Tire pressure gauges

[Soujyu]

After not riding for about a month or so, I went to the garage to go check the tire pressures on my bike so I can ride it tomorrow. After doing so, I'm definitely a bit perplexed, because of the following:

1. The first tire pressure gauge I used was a little one that came with my Slime air compressor/tire flat repair package. It goes to 50psi. I tried it on both the front and the back, and it read 50+ psi (the white bar was completely shot out). I was like... "this can't be right", so I tried it on a tire on my Prius, and it also went 50+ psi.

2. I'm like... okay, I have another tire pressure gauge that Dad tucked into my Prius a while back, which is a lot longer. This one I can't even get into the front tire due to the brake rotors, but this one read 22psi on the back tire. I'm like, "okay, so I lost some air on the back", so I plug in the Slime air compressor, and blew it up for a couple of minutes. It later read anywhere from 20 to 28 psi, which is too low. I suspect this gauge may be suspect as well, so I try it on my Prius and it registered 10psi.

3. Off I go to Autozone, and I buy a digital tire pressure gauge with a flexible hose. I get back home, and used that. Now, the tire reads 70psi front, and 76 psi back! Tried it on my Prius, and it read 45psi!

So, basically I have a few questions:

1. Are ANY of these pressure gauges anywhere close to correct?
2. If none of them are correct, what should I do, short of buying gauge after gauge?
3. Is there some secret to properly using a tire pressure gauge on a motorcycle tire?

[csmith12]

ahhh.... tire gauges.

[Finesse]

I usually use the ones at gas stations that are free. Or one made for a bicycle.

Make sure the valve stem and the tire gauge line up exactly so air is not leaking out while you're measuring the pressure

[fishdip]

Originally Posted by Soujyu

After not riding for about a month or so, I went to the garage to go check the tire pressures on my bike so I can ride it tomorrow. After doing so, I'm definitely a bit perplexed, because of the following:

1. The first tire pressure gauge I used was a little one that came with my Slime air compressor/tire flat repair package. It goes to 50psi. I tried it on both the front and the back, and it read 50+ psi (the white bar was completely shot out). I was like... "this can't be right", so I tried it on a tire on my Prius, and it also went 50+ psi.

2. I'm like... okay, I have another tire pressure gauge that Dad tucked into my Prius a while back, which is a lot longer. This one I can't even get into the front tire due to the brake rotors, but this one read 22psi on the back tire. I'm like, "okay, so I lost some air on the back", so I plug in the Slime air compressor, and blew it up for a couple of minutes. It later read anywhere from 20 to 28 psi, which is too low. I suspect this gauge may be suspect as well, so I try it on my Prius and it registered 10psi.

3. Off I go to Autozone, and I buy a digital tire pressure gauge with a flexible hose. I get back home, and used that. Now, the tire reads 70psi front, and 76 psi back! Tried it on my Prius, and it read 45psi!

So, basically I have a few questions:

1. Are ANY of these pressure gauges anywhere close to correct?
2. If none of them are correct, what should I do, short of buying gauge after gauge?
3. Is there some secret to properly using a tire pressure gauge on a motorcycle tire?

if you find one that reads correct let me know. even the 60.00 one I have is off 3-4 psi

[Alex]

Motorcycle Consumer News did a huge comparo of tire gauges a few years back. Will try and find the text. Was happy to see that some of the best performers were the ones that I had a pile of (Roadgear). They all read very close to one another, no matter which one I grab.

several of these: link

I'd probably splurge on this one if I needed a new one now.

EDIT: found the review

[Soujyu]

Originally Posted by Alex

Motorcycle Consumer News did a huge comparo of tire gauges a few years back. Will try and find the text. Was happy to see that some of the best performers were the ones that I had a pile of (Roadgear). They all read very close to one another, no matter which one I grab.

several of these: link

I'd probably splurge on this one if I needed a new one now.

EDIT: found the review

Looks like I need to quit buying Slime gauges.

[EsrTek]

Originally Posted by Soujyu

Looks like I need to quit buying Slime gauges.

Same here...just went out to bike and took it off and out in trash bin.
Been wanting a digi, cause the slime is hard to read..but frak didn't realize it could be giving false readings.

[Hero Danny]

Originally Posted by Soujyu

so I tried it on a tire on my Prius, and it also went 50+ psi.

[Motofool]

Originally Posted by Soujyu

2. If none of them are correct, what should I do, short of buying gauge after gauge?

Use your bare hands to evaluate temperature after a spirited 15 minutes ride.

Too hot to keep your hand on it = Inflate some more and re-test.

Too cold = You can deflate some for improving riding comfort and traction.

Same for the Prius.

[snot]

@Alex thanks for the review.

[adouglas]

This might seem a silly question, but on the cheap gauge, when you stick it on the valve do you just let the rod shoot out and read it, or do you push down on it a couple of times ("bounce" it against the pressure)?

I believe that stiction and/or the inertia of the rod can cause it to wind up with an inaccurate reading. By pushing down a bit and releasing, you get a consistent result. How accurate it is is another matter.... Mine match the dial gauge, so I'm okay with that.

Have yet to invest in a digital gauge. FYI Motion Pro came out with one since that earlier MC News review. IIRC they tested it and liked it.

[Soujyu]

Originally Posted by adouglas

This might seem a silly question, but on the cheap gauge, when you stick it on the valve do you just let the rod shoot out and read it, or do you push down on it a couple of times ("bounce" it against the pressure)?

I believe that stiction and/or the inertia of the rod can cause it to wind up with an inaccurate reading. By pushing down a bit and releasing, you get a consistent result. How accurate it is is another matter.... Mine match the dial gauge, so I'm okay with that.

Have yet to invest in a digital gauge. FYI Motion Pro came out with one since that earlier MC News review. IIRC they tested it and liked it.

I pretty much push down, and release. Since I don't have much space around the front wheel due to the huge brake rotors, it tends to take me a little bit longer to get the gauge off the stem.

I just realized that there's a Discount Tire Company down the road from me; I figure they would have something that is a lot more accurate than what I have.

[Alex]

Before spending too much $ on just a gauge, at some point it makes more sense to get one of these: 120-volt inflator

Calibrate the gauge mentally against another gauge you trust once, then just use the inflator to both check and fill your tires appropriately every time with one step.

[DaBlue1]

Here is what I found out about pressure gauges.

https://www.ninjette.org/forums/show...0&postcount=13

[krapzed]

This is what I use. Pretty much accurate and very good reviews.

http://www.amazon.com/Joes-Racing-32...8968304&sr=1-1

[menikmati]

I use this Accutire digital gauge. It might be a little tricky to get a reading with the rotor or chain in the way. The problem was gone when I installed Bridgeport 90-degree valve stems. I used the gauge for both my car and bikes.

http://www.amazon.com/Accutire-MS-40...tal+tire+gauge

[Whiskey]

Accuracy for a tyre gauge doesn't matter a ****, as long as it's consistent you can get a feel for if the gauge reads high/low. It may say 40 when it's at 37, but as long as you keep that gauge with you and adjust till it reads 40 you'll have the tyre at 37. Inflate to a couple of psi over & use the deflate button on your gauge until it's right.

[wardie]

Plan on investing about $40-$50 for an accurate oil filled tire gauge. Some sources are Motorcycle Superstore, Competition Accessories maybe your local bike shop and Amazon.com

[Soujyu]

So, it turned out that my tires were overinflated by about 15-20 psi or so. After I drove by Discount Tire Company and had them check my pressures, I now know that the first two gauges I used are garbage (and will be thrown into the big green trash can in my garage), and the digital gauge that I had bought consistently reads 20psi high, which means I probably will be mentally subtracting 20psi from what it says when I use it

Thanks to everyone for your advice on gauges. Now I can worry about one less thing before I go riding, and I'll be spending some money on another good gauge (when this new gauge goes bad).

Originally Posted by menikmati

I use this Accutire digital gauge. It might be a little tricky to get a reading with the rotor or chain in the way. The problem was gone when I installed Bridgeport 90-degree valve stems. I used the gauge for both my car and bikes.

http://www.amazon.com/Accutire-MS-40...tal+tire+gauge

I probably will ask the dealer to put in 90 degree valve stems the next time I take my bike in for an oil change/tire replacement. Trying to deal with that freaking front tire with the rotors was not fun.

[Milsparro]

I gave up on digital, there's batteries. I have a $6 Canadian Tire analog on the bike, it agrees with about 5 other ones I have, the main exception, yes, being the slime one my brother has.

[Worldtraveller]

Originally Posted by fishdip

if you find one that reads correct let me know. even the 60.00 one I have is off 3-4 psi

How do you know?

BTW, I use the built in gauge on my Joe Blow bicycle hand pump, and it works great. Probably +/- 2-3 psi, just based on the scale on the dial, but it seems pretty accurate, and goes to 160 psi.

All the tire guys say not to use gas station air compressors, since they don't get maintained very well, and you wind up with lots of water vapor when you fill the tires. That will be ok when cold, but wind up too high when your tires get hot.

[ally99]

Boy, I use an ol' cheapo bicycle tire gauge and it's pretty accurate when compared with the gauge at my local bike shop. I've used the same one for years without fail.

[dcj13]

A man with one clock knows what time it is. A man with two two clocks is never sure.

[CZroe]

Originally Posted by Alex

Motorcycle Consumer News did a huge comparo of tire gauges a few years back. Will try and find the text. Was happy to see that some of the best performers were the ones that I had a pile of (Roadgear). They all read very close to one another, no matter which one I grab.

several of these: link

I'd probably splurge on this one if I needed a new one now.

EDIT: found the review

Bump! I'm sure the New England Patriots will be using that article in their defense.

[cadd]

I found that when bumped around a lot (dropping it, rattling in the trunk of a car, etc) may make it read erratically. I have 3 gauges. A pencil type, a small digital and a round one with a flexible hose. All kept in my garage. They all read within 2psi of each other. I also have a pencil type that I wedge between the seats of my car (for insulation). That one is also with 2psi of the others.

[Rifleman]

nothing beats a pitot guage for accuracy and repeat ability.

that little "stick" tire gauge is what i use to put 'enough' air in to get home to the shop.

if it's not round, and it's not a needle on a gauge face... spend a few nickles and get a real one. The one I have is connected to my air chuck. Just make sure you get one in PSI

[ninjunk]

yeah i found one of those dial style analog ones in the trash a couple years ago with a broken gauge. I replaced the gauge with a high quality... i think its an ashcroft or maybe US pressure gauge (found laying around at work) and I use that as my go-to.

Those pencil ones i don't trust for anything, and a cheap digital is probably worse. At least the pencil one is based on something, the digital you never know.

I've got one of these
http://www.harborfreight.com/12v-100...sor-69284.html

Lots of the reviews say its junk but i'm pretty happy with it. I took it apart when i first got it and loctited/tightened all the screws, lubed the connecting rod with lithium grease, and put pipe dope on all the connections. It works like a champ. I've probably aired up the equivalent of 50 car tires with it, i had a car with a crusty alloy rim that would leak down and need airing up every other day. I dunno that the included gauge is super accurate, but it seems to be close enough.

[Brother Michigan]

Get an air compressor and set the regulator for the correct pressure. Wait an infinite amount of time and you'll have just the right amount of air.

[dcj13]

Originally Posted by Rifleman

...Just make sure you get one in PSI.

You guys haven't converted to the metric system?
Back tire: 221 kilopascals (or something like that...)

[crazymadbastard]

Originally Posted by dcj13

You guys haven't converted to the metric system?
Back tire: 221 kilopascals (or something like that...)

I use the Bar...

[Rifleman]

or Atmospheres (which is BAR I think)

No kPa in the USA yet

[csmith12]

Originally Posted by ally99

Boy, I use an ol' cheapo bicycle tire gauge and it's pretty accurate when compared with the gauge at my local bike shop. I've used the same one for years without fail.

Lol!

I use a dollar store special, you know the ones in the register isle. I had it tested for accuracy and it's 1.4lbs off every time. $1

My friend Kevin bought up one of those fancy inflators that I use it on occasion.

[dcj13]

Originally Posted by Rifleman

No kPa in the USA yet

What the hell? 1974 was supposed to be the year of metrification in the US.

[ninjunk]

tell me about it, no metric and the middle east is still at war.



D'oh!

[ally99]

Originally Posted by csmith12

Lol!

I use a dollar store special, you know the ones in the register isle. I had it tested for accuracy and it's 1.4lbs off every time. $1

My friend Kevin bought up one of those fancy inflators that I use it on occasion.

Yeah, Kevin's inflator really blows.

[alex.s]

technically, the US is on and has been on the metric system for quite a few years.

[crazymadbastard]

Originally Posted by alex.s

technically, the US is on and has been on the metric system for quite a few years.

I just filled up with gallons of gasoline... cant find 38mm drain pipe at lowes, and had a footlong for lunch and chugged a 16oz soda pop...

[alex.s]

Originally Posted by crazymadbastard

I just filled up with gallons of gasoline... cant find 38mm drain pipe at lowes, and had a footlong for lunch and chugged a 16oz soda pop...

if you payed close attention, the metric fittings at lowes are further down the isle, the footlong isn't really an imperial foot, its more like the size of someones foot. and the 16oz soda pop lists ML before oz. but yeah **** those gassholes

[fast1075]

I'm an hvac/r technician. My gauges have to be accurate, so my tire gauge has a refrigeration analog gauge on it. It has a calibration screw. I calibrate it to "0" PSIG every time I use it. A savvy refrigeration tech knows changes in barometric pressure affect calibration, so it is checked every time.

Also, an analog dial gauge is most accurate mid scale, so choose your gauges accordingly if you are OCD about stuff like that.

[CZroe]

I bumped this because I found it hard to find again when I needed it in a discussion about Deflate-gate on another forum. I am happy to see the discussion continuing, but I was hoping someone had a joke or observation involving Deflate-gate. Come on! Missed opportunity!

Originally Posted by fast1075

I'm an hvac/r technician. My gauges have to be accurate, so my tire gauge has a refrigeration analog gauge on it. It has a calibration screw. I calibrate it to "0" PSIG every time I use it. A savvy refrigeration tech knows changes in barometric pressure affect calibration, so it is checked every time.

Also, an analog dial gauge is most accurate mid scale, so choose your gauges accordingly if you are OCD about stuff like that.

Curious: What do you calibrate it against? Zeroing it out doesn't mean the measurements from zero are correct.