Boris X7 Lasco Crank Nuts Headache Help!- Mtbr.com
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  1. #1
    MidnightBroomstickCowboy
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    Boris X7 Lasco Crank Nuts Headache Help!

    Anyone else having headaches with the Lasco cranks bolts coming loose on the Boris X7? No matter how much I tighten BOTH the bastards they loosen up after a half mile or so. The design was really poorly thought out to have the bolts loosen with counter clockwise rotation. Anyone rigged lock washers or applied anything to fix the problem?
    "As a true patriotic American, I blindly follow what my elected leaders tell me." - Jack English

  2. #2
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    Loctite might be your best bet.
    Jason
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  3. #3
    MidnightBroomstickCowboy
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    I'm trying to understand how other Boris owners with the same stock cranks aren't having similar problems. Loctite is just asking for a bigger problem. Any other suggestions?
    "As a true patriotic American, I blindly follow what my elected leaders tell me." - Jack English

  4. #4
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    Upgrade the crank.
    Jason
    Disclaimer: www.paramountfargo.com

  5. #5
    aka bOb
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    Quote Originally Posted by homeslice View Post
    I'm trying to understand how other Boris owners with the same stock cranks aren't having similar problems. Loctite is just asking for a bigger problem. Any other suggestions?
    Why is Loctite asking for bigger problems? Call BD I'm sure they have someone who can help you get things sorted out.

  6. #6
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    Blue loctite shouldn't be an issue to use. I use it on most everything.

  7. #7
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    I used blue locktite and its fine. My gxp is the same design I think.. Anyways that's locktited too. Make sure to throw some on the extractor screw also I lost mine already.

    Sent from my 831C using Tapatalk

  8. #8
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    Dude! This has been plaguing me too. I put some blue locktite on the retaining bolt and it has held fine for the last handful of rides. We'll see how long it keeps. Anybody know which bottom bracket fits the lasso crankset? I know it doesn't work with shimano, wondering if the gxp stuff is compatible. Mine is pretty toasty already.

  9. #9
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    My has been slipping too! Every 1/2 mile just like you!

    Locktite. And I also found the torquing the plastic exterior cover cap helps too. But still... I'm constantly checking it now on rides.

  10. #10
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    Anyone know where to get the external cap? I ordered one labeled as a gxp but it's way too big. My x5 gxp crankset cap fits but I can't find a replacement and the lbs doesn't know how to get one either.

  11. #11
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    Lock washer!!!! Try it. Used it on a low end crankset not on a boris but a build that I did. Fixed my troubles for .80cents at the hardware store.

  12. #12
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    Hey I know this is an older thread, but I thought I'd add something. My own X7 came with the bottom bracket that had parts in it that are not supposed to be there!

    I failed to check because things spun well when I assembled the bike, and all the parts being black... you would have had to look for it. Anyway... what they did was put a wavy washer UNDER the bearing on the left side as well as a 5mm thick 22mm spacer under the bearing. After a short ride, the left crank arm was loose and there was considerable grinding noise....

    I took off the crank arm on the left side and the bearing and two spacers came off in my hand. Hmmm. The cup was still on the frame. Hmmm. Then I noticed the right side cup being backed off a good bit (lol, about 5mm worth!). It was loc-tight'd into place, but I got it moving quite easily.

    Somebody at the assembly plant didn't know what was going on. Now the right side is tight, the left is back together WITHOUT the added spacer. The wavy washer is 24mm inner diameter (the spacer is about 26mm outer diameter btw). I'm guessing the wavy is optional on the right side if the frame shell is just a weenie bit narrow.

    The way that Lasco setup works is - right side crank holds the right side bearing in place. The crank can ride on the bearing face (or wavy washer's face). The left side has the bearing stop on a ledge on the crank, and the crank arm is bolted down onto the face of the bearing, holding everything tight. There is no preload. It works because the tolerance is supposed to be held rather tight. Should things loosen, the right side crank keeps things from moving left, and the left side keeps things from moving right. You can get wavy's up to .8 mm stock that accomodate... I dunno how much, but maybe 2mm down to .8mm fully compressed? You shouldn't fully compress one btw. Thinner ones are also available.

    My left side bearing falls out of the cup as it was pretty much destroyed by improper assembly (and maybe me riding it too...yeah). Its in place but there's some up down play that shouldn't be there. The play is in the 37mm outer diameter fit to the cup.

    You ought not feel bad about tightening the #$#@$# out of the crank bolt, and using a little blue loc-tight too.

    One problem I also had was the cap over the bolt getting loose. I didn't want to loc-tight that, so I put an o-ring under it, that just fit its inner diameter. Problem fixed.

    And, the SRAM GXP bottom bracket "should" fit the Lasco crank just fine, or you can go with an entire GXP bottom bracket and crank setup, with the same gearing and offset. I think the GXP bottom bracket alone is under $30, crankset about $145ish (or $169ish full price). And for all you considering a change - MEASURE the Lasco crank and any replacement GXP bearing. Ditto for the entire X5 GXP crankset. Reason being that SRAM had some out of spec bearings with reports of the bearing ID being 22.2mm or even 22.25mm, and I have no idea what Lasco does with the cranks (mine's 22.07mm). SRAM stated to "grease and tighten" until the play went away, but really, thats a total BS answer. They're relying on the clamping of the bearing between the crank ledge and left crank arm to make it seem as if the play has been taken out, which in reality, it has not been. Hand pressure won't move the assembly, but pedal pessure from a foot connected to a leg will. If you had .25mm total play thats about .010 inches... sorry but I'm used to working in inches for comparison. Resultant angular wiggle on the right side would be about .15 degrees. Not much, but not good for the bearing, or the crank surface, as its likely to distort the crank surface with prolonged use.

    I plan on getting the GXP bottom only, but you can also be sure I'll be taking my nice Mitutoyo digital caliper to the local shop, if its out of spec, I won't take it.

    And so much for the longish report on the whole enchilada, from an engineering perspective.
    Last edited by CharlieBlues; 06-07-2015 at 07:25 AM. Reason: another thought to add

  13. #13
    NYC Rollin Fattyz
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    Wow!! The content of this thread has got me Nervous!! I've been riding my Boris X7 for little over a week now and have not experienced any issues. How would I know if there's a problem with my Cranks? What should I be looking for?
    The mechanics at my LBS put the bike together after UPS dropped it off to them. There is a language barrier issue between me and my LBS mechanics, as they speak Spanish first and I'm American born and bred and speak English first, so we try to understand each other. He charged me for extra work done on the Bottom Bracket and pointed at it meaning there was a problem there....but he could not speak to me the details of what he had to do or what was wrong....
    Well, so far so good, but this thread scares me a little.
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  14. #14
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    Don't sweat it Phil. Go ride the hell out of it. When something breaks as all bike will with time and use. Fix it then.

  15. #15
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    The one on my son's X7 cratered too. BD sent me a new BB, but never gave me instructions, as I requested, per torques or assembly order - new BB didn't come with a wave washer, the old one had one installed, but it failed and fell off when it broke in half, so I'm not sure what side it was even originally installed on. Since it's not my bike, I never ride it, and he's too young to I.D when things are getting weird, so it got way too loose before I noticed it while riding behind him. I picked up a wave washer from the lbs, reinstalled on non-drive side, torqued things way down w/blue threadlock, and everything has been fine since. But, he weighs 65 lbs. If an adult was mashing this, it might give it up more quickly. Aside from the bb issue, there have been no issues. The V8 are actually a pretty good tire for the little guy, low rolling resistance and seem to do well at his operating psi's - Q tubes at 4 psi. Not complaints of self steer, and he's so light that pinch flats even at these low pressures won't happen.

  16. #16
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    Watermonkey - The wavy washer is supposed to be on the RIGHT side - the drive side. That is the way the crank/BB work. The left side, the non-drive side, is supposed to have that crank arm tightend down against the bearing, and the bearing on that side will then be tight against the shoulder of the spindle. You put the wavy on the left side and its just gonna be a spacer between the crank arm and bearing, as it will fully collapse (not good), and also prevent the crank arm from fully seating on the splines.

    With the left bearing captive between the crank arm and the spindle, the arm is fully seated. The only (possible) left-right slop is that caused by space between the drive side crank arm and the right side bearing. That space is taken up by a wavy washer for simplicity sake. Precision shims would also be an option, but far far more complex.

    I'd personally try to assemble the crank/bb with no wavy washer. Seat the cups tight in the frame. There is no preload spec, its just "tight" enough to prevent them loosening. Seat the crank arm on the splines - tight. Again, no preload spec, its supposed to be tight enough to not come off. With no wavy in place, tap the right side, and left side crank arms at the place they join the spindle. Do you feel left - right play? A tiny amount is acceptable. WAVY WASHERS ARE NOT ALL THE SAME. The thickness of the metal is available in a few grades - something like .4 or .6 or .8mm thick. I think those all have the same 1.25mm wavyness. This is hard to get definitive research on...!!! What this means is you can go from about 1-2 mm on a .8 wavy. You can go from .75 to about 1.5mm on a .6 wavy and about .5 to about 1.25 mm on a .4 wavy. Its not good to fully compress wavys, as they snap. Also... under .4mm play left to right.... I guess is ok, no wavy needed.

    My own X7 Lasco crank had other spacers, but ended up not needing the wavy for left -right play. My problem is bearing to cup being fubar'd by incorrect factory assembly..... soon to be X5 crank/bb swapped out.

    (edit) I'll mention that all the instructions here are for SRAM type, stepped spindle type cranks and bottom brackets.... not for straght spindle Shimano type cranks and bottom brackets. The Shimano sets do have a preload and the crank arm tightens in a different way. Apples and oranges.... completely!

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