder if a cassette with much lower gears would do it. As it stands 17 of these 21 gears are to high to use.
     
  7. Bonefish

    Bonefish Member

    On my crank shift setup, i've got a 12 T drive sprocket on my gearbox, then it runs to a driven 44T chain ring which is bolted to a 24T drive chain ring that goes to my back cassette. The largest cassette sprocket is 34t and it is my driven sprocket. This is the lowest gear ratio. If I switch my cassette to the smallest 17t of my driven sprocket then this is my highest gear. I have a Honda GX35 and I just keep my bike in the lowest gear because I like torque better than speed.
     
  8. Bill P

    Bill P Member

    I have a 34t on the cassette too, I will try it with the small front chain ring and see !
     
  9. Bill P

    Bill P Member

    Just returned and using small front and largest back the gearing is so high it won't start the bike from a stop. I have the same chainrings as you not sure why the disparity in results.I would like you to try the largest front and smallest rear and see what happens, when I say low gear I mean like first gear in a 5-speed manual transmission...Thanks.
     
  10. tomtruty

    tomtruty New Member

    This might help. I built a spreadsheet in both Open Office and Microsoft EXCEL. Download it and you can play with different ratios. http://1drv.ms/1BXO9H8
     
  11. Bonefish

    Bonefish Member

    Using the ratio calculator:
    I have a 5:1 pocket bike tranny, You have a staton gearbox. I'm not sure of your ratio but I think it is around 18.75:1

    So I've got 5:1

    12/44 = 3.67

    24/34= 1.42

    =25.97:1 = my lowest gear ratio

    If I change my rear cassette and put the smallest on it(17) instead of (34) I get

    Pocket bike tranny = 5:1

    12/44 = 3.67

    24/17= .71

    = drive ratio of 12.99:1 is my highest.


    See?!??!?!?
     
  12. Bill P

    Bill P Member

    Which gear would propel you fastest when starting off ?? , highest or lowest ?

    I appreciate the calculators but like I said my large rear(cassette) and small chainring is so high it will not propel the bike after a few pedal kicks.
     
  13. Bonefish

    Bonefish Member

    My 34t would give me enough torque to get the bike moving without pedaling.
    My 17t would give me top speed but would not start the bike moving in a forward direction without pedaling it first.
     
  14. Bill P

    Bill P Member

    And this is on the largest front chainring ? (48t) , thats really weird, thats the exact opposite of mine, I'm perplexed !! lol.
     
  15. Bonefish

    Bonefish Member

    staton's gearbox is the overall basic gearratio that works for both torque and highspeed at 18.75:1. What you do with it after that thru chainrings, drive sprockets, cassettes changes it. The higher number the ratio to 1 it is the more torque and hill climbing power you will get. The lower number the ratio to 1 is the more top speed but less off the line torque you will get. Try using that gear ratio calculator I showed you.
     
  16. Bill P

    Bill P Member

    I have tried all chain ring/cassette combinations, largest chain-ring 48t + smallest cassette 17t produces the highest engine rpm and as a result the most torque.
     
  17. Bill P

    Bill P Member

    ok, after reading an article my terminology is off, I am looking for higher gears not lower ! So, how can I get higher gearing ?, lol.

    High or Low?

    "Higher" gears put more resistance on the pedals. If you select a gear that is too high for the conditions, it will force you into a slower cadence.

    Pedaling slower than your ideal cadence is wasteful of energy. You also run a higher risk of muscle strains and joint damage, particularly to the knees and hips.

    "Lower" gears make the pedals easy to turn, so it becomes easier to spin to a fast cadence.

    Pedaling faster than your ideal cadence can allow you to generate an extra burst of speed, but you will tire yourself out too soon if you try to maintain an excessively fast cadence.
     
  18. darwin

    darwin Well-Known Member

    Low gear aka 1st gear is the smallest pedal sprocket in front powering the biggest sprocket on the rear cassette. Highest gear is using the biggest sprocket in the front powering the smallest gear in the rear. In 1st gear you pedal like crazy but don't go very fast and it's easier to pedal up hills. In the highest gear it's very hard to pedal and once going you get the most speed. Think about it, smallest sprocket in front powering the biggest in the rear. You have to pedal more revolutions to get the bigger sprocket going vs the highest gear which is the opposite. Think of a car and how 1st through 5th gear works...........hope that helps.
     
  19. Bill P

    Bill P Member

    yes, I guess it's backwards with bikes as opposed to cars, iow, if I am driving in fifth gear on the hwy and start going up a grade I downshift to a lower gear to climb the hill. Anyway, I need higher bike gears to get the most out of this crank shift kit. In the ad-type Dave Staton claims this kit will "climb any hill", he goes on to say and I am paraphrasing you may even be able to go uphills that a motorcycle cannot due to going slower. Now, this may be true with high enough gears. My cassette is 14-34, I was gonna try maybe a cassette that starts with a 10 or even less (not sure what they offer), then the kit will be much more useful...Thanks.
     
  20. LR Jerry

    LR Jerry Well-Known Member

    Here is your best set up. It'll give you the widest range. Go from a 21 to a 24 speed. Get either a DNP 8 speed 34-11 freewheel or a 8 speed 34-11 cassette. You'll need an 8 speed shifter also. For the gear box get a 15t gear. The shiftkit comes with a 44t for the engine and 28t chainring so add a 36t and a 44t chainrings. This will be your shift pattern. Uphill and towing 1(1,2,3) which is 28(34,28,24). Level ground 2(3,4,5,6) 3(6) which is 36(24,21,18,15) 44(15). So 3(6) gives you 100% of your gear box output. Downhill 3(7,8) which is 44(13,11) these are overdrive gears. You'll have no problem hitting down hill speeds of 45+ mph.

    The shift points for the front chainrings are when you're in 3 or 6 in the rear. Be sure to get steel chainrings. For stops going up steep hills be in 1(1) before stopping then use that as a starting gear. All other stops be in 2(3) before stopping then use that as a starting gear. Get the tachometer. Then be in a gear where the rpm is a round 7000. That's where your max HP is. If you're going way over 7000 rpm then you need to be in a higher gear. If you way under 7000 rpm then you need to be in a lower gear.
     
    Last edited: Dec 23, 2014
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