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Fork Rake, Trail and Neutral Steering(9 posts)

Fork Rake, Trail and Neutral Steeringbobobo
Feb 12, 2003 3:54 AM
I own a bike which uses a 43 rake Reynolds Ouzo fork and has according to the builder a trail figure of about 5.0. I'm considering changing to a fork with a rake of 41. Can someone tell me how decreasing the fork rake would affect the bikes trail number, steering response and neutral steering. Would the bike steer slower and would the steering move towards a more neutral figure or a less neutral steering? What exactly is a good neutral steering figure for a road bike and what does neutral steering refer to?
Check this out . . .mja
Feb 12, 2003 4:53 AM
re: Fork Rake vs Trailcyclopathic
Feb 12, 2003 5:45 AM
reducing rake increases trail. In mordern view "ideal" trail is 56, and 50 looks on a shorter side. So changing rake from 43 to 41 should bring trail to 52 closer to neutral.
Didn't study your trigonometry, did you??Rusty McNasty
Feb 12, 2003 6:36 AM
In case you don't know (and you don't!), decreasing the rake by 2mm increases the trail by 2/cos^(90-headtube angle). If your headtube angle is 74 degrees, then the increase in trail will be about 2.1mm. There is a difference of about 5% at this angle.
Didn't study your trigonometry, did you??scorpionking
Feb 12, 2003 6:45 AM
Is trail measured usually in centimeters?
not lately, butcyclopathic
Feb 12, 2003 7:07 AM
his headangle isn't 74. As he posted his trail is 5.0

trail = (WheelHight)/tan(HA)-rake/sin(HA) which gives us

trail = (WheelHight*cos(HA)-rake)/sin(HA) or
((trail*sin(HA)+rake)/WheelHight)**2 = 1-sin(HA)**2

or otherwise:

((trail/WH)**2+1)*sin(HA)**2 + 2*trail*rake*sin(HA)/WH + (rake/WH)**2 - 1 = 0

as you can see HA would be different depending on wheel and the tire size. You can only get 50mm trail with 43mm rake and 74 HA on 700c wheels with no tire mounted 8-P
re: Fork Rake, Trail and Neutral Steeringbcm119
Feb 12, 2003 12:52 PM
Go to this link

and email him your question. Include the stats he asks for and he will give you a very helpful reply.
dunno, but someone explain something for meDougSloan
Feb 12, 2003 1:02 PM
Why is it much easier to ride no hands on my track bike (Bianchi Pista) than on my regular road bikes? There is huge difference, and it seems this is opposite to what I'd expect.

No brake shifters and cables on Bianchi. (nm)micha
Feb 13, 2003 2:34 AM