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  1. #1
    mtbr member
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    Mach 5 with 68 deg head angle?

    Hi All,

    In the Turner forum there's a member who managed to make a custom Anglest-type headset for the normal head tube.

    Basically, it's just upper and bottom headset cups that make the steerer tube run through the frame head tube at an angle.

    So, it works like an Angleset but for the normal head tubes.

    Currently there are some people including me who asked if he could do the same for their bikes. At the moment it seems possible and we're in the process of discussing the details.

    What do you think about slackening the HA on Mach 5?

    Currently I run 150 mm Revelation Race 2010 which should give around 68.4-68.5 HA and I seem to like it. The possibility to have even slacker angle with lower BB seems interesting. BB on Mach 5 isn't on the low side so slackening out the HA without putting the BB higher seems quite what the doctor ordered.

    Any opinions on how slack the angle should be are welcome. Currently I'm looking at 1 degree change to have 68 deg with normal 140 mm forks.

    IMO it should give the bike more relaxed and confidence-inspiring feel on the descents and in turns while maintaining it's agile character and keeping the uphill capabilities.

    I'm 6'0 and run a 70 mm stem/680 mm bars on a Large frame and it feels like a good fit so I'm not too worried about stem length.

    I don't know what it will do to the frame warranty but I'm not the first owner anyway and don't have any receipts. I do hope though that it might save me buying Mach 5.7 for the next season?

  2. #2
    Not just famous; infamous
    Reputation: coolhandluchs's Avatar
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    If my math is right (and it may not be) going from 69 to 68 degrees with a 520mm fork gives a difference of 8.4mm horizontally, and 3.4mm vertically. If you're hoping to lower your BB height, one degree of head angle change isn't going to do much. If you're just hoping to slack out the fork and extend the wheelbase for more stability, it should help, but the BB's going to be about the same, assuming the lower stack height doesn't change.

    I like the idea, and I think 68 degrees for a 140mm fork is nice. You'd be about half a degree slacker with a 150mm. With the fat 44mm headtube on the M5, there's probably a good bit of angle change available.

    As far as lowering the BB height, I'm toying with the idea of a 7.5x2" shock on my M5. Still checking for clearance issues, but should be <13.25" with a 120mm fork, get about 120mm of travel in back, and keep the 69/72 degree angles.

  3. #3
    mtbr member
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    Yes, I got the same numbers

    It's not so much about lowering the BB than about keeping it as it is but slackening the HA. And then there's always the option of running 130 mm forks with 68.5 HA and lower BB.

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