Static Friction v. Sliding Friction

For decades, when driving on a slippery surface with a stick shift vehicle, I have been aware that often the traction improves after shifting to a higher gear. Knowing that static friction is greater than sliding friction, only yesterday, did I connect with an idea that I think is the possible reason for the better traction in the higher gear. Maybe, I am the last person in the English speaking world to make the connection and maybe I am wrong in my analysis, but here it is: When changed to the higher gear, the torque requirement on the input shaft to the transmission is increased. Thus, more pressure is applied to the compression springs connecting and absorbing the “rotational” shock between the clutch drive and the rotor on the input shaft to the transmission. So rotational shock absorbed in the clutch springs, allows for an increase in the static friction between the tires and the surface, they drive on. It is possible that spring loaded rotational devices could be used to improve power transmission in other places that are now using solid or fluid coupling.

Traction remains the same whether you are in 1st gear or high gear. The higher gear puts a greater demand on the engine, thus the engine does not have the power needed to cause the tires to lose traction.

I agree with 'ya Rusty!

Engine at a lower RPM has less power to spin the tires.

UUUFFDDAAA Sometimes I'm kinda glad I just looked at da pitures an let da smat kids do the werds

It's late and I'm sure that I missed something, but what the heck kind of clutch and trans is he talking about, sounds like it has everything but rubber bands to make it go???
Bob S.

Steven has it nailed. At lower RPMs the engine produces less HP and torque. Therefore you are less likely to spin the tires. The friction between the drive tires and the ground surface could care less what gear your vehicle is in or what type of clutch and springs you have.

With respect, you are pretty damp.
The friction of a wheel which is not in spinning, but rolling in its motion on ice has hundreds of times more pulling power than when it is slipping melting a water layer under it.
Higher gears lower torque in a way that stays (more often) within this zone of not slipping. Differentials always put the same force into both tires. When one slips, the other pulls, but only as hard as the slipping tire.
The thing is just like hooking a 2X4 about 6 feet long to a pair of cement blocks, and pulling in the middle to drag them. If one gets on ice, it slides and the other stays behing. But the same force is still pulling on each, it is just much less force. JimN

Although what others have stated below, at least in tractor applications, is correct, your thinking on a few things isn't too far off the beaten path, especially on using the "shock absorbing" devices between the drivetrain and the wheels. On dirt track stock cars, there have been available for at least three decades now some devices that basically bolt between the axle shaft and the hub that have rubber in them that are intended to "cushion" the torque applied to the rear wheels to prevent them from breaking traction as easily when accelerating on a slick track. That said, most of the fastest guys don't use 'em anymore, just one more thing to go wrong.

One other related thing though, is that in dirt racing, when the track slicks off, most people go to a lower(higher numerically) rearend gear. This is in applications that already have more power than the track will take so the fact that the engine produces less power at less RPM's isn't a factor here. The theory there is that with a higher gear, once the tires DO break traction, they'll spin much faster and it'll be harder to back off the throttle to the point where they gain traction again. So, a lower ratio(higher numerically) gear is used to help prevent that sudden traction loss and help make it more controllable when it does happen.

None of that racing stuff much applies to your question as related to tractors, just thought I'd put the info up for consideration.