Quantcast

Geometry Calculator?

stoney

stoney

Part of the unwashed, middle-American horde
Jul 26, 2006
21,973
7,823
Colorado
Situation: I'm looking to get a Fox 36 Talas for my 575 and I am trying to calc the minimum steerer length necessary to get the same bar height as I have with my 2003 Fox 32 R.
Does anyone know a good geometry calculator that I can use to figure this out?
thanks.
 
joelsman

joelsman

Turbo Monkey
Feb 1, 2002
1,369
0
B'ham
measure your current: steer tube, stack of spacers under your stem.

sub track the spacer amount from the steer length, this is minimum steer tube length. don't go shorter!

what is the AC length on both forks? whats the difference prolly around 30-40mm. subtract the height of spacers under the stem. this will be how much higher your bars will be after removing the spacers. you can also flip your stem upside down or get flat or flatter rise bars.

another good idea is to measure your bar height from the ground with your current fork and then after you install the 36. don't forget with the talus you can drop the travel to 130mm and end up with basically the similar geometry you have currently. not quite the same but close.
 
stoney

stoney

Part of the unwashed, middle-American horde
Jul 26, 2006
21,973
7,823
Colorado
Steerer stack doesn't work, as I'm going from a 125mm fork to a 160. I will be adding height with the fork AC, but I will also be slacking the HA out, so it will not be a direct measurement. I'm looking for a calculator to get this right, because it will determine whether I need a full steerer (XL frame) and a new fork or if I can get away with a slightly shorter steerer and a used fork. At $500 difference, I want this to be accurate.
 
joelsman

joelsman

Turbo Monkey
Feb 1, 2002
1,369
0
B'ham
well you missed at least 1 of my points, that you can only go so short before it's toooo short for your frame.

Sin of 67* = .856, so your difference in AC x .856 = added vertical bar height.

67* is what the head angle becomes w/ a 36.
 
stoney

stoney

Part of the unwashed, middle-American horde
Jul 26, 2006
21,973
7,823
Colorado
Joel, you are da man. I might need your help again once I get all of my measurements together.
 
joelsman

joelsman

Turbo Monkey
Feb 1, 2002
1,369
0
B'ham
I miss my 05 575, I should have put a 36 or a pike on it and gotten a stiffer wheel set. mine had a f32 vanilla 130RL and deore hubs laced to mavic 317's. one of the new 150mm RS revalations w/ maxle would be good on it too.
 
You must log in or register to reply here.
Top Bottom