Please explain Fork Rake...
09-01-09, 11:48 AM
#1
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Please explain Fork Rake...
Hello,
Would like to replace the heavy as lead Ultra fork on my CAAD9 with a 3T or Easton - what will changing the fork rake do to my set up? Will I notice going from the stock 45mm to 43mm? Is handling the bike going to change? Will I be shortening the wheelbase? Will I care?
Thanks all.
Would like to replace the heavy as lead Ultra fork on my CAAD9 with a 3T or Easton - what will changing the fork rake do to my set up? Will I notice going from the stock 45mm to 43mm? Is handling the bike going to change? Will I be shortening the wheelbase? Will I care?
Thanks all.
09-01-09, 12:47 PM
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It'll shorten the wb by 2mm. All else equal, it make the bike handle a bit quicker and make you feel the front wheel a bit more. You get to decide if this is desirable. To picture it, the fork curves forward a bit less, and the front wheel axle ends up more vertically aligned with your handlebars.
09-01-09, 01:15 PM
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Fork Rake = the amount the axle is offset from the steering tube centerline.
Trail = the distance between where the line drawn vertically from the axle center to the center of the tire contact patch, and where the line drawn thru the center of the head tube intersects the pavement.
Less Rake (offset) = More Trail.
Trail = the distance between where the line drawn vertically from the axle center to the center of the tire contact patch, and where the line drawn thru the center of the head tube intersects the pavement.
Less Rake (offset) = More Trail.
09-01-09, 01:23 PM
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To answer the original post, going to the fork with less rake will result in more trail, resulting in a slower turning, more stable bike.
https://velonews.com/article/7322
https://velonews.com/article/7322
09-01-09, 01:37 PM
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To answer the original post, going to the fork with less rake will result in more trail, resulting in a slower turning, more stable bike.
https://velonews.com/article/7322
https://velonews.com/article/7322
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09-01-09, 01:38 PM
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Oops - dsb and wai are right - I was confusing rake and trail - go with what they said.
09-01-09, 01:44 PM
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09-01-09, 01:44 PM
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do you know what the weight savings will be?
a 2mm difference will be hard to notice, i suspect the weight savings might be too...
a 2mm difference will be hard to notice, i suspect the weight savings might be too...
09-01-09, 02:41 PM
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Trail = R/tanH - (rake/sinH). From this equation it is obvious that all rake reduces the trail. Smaller trails will make the bike steer quicker.
What is often overlooked is fork length. Not all forks are the same length and some don't even list the length. 367mm is quite common, but you might find one as short as 365mm or as long as 374mm That 9mm difference will change the head tube angle (H) by about .5 degree and change the trail by 3mm. That could cancel out any change or double it.
What is often overlooked is fork length. Not all forks are the same length and some don't even list the length. 367mm is quite common, but you might find one as short as 365mm or as long as 374mm That 9mm difference will change the head tube angle (H) by about .5 degree and change the trail by 3mm. That could cancel out any change or double it.
