Specialized Pathfinder Pro, the sleeper hit of gravel tires

[spoonrobot]

Originally Posted by gravelreformist

If you have to lower the pressure in these to avoid the center lump, that kind of defeats the purpose of the tire. At 25psi a pair of these are going to have an extra 10-15w or so of rolling resistance vs. running them at 40psi. And on firm surfaces, 25psi is awfully squirmy.

What is the purpose of the tire?

23-25 psi is fastest rolling for my gravel mixed-surface use, not to avoid the center strip.

At 40 psi there's probably an additional 20w of suspension losses on gravel, much higher the rougher it becomes. It's barely 10% sag for my total system weight, way too low.

[gravelreformist]

Originally Posted by spoonrobot

What is the purpose of the tire?

23-25 psi is fastest rolling for my gravel mixed-surface use, not to avoid the center strip.

At 40 psi there's probably an additional 20w of suspension losses on gravel, much higher the rougher it becomes. It's barely 10% sag for my total system weight, way too low.

A tire like this is best for a mixed paved/gravel use. I'm lighter than you and 23psi feels like riding on an under-inflated balloon on the pavement. All squish and no control. It's also WAAAY under even the most liberal calculators out there - so saying that's what this tire requires to feel confidence inspiring isn't a great sales pitch.

[spoonrobot]

Originally Posted by gravelreformist

A tire like this is best for a mixed paved/gravel use. I'm lighter than you and 23psi feels like riding on an under-inflated balloon on the pavement. All squish and no control. It's also WAAAY under even the most liberal calculators out there - so saying that's what this tire requires to feel confidence inspiring isn't a great sales pitch.

I'm not selling the tire, and this isn't what I've said.

You are not required to use these tires.

[spoonrobot]

Before even leaving your house, you can pump the tires up, sit on the bike, and measure the sag. Figure out what 10%, 15%, 20% maybe 25%.

Then You can do your own rolldown testing to figure out what rolls fastest and where the breakpoint is for the surface you are targeting and the pressure window you are considering.

Then you can find a paved parking lot and try to corner as fast as possible to see at what pressure the sidewall collapses or where the tread starts pushing.

Then you can find some rough gravel and push those corners too, roll down a gravel hill a few dozen times.

Now, in the span of a couple hours on a sunny afternoon, you know more about tire pressure and behavior than 90% of cyclists, and you know 1000% more than you did before.

At this point using an online calculator seems sort of stupid. All the tools are available, for you specifically, in the real world.

A $20 frame pump, a $13 pressure gauge, a $10 stopwatch, some time reading and thinking, some time riding.

You can figure things out for yourself, you don't need to use somebody else's data, somebody else's program prioritized for what they want. You can become the expert of your own domains.

[spoonrobot]

Getting arrested for having my tire pressure too low, but it's a restorative justice jurisdiction so I get right back on the streets and do it again anyway.

[gravelreformist]

Originally Posted by spoonrobot

Before even leaving your house, you can pump the tires up, sit on the bike, and measure the sag. Figure out what 10%, 15%, 20% maybe 25%.

Then You can do your own rolldown testing to figure out what rolls fastest and where the breakpoint is for the surface you are targeting and the pressure window you are considering.

Then you can find a paved parking lot and try to corner as fast as possible to see at what pressure the sidewall collapses or where the tread starts pushing.

Then you can find some rough gravel and push those corners too, roll down a gravel hill a few dozen times.

Now, in the span of a couple hours on a sunny afternoon, you know more about tire pressure and behavior than 90% of cyclists, and you know 1000% more than you did before.

At this point using an online calculator seems sort of stupid. All the tools are available, for you specifically, in the real world.

A $20 frame pump, a $13 pressure gauge, a $10 stopwatch, some time reading and thinking, some time riding.

You can figure things out for yourself, you don't need to use somebody else's data, somebody else's program prioritized for what they want. You can become the expert of your own domains.

I've been racing on dirt, gravel, grass and cyclocross for over 30 years. I know what tire pressures feel like on different surfaces. On cross tubulars we ran on some courses under 15psi. I know from that experience what 23psi feels like on the pavement, and I know from experience what the potential repercussions of taking a hard hit at 45+ mph can do to my wheel at that pressure. The pressure curves of most of the calculators were developed by people doing some variation of the tests you are outlining, and then plotting the data on a curve. There's a reason most people aren't running pressure that low in tires of this size.

[spoonrobot]

What are we arguing here ? - I like 23psi in my front 700cx42 Pathfinder Pro

You don't think you would like the same pressure

Ok, great.

???

I can plot my data on a curve. If I did that and started selling things too, would that lend credence to what I've said? Is that the requirement? Businesses have exclusive authority to dictate reality?

[spoonrobot]

Imagine thinking, after all the things that took place to get to this point in collective bicycle tire knowledge, that an appeal to "most people" is anything other than laughable.

[gravelreformist]

Originally Posted by spoonrobot

What are we arguing here ? - I like 23psi in my front 700cx42 Pathfinder Pro

You don't think you would like the same pressure

Ok, great.

???

I can plot my data on a curve. If I did that and started selling things too, would that lend credence to what I've said? Is that the requirement? Businesses have exclusive authority to dictate reality?

Multiple people mentioned the characteristic this tire has of rolling on/off the center tread. You said that's not an issue if you run 23-25psi. I said - that's awfully low for a tire that spends half its time on the road. And here we are.

[spoonrobot]

Originally Posted by gravelreformist

Multiple people mentioned the characteristic this tire has of rolling on/off the center tread. You said that's not an issue if you run 23-25psi. I said - that's awfully low for a tire that spends half its time on the road. And here we are.

That's not what I said. Here's what I said:

Only when the pressure is too high. Otherwise the contact patch (at the psi I'm running) includes the center strip as well as the first few/several mms of the knob pattern.

I'm around 200lbs total system weight and run my front 42s at 23-25 psi, and they feel nice and neutral. Experimenting a while ago - at around 33ish psi I can feel the center strip. I don't think I can feel it at all in the back.

You're not crazy, it's a common complaint.

To clarify, I don't think the center strip is an issue at any pressure for me. It's a different feeling as the tire scrub characteristics change, but is not materially different than some other knob patterns I've experienced.

As I've noted, it's a common complaint.

Not interested in any more discussion with you.

[gravelreformist]

Originally Posted by spoonrobot

That's not what I said. Here's what I said:



To clarify, I don't think the center strip is an issue at any pressure for me. It's a different feeling as the tire scrub characteristics change, but is not materially different than some other knob patterns I've experienced.

As I've noted, it's a common complaint.

Not interested in any more discussion with you.

Fair enough. I apologize for the mis-characterization.

[Likes2ridefar]

Originally Posted by gravelreformist

If you have to lower the pressure in these to avoid the center lump, that kind of defeats the purpose of the tire. At 25psi a pair of these are going to have an extra 10-15w or so of rolling resistance vs. running them at 40psi. And on firm surfaces, 25psi is awfully squirmy.

this is meaningless without the total weight of the system. Or what rim or hookless or hooked etc…

[Jaybee]

Pulling this back from page 4 to note that Victor Koretzky won a World Cup short track XC event on 47mm Pathfinders this past weekend. This is less to note that Pathfinders are amazing (though I do like mine), but more that I'm amazed at the skill level of XC pros to push those tires through proper XC corners at short track speeds.

[EB]

Originally Posted by Jaybee

Pulling this back from page 4 to note that Victor Koretzky won a World Cup short track XC event on 47mm Pathfinders this past weekend. This is less to note that Pathfinders are amazing (though I do like mine), but more that I'm amazed at the skill level of XC pros to push those tires through proper XC corners at short track speeds.

Yeah, this was not something I’d recommend for a normal human, although the XCC course at Nove Mesto is basically a gravel course, aside from the wood ramp and that one tiny “rough” downhill section. It’s especially in contrast to the XCO course there, which is quite technical, relatively speaking.

I wonder if he would have done it if Specialized offered a true 29er slick - the Fast Trak is more of a semi-slick.

[AngryScientist]

1) I'm no mountain biker, but that looks like a really fun bike to whip around on. Probably not this year, but I'm getting a mtb in the not too distant future.

2) That's a cool bike stand. Anyone know who makes it?