fork rake question for an Extralight...

Discussion in 'Cycling Equipment' started by merkincycle, Mar 24, 2006.

  1. merkincycle

    merkincycle New Member

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    I just got a Merlin Extralight frame (59) and it recommends a fork with 40mm of rake. I was looking at either the Ouzo, which comes in 40mm amoung other rakes, or an Easton EC90, which only comes in 43mm of rake. Would the handling hairy if I went with the EC90? Anybody with any experience with this? Thanks for the input...
     
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  2. free_rideman

    free_rideman New Member

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    With extra rake it will feel weird. Probably too sluggish? Since going the other way definitely makes it hairy (going with less rake than was designed).

    Anyways, I don't know your buddget, but get the Ouzo Pro. It is a really light, and sexy fork.
     
  3. John M

    John M New Member

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    freeride is not quite correct. Decreasing rake increases stability because it increases trail. Most people probably cannot notice 3mm difference in rake, but the technically correct answer is that increasing the rake will decrease trail and make the steering feel quicker. People get confused because many touring and MTB bikes have long rake forks and they are quite stable. That is because they have slacker head angles which also contributes to trail and stability.

    Probably best to get the fork with the rake recommended by Merlin. The Ouzo forks are definitely nice enough to grace your Extralight.
     
  4. free_rideman

    free_rideman New Member

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    sorry about that. not to start new threads, what is trail?
     
  5. merkincycle

    merkincycle New Member

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    well, then 40mm rake it is....maybe those guys at Merlin know a think or two...now anybody have any new excuses for getting extra cash out of the wife...I'm scraping the bottom of the barrel :D
     
  6. Insight Driver

    Insight Driver New Member

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    Trail is the difference in where the tire contact patch is, relative to the imaginary line that goes through the centerline of the headset angle. It is calculated mathematically by taking the headset angle, wheel diameter and fork rake. There are plenty of sites that go into detail on the nuts and bolts. What is counter-intuitive about fork rake is that increasing fork rake actually decreases train, all other things remaining equal. There is online someplace a good article I read about a guy who did experiments with trail, trying to find a bike setup that would be unrideable due to negative trail (you can see negative trail on a shopping cart caster; because it's negative is why you see a lot of them oscillating side to side as you push the cart). The results as I recall (keeping in mind that recall is not like a recording) was that even an unstable trail bike can be ridden successfully. You could see how unstable it was by just pushing the bike without rider. The conclusion was that we are able to control a bike, even if it is unstable. This is why some people prefer to say the steering is quicker or slower.
     
  7. John M

    John M New Member

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    More than you all want to know about fork rake and trail:

    Take a look at this chapter from Lennard Zinn's book which is available through the velonews website that discusses frame geometry and stability.

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

    Another page that defines "trail" nicely:
    http://www.phred.org/~josh/bike/trail.html
     
  8. Insight Driver

    Insight Driver New Member

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    John M, thanks. That is the article on Velonews that I had read. Interesting stuff it is. Free_rideman, enjoy the articles and let us know if you liked them. There is so much fascinating stuff on bicycling online.
     
  9. free_rideman

    free_rideman New Member

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    That was awesome! Some more brain knowledge that I know can pass on in the future!!!!!
     
  10. dhk

    dhk New Member

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    Definately go with the Ouzo Pro in the recommended 40 mm rake for your new Merlin. This is not the time to save a few bucks; get the best fork with the right geometry.
     
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