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D-Fuse seatpost and saddle rotation

IanClementsIanClements Posts: 6
edited December 2017 in Road general
I've not posted on here before so hello everyone, I'm just looking for some advice on a new bike I've bought.

I did a lot of homework before I buying a Giant Defy Advanced Pro (2015) second hand off Ebay a couple of weeks ago but something I didn't realise is that the D-Fuse seatpost that comes with it is D shaped (of course) and cannot be rotated like a round seatpost. I'm used to riding with the saddle slightly to the right and my cleats adjusted so my feet point the same way so a straight saddle like this rubs on the left hand side. I've managed to put some insulation tape down the one side of the post before re-inserting it to get a very slight angle but less then I normally have.

I just wondered if anyone knew of any gadgets out there that might sit between the saddle and seatpost to allow me to rotate the saddle otherwise I might have to be selling the bike on. I don't get on with the 20mm setback either for that matter so any advice there would also be useful.


  • oxomanoxoman Posts: 11,726
    You might be able to physically adjust the saddle rail orientation to suit your required position by bending the rails somehow. Not ideal but people do it occasionally. Regarding the setback I've not come across anything myself, but it's not bothered me on either of my D post bikes. Only issue I've had is post slippage which was cured with carbon grease and a decent torque wrench. What about a noseless saddle or one with a narrower nose to what you have.
    Too many bikes according to Mrs O.
  • Funnily enough a friend of mine suggested that so I tried it with an old saddle but the rails wouldn't budge. I think it would be difficult to keep the alignment between the two rails also.

    I am looking at new saddles at the moment so will take on board your suggestion.
  • The RookieThe Rookie Posts: 27,811
    Setback just lengthens the cockpit, if its too long you bought the wrong sized frame in the first place and should of bought a size smaller.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • sandyballssandyballs Posts: 577
    With regard to the set back you might find it can be adjusted like the TCR vector. See link below and check.

    I do wonder though why you need the seat and your feet not facing ahead?
  • Setback just lengthens the cockpit, if its too long you bought the wrong sized frame in the first place and should have bought a size smaller.

    Point taken but I did check the Giant website for fitting, just assumed I would be able to swap out the seatpost for inline. It's not a major problem, I'm just used to getting more forward on the bike.
    I do wonder though why you need the seat and your feet not facing ahead?

    Though this was quite common in the cycling world? I have one leg slightly longer than the other so my feet naturally point towards the longer leg and pointing them straight causes knee problems.

    I'll open up the seat clamp and take a photo but I'm about to do the club ride so later.
  • Here's a couple of pics of the seat post, one with the clamp and one without. It doesn't look I can do much with it to be honest.


  • I realize this is a little dated now, but I was going to add my 2 cents.
    You could get some machining done at the seatpost cradle parts that contact the rails. I believe the default rail diameter is 7mm, so the default size of seatpost parts would have a 3.5mm radius. If you enlarged that radius an extra 0.75mm by a machine shop, then the parts would fit 8.5mm saddle rails. That might be just enough wiggle room to rotate the saddle. I would guess some 1mm shims might be needed to secure the desired angle. Or you could have a custom angled seatpost cradle machined from scratch for your particular situation.
  • Lol, yes it is a little dated and after a few rides on the Giant I decided it was slightly too big for me and not really any better than what I had, so I sold it on in the end and fell in love with my old Ribble again. As it happens I had a play with my saddle position in general and after several years of having an offset to the right I'm now riding straight and it seems to be fine.
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