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Too much weight on hands

roubaixtomroubaixtom Posts: 316
edited March 2016 in Road general
Hi,

I have just started to ride my 'best bike' as the weather is improving here in the UK and have noticed a problem I have suffered with slightly last season. I seem to have too much weight on the bars.

My winter bike and summer bike are set up exactly the same to the mm, same bars stem saddle etc but for some reason only on my summer bike i seem to get the problem.

Any ideas why this could be the case?

Posts

  • singletonsingleton Posts: 1,786
    roubaixtom wrote:
    I seem to have too much weight on the bars.

    My winter bike and summer bike are set up exactly the same to the mm, same bars stem saddle etc but for some reason only on my summer bike i seem to get the problem.

    Well, as you would expect, the obvious reply is that they would appear not to be set up exactly the same.

    The distribution of weight will be mostly down to geometry, but that would also include the frame geometry and also things like the angles of the handlebars and saddle - if the summer bike has the bars angled forward more then that will move your weight forward, or if the saddle is titlted more then it will throw your weight forward as well.

    Are they the same frame?
    Have you done something like measure with a tape the distance from the front hub and the back hub to the front of the stem and to the front & back of the saddle on both bikes? These are not "usualy" measurements but sometimes taking unusual measurements can help to identify differences.
  • onyourrightonyourright Posts: 509
    Excess weight on the hands usually means the saddle is too far forward. If the summer bike has a more aggressive seat-tube angle (e.g. 74° instead of 73°) that would make the difference.

    Slide the saddle back on its rails and lower it by a smaller amount to keep the saddle-to-crank distance the same.
  • roubaixtomroubaixtom Posts: 316
    The seat tube angle on summer bike is 74.5 and 73.5 on winter bike, would this make a big difference, approx how much more do i need to push the seat back on summer bike?
  • onyourrightonyourright Posts: 509
    It makes a big difference if it results in the saddle being farther forward compared to the bottom bracket. That is, if both saddles are clamped at the same spot on their rails.

    If you get a plumb line (piece of string with bolt tied to one end), hold it against the nose of the saddle, tilt the bicycle slightly off the vertical to let the string swing like a pendulum, wait for it to stop swinging, and measure horizontally from the string to the centre of the bottom bracket, you can adjust the saddles of both bicycles until this measurement is the same.

    If you don’t want to do all that: 73.5° versus 74.5° equates to a horizontal distance of about 13 mm at the saddle, for a typical saddle height (if you’re very short, try 11 mm; if you’re very tall, maybe 15 mm). So move the summer bike’s saddle backward by about that amount. While you’re at it, lower it by a couple of millimetres so the saddle-to-bottom-bracket distance (effective saddle height) doesn’t increase.

    By the way, 74.5° is a steep (aggressive) seat-tube angle and would often result in the problem you describe. Don’t worry if you need the saddle to be as far back as the rails allow.
  • Are the tyres the same? - This make a huge difference.
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  • ddraverddraver Posts: 21,694
    There was an article on the main site last summer about how to set up a road bike and an XC MTB so that you could swap between them. The idea was that you should set up the bikes so that the handlebar and saddle are rotating around a circle with the center at the BB. The idea being that if you shorten the stem or raise the bars, then the saddle position needs to move back and even down too (Or if you set the saddle position around the BB, then the bar position also needs to move).

    It sounds a bit like this isnt quite right between your two bikes. I sympathise as I'm struggling to set up a new winter bike build like my "summer" bike
    We're in danger of confusing passion with incompetence
    - @ddraver
  • Alex99Alex99 Posts: 1,407
    It makes a big difference if it results in the saddle being farther forward compared to the bottom bracket. That is, if both saddles are clamped at the same spot on their rails.

    If you get a plumb line (piece of string with bolt tied to one end), hold it against the nose of the saddle, tilt the bicycle slightly off the vertical to let the string swing like a pendulum, wait for it to stop swinging, and measure horizontally from the string to the centre of the bottom bracket, you can adjust the saddles of both bicycles until this measurement is the same.

    If you don’t want to do all that: 73.5° versus 74.5° equates to a horizontal distance of about 13 mm at the saddle, for a typical saddle height (if you’re very short, try 11 mm; if you’re very tall, maybe 15 mm). So move the summer bike’s saddle backward by about that amount. While you’re at it, lower it by a couple of millimetres so the saddle-to-bottom-bracket distance (effective saddle height) doesn’t increase.

    By the way, 74.5° is a steep (aggressive) seat-tube angle and would often result in the problem you describe. Don’t worry if you need the saddle to be as far back as the rails allow.

    Do the plumb line test as above. That is probably the simplest way to start. The saddle to bottom bracket relationship is your 'fixed point' to build the rest of the measurements on. Have you got the same saddle on both bikes? If you really want the same setup on both, this is important because otherwise, where would you measure to on the saddle? Saddles are all different and you sit on them is slightl different places.

    Once you have the horizontal saddle position measured, it is saddle-BB distance and level. I often do this by measuring just under the front of the saddle to the BB centre, and just under the rear of the saddle to the BB. This takes care of the saddle height and level (nose up vs nose down).

    Once you have got that right, then move on to saddle to handlebar drop and reach using the same fixed point on the saddle. I usually use the tip of the nose of the saddle.
  • roubaixtomroubaixtom Posts: 316
    Yes I do have the same saddles on both bikes. I haven't had a chance to be with both bikes since posting so at the weekend I will do all the tests that have been explained in this post.

    I do remember pushing the seat further back gave me lower back pain. Is it just a case of finding the balance point and pushing the seat slightly further forward than that.

    I wonder why they designed the frame with a 74.5 degree seat angle
  • Alex99Alex99 Posts: 1,407
    roubaixtom wrote:
    Yes I do have the same saddles on both bikes. I haven't had a chance to be with both bikes since posting so at the weekend I will do all the tests that have been explained in this post.

    I do remember pushing the seat further back gave me lower back pain. Is it just a case of finding the balance point and pushing the seat slightly further forward than that.

    I wonder why they designed the frame with a 74.5 degree seat angle

    I wouldn't worry about the angles too much. As mentioned, one degree in seat angle is just 1-1.5 cm adjustment on the saddle fore-aft. You only have an issue if you run out of adjustment range on the saddle rails, but then you can look to other seatposts if you need to. You're most of the way there if you already have one bike set up that works well for you. Just make careful measurements and you should get there with bike #2. Let us know what you find...
  • Alex99Alex99 Posts: 1,407
    roubaixtom wrote:
    Yes I do have the same saddles on both bikes. I haven't had a chance to be with both bikes since posting so at the weekend I will do all the tests that have been explained in this post.

    I do remember pushing the seat further back gave me lower back pain. Is it just a case of finding the balance point and pushing the seat slightly further forward than that.

    I wonder why they designed the frame with a 74.5 degree seat angle

    One more thing... are your cranks the same length?
  • onyourrightonyourright Posts: 509
    roubaixtom wrote:
    I do remember pushing the seat further back gave me lower back pain. Is it just a case of finding the balance point and pushing the seat slightly further forward than that.
    It’s about finding the balance, yes. Literally.

    However, with your weight properly supported on pedals and saddle, and only a small amount on your hands, a degree of core strength is needed – more so the lower you have your handlebars. Lack of that (i.e. lack of practice) may be why you got back pain. But luckily I don’t suffer from back pain, so don’t listen to me about that.
    roubaixtom wrote:
    I wonder why they designed the frame with a 74.5 degree seat angle
    I think it’s just about aping the pros. But pro racers put out much more power at about the same cadence as us, which means they push the pedals much harder. The counterweight of their bum therefore does not need to be as far back to keep their torso weight off their hands. Roughly speaking, the more power you put out, the more forward you need the saddle.

    That said, Boardman’s 1992 Lotus for the individual pursuit had a 72° seat-tube angle. Of course he only sat on the tip of the saddle for a few minutes. But still, it shows that road bikes have got a bit out of hand with seat-tube angles. A driver of steep angles may be the disputed idea that you can rotate your body forward around the bottom bracket for better aerodynamics at no cost.

    As Alex99 said, as long as you can position the saddle where you want, the tube angle doesn’t matter. It’s more of a problem with Brooks saddles as favoured by many long-distance riders, since those saddles sit relatively forward on the seat post.
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