Leisesturm

My squatting form has been called 'impeccable' by observers. I know very well how many inches my hoo hoo needs to move rearward to keep me from falling on my face and it is much more than a couple or three inches! Maybe a crank forward design has that kind of rearward displacement of the saddle but nothing commercially available in a drop handlebar design does. Considerable weight on the hands and arms is thus an unavoidable trade-off to obtain the aerodynamic efficiency that makes commuting and sport cycling enjoyable and practical.

To be technical about it, you do NOT use your core muscles to hold your torso up when you are in riding position. You use your back muscles! Muscles can only contract. Your core muscles can do nothing about the forces that are pressing your torso down towards the bars. Only your back muscles can do that. And they get very strong as a result. Your core, not so much. Your core, however, is constantly needed to oppose the back muscles. To hold a desired position requires the continual interaction of both sets of muscles, one set of which is always working at a mechanical advantage. Over time, the muscles working through more mechanical advantage get weak and undeveloped. It is the imbalance in muscular development between your back muscles and your core muscles that lead to chronic, often acute, back pain and injury.

It was to address this often overlooked aspect of fitness why I mentioned abdominal exercise in my last post. You don't need to do 200 crunches to ride a bike, you need to do 200 crunches 3x/wk so that when you are 55 you won't be sitting in an orthopedic surgeons consultation room learning about the gory details of your upcoming back surgery. One of my riding buddies is 63 and he was facing surgery. One of my good friends is a chiropractor and he told me to try and convince my riding friend to opt out of a surgical intervention. Luckily his wife was also of that opinion and so between the two of us we got him on an abdominal exercise regimen. At present he is no worse than many people who have actually undergone back surgery and does not have any of the expense or possible complications of back surgery. Lets get back to bikes.

Riding very erect will take the weight off your arms and hands but, as noted will kill your aero big time. It also reduces the amount of power you can apply to the pedals. This is a double hit on performance. You are not going to show up to a club ride on a cruiser and wipe up the floor with roadies rocking quasi-time trial machinery. It's just not gonna happen. You can train your arms to hold up a lot of the weight of your torso and the ladies will love you for it. Your hands may complain. Drop bars have lots of alternate positions to give hand muscles opportunity to relax and get blood flow. Use them. Ride the drops occasionally even if you aren't going after a personal best.

The bottom line is, if you are set up correctly, there is going to be considerable weight on your arms and hands on even what we call flat-bar road bikes. You have to go to a very extreme cruiser or Dutch bike riding position where the bars are not only 4" to 6" above saddle height but are also pulled towards you so that the grips are practically in your lap. The Dutch ride like that around town for a couple or three miles but when they want to cover distance they ride bikes that look much like what we use and call drop handlebar road bicycles. I'm surprised no one has mentioned recumbents <running, ducking>

GeneO 

No, it is right. If you are moving the handlebars straight up, you are stretching yourself out more and may even move the COG forward, putting more stress on your hands.

If you are rotating your whole body up while maintaining the same reach R (say by rotating a stem or both raising the bar and shortening the stem say), and the result is a bar higher by height H then you have shifted the horizontal projection of your reach back by distance R*(1 - sqrt(1-(H/R)**2). For H small compared to R, this is (R/2)*(H/R)**2. So if you move rotate your bars up to a height of say 3" this is something like a 0.2" shift of your back. Not much.

Leisesturm

Your entire first paragraph is nonsensical and wrong. Hamilton is saying a lot of correct things in his posts, without using abstract geometric formulae and verbiage which just get in the way of what is rather simple physics.

H

GeneO 

If you are pitched forward because your center of gravity is far too forward, raising the bar will not help. IMO you should get your balance on the bike independent of where the handlebar is by adjusting the seat fore/aft.

As for my first paragraph being nonsensical, do an exercise. Face a wall and put your arms out straight out with your fingertips touching the wall. Now raise your hands 3 to 4 feet up, keeping in touch with the wall and not moving your butt. Exaggerated, but that is all I meant. Head tube angle probably keeps your reach constant as you raise the bar though.

Leisesturm

Really? Weren't you the one who said: "...then you have shifted the horizontal projection of your reach back by distance R*(1 - sqrt(1-(H/R)**2). For H small compared to R, this is (R/2)*(H/R)**2. ..this is something like a 0.2" shift ... Not much. ". A wise person once said 'a little knowledge is a dangerous thing". I won't take anything seriously in this forum until road bikes come stock with the kind of adjustment capability found in the average folding bicycle. However even folding bikes rarely adjust for reach. My old folder had a reach such that I could achieve a similar position to my commuter. My new folder has such a short reach that when I put my elbow on the seat the handlebar is at my knuckles!! You know what? Even with that erect a torso, and you better believe it is pretty erect. I have enough pressure on my hands to make Ergon grips worth the $$$.

H

jyl

I'm not sure if raising the stem will stretch the rider out further? But the original point was, I think, correct. The more leaned-forward the rider's torso is, the less the rider's CG moves rearward for a given raise of the handlebars.

As an extreme example, suppose the rider is initially in a completely flat back position, such that the line segment from his hips to his shoulder is parallel to the ground. His CG is roughly at his belly button. Then raise his hands a few inches. That raises the shoulder end of the line segment by a few inches, raises his CG by a couple inches, and moves his CG rearward by only a very small amount.

Attached below is a stick diagram illustrating this. Assume shoulder-to-hip distance 24 inch, start with shoulder-to-hip line horizontal (0 degrees), now raise shoulder 4 inch, the shoulder-to-hip line is now at 9.6 degrees, assume CG is on the shoulder-to-hip line 8 inches from hip, the CG is moved rearward by 0.1 inch.

This is just an approximation. In such a position, the CG is actually probably below his belly button (outside of the rider's body).

Of course, as the rider's initial position gets closer to fully upright, then raising the handlebar has a larger rearward effect on his CG position.

wphamilton

You're off by an order of magnitude in your example. I'm not going over the math but you'd be better off using trig directly.

The bolded part is also incorrect, for several reasons, but it's not really worth arguing over.

Raising the handlebar will reduce weight on the hands, and reduce stress on the core. Increasing the reach, by either longer stem or moving the seat back will slightly increase static weight on the hands.

I'll stand by my earlier surmise that those considerations are mostly irrelevant, and that core strength and hand positioning is more apt to provide a solution.

GeneO 

Well I said if you moved the bar straight up. But that is not what you usually do and because of the head tube angle, the bar moves up and back. I was just trying to illustrate you have to change the bar height a lot to get a small change in the COG.

The calculation of the geometry I did was the same as in your figure, but I expressed it in terms of vertical height instead of angle.

GeneO 

[QUOTE=wphamilton;16985890]You're off by an order of magnitude in your example. I'm not going over the math but you'd be better off using trig directly.
QUOTE]

Please if you are stating I am off by an order of magnitude, then do the math and show me. I am not off. I will draw a picture for you later if I get time if it will make you happy.

wphamilton

Apologies, but I was serious that I'm not going over the math. Make some reasonable assumptions on torso angle eg 40°, torso height, head tube angle etc and use actual trigonometry and it will be more clear.

jyl

Yes, when doing a deep squat with 200 lb on the bar, your butt has to move way far back to keep you fully balanced - about as far as your thighs are long, assuming you go to thighs horizontal. On road bike, we are not carrying 200 lb on our shoulders, not doing a deep squat, and we don't need to get completely balanced - since we can tolerate applying a small force on the handlebars with our hands, and our core muscles (including the back) are only being asked to support our torso, not torso plus 200 lb. So moving our butt back even a couple of inches has a sufficient effect, in terms of reducing the force of hands on handlebar from "too much" to "okay".

Agreed, it is important to maintain core strength as we age. But I don't think riding a road bike is the biggest demand on our core strength, assuming the person is normally active. If all we do is lay in bed when we're not riding the bike, then maybe it is.

GeneO 

Those factors have only a second order effect and don't change things.

This is turning into a pointless argument as you are not willing to show me how raising the bar really helps (assuming it is weight too far forward), so I have said my piece and stand by what I posted - that if there is too much pressure on your hands, it is probably because your COG is to forward, and the first thing you should try is to make sure you are balanced and set your seat back if you are not.

I think jyi and I are in agreement here.

wphamilton

As I said, I don't argue about math - it's either right or it isn't, and any arguing over it is pointless.

COG forward is just another way of saying leaning forward. The weight is relative to the seat and bar (not the feet), dependent on total torso weight (and including arms weight), torso angle and how much if any is reduced by pedal pressure. That's it for weight. That's enough for anyone to reason through these issues.

There can also be a small amount of horizontal pressure, especially if there is a fit problem. I believe that moving the seat back, or perhaps tilting up, can sometimes alleviate that. That's really where "bike fit" comes into play - all this about crouching over the seat and sliding back in your easy chair is just misapplied analogy.

StanSeven

Yes. The saddle is pointed way down. You mentioned trying different positions including level and up but is your "level" have the nose even with the center of the saddle (part you mostly sit on) or the back of the saddle. "Level" for most saddles is the nose to about the middle. You have all the classic symptoms of a saddle tilted forward.

skycyclepilot

That must be an optical illusion created by the angle of the camera with respect to the bicycle. I leveled the saddle by placing a flat board on top of the saddle - a board big enough to completely cover the saddle. The board was resting on the highest spots at the front and at the rear of the saddle. I then placed a digital level on the saddle. I then set the tilt to 0.0°.

wingtipsdown

This is my reply, only my opinion.

I started getting a little pressure in my hands that wasn't there in my old Schwinn.

The actual fix was me reminding myself to position my weight through my tail bone. Stop letting your upper body weight against your hands into the handlebar. In other words balance yourself on the saddle and relax.

Your neck. Just don't look all the way out in front so often. Relax your neck and only look a little ahead, but look further out time to time.
Example: I look out 200 yards, relax and only look out about 40 yrds. I go that 40 yrds, then look out to 200 yrds again, relax go 40 yrds, then look out again. I'm not constantly bending my upper neck to look as far as I can all the time.

Good luck...

wphamilton

I think that the photo is slanted by about 5° because the bike seat looks exactly in line with the baseboard, perfectly level.

skycyclepilot

Probably so. I took the photo with a tablet - no tripod. At one point, I did have the saddle nose down by 2°, but never more than that.

skycyclepilot

I'll check this when I get home, but looking at the geometry table for the bike, the top tube and stem total 26", and my elbow to fingertip length is 20". The seat is four or five inches in front of the post, but that still makes the nose to handlebar length 21 or 22". My fingertips are probably going to come up an inch or two short of the bar, if not more.

wingtipsdown

Did you purchase your bike from Middletown cycle and fitness?
If not, call them - they are good people that could possibly help. Giant Dealer

I have your same bike, but I have the stock seat.
What I listed above is what works for me, I'm 49 and have only been riding for a few months.
My 1982 Schwinn felt great. When I was actually fit to the Defy 1 - everything felt different for a few days, but all as settled in well for me.
I will be replacing the seat by mid September. I need a more comfortable seat, but the current seat isn't killing me. Hopefully by September - I will be a little lighter as well.

Leisesturm

In the center photo there are viertical lines that are reasonably close to vertical in the photo. There have been worse photos submitted for evaluation purposes. That said. I agree, and said as much earlier, that the saddle is not level. I don't really care about the care that was taken in measuring level. And neither does the riders butt. I have two saddles that are constructed in such a way that I have to tilt the nose of the saddle rather steeply upward to achieve a level surface at the rear section of the saddle where actual contact is made. On such a saddle there will be perineal pressure if the saddle is too far rearward leading to a constant low level tractive force being generated by the arms as they strive to pull the body forward to a more comfortable 'reach' to the bars. That's really what this thread comes down to: a saddle that is not quite level and a rider that has not built up enough mileage to normalize some of the discomfort that comes from riding modern bicycles.

I've heard it said a number of places that a Bumblebee cannot fly. They have too much mass to wing surface, and their power to weight ratio produces a negative coefficient. None of this theory affects the bees themselves and I see them occasionally as they visit flowers near my home in the summer. Maybe I shouldn't be using (vertical) stem extenders to raise my bars when I want less weight on my hands. The theory says that this does not work. It has worked well in practice, however. I employ the technique on a couple of bikes. FWIW.

KOPS is not an absolute, we've agreed on that but I think we can make suome rules about KOPS that are supported by the bicycle industry if not by theorists and fit experts who are peripheral to the design process. I think it is safe to say that if one intends to spin high rpm at the crank then a position at or even slightly forward of KOPS facilitates the rapid motions of the lower leg as they spin up to 120rpm and beyond. On a cruiser where 60rpm might be a maximal output a position considerably rearward of KOPS as much as 2" and more (think crank forward) behind KOPS works well for this purpose. Track and time trial bicycles will always have steep seat tubes to get the rider forward, zero setback seatposts also aid this. The usual 73* seat tube and 25mm set-back seatpost puts most riders a tad behind KOPS for the ~80rpm that most general purpose riding entails.

H

Leisesturm

What do you mean "total 26""? I know of no production bikes that have seat and/or top tubes that approach 26". Let's wait until you get home I do think that you will find that your fingers come closer to the bars than you think they will.

H

wphamilton

You're right it does look pointed down compared to the vertical door jam.

@skycyclepilot That's free and easy to try and makes sense, why not bring the nose up two or three degrees and try it for a ride changing nothing else?

skycyclepilot

The top tube is 575mm, according to the Giant website. The stem is 110mm. 575 + 110 = 685mm. 685 / 25.4 = 26.97". Subtract a few inches for the nose to post distance, and perhaps a little because angles are involved, but I'll be surprised if all that gets me close to 20". Someone else suspected, in another post, that the bike may border on being too big for me. I'm beginning to suspect the same. I'll check the arm thing tomorrow.

Kopsis

This is where I disagree. You can't apply a force to the pedal without an equal and opposite force acting on the rider's torso. Treating this as a simple "beam supported at two points" statics problem is an over-simplification that is not valid for any riding scenario except coasting.