Engine for a Fatbike, for snow/swamp riding

Discussion in '2-Stroke Engines' started by lazylightning@mail.r, Dec 27, 2011.

  1. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Has anybody put an engine onto a fatbike, like the Surly Pugsly for example? It's possible to ride on snow, soft deep sand, shallow swamps without really sinking in. Now sure what will happen if you get off and take a step though. There will definitely be a need for chain line engineering here. I'm thinking the go ped CVT may be helpful in many ways here. http://www.gopednation.com/forum/showthread.php?t=263571

    It's actually possible to ride on top of deep snow without really sinking in.




    I've been riding my motorized mountain bike with standard 26X2.1 tires in the snow. If I pedal hard standing and give it plenty of gas, then I can ride through deep snow up to my pedals and axels. It looks crazy, but it actually works. Just don't lose momentum and watch out for naked ice if you don't have studded or screwwed tires. I think it would be super on a fatbike. I plan to put screws in my tires and run up and down the big Moscow river here when it finally freezes over)))

  2. wheelbender6

    wheelbender6 Well-Known Member

    I have not seen a motorized Pugsly, but I want one. It would look great with a Russian D engine.
  3. lazylightning@mail.r

    lazylightning@mail.r Active Member

    I have a Chinese one, but I want a more sporty European engine. I'm not sure the Russian D series is so good) I saw one once in the park neaby, a Russian Rasta man on an old rusty chopper with a banana seat and sissy bar, in dreds and in a helmet. Stoned to the bone I think)
    Last edited: Dec 27, 2011
  4. HeadSmess

    HeadSmess Well-Known Member

    learn how to lace double rims :)

    tricky, but possible.

    if you get some of those ridiculous "bling" hubs with about 60 odd holes you can even go for triple laced rims... 18 spokes per rim, etc...

    you need a spacer between each rim so the tyres can sit on nicely.

    or..make a skidoo! old cruiser with half a ski and a spring on front, and two little trolley wheels on a swingarm with the tread section of a motorbike as a belt...

    wish i had snow :(
  5. lazylightning@mail.r

    lazylightning@mail.r Active Member

    lace double rims? What for? Snow doesnt require stronger rims, but better if they are very fat and having low pressure. That will require a fatbike frameset and special rims and tires, no way around it.

    I think you had this in mind? http://www.youtube.com/watch?v=_8FefRzcWjg
  6. lazylightning@mail.r

    lazylightning@mail.r Active Member

    I'm getting closer....
  7. HeadSmess

    HeadSmess Well-Known Member

    doubled rims isnt necessarily stronger, what with half the number of spokes in each rim, depending on the hubs...

    its all about the width!!!!

    i cant find any good pictures :(

    theres always the snowcat rims though :)


    i dont got snow, just mud n sand :(
  8. Cavi Mike

    Cavi Mike Member

    You can get rims as big as 26x4 from here:

    I think the biggest problem will be having the power to get the bike to move in that snow. Sinking down 4" in that stuff will require a lot of torque that these little engines just don't have. You'll need to be able to gear way down so I think the only option would be to run a shifter kit and even then I think you'll need to pedal a bit.

    Turn on the "macro" setting on your camera. It's the button with the picture of a flower. It allows the camera to focus on objects real close to the lens.
  9. mabman

    mabman Member

    Not too fat but spiked to the gills. I believe this bike is in Russia also?
  10. lazylightning@mail.r

    lazylightning@mail.r Active Member

    I pedal too in the deeper snow. On a snowy yet beaten path underneath, it's okay, but on untouched grassy field, I have to stand on the pedals, crank and give it alot of gas too =-) It's fun. I don't move terribly fast, the motor rev's and I'm cranking away standing and moving steadily yet slowly through the snow. The rear wheel slips a bit as I go and the pace of the engine sounds like the pace of my pedaling))) I've driven in 10 inch deep virgin snow before. The main thing is not to stop in the deep stuf that as no packed snow trail under it, else you won't be able to pedal it going again. Especially if you have to start going uphill. I pick up the bike and push start the engine with the pedal, pull in the clutch and then try to start pedaling with the engine going and rlelease and pedal and all.

    The nice thing about the 4 inch tires is that you could easily let some air out. Surprisingly, soft tires don't sink into sand, snow or swampy ground very much. A giant tire with low pressure doesnt sink in at all. But naked ice is still a real bummer and any tire without studs will let you down fast on that stuff. I wear a helmet))) Here the kill switch is really handy when you are sliding on your but on the ice with your shoe caught in the rear spokes and the engine is still reving cause the accelerator is sliding on the ice too. Looks like slapstick I think)

    My bike frame probably couldnt handle the 4 in 26er's, would be nice though. It's rather narrow in the back.

    Will have spike wheel ready soon. But now, it's above freezing in Russia, the snow is melting %-) It's really crazy weather for January I'll tell you! Waiting for the next freash new snow...muhuhahahah....nobody around in the forest park at night. I can see fine without light because the white snow everywhere lights everything up. Heavan) And my carb likes the cold air)))
  11. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Wow that's funny! But I'm sure it will make the bike much heavier) I think two would have been more than enough)
  12. HeadSmess

    HeadSmess Well-Known Member

    maybe the weight is the idea too?

    two on the front end would help surely?

    as long as its balanced...

    more traction :)
  13. mabman

    mabman Member

    If you want to see what snow biking, the non motorized version anyway, is all about check out the three segments here: http://lacemine29.blogspot.com/2010/12/iditatour-part-one.html

    Mike is a friend of mine and about as genuine a person as you will ever meet. He doesn't think much of my motorized exploits but has gotten used to them over the years.

    One thing for sure though is that that trip would not be possible except for the snow machine traffic that packs down the trail in advance of the Iditarod Dog Race. The bicyclists go before the dogs to take advantage of this.
  14. lazylightning@mail.r

    lazylightning@mail.r Active Member

    Cool Blog! He made a great trip. The gasoline engine would have really helped him at times, but it would have made the load a little heavier when pushing and carrying over rocks would have come into play. Also, the problem with long distance travel with a motorized bike is that you have to carry a gas supply, especially when you are out far somewhere. A strong bicycle trailer or a sled might have been in order here for your friend or on long wilderness snow trails with a motored bike))) I took an empty 5 gallon gas can with me on the train(in a box) and put my boxed up bike in the baggage wagon and went way out in the north of Russia in Karelia this summer. Filled her up when I got there and took a taxibus about 70 miles out in the middle of nowhere. Lived there for 3 weeks and my bike was my buddy. You can be sure it really came in handy on those endless abandoned forest roads. Lot's of boulders sticking out here and there to dodge...it was a sand road too))) Two wheeled bike trailers need big fat wheel barrow wheels for off roading it though. Otherwise the large weight and uneven rocky roads will make your wheels curvy in a heartbeat)
    Last edited: Jan 11, 2012
  15. mabman

    mabman Member

    Your adventure to Karelia sounds like a good one also. Mike does carry his camp stove fuel in his frame and fork. He tried a single wheeled trailer one year with the same type of wheel/tire, in fact all the wheels where rear type wheels, but it did not work well for him and he never did it that way again.
  16. Davidst

    Davidst New Member


    I am going to do that...will post progress
  17. HeadSmess

    HeadSmess Well-Known Member

    had a book way back that went into some minor detail on "snow bikes" back in the day before these 4 inch fat tyres became available...

    things like double lacing rims onto one hub...ie, use two 24 spoke rims on a 48 hole hub, and spacing the rims apart to allow for the fattest tyres around at the time... obviously frames need tweaking to suit.

    some company online somewhere sells the fat tyres with replaceable (screw-in) steel or carbide spikes. not cheap. oooh, a search found a completely different one...! http://fat-bike.com/2012/12/grip-studs-customizable-traction/

    cus my country is silly i think i would have to follow a double lace setup and just make do with mud...

    the old idea of two "wheelbarrow" tyres on a frame with a big moto/tractor tyre stretched over them as a belt? cut out the sidewall...