Weight distribution

aquanaut

Hi - I've only had my road bike a few weeks now so still getting used to it, but it seems like all my weight is on my hands - rather than centred on torso, also keep wanting to move further back on saddle (so moved saddle back) and not sure how that effects alignment. Finally - I used to be able to cycle when young with no hands - on this bike I can't even take hand off to scratch nose without wobbling all over the road - any help would be appreciated - thanks

paddymacsporran

maybe you need a longer stem as you're actually slipping forward, thats why you feel you want to move back in the saddle.

that would answer the extra weight on the hands too - quick test for you - If you put your elbow on the nose of the saddle, your fingertips should fall just short of the bars.

Some good info on this site, or just google 'road bike saddle position' and you'll find enough advice to blow yer mind!

http://www.bicyclesource.com/bike/fitting

aquanaut

Did the test - 1 1/2" between finger tips and handle bars! - when you say longer stem, do you think my frame size is too small? I am 6ft (32" inside leg) - 58cm frame, Trek 1.5 - thanks

Junior

Your saddle position might be too far back, also the geometry of the frame might be different to what you were used to. Did you get fitted to the bike at all ?

aquanaut

Yes - I was fitted in the shop. I'm thinking about moving the saddle forward a bit tomorrow and also raising the nose of the saddle a bit just to see if it helps.

Junior

aquanaut wrote: »

Yes - I was fitted in the shop. I'm thinking about moving the saddle forward a bit tomorrow and also raising the nose of the saddle a bit just to see if it helps.

The saddle should be as flat as a pancake dude otherwise you'll have pressure on nether regions..

paddymacsporran

Good advice re the saddle, I use a spirit level on mine to make it level!

And just make small adjustments, and only change one thing at a time. otherwise you won't know what the hells going on....

These guys do a bike fit, up in Dun Laoghaire but well worth the cash when I used them, was €50 - www.irishfit.ie May well be someone closer to you?

What length is the stem? It will be stamped on it somewhere. Your bike would be too big for me, I'm 32 inseam and 5.10. I ride a 54. However you must have a much longer torso if you're 3 inches taller than me and our legs are about the same.

aquanaut

Stem: Bontrager SSR, 10 degree, 31.8mm - I did actually ask for a second opinion as I know 6ft people who got the 56cm, but both shop people said 58cm as between the frame and my crotch was about 1 - 1.5" when stood over the bike. Maybe I just need to get used to the 'wobble' but even taking one hand off to get my water bottle I was all over the shop - freaky!

Lumen

If you move the saddle forward it will increase the weight on your hands, not decrease it. Read some of Steve Hoggs stuff. Arse out balances arms out.

Maybe start by getting the scales under the front and rear wheels and finding out your actual weight distribution.

Probably just teething problems, but a more rearward position can help ease the stress as your body adjusts.

You will definitely have more "no hands" stability with a rearward position.

lescol

A good starting position for saddle placement:-


Find fore/aft seat position: This adjustment requires a helper, too. Place your bike on a level surface next to a wall or post so you can hold yourself upright (or put it on a trainer, but be sure to level the bike). Put on your biking shorts and shoes, get on and pedal backwards until you’re sitting in the “sweet spot” on the seat. Move your feet into the position shown in the photo. The forward crankarm and pedal must be level with the ground. The fore/aft seat adjustment is correct when a plumb line (any piece of string with a weight on the end) hanging from the bony protrusion just below your kneecap, bisects the pedal axle.

Notes

As with the other adjustments, this is a safe starting position.
If you’re over 6-feet tall, ride long distances, climb a lot and pedal at about 90 rpm, you may prefer to be as much as 1 to 2 cm behind the pedal axles.
If you’re less than 6-feet tall, spin at 95 rpm or faster and like to sprint, you’ll probably prefer to be directly over the axles.

This is taken from http://www.jimlangley.net/crank/bikefit.html which is a nice place to browse, the bike fit advice is good. It sounds as if a little tweaking of your position will resolve the problems. I'm about 6' also on a 58cm frame, my inseam is closer to 34" though.

The "wobbling" is more likely due to road bikes having a smallish "trail" (see:- Trail is the distance from the center of the contact point of the front wheel with the riding surface to the intersection of the steering axis (head tube) with the surface. The trail is a function of the head angle, the fork rake, and the tire diameter. Trail has a major effect on the handling of a bicycle. More trail increases the bicycle's tendency to steer straight ahead. A bicycle with a largish trail dimension will be very stable, and easy to ride "no hands". A bicycle with a smaller trail dimension will be more manuverable and responsive. from http://www.sheldonbrown.com/gloss_tp-z.html). This is something you get used to over time as the road bike is very responsive and maneuverable for riding in groups, a function you will find extremely helpful in the future!

aquanaut

Thanks for all the advice - went through loads of stuff this morning with the bike - I have decided one thing, and that is that I feel that i'm in a real race position compaired with with MTB - nothing wrong with the race position, just a big change, then I noticed that my bike came with the stem flipped, so it is horizontal. There are loads of threads about flipping your stem but nothing about the results of unflipping your stem, but i'm wondering if unflipping it will make it feel more 'casual' I suppose???

Lumen

The basis of bike fit theory is that there is a fairly narrow range of hip angles which produce comfortable power.

You can rotate yourself backwards or forwards over the bottom bracket and you'll change your aerodynamics and weight distribution without affecting the hip angle.



Stems usually have an angle of about 6-10 degrees, and the head tube angle is about 73 degrees, i.e. 17 degrees from the horizontal. In a normal set up, you have a stem angle of (say) 17-8 = 9 degrees, which is still "up". If you flip that stem, you'll get (say) 17+8, which is 25 degrees, which looks a bit mad (Ted).

The actual rise is easy to calculate using basic trig, and depends on HT angle, stem angle, stem flippage and stem length. A typical 73 HT/110mm/8 degree setup will have rise of 17mm/51mm for normal/flipped respectively, i.e. will rise 34mm when flipped up the "wrong" way. This is a lot.

aquanaut

Okay - here's an update. Just back in after only 20km but the weather was ****. Flipped stem the correct (or uncool) way up. Feel alot more centred and in control now (apart from when doing 42kph down hill and thinking 'do I tighten up the...'). Slight lower back irritation while riding and the riding was a lot tougher but we'll get there) seems a lot better - maybe a few adjustments to make yet.