User Tag List

Likes Likes:  0
Results 1 to 7 of 7

Thread: Steep seat tube angle!

  1. #1
    Join Date
    Dec 2011
    Location
    Greenville, SC
    Posts
    543
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Steep seat tube angle!

    An acquaintance is getting rid of a few bikes and offered me a decent deal on a carbon Wilier. It seemed like a reasonable fit, based on top tube, head tube length and seat tube length. Then I noticed that the 54cm (Medium) frame has a 74.5 degree STA. All Wilier frames have the same geometry. This is quite a bit steeper than a typical 54cm off the peg frame.

    I have long femurs for my height so this bike would be worthless to me without a 40mm setback post. That would not be proper. Is Wilier marketing to dachshunds?
     

  2. #2
    Join Date
    May 2008
    Location
    Better to be ruined than to be silent atmo.
    Posts
    19,887
    Post Thanks / Like
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    The angle is insignificant - the placement of the saddle above the central movement is what controls the lower body position. What is your saddle nose setback, and can it work on another frame you are looking at?

    No bike is worth anything, free or otherwise, if it doesn't fit atmo.

  3. #3
    Join Date
    Feb 2011
    Location
    Berkeley
    Posts
    1,010
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    Taller than you, also long of femur. Have an XL Wilier. The geo chart isn't in front of me but I found it not a great compromise. If I got back to leverage the femurs the steering was too twitchy for my taste. The best handling involved getting too far forward. Like the bike but too fussy to overlap fit and geometry venn diagrams. Bike was demoted on acquistion of a Pegoretti of the same TT length.
     

  4. #4
    Join Date
    Dec 2011
    Location
    Greenville, SC
    Posts
    543
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    Quote Originally Posted by e-RICHIE View Post
    The angle is insignificant - the placement of the saddle above the central movement is what controls the lower body position. What is your saddle nose setback, and can it work on another frame you are looking at?

    No bike is worth anything, free or otherwise, if it doesn't fit atmo.
    Please pardon my ignorance on this subject. I have 75mm of setback with my current setup. I could achieve the same position by rotating all contact points around the BB spindle? Lower bar and longer stem and I would be OK?

    I passed on the bike. Another black carbon bike from Asia is not my goal any more.
     

  5. #5
    Join Date
    May 2008
    Location
    Better to be ruined than to be silent atmo.
    Posts
    19,887
    Post Thanks / Like
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    Quote Originally Posted by houston View Post
    Please pardon my ignorance on this subject. I have 75mm of setback with my current setup. I could achieve the same position by rotating all contact points around the BB spindle? Lower bar and longer stem and I would be OK?
    No it wouldn't be okay. Because even though you may recreate your contact points, the wheels, their placement in the equation, and the CG won't change since the bicycle is already built. Even free would have been too much to pay atmo.

  6. #6
    Join Date
    Dec 2011
    Location
    Greenville, SC
    Posts
    543
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    Thank you for the insight. A huge markdown from "retail" can grab my attention more than it should.
     

  7. #7
    Join Date
    Nov 2008
    Location
    Alexandria, VA
    Posts
    1,405
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Steep seat tube angle!

    Quote Originally Posted by houston View Post
    Please pardon my ignorance on this subject. I have 75mm of setback with my current setup. I could achieve the same position by rotating all contact points around the BB spindle? Lower bar and longer stem and I would be OK?

    I passed on the bike. Another black carbon bike from Asia is not my goal any more.
    eR is (of course) right on this one, referring to his response below. "Rotating" changes everything and can go from an all-day comfortable position to a shit-I-can't-believe-how-terrible-this is, even with the same reach.

    But it can be complicated to go from one bike to another, cause even with replicating a position perfectly, there are a bunch of things on the builder's end that'll change how the bike feels. But here's how I look at translating one bike to another. Here's the buildsheet for my Hampco to help illustrate things:


    Round 2 by Cody Wms, on Flickr

    Reach is usually measured as front of the saddle to bars (let's ignore bar shape, drop, and stuff, too for now, though that can have a big effect). Reach now has two parts related to the bottom bracket, the saddle setback and the remaining reach from the center of the bottom bracket to the bars. Plug these two numbers in, get your saddle height and handlebar drop right and you'll have an idea if it'll work.

    I know with me, what you see with the Hampco is juuuust right. It's not uncommon for me to find a bike with 2 degrees more in seat tube and a cm or 1.5 cm in top tube. Now, if I actually fit myself to a bike that had both of these (~2cm of reach virtually added from the increased seat tube, and 1.5 in the actual top tube) I'd end up with an 85-90cm stem, which I feel is too short.

    Hope this helps.

Similar Threads

  1. Larger diameter top tube than Seat Tube
    By Micah Lee Vestal in forum The Path
    Replies: 19
    Last Post: 10-31-2012, 12:03 AM
  2. Cyclocross/gravel bikes and head tube angle
    By hummus it in forum General Discussion
    Replies: 10
    Last Post: 10-20-2012, 10:38 AM
  3. Seat Tube Angle vs. saddle set back vs weight distribution
    By Cfish in forum General Discussion
    Replies: 11
    Last Post: 02-10-2012, 07:50 PM
  4. head tube angle on MTB bikes
    By luaxwe in forum General Discussion
    Replies: 0
    Last Post: 11-01-2010, 10:58 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •