Smaller rear tire?

Discussion in 'General Questions' started by Sterno666, Aug 5, 2010.

  1. Sterno666

    Sterno666 New Member

    I have an idea to put a smaller rear tire on my bike, mainly for looks. How would this effect speed/torque? I'd think it would speed the bike up and lower the torque, but I'm not sure.

    I was thinking of going from a 26' to a 24', maybe 22'.
     

  2. GearNut

    GearNut Active Member

    More torque, less speed will be the result.
    You will get up to speed quicker, but have a slower top speed.
     
  3. Porkchop

    Porkchop Member

    Depends on what kind of engine set up you have, like chain/hub drive vs. friction drive. Also by lowering the back end, it will most likely lower the peddles to the ground and cause big time interference between them and the ground, especially during turning.
     
  4. motorpsycho

    motorpsycho Active Member

    a shorter rear tire will raise your gear ratio and give you more bottom end torque, and less top end speed. a taller tire will do the opposite.
    putting a shrter rear tire on would be the same as putting on a bigger sprocket.
    putting a taller rear tire on would be the same as putting on a smaller rear sprocket.
    an inch or 2 difference in tire height will make a significant difference in your gear ratio.
     
  5. Sterno666

    Sterno666 New Member

    More torque is kinda what I'm looking for. I'm not really worried about top speed. If I wanna go fast, I'll ride my motorcycle. I am now wondering how low I can go before pedal clearance is a problem. I've got 5" from the bottom of the pedal to the ground right now.

    If I changed the rear wheel from a 26" to a 24" I guess that it wouldn't drop the pedals 2", but more like 1 1/2". Is that correct?
     
  6. motorpsycho

    motorpsycho Active Member

    I wouldn;t worry about peddle ground clearnce becoming an issue if you are just going from a 26" wheel to a 24". you may not even see a 1.5" drop in the peddles because the RIM is 24" in diameter, and depending on what tire you use, the overall diameter of the tire and rim may only be 25". so you may only loose 1-1.5 inches in ground clearance at the peddles, depending on the tire size. consider that you are only dropping the rear (leaving a 26" wheel on the front right) and you are not dropping the entire bike straight down. you will be creating a rake and the front will be slightly higher than the rear. and since the peddles are in the middle of the frame, the only place that the pedals should actually drop is at the rear when the peddles are at the rear of the stroke. i think you should be fine, especially since you have 5 inches of ground clearance at the peddles.
    one of my bikes only has 1.5 - 2" inches of ground clearance at the peddles and i have never had the peddles hit the ground. i just make sure that the peddles are horizontal all the time. i use my peddles for foot rests and to operate the coaster brake...i rarely peddle either one of my bikes. one of my bikes has a coaster brake, the other has caliper brakes and a free wheel hub in the rear.

    my friend built a bike using a 24" frame with 20" forks and 20" wheels. his peddles do hit the ground all the time and you can not peddle his bike. we have the cranks locked so the peddles are horizontal, andf you can only peddle backwards far enough to operate the coaster brake.
    but, on his bike, you are talking a 3.4 - 4 inch drop front and rear simply by using the 20" forks and wheels. plus the 24" frame is a lot bigger than a 20" frame.
    he is using short 4" schwinn stingray cranks on it too.
    needless to say, his bike is a ground scraper, and we actually had it set up to drag one of the peddles when riding at night to create a shower of sparks behind the bike.
    dangerous? probably. fun? absolutly!!
     
    Last edited: Aug 7, 2010
  7. Sterno666

    Sterno666 New Member

    Awesome.

    Thanks for all the input!
     
  8. w31john

    w31john Member

    I went to a 24" rim with no problems with the pedals. I did relocate the back brakes but I got a lot more low end, it's less mass to spin.
     
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