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  1. #1
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    What's My Trail?

    I was wondering how much trail changes when a front suspension is compressed. I have been thinking about making an app for my phone to calculate trail. So I made one that will calculate the change in trail, head tube angle and wheelbase when front fork compresses.

    I only know how to make Android apps, it is free with no advertisements/spam. I just uploaded it to the Google play store so it might be a few hours before you can find it. It is called "What's My Trail?".

    It only uses inch right now but I will update it to use both inch and metric this weekend.

    The app has two parts.
    1. Enter the wheel size, fork offset/rake and the head tube angle. Push the What's My Trail? button and it calculates the trail. This can be used on any bike with or without front suspension.

    2. If you have a front suspension fork enter the Axle to crown race height also called ride height of your fork, the amount of travel it has or the amount it usually uses, next enter the wheelbase. Wheelbase is needed because when the fork compresses the pivot point is at the back axle. Push the What's My Trail Now? button and it calculates the trail, head tube angle and wheelbase with the fork compressed.

    What's My Trail?-trail1.png

  2. #2
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    Wow that's very helpful! Now I wish I didn't have a dang iphone
    andy walker

  3. #3
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    Looks like you can find it on Google play now. https://play.google.com/store/apps/d...c015VHJhaWwiXQ..

  4. #4
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    Quote Originally Posted by Integrexman View Post
    Looks like you can find it on Google play now. https://play.google.com/store/apps/d...c015VHJhaWwiXQ..
    Yeah, I couldn't find it earlier on my tablet but did just find it on my phone. I'll do another search on the tablet and see--but it's a rooted Nook w/ CM10.1 and GAPPS from 121212 so I'm not sure it I'll find it in a search or not. If not, at least I have the link now and I'll find it that way. Thanks for the effort.

  5. #5
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    Quote Originally Posted by jay_ntwr View Post
    Yeah, I couldn't find it earlier on my tablet but did just find it on my phone. I'll do another search on the tablet and see--but it's a rooted Nook w/ CM10.1 and GAPPS from 121212 so I'm not sure it I'll find it in a search or not. If not, at least I have the link now and I'll find it that way. Thanks for the effort.
    I can post the APK file online so it can be installed manually if a rooted device can't see it on the market.

  6. #6
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    Quote Originally Posted by afwalker View Post
    Wow that's very helpful! Now I wish I didn't have a dang iphone
    andy walker
    Andy,

    I found a app on the app store that calculates trail and spoke length but it is only for a rigid fork like the top half of my app. It is called Veloculator Plus. for $0.99.

  7. #7
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    I updated "What's My Trail?" to work with metric numbers. Before you try to use it please read on. https://play.google.com/store/apps/d...NNeVRyYWlsIl0.

    Some people make apps that switch between using metric or imperial. I made this one to use both at the same time. You can input numbers three ways.

    1. On the left column you can input inch numbers and when you push the button the app converts the numbers to metric.

    2. On the right column you can input millimeters and when you push the button the app converts the numbers to inch.

    3. You can enter some dimensions as inch and some as metric and when you push the button the app converts what needs to be converted. This is good if you know your wheel is 26" and the fork offset, travel and ride height are all in mm and you measured the wheelbase with your tape measure in inches.

    Lets say you input some numbers push the button to see the results using all 6" of travel on your fork, then you think most of the time I actually use only 4" of travel so you change the inch "Fork Travel" textbox from 6" to 4". When you touch the inch "Fork Travel" textbox to change it from 6 to 4 the app should clear the right mm "Fork Travel" textbox so it will be updated when you push the button and show the new trail numbers with 4" of travel.

    Some devices this does not always work every time though, so you may have to touch the left then right textbox a couple of times to clear a number. If a number is changed in one column and the other is not cleared, the math that gets run when you push the button may not come out right.

    What's My Trail?-trail1mm.png

  8. #8
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    Thanks for the link for iphone I'll check it out. You got me thinking so I searched and found a webpage calculator that also does wheel flop. Would this be helpful to add to your app?
    Bicycle Trail Calculator | yojimg.net
    I just want to have a fork you can ride hands free and not worry
    I'm trying to learn all the factors that go into a great ride.
    cheers
    andy walker

  9. #9
    pvd
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    Kinda neet.
    It's got an issue in that it's calculating ground trail (I assume). Ground trail isn't used in frame design. It's just used in bike shops and in magazines. You should add a mechanical trail option for real bike designers.

  10. #10
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    Quote Originally Posted by pvd View Post
    Kinda neet.
    It's got an issue in that it's calculating ground trail (I assume). Ground trail isn't used in frame design. It's just used in bike shops and in magazines. You should add a mechanical trail option for real bike designers.
    By mechanical trail do you mean this Bicycle and motorcycle geometry - Wikipedia, the free encyclopedia I will add it.

  11. #11
    pvd
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    Do not read wikipedias entries on bike geometry. One guy is overlording it and he's often wrong.

    see: Mechanical Trail - Pvdwiki

  12. #12
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    Interesting resource, Peter. Gonna soak up all that info in there.

    Wow. That's gonna take me a while to read through Tony Foale's book. Didn't expect the link to take me to the entire thing. I guess I'll start with 2-30 and go back if I need more context to help me understand. Oh, nm, some pages are omitted I see, and I also see there's a ton of great related info starting at 2-1.
    Last edited by dv8xin; 03-24-2013 at 08:48 PM.
    I like to jump to conclusions, oversimplify, gossip, and participate in popularity polls.

  13. #13
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    I added mechanical trail to What's My Trail?.

  14. #14
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    Nice. I was able to install from the link on my CM10.1 tablet. Thanks.

  15. #15
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    I added a cadence calculator to What's my trail app.

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