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DannyC
02-06-2015, 07:47 AM
Hi folks,

My Street-Fox plan says (p84) "ensure that the dérailleur tube is close to 56-degrees". So does the Tomahawk plan.
My Delta-Wolf plan says (p103) "In order to allow the front derailleur to properly move the chain from one chain ring to the next, the angle of the derailleur tube must be set to 67 degrees to the main boom as shown in Figure 97."

So which is correct?

My common-sense says "go measure a normal bike's angle from chainstay to seat-tube to get the "normal" angle used.

Twinkle
02-06-2015, 08:55 AM
Hi Danny

Both could be right or wrong or might not do what you want .




It is not the boom to front mech tube angle that is CRITICAL , the actual angle is the chain line angle . this is more critical as it is the angle that the mech sits with respect to the chain . this is the dimension that dictates if the front mech fouls on the bridge or the chain sits on the lower roller .
with an uplifted front boom eg my voyager and your terra-fox the angle changed , I had to make the front angle / bb assembly after I had fitted the front pulley

regards emma

DannyC
02-06-2015, 10:42 AM
Ok, got it, thanks.

Radical Brad
02-06-2015, 07:50 PM
Yes, the chain line is the key.
The higher the bottom bracket, the greater the derailleur tube stub angle.

http://www.atomiczombie.com/Tutorial%20-%20Front%20Derailleur%20Basics%20-%20Page%202.aspx

Brad