Building a Chain Drop Box - Page 2

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  1. #16
    Registered User
    Join Date
    Feb 2003
    Edmonton, Alta
    Around here, (central alberta) chain drives like what you describe are quite common on large equipment for winches etc. Try places like BC Bearing for the gears and chain or possibly try a truck rig up shop like Danco supply or maybe a shop that works with PTO equipment like Pat's Driveline. A little yellow page reading should give you a few alternate choices.
    Your idea is sound for what you want to do and will act just like a divorced t-case.
    Doing it this way would allow you to use a engine/trans out of any 2wd rig.

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  3. #17
    Registered User
    Join Date
    Apr 2004
    Well this is what I've come up with.

    Double 60 sprocket, 48 teeth,
    weld on hubs
    Pillough blocks, and bearings.
    And run the setup on a 3/4" keyed shaft
    for the 2nd sprocket us on with 24 teeth.

    Do you guys think 3/4" shaft will be strong enough.?

  4. #18
    Registered User
    Join Date
    Jul 2002
    Chwk Lake Road
    No I don't, and I don't think double 60 will be enough either, but what do I know?
    I know mud boggers use it, and I know that some rail buggies use chain to drive the axle shafts, so it works obviously.

    Now what I do know. You'll be better with two, three, or whatever, single strand chains than using multi-strand chain. The separate chains will handle misalignment of both shaft and sprockets better. Multi-strand chains are very alignment sensitive.
    While you're at Western Equipment ask them for some handout literature, they should have some stuff from Reynold, or one of the other chain manufacturers, that will have chain drive design suggestions and guidelines. There will also be charts for HP capacity, torque handling, etc.
    Basically you want the biggest drive sprocket you can manage while still getting the ratio you want in the space available. Chain and sprocket power handling capacity and life span goes down a lot when it's run on a small sprocket. Power handling capacity also goes down as speed decreases, and down at high speeds as well. I don't think you'll have a problem with high speeds though.
    The main question in my mind is whether it can handle the shock loads it's going to get on the trail. In mud once the tires are spinning there isn't a bunch of shock load, on the trail, well...
    I think I'd try at least 1 1/4" shafting, the stronger the better, 4130 or better I'd say, and keep the distances between the bearings as close as possible. The chain will side load the shafts, so they need to be able to handle the radial loads, as well as torsional loading. The larger shaft and hubs will also allow bigger keyways and keys, and bigger bearings.
    The power and torque you'll be putting through there will exceed the manufacturers recommendations at least 10 fold, but like I said, works for the mudboggers, so give her a try. I'd be interested to know how it works.
    Oh, here's a link that might help with planning.
    Last edited by frank; May 2nd, 2004 at 09:31 pm.

  5. #19
    Registered User
    Join Date
    Aug 2001
    Check out the mud racing section of the message board at The guys have sort of been discussing it there...a number of the eastern BC mud drag guys have built them and may be able to help you out with some of your questions.

    I just did a quick look. Here is the direct link...
    Wes Kibble
    Toronto, ON

  6. #20
    Registered User
    Join Date
    Aug 2000
    Delta, BC
    Originally posted by 78Jimmy

    Do you guys think 3/4" shaft will be strong enough.?
    You want your key to break before the shaft.

  7. #21
    Registered User
    Join Date
    May 2003
    Originally posted by jeepFREAK

    You want your key to break before the shaft.
    haha to true, i dont know what hp or torque you r running, ive seen these on big mud trucks. they are easily serviced. id go with 3/4" to 7/8" thick shaft.
    97 F-250 POWERSTOKE, 8" lift, 37" tires, killer stereo, OBA, ARB, etc .....still not finished
    2000 VW Jetta TDI
    1997 F-350 POWERSTROKE, parts truck
    1982 Suzuki LJ80-Hunting Rig


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