Jackshaft Got gears -jackshaft kits

Discussion in 'Transmission / Drivetrain' started by adrian101, Sep 9, 2012.

  1. adrian101

    adrian101 Member

    Does anybody that has a jackshaft kit from SBP know if the 2 bearings on the bracket where the drive shaft goes through needs to be greased or lubed?

    If so, what do you use?

    thanks in advance.

  2. Fabian

    Fabian Well-Known Member

    From what i understand, they are a sealed bearing commonly used on small agricultural machinery.
    For whatever reason, the 5/8 keyed shaft is made from soft metal and the hardened inner bearing shell will cut a grove in the surface of the jackshaft if this area is not regularly lubricated.

    When the wear becomes significant (1mm into the surface on both sides of the jackshaft), it changes the angle of the jackshaft relative to the chain as the small 10 tooth (or optional 9 and 11 tooth) sprocket meshes with the chain side plates.
    With 8 speed chain, it doesn't seem to be much of a problem but when using (narrower) 9 speed chain, the wear shows up by having the sprocket teeth smash side plates in half.
    Typically (and in my situation which includes a lot of off-road riding) i've found that it takes around 6,000 kilometers before the jackshaft shows wear that makes it unusable; needing replacement.

    Having said, regular lubrication with a graphite based motorcycle chain lube, significantly reduces wear at the point where the inner bearing shell meets the 5/8 keyed shaft.

    As things currently stand, i've upgraded the 5/8 keyed shaft from mild steel to stainless steel, but have yet to see how it stands the test of time.
  3. adrian101

    adrian101 Member

    Thanks for all the information :) 6,000 kilometers is a fair bit of distance. So you use yours for off road use, do you have any problems with chains coming off? I keep getting the problem of the setscrews coming loose and the left cog almost sliding off the shaft.. blue locktite, and a nice sized filed groove in the shaft for the setscrews to sit in but it still comes loose..
  4. Fabian

    Fabian Well-Known Member

    I have experienced "all" of the issues you are experiencing with regards to setscrews working their way loose and chains coming off; creating a heck of a lot of damage when the derailleur smashed into the rear wheel; consequently destroying the rear wheel beyond repair when riding on poorly maintained dirt roads filled with cavernous potholes, hence the reason for my chain stabilisation system.

    The solution for the setscrew issue is to make sure that the threads (internal and external) are spotlessly clean, because loctite 243 will not adhere to oil and grease contaminated threads.
    Take your setscrews and sprockets and first soak them in mineral turpentine, then blast the turps from these items with compressed air (repeat step 2 or 3 times) - it will remove any oil or grease.
    Next, soak the setscrews and sprockets in Methylated Spirits (alcohol) and repeat the procedure; blasting these items with compressed air to remove the turps residue on the internal and external threads.

    Your parts will now be perfectly clean.
    Assemble items and secure the setscrews with loctite 243.
    Make sure that the keyway is installed in the sprockets when fixing these parts to the jackshaft.

    If done correctly, you will need to use heat from a small propane torch to soften the loctite 243 if wishing to remove the setscrews and sprockets.

    PM coming your way for the chain stabilisation system.
  5. The_Aleman

    The_Aleman Active Member

    If you file a little groove in the keyed shaft for the set screws, that should cut down on the gears sliding on the shaft. The set screws need to be checked periodically tho.
  6. adrian101

    adrian101 Member

    I have it running awesome now.. I love the jackshaft kit.. will never go back to the stock sprockets again!!
  7. Fabian

    Fabian Well-Known Member

  8. adrian101

    adrian101 Member

    Hills are no match anymore.. I love it!
  9. Fabian

    Fabian Well-Known Member

    If you think hills are no longer a problem with the standard setup, just wait till you do the Tetra Chainwheel Modification; opening up a whole new world of heavy haulage; being able to drag 500 lbs uphill in low range first gear, yet still having your normal top gear ratio. :banana:
  10. Lunardog

    Lunardog Member

    I have a 66cc Stinger with an RT carb, Rock Solid reed valve,good NGK plug,wire and boot. 7 spd shimano cassette with a SBP shift kit. Living here in the mountains of Pennsylvania I am either basically riding uphill or downhill, very little in between. I started with an NT carb and went through 60,65,70,75,80 jets and every needle adjustment known to man. I recently put on the RT mainly to try but also because I had made so many tests and adjustments to the NT that the top cap cracked and the slide tube was warped form uninstalling and reinstalling so many times.(my fault for over tightening clamps) Anyhow I have still not found a combination that will pull my 190 lb butt and around 15 lbs of tools and gear up some of these hills even in the lowest gear. I am talking about serious grades in the 8 and 10 percent catergory. Pulls fine on lesser grades, not breaking any speed records of course but usually maintains around 9 or 10 mph. Is this the best its going to get or am I doing something wrong here?
  11. Fabian

    Fabian Well-Known Member

    Oh please!
    An 8 to 10% grade is only chicken feed. Now a 22% grade and above is starting to get mildly serious with a trailer loaded up with 150 lbs hanging off the back of the bike.

    You are not going to get that kind of heavy haulage unless modifying the front chainwheel system to a Tetra chainwheel arrangement with a minimum of a 34 tooth rear cassette sprocket, but preferably a 36 tooth sprocket ripped from a 29'er cassette, grafted onto a conventional 34-11 cassette; using an 8 or 9 speed arrangement, but 8 speed being the better option, as the chain isn't rubbing up against the adjacent gear (especially if using 9 speed chain on 8 speed sprocket spacing), giving a better fudge factor for misalignment.

    On flat ground, you should have no problems getting 500 lbs moving with this method, in fact, maybe more because i've had two bikes and riders connected up to my bike with a tow rope going between all three of us as i've towed them up a good 8% incline, and that includes not only my attached trailer but their trailers also.
    Each (towed) rider and bike and trailer combination would have weighed 180 lbs for the rider, 25 lbs for the bike and panniers and 40 lbs for the trailer x 2 sets = 490 lbs (give or take a bit) + my bike which weighs 90 lbs and the trailer and gear which weighs around 100 lbs and myself being a good 180 lbs.

    So overall the mega low range gearing was able to haul 860 lbs - a staggering amount of weight when you think about the torque going through the pawls in the rear hub.

    I've had no problems climbing in excess of 30% gradient with 150 lbs hanging off the bike, maybe even a good 40% gradient but it got to the point where i couldn't climb any further because i wasn't able to lean far enough over the front handlebars to stop the front wheel lifting off the ground and flipping the bike.

    Maybe if i attached lead weights to the bottom of the front fork legs, i might be able to keep the front wheel on the ground and climb steeper gradients with a tetra Chainwheel Setup!