tire warm-up?

[FriendlyFoe]

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Street tires work fairly well in the cold. We're not talking DOT or a race tire here, and even if not up to temperature a street tire will offer a certain level of grip.

Being a newer rider i would say lack of proper body positioning and smooth controls is more likely to crash you in cold temps then the tires not being good enough. Good skills will give you a lot more warning when it comes to tires sliding where as bad form and overloading the rear tire will cause it to lose traction suddenly.

Just take it easy, keep the spirited riding to the track and track schools, build skills and technique and then apply to your street riding.

 

[daught]

I doubt any beginner can push their their bike far enough to require their tires to warm up. This whole warm up thing is a bit overrated for most street riding. I used a grooved pirelli slick as my front tire and aven at 5C I always pulled a stoppie when exiting the garage.

 

[fastar1]

Care to share your source of information regarding a tire slipping when going straight, at a fixed speed!

Are you perhaps confusing straight line riding with slip angle while turning?

Milliken & Milliken. Race Car Vehicle Dynamics.
Section 2.3 - Longitudinal Force

In a nutshell...
"The mechanism in the tire for developing longitudinal forces bears some relationship to that for lateral forces inasmuch as there is an elastic distortion region (in this case longitudinal stretching) and a sliding or frictional region".

They call it slip ratio.

 

[mike.from.canmore]

Milliken & Milliken. Race Car Vehicle Dynamics.
Section 2.3 - Longitudinal Force

In a nutshell...
"The mechanism in the tire for developing longitudinal forces bears some relationship to that for lateral forces inasmuch as there is an elastic distortion region (in this case longitudinal stretching) and a sliding or frictional region".

They call it slip ratio.

Right... but you are skipping over the fact that this situation I made reference to is AT A FIXED SPEED.

At a fixed speed (not accelerating or decelerating) - the slip ratio would be 0.000



Now don't come back and say, at 400 kph, the slip ratio is greater than 0 due to wind resistance etc....

We are talking about street riding, city streets, per the OP's situation.

"The mechanism in the tire for developing longitudinal forces bears some relationship to that for lateral forces inasmuch as there is an elastic distortion region (in this case longitudinal stretching) and a sliding or frictional region".

There are 2 regions:
Elastic distortion (NOT SLIPPING)
and
Sliding/frictional region (slipping).



As I said - Rolling - does not mean slipping!

 

[fastar1]

Right...

The slip ratio is never 0, unless the vehicle is at rest.

For all practical purposes, the slip ratio is assumed to be zero when the vehicle is coasting but I contend that even then it is always fluctuating above or below 0. That's just the nature of dynamic systems.

Of course, at that level of minutea it makes no difference to the original inquiry, it just happened to form a part of the simple answer that I provided, which did address his question. You're the one who wanted to delve into the finer detail of the subject.

In any case there is no question that at any steady-state speed, the slip ratio is significant.

 

[mike.from.canmore]

The slip ratio is never 0, unless the vehicle is at rest.

For all practical purposes, the slip ratio is assumed to be zero when the vehicle is coasting but I contend that even then it is always fluctuating above or below 0. That's just the nature of dynamic systems.

Of course, at that level of minutea it makes no difference to the original inquiry, it just happened to form a part of the simple answer that I provided, which did address his question. You're the one who wanted to delve into the finer detail of the subject.

In any case there is no question that at any steady-state speed, the slip ratio is significant.

I agree with your post in its entirety - except the last sentence.

I would have said

In any case there is no question that at any steady-state speed, the slip ratio is insignificant / negligible.



The difference from coasting and steady state is very minor (at street legal speeds), and this assumption of zero slip ratio when coasting is because it's so minute, it's essentially irrelevant.

 

[mike.from.canmore]

You again.



Yes.



The slip is already accounted for when it's calibrated, within the range of precision of the instrument.

No, no it's not. The slip ratio is not accounted for when it's calibrated - instead, the slip ratio is assumed to be at zero.

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