Forum home Mountain biking forum MTB beginners

Wrong size bike?

RockmonkeySCRockmonkeySC Posts: 15,247
edited July 2010 in MTB beginners
I have just picked up a nice new Giant Trance X. When I rode it around the shop car park it felt fine but after a blast around the local woods I realised that my seat post is raised to its limit line & I need another inch (maybe inch and a half). Have I bought the wrong size frame or can I fit a longer seat post?
I didn't seem to have enough clearance over the top tube on a large frame. I normally ride a 19" hardtail and my new bike is a medium (18")

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    stand over clearance does not really apply to fullys.

    yes the bike might be too small.

    I would be on the phone to the shop about your options as it is so new.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • RockmonkeySCRockmonkeySC Posts: 15,247
    censored . I'm not sure if they will take it back. I know Giant have sold out of large & medium Trance X's so they won't be able to exchange it. I had to phone around several dealers to find this one.
  • stu8975stu8975 Posts: 1,334
    Tis deceptive on the Trance X as the top tube isn't a straight tube, so bit harder to judge, but depending on what size post you have fitted, new one is easy fix, but you haven't mentioned how tall are you/inside leg? to check if frame is too small..Measure your frame..My 2 Anthems I've had were both mediums and both measured 17.5in (older version and my current Anthem X).
  • RockmonkeySCRockmonkeySC Posts: 15,247
    It's a 350mm post. I'm 5' 11"not sure of my leg length.
    The frame is 18"
  • nickfrognickfrog Posts: 610
    You need to measure the effective top tube, ie from the top centre of head tube to where a horizontal line crosses the middle of the seat post and then compare to whatever effective top tube lenght you had on previous bike. I guess you need around 580mm/590mm depending on your morphology? 400mm seat post is easy to source.
  • nicklousenicklouse Posts: 81,520 Lives Here
    guess what Giant list as the TT length. again dont know how they measure it but 585mm

    again talk to the shop that sold it they will be more than likely be more than happy to sort you out.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • AnonymousAnonymous Posts: 79,692
    nicklouse wrote:
    stand over clearance does not really apply to fullys.
    Ah, was that the result of your experiment? I was wondering wht happened to that.
  • RockmonkeySCRockmonkeySC Posts: 15,247
    The shop won't take it back. They said they cant take back any bike that has left the shop unless it has a fault.
    My inside leg measurement is 33/34 inches, the person I spoke to at the shop said that a medium frame should be right for me and that I should try shifting the saddle on it's rails and maybe fit a 400mm seat post. He also suggested that maybe I was trying to raise the saddle a little too high for mayelf and that maybe I had it too high on my other bike
  • jaysonjayson Posts: 4,606
    A slightly smaller is sometimes preferable over a larger one interms of how the bike feels underneath u, its more nimble and agile than a bigger bike.

    Its easy to fit a longer seatpost no probs at all but to be honest you'll prob be standing up most of the time when ur off road anyways so it really wont be an issue.
  • RockmonkeySCRockmonkeySC Posts: 15,247
    Thanks for the advice. I will fit a 400mm seat post & maybe experiment with moving the seat on it's rails & maybe a slightly longer stem.
    I spoke to a friend today who used to race a lot, he is an inch taller than me & rides a 17" GT Avalanche because he prefers the feel of a smaller bike.
  • nickfrognickfrog Posts: 610
    What's important is not so much the size of the seat tube but the length of the top tube anyway.
  • RockmonkeySCRockmonkeySC Posts: 15,247
    I raised the seat post half an inch above the limit line & the bike feels spot on! I cant belive half an inch made so much difference to the feel on the bike!
    The riding position is now much better than my specialized. Now I just need too fight off the Glastonbury festival sickness & diarhea bug so that I can get out for a proper ride! Quantocks this weekend I think.
  • RockmonkeySCRockmonkeySC Posts: 15,247
    I have now fitted a longer seat post, it's about an inch higer than shown in the photo http://www.bikeradar.com/forums/viewtop ... t=12712794

    It looks a bit high for the frame, it feels ok to ride. I'm still not sure if I should sell the bike (or frame) and go back to a 19" hardtail?
    Should I have gone for the 20" large frame, I'm 5"11 with 33"/34" inside leg?
  • nickfrognickfrog Posts: 610
    Again (and apologies if I repeat myself), the height of the seat tube is irrelevant, it's the TOP TUBE length that is important, ie the reach. Have you measured/compared it bike to bike ?
  • RockmonkeySCRockmonkeySC Posts: 15,247
    Not sure exactly how the top tube is measured. I measured from the centre of the head tube to the centre of the seat post, measuring this horizontally the Trance is near enough exactly the same length as my Hardrock, though the Trance actually feels a little longer.
    I went out for another ride this afternoon & it felt pretty good, I landed a couple small jumps nice & smooth, rode rocky downhills fast & smooth (for me) though I did find pedaling more hard work than the Hardrock but that bike does have slicker tyres & lower bars & I kind of expect the Trance to be a little more hard work though it does climb better than the Hardrock.
    It still looks wrong to me having the seat post out that far. I have fitted an Easton 400mm post which is out about 15mm higher than where the limit line on the 350mm Giant seat post was.
  • nickfrognickfrog Posts: 610
    Don't worry about it. That's precisely why they make 400mm posts, isn't it ?
  • Happy HarryHappy Harry Posts: 345
    Good to see you're out and about again, Rockmonkey. I hope your arm's healed up OK!
    Canyon XC 8.0 '11
    Whyte 19 steel '10
  • RockmonkeySCRockmonkeySC Posts: 15,247
    It's not too bad. A week on Cornwalls sunniest beaches helped! Riding this morning didnt hurt but picking up a bag of shopping this afternoon was very painfull (arm & wallet). Looking forward to 10 miles of excellent woodland singletrack before work tomorrow morning.
    Maybe if I fit one of those new Rockshox seat posts it won't look so odd.
Sign In or Register to comment.