Forum home Road cycling forum Workshop

De Rosa SK 2017 and saddle height

fr4ncisfr4ncis Posts: 4
edited January 2019 in Workshop
I just got a De Rosa SK 2017, size 52 (so it should fit perfectly as I am 5ft7), the saddle, however, does not seem to go down than 1.5cm from the minimum insert, which seems to me very little to play with in terms of saddle height.

Does anyone with an SK encounter the same issue? Does the inside of your frame have the same obstruction (as in the pictures) preventing the saddle from going any lower?

Inside the frame, the obstruction:
IMG_20171111_210357405.jpg
Highest set up:
IMG_20171117_081000042.jpg
Lowest set up:
IMG_20171117_081013892.jpg
Lowest set up, outside the frame:
IMG_20171117_081058941.jpg

Posts

  • This isn't uncommon in bikes that come with one size of post to fit all frames. You'll need to cut the post.

    My Foil in small came with a size specific post, but I needed a 25mm set back so had to get the large post which required 30mm off the end to fit in the frame.
  • Thank you for your reply.

    The problem with cutting the post is that I would have only ~1.5cm to move the saddle up later on, in case I want to go for a more aero position (between the minimum insertion and the lowest possible saddle position, see highest/lowest position pictures).

    Is it normal for aero road bikes to allow an adjustment of only 1.5cm in saddle height?
  • 52 is pretty big for your height. I'm nearly 5'9 and ride a 52 SK and could have probably gone smaller. Having said that, I'm long legged and short torso so I find the long top tube a stretch on aero road bikes.
    I had a 52 idol and that came up bigger than any other 54 bike I've ever ridden. I had to cut a fair chunk off my SK seatpost. Not sure what you mean about going for a more aero position. That's surely dictated by bar height not seat height?
    argon 18 e116 2013 Vision Metron 80
    Bianchi Oltre XR Sram Red E-tap, Fulcrum racing speed xlr
    De Rosa SK pininfarina disc
    S Works Tarmac e-tap 2017
    Rose pro sl disc
  • That obstruction in the seat post should not be there. Clearly a manufacturing defect. There is no way the seat height adjustment should be so limited. Do not do any cutting until you've spoken to the vendor and the manufacturer. A selection of long square and triangular files may clear the obstruction assuming that it's no more than a resin deposit. Even then I wouldn't start messing around until you have clarity as to whether there is a potential structural problem with the seat tube.
  • That obstruction in the seat post should not be there. Clearly a manufacturing defect. There is no way the seat height adjustment should be so limited. Do not do any cutting until you've spoken to the vendor and the manufacturer. A selection of long square and triangular files may clear the obstruction assuming that it's no more than a resin deposit. Even then I wouldn't start messing around until you have clarity as to whether there is a potential structural problem with the seat tube.
  • gazza1286 wrote:
    That obstruction in the seat post should not be there. Clearly a manufacturing defect. There is no way the seat height adjustment should be so limited. Do not do any cutting until you've spoken to the vendor and the manufacturer. A selection of long square and triangular files may clear the obstruction assuming that it's no more than a resin deposit. Even then I wouldn't start messing around until you have clarity as to whether there is a potential structural problem with the seat tube.

    I'm pretty sure you'll find you have to cut the post. By all means contact the supplier if it concerns you but the base of the post is only going to go as far as the curved seat tube will allow it to. There has to be an obstruction manufactured in to an aero bike seat tube otherwise if the post slips down it's likely to break through the curved part of the tube surrounding the rear wheel. Being an owner of an SK I'm fairly convinced you don't have a problem although I'd be very tempted to swap it for a 50cm size if I were you.
    argon 18 e116 2013 Vision Metron 80
    Bianchi Oltre XR Sram Red E-tap, Fulcrum racing speed xlr
    De Rosa SK pininfarina disc
    S Works Tarmac e-tap 2017
    Rose pro sl disc
  • 47p247p2 Posts: 329
    The seat tube is designed to not allow the post to slip down and therefore you need to cut the bottom of the post to obtain the correct height. Best to remove the excess material a little at a time, make sure you cut the post square with a fine tooth saw then a light rub with fine sandpaper and apply carbon paste before refitting
  • Thank you all for your replies,
    noodleman you confirm your saddle on the SK can move up and down only by 1.5cm?

    Attached for reference are the measurements of min insertion and the deepest (max height), as you can see it's less than 1.5cm.

    IMG_20171118_171104204.jpg
    IMG_20171118_171040388.jpg
  • The guys above are correct, and I repeat my own post, you need to cut it to fit in a smaller frame. If you put that post in a larger frame you would have more room to move and even more room to move in the size above that, because it’s a one size post.
  • fr4ncis wrote:
    Thank you all for your replies,
    noodleman you confirm your saddle on the SK can move up and down only by 1.5cm?

    Attached for reference are the measurements of min insertion and the deepest (max height), as you can see it's less than 1.5cm.

    IMG_20171118_171104204.jpg
    IMG_20171118_171040388.jpg

    My seatpost measures 55mm from the red dot of the minimum insertion point to the base. With that you can see compared to yours how much I cut off. At this length it exactly hits the stop point but into the seat tube. It's honestly not a design fault and in fact I had to do the same with my wife's liv envie seatpost. Hope this helps. For what it's worth my post is set at number 4 on the markings. Cheers.
    Edit: With your height I guess you'll be around 3 or so on the seatpost markings. You'll need to cut a fair amount off. I actually think it's a good idea to cut it so that it sits on the stops in the tube. That way if you have any seatpost slippage it won't cause a problem and you'll also know you've left a safe amount inside the tube.
    argon 18 e116 2013 Vision Metron 80
    Bianchi Oltre XR Sram Red E-tap, Fulcrum racing speed xlr
    De Rosa SK pininfarina disc
    S Works Tarmac e-tap 2017
    Rose pro sl disc
  • Could an owner of a De Rosa SK do me a great favor and measure the total seat post length? Preferably on a size 540?
    I have heard 380mm but would love to see it confirmed before ordering a frame... Many thanks in advance!
    What are your experiences with the frame?
Sign In or Register to comment.