Stack V Head Angle.
 

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[Closed] Stack V Head Angle.

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Posts: 19
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I am trying to suss this out in my head but....

If a bike has a 68degree headangle and you fit a 1 degree angleset you would need to fit a 2cm or 1cm linger for to maintain the same stack height.

I know the wheelbase will grow.

Thoughts?


 
Posted : 15/11/2015 12:35 pm
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The stack won't change because your upper headset cup will most likely have to become external to accommodate the steerer offset. Reach will become shorter though.


 
Posted : 15/11/2015 1:33 pm
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Wtf is a linger?


 
Posted : 15/11/2015 3:29 pm
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If by "stack" you mean the height of the front end relative to the bottom bracket, then yes it will go down a bit, and also your bottom bracket will go down a bit.

Relative to the ground the front end will drop (ignoring a few teeny bits) by
[ac] x (degrees slackening) x Pi/180 x cosine(head angle)
where [ac] is the axle to crown of your fork.
Your BB will drop by a around half that, so your stack will drop by around half that.

Plugging some numbers in taken from a random bike on the internet (medium sized Trek Fuel) we have stack 58, reach 44, chainstay 44 (give or take a few mm) fork a-c 50 (in cm). We get around 3mm of drop in the front end. You would need to increase the a-c of your fork by a bit more than that to get the heights back to where they were.


 
Posted : 15/11/2015 5:34 pm
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So, back to what I said. A zs44 top cup becomes external when you fit an angleset. Actual stack won't change.


 
Posted : 15/11/2015 5:42 pm
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Thank you very much for clearing that up for me.


 
Posted : 15/11/2015 5:44 pm
Posts: 19
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Hyperthetically speaking if you wanted to keep everything else constant like seat post angle and BB drop you would need to increase the fork axle to crown measurement.

A 1cm increase would do this? I cannot change my fork in 5mm increments.


 
Posted : 15/11/2015 5:49 pm
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I wouldn't bother, both of those changes are positive in my books.


 
Posted : 15/11/2015 5:52 pm

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