Bikeguide.org - Bike maintenance for BMX'ers
The Street => The Bike Shop => Topic started by: blueee on September 28, 2015, 01:26:11 PM
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anyone feel like their wheel is about to collapse if they carve a bowl hard with low psi? like 65psi or so? and then maybe dont get that sensation if the tires are pumped up higher... or is that just me?
feels like my wheel is about to taco sometimes if i hit a bowl corner hard enough
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Definitely, my spokes tend to unscrew themselves too.
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Yeah, smooth bowls call for high tire pressure for sure.
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i feel like low psi gives me more grip
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Either low tire pressure is 75+ or you're going slow. If my shit is under 70psi and I go through a corner it just smashs down and I lose effectively all my speed.
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90+ is definitely best for bowls and general ramping. 65 is pretty much unrideable for me
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Well yeah, of course. Try and pump or carve on a low preassure tyre and it will give after and possibly make you slid out. Just pump that tyre up
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Every time I read the subject of this thread I just think to myself "No! Don't do that!" haha. If I show up to a cement bowl and I have low PSI it fucking ruins my day. I try to always have a pump in my car to make sure this doesn't happen.
Another indicator if you are running too low of PSI is if your valve stem starts to go crooked from your rim (assuming it was straight up and down to begin with).
Ramp on, my blue brothers.
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Of all the tires I've ever run, the first gen Aaron Ross tires are the worst for this. I swear I can feel each key click when I'm carving if my air pressure is below 85 psi.
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It's like, "yo bro, you gettin' this on your GoPro, bro? Feels like my tires are low. Think I need air if my shits feel like jello bro?"
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would tyre sidewall thickness be a factor in this? i know youve been running skinny lightweight race style tyres before blue. maybe you could get away with lower psi with tyres that have more substantial support on the sides?
i run like 50-60 psi normally, anything more feels disgusting for hops and stuff, but yeah more pressure deffos feels better for bowls and stuff. i just dont ride transitions and stuff enough to merit it though so i go for what feels best for everything else
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You don't think smashing through a berm on race tires is equivalent to carving a bowl?
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yeah but what pressure do racers run? with low psi i bet theyre a lot squishier than tyres with thicker sidewalls
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My Donnasqueaks feel ducking terrible carving around the bowl with anything under 70psi. Could be 2.25" on the rear or that I weigh 210lb.
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yeah but what pressure do racers run?
Legit question.
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i looked into it quickly cos i was curious, seems they generally like 50-60 psi, but theyre running much thinner tyres than us, 1.5" powerblocks, and someone did comment the 1.95 version was super squishy. with the kevlar bead version some are running higher pressures cos theyre rated for up to 110 psi.
thinking how fatter tyres feel slower and more sluggish at lower pressures than a thinner one at the same pressure, im assuming that a really thin tyre would hold its structure a lot better at a lower pressure as theres less tyre to flop around and squish about
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It comes down to contact patch size, and there is a ton of reading available if you look at road bike sources. A larger tire will require more PSI to keep a similar size contact patch to a narrow tire.
There is a huge debate in the road bike industry over the optimal tire width and whether the current trend of pushing them narrower and narrower is correct.
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Somewhere there is a video where I do a gap into a big skatepark pool and when I carve the facewall you can hear my rim dragging the facewall because I only had about 60 psi in the tube. I watch my psi moderately better now.
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There is a huge debate in the road bike industry over the optimal tire width and whether the current trend of pushing them narrower and narrower is correct.
The current trend is far from that, with professional riders mostly using a 25c tyre as opposed to the 22 and 23s that would of been more common a few years back, and non-racers opting for 28c and sometimes even 30c if it will fit, especially with the state of the roads where I live.
I'm sure the science has been proven now that the 25c provides better rolling resistance, and when roads are anything but perfectly smooth then the added cushioning and bump soaking of a wider tyre far offsets the minimal rolling resistance gains of a smaller one.