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  1. #1
    Senior Member Spld cyclist's Avatar
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    Another frame alignment question

    This seems to be a theme over the last few days. Reading the other two threads has been a help....

    I have a new steel frame Motobecane Fantom CXX bike from Bikes Direct. The alignment of the rear wheel is just a little off vertically. The side of the rim is about 1/8-inch closer to the right (drive side) seat stay than the left.

    I checked the dish of the wheel with a dishing gauge and also by flipping it around in the frame. It checks out ok with both tests - the dish is right on and the distances to the seat stays remain the same either way.

    I checked the alignment of the rear triangle with the string test where you tie the string to one dropout, run it around the head tube, and then back to the other dropout. The measurement from the seat tube to the string is exactly the same on both sides, so that checks out ok.

    As far as I can tell, the dropouts appear to be approximately parallel and the right spacing, but I think it is hard to measure this with enough precision to rule out a problem. I think a small issue there could explain the misalignment. The wheel definitely installs smoothly.

    Is there anything else I can do to diagnose this, short of taking it to the LBS?

    Assuming I'm on the right track (usually a dangerous assumption ), can this be considered within normal tolerances for a frame in this price range? ($800 for the complete bike)?

    Is this likely to be even noticeable in the way the bike handles? If the wheel would track 1/16th of an inch further to the left, it would be exactly centered in the frame. Does 1/16th of an inch matter?

    I know it's new and I can insist on getting another frame under warranty, but returning it is something of a hassle and I have already invested substantial time in getting the bike set up the way I want it. If only I had seen this right off the bat. Other than this issue, I really like the bike.

  2. #2
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    Well, most big manufacturers hold such tolerances to 2 mm. One-eighth of an inch is nearly 3 mm., which to me makes it replaceable under warranty. But you've already asked the key question: does it matter? The answer comes from riding it. If it tracks straight with no hands, maybe you don't need to worry about it. But there is a caveat: if the wheels don't track straight, it's going to create some extra friction, which will rob you of some speed. This may or may not be detectable, but if it's the sort of thing you'd worry about, then...
    Last edited by Six jours; 02-10-12 at 11:42 PM.

  3. #3
    Senior Member Bill Kapaun's Avatar
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    I think I'd throw a 1/16" spacer on the drive side and not worry about it.

  4. #4
    Senior member Dan Burkhart's Avatar
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    Quote Originally Posted by Six jours View Post
    Well, most big manufacturers hold such tolerances to 2 mm. One-eighth of an inch is nearly 3 cm., which to me makes it replaceable under warranty. But you've already asked the key question: does it matter? The answer comes from riding it. If it tracks straight with no hands, maybe you don't need to worry about it. But there is a caveat: if the wheels don't track straight, it's going to create some extra friction, which will rob you of some speed. This may or may not be detectable, but if it's the sort of thing you'd worry about, then...
    You meant to say mm there, didncha?
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  5. #5
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    It sounds like your analysis may be right, especially if the error is consistent when you remove and replace the wheel. It takes only a very small error in dropout height to create this kind of error since the rim deflection will be about 5 times the difference in axle height.

    There's one definitive test you can do to confirm that the rear wheel is out of plumb. You'll need a bubble level or tri-square and a straight edge long enough to span the wheel. With the tri-square fixture the bike, (OK to lean it on a wall with someone holding it) and fine tune until the seat tube is in the vertical plane as proven with the tri-square. Now lay the straight edge across the rim and see if the wheel is also vertical.

    The same measurements can be done laying the bike flat, but it'll take some extra work to get the bike braced in the horizontal plane.

    Be sure your straightedge is straight the way you use it (a flat straightedge is only true on it's edge, it can sag if laid flat).

    The remedy is straightforward, (measure and confirm first) use a rat-tail file to file the lower dropout slot (the side the rim leans toward) higher. Work slowly rechecking often because it's a tiny correction (less than 1/64" to move the wheel 1/16" to center). If you get carried away, you can then correct the other side, but remember that's how folks make coffee tables when trying to level a dining room table.
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    I've had a couple old horizontal dropout bikes that seemed to have a small vertical difference between the dropouts, so that the rear wheel didn't seem aligned vertically with the seat tube when centered between the chainstays.
    I was just wondering, if the wheels are parallel with eachother and the bike, as if looking down on it from above, but have a small sideways offset or vertical tilt, would those affect the way it rides or tracks? If you're fiddling around with wheel position in horizontal dropouts and test riding for feel regardless of how it looks, it seems like the main effect would come from how straight the wheel is front to back, not whether it's off center or tilted. I think it's worth trying to fix if possible, just wondering if it might not necessarily be a functional problem.
    If it's just a small amount, you could also maybe file down the threads off the axle at one spot instead of the dropout, and mark it's orientation.

  7. #7
    Senior Member Spld cyclist's Avatar
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    Quote Originally Posted by FBinNY View Post
    There's one definitive test you can do to confirm that the rear wheel is out of plumb. You'll need a bubble level or tri-square and a straight edge long enough to span the wheel. With the tri-square fixture the bike, (OK to lean it on a wall with someone holding it) and fine tune until the seat tube is in the vertical plane as proven with the tri-square. Now lay the straight edge across the rim and see if the wheel is also vertical.
    Thanks. I'll try testing with a level and see how that looks. The fix you described seems pretty straightforward, but I think I'll wait and see what the manufacturer says.

  8. #8
    Senior Member Spld cyclist's Avatar
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    Quote Originally Posted by dnomel View Post
    I've had a couple old horizontal dropout bikes that seemed to have a small vertical difference between the dropouts, so that the rear wheel didn't seem aligned vertically with the seat tube when centered between the chainstays.
    I was just wondering, if the wheels are parallel with eachother and the bike, as if looking down on it from above, but have a small sideways offset or vertical tilt, would those affect the way it rides or tracks? If you're fiddling around with wheel position in horizontal dropouts and test riding for feel regardless of how it looks, it seems like the main effect would come from how straight the wheel is front to back, not whether it's off center or tilted. I think it's worth trying to fix if possible, just wondering if it might not necessarily be a functional problem.
    If it's just a small amount, you could also maybe file down the threads off the axle at one spot instead of the dropout, and mark it's orientation.
    In this case, the wheel does center between the chainstays, so the wheels should track parallel even if the vertical tilt does cause a small offset between the tracks. I've ridden the bike a few times and it doesn't feel like something is wrong. On the other hand, I haven't experienced riding it with a perfectly aligned frame, so I don't know how good it could be.

  9. #9
    Senior Member Spld cyclist's Avatar
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    Update: Got an e-mail back from Motobecane USA today. They're not interested in helping me out with this. The message was longer but it boils down to this:

    "In order to qualify for replacement under warranty, a frame must be rendered in-operable or unsafe by an inherent defect not caused by external forces."

    Before I got their reply, I was feeling a little optimistic after reading the warranty page, but I shouldn't have. This is their intro on the warranty page:

    "At Motobecane USA, we are proud to produce the highest quality bicycles available and back them up with one of the best warranties in the bicycle industry. High grade bikes rarely have manufacturing defects, few cyclists ever encounter a defective bicycle, and Motobecane USA has quality control that almost completely eliminates defects." Hmm, not so much.

  10. #10
    Senior Member Bill Kapaun's Avatar
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    Let them know you posted their response on BF.
    They may do an about face?

  11. #11
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    I don't know that this qualifies as a defect. I don't know that there's an industry standard for this, except that pricier frames are built closer than cheaper ones. All the manufacturer has to say is that it's within their tolerance standard, and that's the end of the story.

    Take the time to measure it carefully, and determine the exact nature of the problem; side to side deflection, or wheel twist, or wheel not dished right, or some combination of all three. then you can decide what your options are.

    BTW- let me warn you that I've seen frames with the wheels vertical and centered exactly, but the bridge itself is off a bit, so it can be tricky knowing the exact nature of the problem.

    To the OP- you're in Springfield Mass, not that far from me here in NY. If you wish, you may send me the frame and I'll look at it and let you know where it's off, and my recommendation for how to best correct it.
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  12. #12
    Senior Member Spld cyclist's Avatar
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    Quote Originally Posted by Bill Kapaun View Post
    Let them know you posted their response on BF.
    They may do an about face?
    I replied to their e-mail today, so I'll see what they say tomorrow. I'm guessing they'll tell me to go pound sand.

    I would love to hear from any bike shop owners/mechanics about what you think. Is it common to see these kinds of issues on the brands you sell? Do the manufacturers replace frames without complaint, or is this something you just fix for the customer (if it's fixable)?

    If someone could tell me that the degree of misalignment on my bike is common and no big deal, then I would feel better about it. If this is something that most manufacturers would make right without question, then I would be more inclined to be a jerk about it. I just don't know what is reasonable here.

    Jim

  13. #13
    Senior Member Spld cyclist's Avatar
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    Thanks FB. I wrote my last post with questions before I saw the one you just sent, yet somehow you anticipated my questions and answered them. (If that makes any sense). You're right, I need to spend more time studying this, and maybe I will have a better idea of how to proceed.

  14. #14
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    Quote Originally Posted by Spld cyclist View Post
    If someone could tell me that the degree of misalignment on my bike is common and no big deal, then I would feel better about it. If this is something that most manufacturers would make right without question, then I would be more inclined to be a jerk about it. I just don't know what is reasonable here.

    Jim
    There's no easy answer. It partly depends on the price of the bike, and what it's marketed as. On entry level bikes, it's par for the course, and dealers either mount the wheel not fully in the dropouts, or ignore it and set the brakes to the wheel. I've seen worse on new forks. As you move higher, you have the right to expect greater precision, but there's no magic formula that set's a relationship between tolerance and price.

    If you've never ridden it you might have better results via their general return policy, as in I'm not happy with it, or it doesn't fit. Some internet sellers are very good about this, and are used to and accepting of returns from disappointed customers or those who simply changed their mind.
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    An ounce of diagnosis is worth a pound of cure.

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