AM tyres... what you running?

[Cruz Addict]

Mountain kings are the best tire i have every used, going to be looking for a new set soon as mine are almost at the point of replacement.

have been told to look at the hans damphs which i may do as well.

mate of mine( actually the same mate that suggested i try the MK's) is running a set of WTB bronsons, he swears they are as good if not slightly better than the MK. at about half the price that may be my next option though.

[Bazinga]

So went for a ride tonight and ran the front at 1.8 bar and man it gripped so much more. I almost want to drop it lower. I forgot the rear was on 2.5 or maybe even more and the ass was all over the place. So much fun. Am I right in saying you can run the bigger volume tyres (2.5 inch) at lower pressures with lower risk of bottoming out i.e. hitting rims?

[Captain Fastbastard Mayhem]

So went for a ride tonight and ran the front at 1.8 bar and man it gripped so much more. I almost want to drop it lower. I forgot the rear was on 2.5 or maybe even more and the ass was all over the place. So much fun. Am I right in saying you can run the bigger volume tyres (2.5 inch) at lower pressures with lower risk of bottoming out i.e. hitting rims?

 

Yeah, you are. That's because there's a higher volume of air in the tyre, so even though it's running at a lower pressure, there's more air for it to travel through.

 

Change to tjoopless, and you have an even higher level of grip - tjoops cut out a large percentage of the tyre's & rim's available volume.

[Captain Fastbastard Mayhem]

Plus, no snakebites!

[Cruz Addict]

So went for a ride tonight and ran the front at 1.8 bar and man it gripped so much more. I almost want to drop it lower. I forgot the rear was on 2.5 or maybe even more and the ass was all over the place. So much fun. Am I right in saying you can run the bigger volume tyres (2.5 inch) at lower pressures with lower risk of bottoming out i.e. hitting rims?

Yes you can but don't think its the bottoming out you need to worry about, I would be more concerned about burping or snake bits of you are running tubes.

Last weekend at avalanche I was running my mk's at about 1.5 and had awesome grip, much better than I expected to be honest!

I stand to be corrected though so don't take my word as gospel by any means.

[Capricorn]

So went for a ride tonight and ran the front at 1.8 bar and man it gripped so much more. I almost want to drop it lower. I forgot the rear was on 2.5 or maybe even more and the ass was all over the place. So much fun. Am I right in saying you can run the bigger volume tyres (2.5 inch) at lower pressures with lower risk of bottoming out i.e. hitting rims?

 

unless your sidewalls automagically get stiffer as you drop the pressure, no, you are not at lower risk. in fact it goes up. There's a sweet spot for the pressure that's very much dependant on your riding style. Generally, the lower the pressure, the increased contact patch with the ground, and thus the great your traction.

 

However, sidewall stiffness is dependant on pressure as well, so as you drop the pressure, the more likely the sidewalls are to fold. In the extreme, if you lose all pressure, the sidewalls fold completely and your tyre collapses into a squiggly mess with that wheel having the directional control and precision of a hovercraft...ie, not much and you float all over the damn place.

 

Simply stated, lowering the pressure increases the traction (with caveats), but you will increase the risk of dinging your rims and/or causing snakebites. That is the tradeoff when playing with lower air pressure.

 

Going up in pressure increases sidewall stiffness and thus lowering your risk of dinging the rim, but your traction starts circling the drain.

Edited July 24, 2013 by Capricorn

[Captain Fastbastard Mayhem]

Meh. Must have had sugar-brain. Capricorn is righter than I am.

 

With higher volume tyres, you CAN run lower pressures, but there is a tipping point where low pressure becomes too little to support the sidewalls upon impact.

[J0KER]

Hey, Patches should be able to help you on this one! Wait.., nevermind

[DubbelBuys]

unless your sidewalls automagically get stiffer as you drop the pressure, no, you are not at lower risk. in fact it goes up. There's a sweet spot for the pressure that's very much dependant on your riding style. Generally, the lower the pressure, the increased contact patch with the ground, and thus the great your traction.

 

However, sidewall stiffness is dependant on pressure as well, so as you drop the pressure, the more likely the sidewalls are to fold. In the extreme, if you lose all pressure, the sidewalls fold completely and your tyre collapses into a squiggly mess with that wheel having the directional control and precision of a hovercraft...ie, not much and you float all over the damn place.

 

Simply stated, lowering the pressure increases the traction (with caveats), but you will increase the risk of dinging your rims and/or causing snakebites. That is the tradeoff when playing with lower air pressure.

 

Going up in pressure increases sidewall stiffness and thus lowering your risk of dinging the rim, but your traction starts circling the drain.

 

Nice explanation Capricorn.

 

OK, so is anyone (besides Slick's wife) running Spez Purgatory ? (ies?)

 

What sizes are avbailable in SA? 2.2 & 2.4 or is it only 2.3 now?

 

http://www.specialized.com/za/en/ftb/mtb-tires/all-mountain-tires

 

In 26" of course

[Headshot]

still rollin on my Hans Dampf SG - cant fault it yet even in slithery muddy off camber rooty stuff as we found Jonkers on saturday. It outshines the Purgatory at the back by a margin, which is fine and safer...

[Nofearnofun]

Nice explanation Capricorn.

 

OK, so is anyone (besides Slick's wife) running Spez Purgatory ? (ies?)

 

What sizes are avbailable in SA? 2.2 & 2.4 or is it only 2.3 now?

 

http://www.specializ...-mountain-tires

 

In 26" of course

 

I had a 26x2.2 Purgatory on the front until yesterday, decided to drop my tyre pressure a bit (a bit to much I guess) and slashed the side wall. I would like to say that it was my fault and not that the tyre has a soft side wall

 

The 2.2 felt as wide as a Conti 2.4 .

 

Need to decide which of these three to replace it with.

• Purgatory 2.3
  
• Ardent 2.4
  
• High roller 2.4/2.5?
  

Edited September 16, 2013 by Nofearnofun

[Captain Fastbastard Mayhem]

.

Edited September 16, 2013 by cpt armpies mayhem

[Captain Fastbastard Mayhem]

Minion 2.5 super tacky

Hans Dampf 2.35

 

[Captain Fastbastard Mayhem]

.

Edited September 16, 2013 by cpt armpies mayhem

[Hairy]

I had a 26x2.2 Purgatory on the front until yesterday, decided to drop my tyre pressure a bit (a bit to much I guess) and slashed the side wall. I would like to say that it was my fault and not that the tyre has a soft side wall

 

The 2.2 felt as wide as a Conti 2.4 .

 

Need to decide which of these three to replace it with.

• Purgatory 2.3
  
• Ardent 2.4
  
• High roller 2.4/2.5?
  

Out of that selection I would go Ardent

[Hairy]

Or as per cpt, the minions ... was looking at them this morning actually and they look rather rather nice with that supertacky feeling like you throw the tyre up against the ceiling and it would stick there!