Correct Weight Distribution

[Krank]

i read that your riding position should put 60% of your weight on the back wheel and 40% on the front. This is important for bike control as well as comfort.

how do you actually measure this weight portion when on bike?

krank

[human909]

Comfort? Most comfort bikes have a much higher percentage weight on the rear.

[greyhoundtom]

i read that your riding position should put 60% of your weight on the back wheel and 40% on the front. This is important for bike control as well as comfort.

how do you actually measure this weight portion when on bike?

krank

If you wanted to check this it would mean two sets of scales......one wheel on each, and with you sitting on the bike in your preferred riding position.

[TDC]

You can use one set of scales and a phone book (or similar) to ensure that the bike is level to the ground.

First weigh yourself holding the bike, then position the front wheel on the scales and the rear wheel on the phone book. Get on the bike into your riding position and the read the weight on the scales. Use the results to calculate the percentages.

Comfort? Most comfort bikes have a much higher percentage weight on the rear.

OP does not mention "comfort bike".

[Krank]

many thanks.

if you measure your own weight distribution, what results do u have?


krnak

[DoogleDave]

I'd hazard a guess that just through the geometry of the bike and how you sit on the bike (with your torso behind the bottom bracket), that the weight distribution is going to fall around the 60/40 ratio - simply because more of your body's weight is more rearward on the bike, even though you are leaning forwards.

Would you also need to factor in momentum and the forces you apply to the bars and pedals as they push forward on the bike as you pedal (with effort) - as sitting statically on the scales may not prove accurate for this - as this is how the bike is weighted when riding (which is what matters), not when you're sitting on the bike leaning against a wall.

Also, how hard and fast is the 60/40 ratio? what if it's 57/43 or 62/38...is it going to make that much difference or is the 60/40 rule just another generalisation?

Interesting question though....

Dave

[toolonglegs]

Honestly mate why would you bother ... your weight distribution will change hugely on just one set up. Riding in the drops seat, drops standing on a climb, drops sprinting, tops climbing, tops cruising, hoods climbing, hoods while on the front of the saddle powering, bum over the back on the drops descending ... I can think of a dozen ways you vary your front / rear distribution before even going into bike set up / type / body type ( even if I know that you are talking road race set ups ).
Personally my bike is set up per Steve Hogg many many moons ago in regards to saddle position... but my bars sit high due to an enormous head tube, when I train I do so mainly on the hoods, when I race I never leave the drops... so huge change in body position... but where does knowing the actual break down % make any difference?.
You want to go fast get low... and if you are like me you will have to put up with a bit of discomfort in certain parts to get the aero benefit ( hands, upper arms, hamstrings for me ). Just up to you personally to decide where to compromise.

[barefoot]

If I have two custom bike frames built, identical front end geometry, built up identical stem, bars, saddle etc., but one frame has long chainstays and the other has short chainstays... my weight distribution is going to be very different on them even though I'm fitted in exactly the same position.

As a rule of thumb, I guess you'll find that a generic rider on a generic road bike will have somewhere close to 60:40 weight distribution. I wouldn't read any more into the numbers than that.

tim

[il padrone]

+1 to the above three comments. The weight distribution will be determined by the bike design and the set-up you have on it. An it's only a general guide to use and be aware of, especially re wheel build and tyre wear. If you were to go shopping and carry a load of groceries home in rear panniers you're not going to re-do your bike set-up, just ride with some awareness of the relatively lighter front wheel/heavier rear wheel.

[sogood]

+1 on 2LL. Weight distribution is one for the frame builder and hardly an option for the rider. For the rider with a frame, fit trumps all. Once that's dialed in, weight distribution will fall by default. If the distribution is off your arbitrary mark, most likely one will need to rethink the frame type and geometry. Contorting the body to obtain an ideal weight distribution is not the way to optimising one's setup.

[Mulger bill]

If I have two custom bike frames built, identical front end geometry, built up identical stem, bars, saddle etc., but one frame has long chainstays and the other has short chainstays... my weight distribution is going to be very different on them even though I'm fitted in exactly the same position.

As a rule of thumb, I guess you'll find that a generic rider on a generic road bike will have somewhere close to 60:40 weight distribution. I wouldn't read any more into the numbers than that.

tim

Longer stays will shift the CG forward by a fair margin (dependant on the length of course). BMX and Trials bikes commonly run the shortest stays possible to make it easier to lift the front.

[ausrandoman]

Ooh, I hope winstonw turns up here soon. Physics! Levers! Statically indeterminate loads! It will be so much fun