Saturday, January 07, 2012


So what's torque? Torque makes you go! Are bike fitters just making a movie, putting on a sales production? People are paying good money for these services and many mass marketing fit systems only produce one fit style?

"It is said, they will never know the difference, I already paid for that bike, I don't want to hear that it not the correct size? I need to get it off the floor"

Torque is a measure of the LOAD on a rotating part. As far as any cyclist is concerned it is the load imposed on the primary drive gear, the one attached to the crank, or better through the human/pedal interface, starting with the interacting human linked chain, footbed, shoe, pedal, pedal shaft. If you over-torque the any part of human or tool, even a bolt on the bike, you’ll likely to break something.

Poor bike fitting can place or remove torque to the motor (human)! Too much torque on any of the many parts and failure can occur i.e. ouch. Remove the much needed torque and you don't go better. Now think of some weaker part father down the drive train, after WN is able to teach you how to find the torque.

One day, we had Nat Ross a Gary Fisher pro mtb racer producing so much torque from his engine, the loads through the energy, through the gears, the drive chain, was snapping off parts on his 29 inch bike. Nat knew our WN mtb fit allowed him to get the torque through his body, to the pedal. It made a difference, even in the 24 hour races.

Super, we can use our WN CAD to make you more powerful. But when you're designing a human engine from scratch all the gear ratios are undetermined and you can't even calculate the load from the human engine torque alone because the load is equal to human engine torque times gear ratio?

The torque is further multiplied by ft lbs. Let's say that we loose 20% of our torque do to "transmission losses", we end up with ft lbs of torque at the rear wheel. This is the maximum amount of torque at the rear wheel of the bike in first gear and will only be available at one rpm, peak torque’s rpm. At all other rpms the torque will be less. Actually, if you rev the engine, you’ll have much more torque available. Because the energy stored in the rotating crank, etc. is released. Loads, where are they stored?

The heavier these parts are, the more load you put on the transmission, chain, the rear wheel spokes, and rear tire. It feels like you have more power but what you’ve done is "store a lot of energy" in rotating masses and then applied it to the bike. With you can't transmit the loads, you have losses.

Once the engine and rear tire is in sync only the engine torque will accelerate you and any extra mass of the will actually slow you down. It’s impossible to tell the difference between low end torque and heavy torque regarding the effect when you rev the engine. That is why power is very hard to study. Plot all you wish, you very hard to make sense of it.
Now, to make rear wheel torque useful for calculating acceleration we must convert it into lbs of force at the rear tire’s contact patch by dividing the rear wheel torque by the rear tire radius. If our bike weights in with rider, that's lbs of weight. From one of Newton's laws of motion: f = ma. .

Now, in the real world, not in a lab, the maximum acceleration will be much less because we've got to fight the wind. In reality, to produce numbers in a lab don't help in the real world. Actually, the maximum acceleration will occur at a speed just below maximum torque since lowering the rpms reduces the torque just a little but the reduction in speed reduces the wind resistance by a lot.

Good thing we have a new science that will allow you to increase the torque. It means you will be able to reduce losses at the pedal.

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