Bicycle Mechanics - Tire guage -- what's the least expensive accurate one??

I'm asking the question in this forum because having an accurate tire gauge feels like a mechanical issue, or possibly a mechanical-avoiding issue. :D

So: what's the least expensive carry-around pressure gauge? I bought a RoadMorphG pump which is nice enough as a pump but its gauge seems like rubbish to me. I don't want to rely on it.

(edit: corrected typos)

What size tires do you plan to gauge? With high pressure low volume road bike tires an independent gauge is nearly a waste of time because you'll loose too much pressure just testing it. Best to use a floor pump with built-in gauge.

Al

What size tires do you plan to gauge? With high pressure low volume road bike tires an independent gauge is nearly a waste of time because you'll loose too much pressure just testing it. Best to use a floor pump with built-in gauge.

Al
Now THAT's an interesting thought, and one I hadn't considered. I've always aimed to inflate to 75% of the tire's rating, with the idea that I'd end up in the middle after testing. My assumption has been that doing that would give me a margin for gauge error.

Which floor pumps have accurate gauges, do you know?

You'll eventually be able to gauge pressure simply by feeling the tire with your thumb.

I'm kinda with The Fixer on this one. Get a good floor pump for home use, pump it to your desired pressure and practice feeling that with your thumb, then when you're out on the road you can get pretty close even without a gauge (good to know if you're using a CO2 system). It's not like accuracy is all that critical for bike tires anyway. Most people are not going to notice +/-5psi, maybe even more.

Also I'm not sure I understand this bit:

I've always aimed to inflate to 75% of the tire's rating, with the idea that I'd end up in the middle after testing.
Maybe it's just me, but the way it's worded makes me think that you are using 50% of the tire's rating as your target inflation pressure, which is not necessarily a good target. I recommend having a read through this article (http://sheldonbrown.com/tires.html#pressure) to arrive at a better target inflation pressure.

Actually, I do gauge it with my thumb (or rather my whole body by leaning on it). But that has always seemed a hit-or-miss method compared to an accurate gauge. Maybe I'm being anal-retentive.

You're right about my 50%-of-rating-range aim, that is indeed what I've most often done. And thanks for the pointer to Sheldon's article, it was very interesting. I've always tried to err on the low side since the idea of having a tire go bang from overinflation petrifies me--either it'd go bang in my face, or while I was in a busy street, either way With Disasterous Consequences. I've probably got too good an imagination or something. It's nice to know that there's probably more margin for error than I'd thought.

Maybe I'm being anal-retentive.
well, I didn't say it! :)


It's nice to know that there's probably more margin for error than I'd thought.
Yes, quite a bit more.


Let me guess...former Firestone Wilderness AT owner or something? :D

Actually, I do gauge it with my thumb (or rather my whole body by leaning on it). But that has always seemed a hit-or-miss method compared to an accurate gauge. Maybe I'm being anal-retentive.

You're right about my 50%-of-rating-range aim, that is indeed what I've most often done. And thanks for the pointer to Sheldon's article, it was very interesting. I've always tried to err on the low side since the idea of having a tire go bang from overinflation petrifies me--either it'd go bang in my face, or while I was in a busy street, either way With Disasterous Consequences. I've probably got too good an imagination or something. It's nice to know that there's probably more margin for error than I'd thought.

You're more likely to have problems from underinflation. Don't know what kind of bike you have but with typical road bikes on 700 X 23 tires most people run between 105 and 120 psi pressure. These tires lose 10 to 20 psi overnight and should be re-inflated with every ride. Mountain bikes and hybrids with larger tires run much lower pressures and loose air at much lower rates. I run my road bike rear tires at the maximum recommended pressure shown on the tire. Front tires I run about 5% lower pressure due to lower share of the weight.

Al

Actually, I do gauge it with my thumb (or rather my whole body by leaning on it). But that has always seemed a hit-or-miss method compared to an accurate gauge. Maybe I'm being anal-retentive.

You're right about my 50%-of-rating-range aim, that is indeed what I've most often done. And thanks for the pointer to Sheldon's article, it was very interesting. I've always tried to err on the low side since the idea of having a tire go bang from overinflation petrifies me--either it'd go bang in my face, or while I was in a busy street, either way With Disasterous Consequences. I've probably got too good an imagination or something. It's nice to know that there's probably more margin for error than I'd thought.

Better to have it close to the limit and avoid pinch flats every time you hit a pothole or bump! If you're running low pressure to get a comfortable ride, you should probably consider switching to different tires/wheels rather than running high-pressure tires improperly.

A tire won't "go bang" from overinflation unless you're WAY over and/or the tire was defective to begin with. IMHO, many sudden tire deflations are probably due to pinching the tube during installation, more so than overinflation.

So what size tires are these and what maximum pressure is printed on the tire(s)?

I use a guage call Accu-Gage for when I'm touring. It seems to work well and I don't seem to lose too much pressure when I slip it on and off the valve stem, but then I never did tests to see if I did. Here's a link to what I've been using http://www.rei.com/product/1634.htm. I'm not sure I know how much I paid because I got it from my lbs. What I like about it is after you check your pressure, the needle is stuck in place until you release the button. Works on both valve types.

So what size tires are these and what maximum pressure is printed on the tire(s)?
Up til now I've been riding an MTB as a sort of "urban dreadnought", so they're 26x2.1 with a marked range of 35 - 65psi. I've been keeping them around 50 and that's seemed to work rather well.

But I'm switching over to an older mixte tourer, with narrow hi-pressure 27 inchers, so that feels more scary and prompted my question. Since I'll still ride in the same manky urban roads, I'm wondering whether I can switch down to 650s or at least 700s and fatten up the tires. But I don't know yet whether that will bugger up the pedal clearance...I might be stuck with the 27s.

I bought a digital tire gauge from Radioshack for five bucks. It even speaks out the tire pressure in psi. I use it when I'm on the road. Haven't had any problems with it.

I use a guage call Accu-Gage for when I'm touring. It seems to work well and I don't seem to loose too much pressure when I slip it on and off the valve stem, but then I never did tests to see if I did. Here's a link to what I've been using http://www.rei.com/product/1634.htm. I'm not sure I know how much I paid because I got it from my lbs. What I like about it is after you check your pressure, the needle is stuck in place until you release the button. Works on both valve types.
Thanks for the pointer! Between your recommendation and its well-made appearance, it's on my shopping list.

I bought digital tire gauge from Radioshack for five bucks. It even speaks out the tire pressure in psi. I use it when I'm on the road. Haven't had any problems with it.
Thanks...I'll have a look at that one too. Five bucks is even nicer that twelve, tho I'm always a little suspicious of things from Radio Schlock.

I'm asking the question in this forum because having an accurate tire gauge feels like a mechanical issue, or possibly a mechanical-avoiding issue. :D

So: what's the least expensive carry-around pressure gauge? I bought a RoadMorphG pump which is nice enough as a pump but its gauge seems like rubbish to me. I don't want to rely on it.

(edit: corrected typos)

I have 2 older Zefal gauges that I bought years ago from Nashbar. One for presta and one for Schraeder. These were like $8 each. These have an easy to read dial and hold the pressure reading. The newer Zefal pressure gauge is dual purpose, it handles both valve types. I think these are like 12 or 15 dollars. These are way better than automotive gauges, they read accurately all the way up to 140 psi. I usually go about 5 to 10 pounds OVER the stated maximum on the sidewall, and yes I have blown tires before due to excessive pressure. I agree with whoever said that you are more prone to (pinch) flats when tires are under-inflated. My Michelin Pro 2 Race 700 x 25c tires are rated for like 102 psi max - I run them a hair over 110psi and they run great. The 70 x 23c version of the same tire is rated a bit higher at ~116 psi, I would probably put up to 120 psi in that one. Some would argue that too hard of tires degrades the ride quality causing bouncing and poor traction. All I know is that at a little over #230, I go faster and feel safer at these slightly higher pressures, and yes I can tell there is as little as a 10psi difference in pressure.
As for the person who said your going to go for some guesstimate, thinking you'll be off by 25% or more due to gauge inaccuracy - I say: if you're that far off you've got a ridiculously inferior gauge. Try the Zefal, its highly accurate and dependable, and so long as you don't drop it hard it should last a long time for very reasonable amount of cash.:)

Thanks...I'll have a look at that one too. Five bucks is even nicer that twelve, tho I'm always a little suspicious of things from Radio Schlock.Most of them are made in China.....what difference does it make?...:D