Fork rake - does 5 mm make much difference?



grahammackie

New Member
Aug 7, 2005
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Trying to build up my new Kinesis Racelight KIC frame on a budget as a trainer and need some carbon forks. Have found a pair in the classifieds but they are a 40mm rake - I thought that 45mm was 'standard'. What differnce to the handling/ride will a 40 mm rake make - will it be noticeable when riding ?

thanks
 

531Aussie

Well-Known Member
Apr 11, 2004
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It may feel more twitchy, but it's not a certainty. Different materials and blade design have more effect on handling than rake. So, if it's a totally different fork, it might feel totally different in spite of the rake.

Unless the blade length is very different, it should bring the front wheel ~5mm closer to your toes
 

serenaslu

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Feb 3, 2004
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grahammackie said:
Trying to build up my new Kinesis Racelight KIC frame on a budget as a trainer and need some carbon forks. Have found a pair in the classifieds but they are a 40mm rake - I thought that 45mm was 'standard'. What differnce to the handling/ride will a 40 mm rake make - will it be noticeable when riding ?

thanks
As Aussie said it's hard to quantify what effect will be noticeable. One thing to keep in mind, however, is that what really affects the bikes handling is the change in trail, which is set not only by the fork rake but also the frames geometry. So rake change will have different overall impact depending upon the frameset. The effect can often be counterintuitive to one's first thoughts. A pretty good concise explanation of trail can be found below.
This link has a pretty good discussion of the effect of rake on trail and it's relationship to handling. Other minor issues such as wheelbase extension, etc. are ignored though.

http://www.phred.org/~josh/bike/trail.html

( link excerpted from http://www.sheldonbrown.com/gloss_tp-z.html#trail )
 

John M

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Jun 21, 2005
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531Aussie said:
It may feel more twitchy, but it's not a certainty. Different materials and blade design have more effect on handling than rake. So, if it's a totally different fork, it might feel totally different in spite of the rake.

Unless the blade length is very different, it should bring the front wheel ~5mm closer to your toes

I agree with the comments about fork material and the wheel being closer to the toes, but I believe that decreasing fork rake will increase trail and make the bike feel more stable (less twitchy).

See Zinn's chapter:

http://www.velonews.com/media/Block40.pdf
 

531Aussie

Well-Known Member
Apr 11, 2004
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yes, all very important information, but I'm tellin' ya that blade design, material, length and rigidity/flex do much more to alter handling than the geometric variables.:)