upgrade or not?

[Johan Bornman]

Dear Deon

 

It doesn't seem like I'm getting through to you. Perhaps it is your incredible urge to contradict anything I say that's doing this. I'm sure you're a nice guy, so I'll try and explain again.

 

If the rear wheel lifts, you loose traction. However, this loss of traction cannot be ascribed to the tyre tread pattern. No matter what the pattern, if the tyre is spinning in the air or just-just on the surface of the path, you've got a situation that cannot be remedied by a better or different tyre.

 

I still don't understand how some tyres can climb better than others.  If you have no loss of traction, then there is no movement between tyre and surface and all tyres will climb the same.  I don't think spinning wheels were ever in the equation.

 

Different tread patterns don't generate better grip. I stick to my guns. I shall however qualify my statement by taking out the two extremes in the scenario: a) completely smooth tyre rolling on anything other than hardpack or tar/cement. b) a smooth tyre with sparcely-spaced aggressive knobblies running on soft surface.

 

In between these two extremes tread patterns is largely irrelevant due to the absolute random nature of the surface we ride on.

 

Directional tread, such as that designed for a tractor's rear wheel and mimicked on the Velociraptor's front-specific tyre (the type with an aggressive V-shape) is designed for squeezing out mud from the tractor's tyre.  It works very well on a tractor but the principle doesn't scale down to bicycle tyres, us being much lighter and the scale just to small to squeeze any mud out there.

 

Grip on such bicycle tyres is purely a function of the co-efficient of friction between the two surfaces and not a function of the leading edge of the blocks on the tread. The leading edge only comes to play occasionally when there happens to be a mechanical interlock. However, the substrate has to be stable to benefit from such an interlock.

 

A very good example of this is to look at one of the Larsen tyres. These have a squareish block with a ramp at one end and perpendicular edge at the other end. If you follow the tread around to where it makes contact, you'll see that the leading edge is the ramp, not the square edge. This is counter-intuitive to what most people would have thought. After all, this is the slippery side, isn't it? If you turn this tyre around, it vibrates and buzzes, but doesn't loose traction.

 

The best all-purpose tread is one where the knobblies are reasonably dense and reasonably shallow. This gives us the minimum rolling resistance, the minimum sideways "walk" when cornering, good grip and long life.

 

This "best" tread doesn't work well in mud where it quickly clogs up and effectively becomes a slick. Here a long spikey knobbly works best for the reasons you describe - penetration to hopefully something more solid and, of course mud shedding.

 

To get back to the anecdote of the rookie who found she could climb better with X tyre after two weeks. We never defined "climbing better" and it could mean a number of things including fitness or traction. I'll assume the latter.

 

I think someone can be taught to climb better in two hours, using the same tyres and same hill, just working on technique. We don't know which of these elements were present in your sample and I therefore choose to ignore that as evidence. I think that's fair and unless we describe the situation better, should not be used in this argument.

 

 

I hope my argument is clear and unambiguous. I look forward to your positive comments.

 

 

 

 

 

 

 

[Oiltrash]

Minty/ Johan, an interesting and informative debate. Take no notice of the comments from some of these trolls.

[MintSauce]

 

Dear Deon

 

 

It doesn't seem like I'm getting through to you. Perhaps it is your incredible urge to contradict anything I say that's doing this. I'm sure you're a nice guy' date=' so I'll try and explain again.

 

If the rear wheel lifts, you loose traction. However, this loss of traction cannot be ascribed to the tyre tread pattern. No matter what the pattern, if the tyre is spinning in the air or just-just on the surface of the path, you've got a situation that cannot be remedied by a better or different tyre.

 

I still don't understand how some tyres can climb better than others.  If you have no loss of traction, then there is no movement between tyre and surface and all tyres will climb the same.  I don't think spinning wheels were ever in the equation.

 

Different tread patterns don't generate better grip. I stick to my guns. I shall however qualify my statement by taking out the two extremes in the scenario: a) completely smooth tyre rolling on anything other than hardpack or tar/cement. b) a smooth tyre with sparcely-spaced aggressive knobblies running on soft surface.

 

In between these two extremes tread patterns is largely irrelevant due to the absolute random nature of the surface we ride on.

 

Directional tread, such as that designed for a tractor's rear wheel and mimicked on the Velociraptor's front-specific tyre (the type with an aggressive V-shape) is designed for squeezing out mud from the tractor's tyre.  It works very well on a tractor but the principle doesn't scale down to bicycle tyres, us being much lighter and the scale just to small to squeeze any mud out there.

 

Grip on such bicycle tyres is purely a function of the co-efficient of friction between the two surfaces and not a function of the leading edge of the blocks on the tread. The leading edge only comes to play occasionally when there happens to be a mechanical interlock. However, the substrate has to be stable to benefit from such an interlock.

 

A very good example of this is to look at one of the Larsen tyres. These have a squareish block with a ramp at one end and perpendicular edge at the other end. If you follow the tread around to where it makes contact, you'll see that the leading edge is the ramp, not the square edge. This is counter-intuitive to what most people would have thought. After all, this is the slippery side, isn't it? If you turn this tyre around, it vibrates and buzzes, but doesn't loose traction.

 

The best all-purpose tread is one where the knobblies are reasonably dense and reasonably shallow. This gives us the minimum rolling resistance, the minimum sideways "walk" when cornering, good grip and long life.

 

This "best" tread doesn't work well in mud where it quickly clogs up and effectively becomes a slick. Here a long spikey knobbly works best for the reasons you describe - penetration to hopefully something more solid and, of course mud shedding.

 

To get back to the anecdote of the rookie who found she could climb better with X tyre after two weeks. We never defined "climbing better" and it could mean a number of things including fitness or traction. I'll assume the latter.

 

I think someone can be taught to climb better in two hours, using the same tyres and same hill, just working on technique. We don't know which of these elements were present in your sample and I therefore choose to ignore that as evidence. I think that's fair and unless we describe the situation better, should not be used in this argument.

 

 

I hope my argument is clear and unambiguous. I look forward to your positive comments.

 

 

 

[/quote']

 

 

 

You're not getting through to me...? It's got nothing to do with my incredible urge to contradict you.

 

 

 

Please don't take the fact that someone has a different opinion to yours so personally.

 

 

That being said, yes, I have stated quite clearly on this forum how I feel about you. That is not the issue here.

 

 

 

I simply don't agree with you on the issue at hand. I find it interesting that you seem to

disregard some of my statements as 'anecdotal evidence' yet you fail to

provide any factual evidence for your own views.

 

 

 

What is it that causes your opinion to carry more weight than mine...?

 

 

 

If you care to provide evidence for your views that contradict mine, I will gladly recant.

 

 

 

I personally don't have any such evidence to back up my arguments.

 

 

 

What I do have is 16 years of riding the crap out of my bikes. I, and

every person I've ever spent significant amounts of time riding with,

have often discussed the merits and characteristics of different

tyres.

 

 

 

I'm not going to repeat myself over and over because it simply feels

like you refuse to even entertain the thought that someone else might

have a valid point.

 

Repeating myself is exactly what I'd be doing if I go into the details of your last post.

 

I'm done here. My comments stand.

 

 

 

One more thing....can you be any more condescending?

 

 

 

 

 

[GoLefty!!]

Traction between two surfaces usually depends on several factors including

Material properties of each surface.

Macroscopic and microscopic shape or "roughness".

Force of contact.

Area of contact.

Contaminants at the material boundary including lubricants and adhesives

We can consider the material properties to beconstant since the friction between a dirt road and any rubber will be functoinally similar.

For the same rider the force will be the same if the correct climbing technique is used.

 

Where a tyre could exhibit better traction properties is in it's construction and the flexibility of the rubber and casing.

 

More flexible rubbers on a more flexible casing will conform to the irregularities more efficiently than a harder rubber on a less flexible casing.

 

Not all tyres are created equal..