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  1. #1
    Lightly salted
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    Angleset headsets and increased wheel base?

    Thought I would post this question here since alot of all mountain riders use angleset headsets.
    Does anyone know how much a 1* slacker headtube angle would increase wheel base and also by how much would it lower your bottom bracket?
    My bike is an ibis HD 160 size small. This frame has a 43" wheel base and 13.8" bottom bracket height with stock 67* head angle.
    Im actually more interested in increasing my wheel base and lower bottom bracket than I am the slacker headtube.
    Will the extra wheel base be noticable? Any thoughts?

  2. #2
    > /dev/null 2&>1
    Reputation: Procter's Avatar
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    Re: Angleset headsets and increased wheel base?

    SOHCAHTOA:

    Sin ( 1 degree ) = O / H,

    Where H is the distance from the tire / ground contact to the top of the headset.

    Solve for O and you have the increase in the wheelbase:

    Increase in wheel base = sin (1 degree ) * H
    What doesn't kill you makes you stronger. Unless it does kill you, in which case, you wouldn't be here to dispute the point.

  3. #3
    Living Ghetto Fabulous!
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    Quote Originally Posted by ddprocter View Post
    SOHCAHTOA:

    Sin ( 1 degree ) = O / H,

    Where H is the distance from the tire / ground contact to the top of the headset.

    Solve for O and you have the increase in the wheelbase:

    Increase in wheel base = sin (1 degree ) * H
    Engrish pleez?

    One of the factors this equation might not allow for is head tube length. The shorter your headtube, the more angle change you'll see. (With an Angleset.)

    To the OP: You could play around with this calculator to get an approximate measurement.
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  4. #4
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    Quote Originally Posted by Uncle Cliffy View Post
    To the OP: You could play around with this calculator to get an approximate measurement.
    This x2.

  5. #5
    > /dev/null 2&>1
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    Quote Originally Posted by Uncle Cliffy View Post
    Engrish pleez?

    One of the factors this equation might not allow for is head tube length. The shorter your headtube, the more angle change you'll see. (With an Angleset.)

    To the OP: You could play around with this calculator to get an approximate measurement.
    You make a good point: for a 1 degree angleset, the real change in head angle will vary slightly depending on the length of the head tube. But, the calculator doesn't account for that either, it prompts the user for the head angle, it does not calculate one based on head-tube length for a 1 degree angleset.


    Moreover, correct me if I'm wrong but the calculator you provided doesn't seem like it provides the calculation that OP asked for at all. This calculator allows you to enter existing wheelbase, head angle, etc., then recalculates those for a new fork with new A2C.

    It doesn't allow keeping the A2C and all other variables constant, change the head angle, and get a new wheelbase calculated.

    Try it for yourself: Keep the fork the same, change the head angle. Wheelbase doesn't update, either in the green on the right-hand 'red shaded' calculated part.

    Anyways, I did say H is to the top of the headset (i.e. top of head tube) which somewhat accounts for the wheelbase change for longer or shorter head-tube lengths, to be fair still assuming an exact 1 degree change. The top of the headtube is the apex / origination point of the change in angle, on a typical angleset. But agreed that its approx because you still have to assume that the angle change is exactly 1 degree, it might be slightly higher or lower based on head tube length.

    So . . . eqn is not perfect, but, its a pretty good approximation.

    I did realize an error though: H should be axle to top of head tube, not tire contact point to top of head tube, since, the tire contact point will always move out horizontally by the exact amount that the axle does.
    Last edited by Procter; 01-31-2013 at 03:58 PM.

  6. #6
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    Quote Originally Posted by ddprocter View Post
    Moreover, correct me if I'm wrong but the calculator you provided doesn't seem like it provides the calculation that OP asked for at all. This calculator allows you to enter existing wheelbase, head angle, etc., then recalculates those for a new fork with new A2C.

    It doesn't allow keeping the A2C and all other variables constant, change the head angle, and get a new wheelbase calculated.

    Try it for yourself: Keep the fork the same, change the head angle. Wheelbase doesn't update, either in the green on the right-hand 'red shaded' calculated part.
    Further below the existing bike values, there's a ha insert +/- parameter. If you adjust this, the wheelbase will change all the red columns. It changes all the values actually.
    Quote Originally Posted by ddprocter View Post
    So . . . eqn is not perfect, but, its a pretty good approximation.
    ^this.
    Quote Originally Posted by kidwoo
    The internet sounds like a tough place to ride.

  7. #7
    bikeaholic
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    Quote Originally Posted by ddprocter View Post
    SOHCAHTOA:
    Brought me right back to 9th grade trig, thanks.

  8. #8
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    I've got a works 1.5 degree headset in my Sunday that installed. I would say the change in head angle is much more noticable than the change in wheel base.

    AL

  9. #9
    Appalachian Singletrack'n
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    Ive changed a few bikes with Works cups now. Wheelbase changes are the most noticeable part, you can tell the front wheel is further out in front of you. Os discussed above there is math involved to calculate. BB height change isn't measurable on the bike. The slightest difference in the bike being anything but 100% vertically plumb is a bigger difference in BB height that the angle set will make.

    I've done calculations on what the angleset should do to the bike each time i've installed one and my actual measurements always deviate in some way from the calculated ones. I'm an architect and very detailed oriented person and I'm eluded by my findings each time. And the works cups i find to be superior to the CC angleset.

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