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  1. #1
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    Is this aluminum frame normal?

    Hi guys. I have a trek 2.1c aluminum bike which I bought as my first road bike in 2012. For several years, I felt that my body is tilting to right side when riding so I replaced saddle and seatpost and handlebar and etc which could affect my balance. But nothing worked for me. So I tried to confirm a problem on my frame and took some photos. I think my frame has a problem so I uploaded a photo that the frame is on tacx spider team bike stand. I draw red line(center of seat tube) and green line(center of head tube) on this photo. The point is that those two center is not on same line. Considering that rear triangle is almost symmetrical by red line, right sided top tube is not normal in my opinion. I brought this bike to some bike store but they didn't agree with my opinion. I think they didn't notice quite a slight difference. So I hope any experienced rider or framebuilder to look at this photo and leave a comment. I appreciate for any comments in advance. Thank you for taking your time. trek 2.1c frame.jpg

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    The key to confirming alignment is to establish the central plane and confirm that the saddle, wheels and steering axis all sit in it. This us usually and most reliably done by bolting the frame parallel to a table and measuring to all key points, while confirming that the axles are perpendicular and correctly centered.

    I don't know where you live, but if there's a local builder with frame table, that's where to go. Sorry, but a photo simply doesn't cut it.

    BTW- if all you want is to confirm that you don't need to cant the bike to either side when riding, you can do that with a square and bubble level but you need to be patient and make many observations over time because the bike moves under you. If the bike is off you'll see a pattern of readings off to one side more than to the other.
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  3. #3
    Randomhead
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    it would be really easy to fool yourself with a camera. I would try the "string test" as a start. If the bike is pretty close using that test, it's ok. An alternative is if your shop has the Park Tool Frame Alignment Gauge 1 (acronym in the forum's censor). A framebuilder would be able to tell you authoritatively

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    Quote Originally Posted by FBinNY View Post
    The key to confirming alignment is to establish the central plane and confirm that the saddle, wheels and steering axis all sit in it. This us usually and most reliably done by bolting the frame parallel to a table and measuring to all key points, while confirming that the axles are perpendicular and correctly centered.

    I don't know where you live, but if there's a local builder with frame table, that's where to go. Sorry, but a photo simply doesn't cut it.

    BTW- if all you want is to confirm that you don't need to cant the bike to either side when riding, you can do that with a square and bubble level but you need to be patient and make many observations over time because the bike moves under you. If the bike is off you'll see a pattern of readings off to one side more than to the other.
    Thank you for your quick comment! Actually I did a long observation for a few months on this and spotted angle difference between head tube angle and seat tube angle. Using smartphone level app, I can confirm that there is one degree left-right angle difference between head tube and seat tube(literally on top of those tubes-just frame). Also I can see that difference when the frame is fully equipped. In this condition, I can see that seatpost is going up to left side. I also uploaded three photos which I took the other day. Actually, there is no framebuilder near my city so I asked for some opinion for this.

    front.jpgrear.jpgfull.jpg

  5. #5
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    Quote Originally Posted by unterhausen View Post
    it would be really easy to fool yourself with a camera. I would try the "string test" as a start. If the bike is pretty close using that test, it's ok. An alternative is if your shop has the Park Tool Frame Alignment Gauge 1 (acronym in the forum's censor). A framebuilder would be able to tell you authoritatively
    I appreciate your comment! You are right. I tried string test but that test doesn't show probable difference(maybe I did wrong). As you said, I think I should go to bike shop which has frame alignment tools.

  6. #6
    Andrew R Stewart Andrew R Stewart's Avatar
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    There are many frame alignment issues that a sensitive person can feel but not easily find unless they also are a skilled frame alignment guy. But there are also body alignment ones too.

    The photo at first looks to show a possible rear triangle offset to one side. But photos aren't how these things are discovered. If it was only a simple case of the rear triangle being off to one side your body would still touch symmetrically about the front triangle/contact points. A twisted front triangle might place your hands to one side WRT your hips but sliding the bars over within the stem a touch could adjust for this. But there's no suggestion that the bike tracks off to one side. (not that this is always the case with a twisted main frame). A twisted Bb could also cause issues. Not that the photo will tell us anything about this possibility. Even different length crank arms can, for a same leg length body, throw off the hips. Again this photo doesn't speak to that.

    So what's really going on? Can't say without far more info and assessment. Both the bike and the Op need to be checked out. Andy.

  7. #7
    Andrew R Stewart Andrew R Stewart's Avatar
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    Quote Originally Posted by rtr1513 View Post
    Thank you for your quick comment! Actually I did a long observation for a few months on this and spotted angle difference between head tube angle and seat tube angle. Using smartphone level app, I can confirm that there is one degree left-right angle difference between head tube and seat tube(literally on top of those tubes-just frame). Also I can see that difference when the frame is fully equipped. In this condition, I can see that seatpost is going up to left side. I also uploaded three photos which I took the other day. Actually, there is no framebuilder near my city so I asked for some opinion for this.

    front.jpgrear.jpgfull.jpg
    All this speaks to is that the top ends of the two tubes are not parallel to each other. Not that the tubes' axis are off. Or that the I phone is not sitting flat Again get both you and the bike to a pro. Andy.

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    Quote Originally Posted by Andrew R Stewart View Post
    There are many frame alignment issues that a sensitive person can feel but not easily find unless they also are a skilled frame alignment guy. But there are also body alignment ones too.

    The photo at first looks to show a possible rear triangle offset to one side. But photos aren't how these things are discovered. If it was only a simple case of the rear triangle being off to one side your body would still touch symmetrically about the front triangle/contact points. A twisted front triangle might place your hands to one side WRT your hips but sliding the bars over within the stem a touch could adjust for this. But there's no suggestion that the bike tracks off to one side. (not that this is always the case with a twisted main frame). A twisted Bb could also cause issues. Not that the photo will tell us anything about this possibility. Even different length crank arms can, for a same leg length body, throw off the hips. Again this photo doesn't speak to that.

    So what's really going on? Can't say without far more info and assessment. Both the bike and the Op need to be checked out. Andy.

    I agree with you. There could be a lot of reasons for balance issues. I just want to know whether frame is balanced because it could be one of those reasons. It seems to be difficult to confirm any issues from some photos not by person. I'm going to go find some professionals to look at this and give me an answer. After that, I'll leave a comment whether this frame is really okay or not. Thank you for your comments.

  9. #9
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    Have you tried different wheels in the frame?

    dave

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    Quote Originally Posted by Dave Kirk View Post
    Have you tried different wheels in the frame?

    dave
    Yes I did. Actually those wheels on the photo are almost new one I bought just 6-7 months ago. While seat tube(and seatpost) is vertical from rear view, head tube(including handlebar and wheels) is tilted very slightly somehow..

  11. #11
    Decrepit Member Scooper's Avatar
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    Quote Originally Posted by rtr1513 View Post
    Yes I did. Actually those wheels on the photo are almost new one I bought just 6-7 months ago. While seat tube(and seatpost) is vertical from rear view, head tube(including handlebar and wheels) is tilted very slightly somehow..
    If that's true (the head tube and seat tube are are not aligned in the same plane), I don't believe there's any way to correct the problem on an aluminum frame.
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    Randomhead
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    it's really hard to correct that on any frame once the seat stays are on. Trek has a tolerance for alignment, not sure if this is within that tolerance or not. I've heard it's not a particularly tight tolerance

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    Do you know how to use string a a basic alignment test? It's super easy to check that the frame is all on the same plane with string.

    The string test will not tell you if the seat or head tube is twisted relative to frame's center plane but you can use a good straight edge to check that as long as the BB faces are good.

    Let me know if you need guidance to do these things.

    dave

  14. #14
    coprolite fietsbob's Avatar
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    Normalizing and re heat treating a welded Aluminum frame can result in the end points, jigged for alignment in the Oven, being fine, when its done.
    though the tubes may have had to compensate for stresses released while hot by not being perfectly straight lines beween 2 points..

    Had some Early Cannondales, in Shops . look a bit odd, brand New . but assembled and rode fine..


    As You said :
    I have a trek 2.1c aluminum bike which I bought as my first road bike in 2012.
    given Treks lifetime original owners frame warrantee , on materials and workmanship applies even to the
    newer Frames and Bikes they no longer make in Wisconsin . talk to the Dealer you bought it from

    Or if you still have the proof of Purchase receipts , any Trek Dealer, and see what they can Do.

    If you bought it used that's a different situation.
    Last edited by fietsbob; 02-18-15 at 01:10 PM.

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    I'v read all of comments all of you wrote. Thank you for that. Actually, my question started with sunscreen rub in the right side of top tube. This make me think that there could be some problem(although the rub could be happening by other reasons..but I tried a lot of fitting things). Also, I felt some kind of imbalance when I'm on my bike for a long time so I tried to find out some problems on the frame. So I took a lot of photos and find that seat tube is not vertical. Anyway, I'm going to get my frame to a professional and I'll leave a comment later.
    rub.jpgseat tube.jpg

  16. #16
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    Hi guys. I brought my frame to professional and got an answer. Head tube and Seat tube are on same plane and vertical(I was wrong). But it turned out that rear center is left-sided(the problem) so I think that difference makes knee-rubbed stain on the right side of top tube. In my calculation, that difference is 2-3mm. The pro said it might be caused by some external shock. But I have had a kind of unbalance riding my bike consistently and there is no sign of bend or something weird in welding area. So I'm curious that this difference could be happening in manufacturing process. I upload the picture of mine below and the green rectangle show that rear wheel center is not in right place. Thanks to all of you who read and reply to my thread.
    rear center.jpg
    Last edited by rtr1513; 03-31-15 at 09:17 PM. Reason: Sorry I think the differece is about 2-3mm.

  17. #17
    Senior Member Wilfred Laurier's Avatar
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    Perhaps the rails in your saddle are bent.

    NM. 5mm of offset in the rear triangle will almost certainly result in a funny riding bike.
    Last edited by Wilfred Laurier; 03-31-15 at 09:09 AM.

  18. #18
    Randomhead
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    I think it is on the edge of what will cause shimmy, but there are plenty of bikes out there that are off by 5mm and people are perfectly happy with them. Of course, that depends on how you are measuring the 5mm

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    Sorry I think the differece is about 2-3mm(not 5-6mm). Actually this is just my assumption but I'm sure the difference exists. Also I agree with you to say that unbalance could result from other elements like saddle tilt and other things. I didn't know that there are bikes which have the unbalanced rear center. Could somebody let me know which difference is acceptable for fine ride? I think that will help when buying new bike someday. Lesson learned anyway..

  20. #20
    Andrew R Stewart Andrew R Stewart's Avatar
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    Quote Originally Posted by rtr1513 View Post
    Sorry I think the differece is about 2-3mm(not 5-6mm). Actually this is just my assumption but I'm sure the difference exists. Also I agree with you to say that unbalance could result from other elements like saddle tilt and other things. I didn't know that there are bikes which have the unbalanced rear center. Could somebody let me know which difference is acceptable for fine ride? I think that will help when buying new bike someday. Lesson learned anyway..
    What's acceptable for one rider might be very noticeable for another. This is why alignment standards are so nebulous and often privet to the manufacturer. Here's a story about this topic.

    Back in 1979 I took Albert Eisentraut's frame building 2 week class in Rutland VT. There were 8 students, only I had built a few frames before. During the first week as we were doing much of the mitering and pre brazing prep one student after another would call Albert over and ask if this or that was right or good enough. Albert was getting more and more frustrated and finally "threw up his hands" and proclaimed that we were making bikes, not rockets. He explained that we all had body asymmetries- leg length differences, curved spines, strength sidedness. He offered to make the perfect frame when some one brought him a customer with a perfect body.

    I have remembered this ever since. Each frame I have built since has gotten closer to that perfect frame but every one isn't perfect. I work in a shop that does a lot of fittings by some one who is likely the most experienced fitter in Upstate NY. Just yesterday he rotated a client's seat off center by a few degrees to address a pelvis that wasn't symmetrical. (the rider felt the benefit right away). Take that bike into most shops and they will straighten the seat, the rider will suffer and that shop will claim that the first shop was careless.

    So the only answer that holds water (as to how far out of align can a bike be) is to ride that bike (and wheel combo) and make up one's own mind as to how it rides. Andy.

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