top tube length...............

brutaldeluxe09
brutaldeluxe09 Posts: 96
edited August 2010 in MTB general
I'm having a little trouble with my top tube length on a new second bike that I have, I feel like it is a little too short but it is in fact a fraction longer than the top tube on my main bike, which feels just right. The angles are different on each as they are for slightly different purposes with this new bike having a steeper head and seat angle which I think may be the problem.

I've put the measurements down, anyone got any ideas why the top tube feels short and what would be the best way to lenghten my reach? I suppose longer stem is my only option?

New Bike: Old Bike:

Seat Tube 16" 17.5"

Top Tube 23.18" 23"

Head Angle 70 66

Seat Tube Angle 73 70

Standover 28.18" 29.6"

Stem Length 50mm 50mm

If I've missed anything let me know.

Thanks

James

Comments

  • nicklouse
    nicklouse Posts: 50,675
    ok so what are the two bikes?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • supersonic
    supersonic Posts: 82,708
    Is it actual or effective top tube length? Look at the seat angles - the slacker the angle,the further back you are sitting behind the bottom bracket. Your new bike is steeper, you are further forward, possibly decreasing the ETT.

    Try sliding your rails slightly back on the saddle.
  • got a Cove Stiffee 2007 which I use for all sorts, also now have an On-One Inbred set-up single speed which I use to ride to work and then hit the local woods on the way home. Riding the Stiffee to work was overkill but still wanted something that could take lite trail riding too.

    Yeah I see how seat angle is playing a big part in the feel of the top tube length, didn't think about that when sizing up, I was just looking at seat tube / top tube length. So the 3 degrees makes about the right difference, will try moving saddle to see if that helps but I think I may have already moved as far back as possible. Is there a general rule as to how much length I will need to add to a stem for each degree of difference in seat tube angle.
  • supersonic
    supersonic Posts: 82,708
    No rules, just what feels best to you. If you cannot get a good handling, comfortable set up then I am afraid you have bought the wrong frame, or frame size.
  • nicklouse
    nicklouse Posts: 50,675
    so the stiffee is the old bike.

    also consider this do both the makers measure the same way?

    are both ETT Length or is one "measured"

    do you have a lay back seat post on the On One?

    and i would be looking at a 100mm stem on a SS XCish bike.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Yeah I keep thinking that maybe it's just not the bike for me but I do like it alot, I went for medium and at 5ft 8" I thought that sounded OK, I certainly think large would be to big at 18" and small too small at 14". I will try to add 10-20mm to the stem I suppose and see if that helps.

    So I'm going to look at a full suspension soon to replace the Cove, quite like the Blur 4x but the medium has got an even shorter 22.3" top tube and a 73.5 seat angle although a 68.5 head angle so will that be even worse? or will the slacker head angle help enough to not make it feel to small?

    Appreciate the speedy reply by the way, just tried to talk it through with the lady as she loves a good maths problem but when she found out it involved bikes she soon switched off. :D
  • nicklouse
    nicklouse Posts: 50,675
    sorry get arse on bike.

    or find out how they have measured things and make sure you use the measurements that are worked out the same way.

    the hardest things are the angles are they measured at Sag? full fork extension? or with a fork of AC length of X?

    my SS XC has a seat tube of 44cm and a ETT of 56cm 17" and a bit and 22 and i run a 105mm stem and no set back on the seat post. and i am about your height but dont know about leg length.

    have fun.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Anonymous
    Anonymous Posts: 79,667
    It might just be different to your old bike, which will take some getting used to.