You're not. Although I did not know which mfgr mine was until you mentioned SKS.
How do you check the air pressure in your tires?
- Thread starter Sandwich
- Start date
2psi is a big difference, at least for me and my tires. I make .5 and 1psi adjustments for terrain.
i usually just give a squeeze
if it feels extra squishy i pump with crap specialized floor pump, stop when wildely inaccurate guage gets in the neighborhood of 30, and squeeze a bit, release a bit...
if it feels extra squishy i pump with crap specialized floor pump, stop when wildely inaccurate guage gets in the neighborhood of 30, and squeeze a bit, release a bit...
I agree with @atrokz and @Lelandjt . Changes of 1psi make a difference, so if you're not setting your pressure precisely everytime you ride, you're leaving margin for improvement. Squeezing your tire to check pressure can't be more precise than ±5psi, in which case I've found is the difference between a sliced tire/rim smash combo and "hmm, that hit was a little bit of a thing. Oh well, this next corner is coming up fast!"
That brings me to my next point: bike tire pump gauges have traditionally been terrible. In an attempt to make a pump compatible with any bicycle related machine ever made, the gauges typically read up to 160 - 200+ psi, which makes it useless for a mountain bike, as pressure gauge accuracy is questionable in the top and bottom 20% of the range. Additionally, when the minimum marked gradients are 10psi, it's hard to make 1psi changes.
I replaced the gauge on my pump with one from McMaster that reads up to 60psi, with 1psi gradients. After some goons borrowed it and broke the gauge trying to seat tubeless tires, it now has a 100psi gauge and a pressure snubber to idiot-proof it. The 100 psi gauge isn't as good, and I may go back to a 60 and just be a dick about how it gets used.
That brings me to my next point: bike tire pump gauges have traditionally been terrible. In an attempt to make a pump compatible with any bicycle related machine ever made, the gauges typically read up to 160 - 200+ psi, which makes it useless for a mountain bike, as pressure gauge accuracy is questionable in the top and bottom 20% of the range. Additionally, when the minimum marked gradients are 10psi, it's hard to make 1psi changes.
I replaced the gauge on my pump with one from McMaster that reads up to 60psi, with 1psi gradients. After some goons borrowed it and broke the gauge trying to seat tubeless tires, it now has a 100psi gauge and a pressure snubber to idiot-proof it. The 100 psi gauge isn't as good, and I may go back to a 60 and just be a dick about how it gets used.
German Bike magazine tested the following gauges:
SKS Airchecker: constant 0.15 bar below reference pressure
Schwalbe Airmax Pro: constant 0.12 bar below reference pressure
Topeak Smart Gauge D2: constant 0.2 bar below reference pressure
DRC G101: constant 0.1 bar below reference pressure
So in summary, it doesn't matter which gauge you use, if you use the same you reliably get the same pressure in your tires. If you want to set a certain reference pressure then you end up with too low pressure with all gauges.
SKS Airchecker: constant 0.15 bar below reference pressure
Schwalbe Airmax Pro: constant 0.12 bar below reference pressure
Topeak Smart Gauge D2: constant 0.2 bar below reference pressure
DRC G101: constant 0.1 bar below reference pressure
So in summary, it doesn't matter which gauge you use, if you use the same you reliably get the same pressure in your tires. If you want to set a certain reference pressure then you end up with too low pressure with all gauges.
i carry a C clamp around and test my tires by tightening the clamp on the tire; way more powerful and accurate than hands
Statistical outlier
I didn't articulate the situation very well. You are correct that a snubber only works for transient surges.
The snubber is for when goons shove the pump handle down as fast as they can when inflating a tire, but their sealant clogged valve stems have effectively pin hole pathways for the air, and it causes a large spike in pressure. That's what the snubber is for. The 100psi gauge also gave more headroom there as well.
Finally that's starting to happen. It means I may be able to inflate tires like a normal person instead carrying around my nerd pump.
So does that mean that when my SKS says I have 25psi it's actually 27psi? Was this test done using one example of each gauge or did multiple SKSs all read about 2psi lower than actual?
I'm pretty sure the former one. German Bike magazine is well known for having half decent ideas about tests but fail pretty hard on the (proper) execution.
Precision > accuracy for setting tire pressure. Just make sure to use the same gauge all of the time and you're good, as long as it is consistent.
SKS for me as well.
210lbs no kit.
2.35 Wild Rockr2 Advanced
Rear - 28psi +2/-1 for conditions.
Front 26psi +/- 2 for conditions.
Checked and set before every ride.
210lbs no kit.
2.35 Wild Rockr2 Advanced
Rear - 28psi +2/-1 for conditions.
Front 26psi +/- 2 for conditions.
Checked and set before every ride.
Yep. They didn't describe the test procedure but I guess they used the same gauge multiple times to see how reliable it was.
I hate the SKS thingy, it just sucks with Presta valves. The 30PSI gauge that Sandwich got from Jenson is IMHO much nicer and more reliable to use. Unfortunately, it is big and heavy for a camelback pocket.
I also picked up a 0-30 psi Meiser Accu-Gage last summer and now use it before every ride. It definitely makes the hand squeeze test useless, especially given the variety of rims and tire sizes I am using as different combinations can feel the same even though the pressure is say 5+ psi different. My pump gauge always reads about 3-5 psi higher than the Accu-gage but seems to be mostly consistent.
I am now running around 20psi +/- 2 in my 27.5 2.4 Goma's on i28 carbon rimz on my Spitfire.
I run about 20psi front, 24psi rear in my 29er 2.3 Minions on i23 rims on my Honzo.
DH bike usually gets close to 30psi, sometimes a bit lower depending on how rocky it is where I am riding.
I am now running around 20psi +/- 2 in my 27.5 2.4 Goma's on i28 carbon rimz on my Spitfire.
I run about 20psi front, 24psi rear in my 29er 2.3 Minions on i23 rims on my Honzo.
DH bike usually gets close to 30psi, sometimes a bit lower depending on how rocky it is where I am riding.
Hmmm...I wonder if you were using an older one? 'Cause the one I have couldn't be easier with presta valves.
This fcuker? Maybe I have just a bad item but it gives me obviously wrong readings with too low pressure (confirmed by the beep) so I have to measure multiple times and lose air in the process.
I sprint into a cinderblock wall and see how far I bounce back. 6 feet is usually a good 30psi.
For the back I jump in front of a bus on a highway with a 55mph speed limit. Looking for about 54 feet there...good for about 35psi.
If I'm off just reinflate, repeat procedure.
For the back I jump in front of a bus on a highway with a 55mph speed limit. Looking for about 54 feet there...good for about 35psi.
If I'm off just reinflate, repeat procedure.
lots of school busses in your town
I don't even know what that means.
Asian tourist buses work better anyway. Less chance of seeing me and actually braking. If they actually make to where I'm standing that is. Sometimes there's just swerving, drifting and stopping for no reason.
Hmmm... that's the one. Works fine. Perhaps operator error?This fcuker? Maybe I have just a bad item but it gives me obviously wrong readings with too low pressure (confirmed by the beep) so I have to measure multiple times and lose air in the process.
Perhaps he needs to Czech the fucking manual?Hmmm... that's the one. Works fine. Perhaps operator error?
It's in German
For what it's worth I have access to 4 SKS guages: mine, my girlfriend's, the shop's in the repair area, and the shop's in the rental setup area. They all agree.
I agree with mtg. If my pump says 30psi and that's where I like it, then Wtf does it matter if it's actually 28psi that I'm riding at? The lines on the pump might not be accurate, but they're consistent. People talking about half psi's are delusional. Seriously, it's all in your head. There are so many factors in a ride that can come into play. When your 100oz camelbak is down to 30oz do you lower your shock pressure?
I get an mri of my colon contents right before every ride so I can accurately assess any needed changes to suspension and tire pressure.
that reminds me.. i swallowed my data logging stuff last night.. time to ride and log
brb
On Presta valves, I put my mouth over the valve and depress the core with my tongue. If the air whistles out the fractured orbit in my right eye at anything lower than F#, I add air.