Under inflated tires =

[WonderMonkey]

.... pain. Before my lunch time ride I felt up my tires (they like the attention) and deemed them "almost ready for some air.." and went on my ride. Welllll the wind was picking up and I'm just getting back in shape and I had ridden hard the day before and I'm a pansy and and and..... As I mentioned in there the wind was whipping around and about 25% into my ride I could feel my legs burning a bit. I was horribly sorry that I didn't top off my air as that would have helped a tad. However I pushed on and to punish myself for being a fatass and too stupid to fill my tires I went just a bit further then I normally do and pushed myself harder then I would have. On the way back I actually thought I felt a small cramp in my thigh but it went away with a jedi mind trick.

I swear I could FEEL my tires being under inflated, is this possible?

[Tom Stormcrowe]

Yes, it's possible. ;)

[The Historian]

.... pain. Before my lunch time ride I felt up my tires (they like the attention) and deemed them "almost ready for some air.." and went on my ride. Welllll the wind was picking up and I'm just getting back in shape and I had ridden hard the day before and I'm a pansy and and and..... As I mentioned in there the wind was whipping around and about 25% into my ride I could feel my legs burning a bit. I was horribly sorry that I didn't top off my air as that would have helped a tad. However I pushed on and to punish myself for being a fatass and too stupid to fill my tires I went just a bit further then I normally do and pushed myself harder then I would have. On the way back I actually thought I felt a small cramp in my thigh but it went away with a jedi mind trick.

I swear I could FEEL my tires being under inflated, is this possible?

Depending on the bike, sure. I ride at psi 110 on my 32 cm commuting tires, and if the pressure is lower than that, I work harder.

[WonderMonkey]

Speaking of you riding at 110 psi, are your tires rated for that? My tires say xx-65, can I go above that?

[Tom Stormcrowe]

Maybe....but I don't recommend it. Just check the pressure before each ride and make sure you add the appropriate air to keep to the needed pressure.

[road_rascal]

Yup- riding into work this morning I'm thinking "why is this tougher than usual"? Checked the rear and it was at 35psi. Just filled them up the other day to 80. So I have a leak I have to deal with.

[WonderMonkey]

How often is "normal" to add air?

The main reason I didn't add air is all I had was my emergency pump which sucks. I brought in my full sized pump today and plan on getting a different emergency pump for my bike.

[bautieri]

How often is "normal" to add air?

That really depends, I usually lose 10psi out my rear tire and 5 psi out my front every week.

[Jynx]

I top off every 2 days. Day to day I lose maybe 3-4psi a tire.

[WonderMonkey]

OK. I feel pretty good then given your losses.

[piper_chuck]

How often is "normal" to add air?

The main reason I didn't add air is all I had was my emergency pump which sucks. I brought in my full sized pump today and plan on getting a different emergency pump for my bike.

I do a thumb check before every ride. Typically I add air at least once a week, sometimes twice. I've had a Zefal HP frame pump (http://www.yellowjersey.org/hpx.html) since the early 90s. It works great and if it ever dies I will buy another.

[The Historian]

Speaking of you riding at 110 psi, are your tires rated for that? My tires say xx-65, can I go above that?

I don't believe in over-inflating tires. I don't want to test the limits. :D

[WonderMonkey]

I do a thumb check before every ride. Typically I add air at least once a week, sometimes twice. I've had a Zefal HP frame pump (http://www.yellowjersey.org/hpx.html) since the early 90s. It works great and if it ever dies I will buy another.

I have a smaller version of that style. However when I tried to use it yesterday all I did was lose air in my tire.

[WonderMonkey]

I don't believe in over-inflating tires. I don't want to test the limits. :D

I agree. I didn't know if it was common practice to do so. I usually go a pump over to account for the air I might lose when disconnecting my hose.

[CliftonGK1]

Underinflation can also = pinch flats.

I top off my tires every couple of days, but I run 'em near the top of the pressure limit and like to keep them there. (700 x 28 Ultra Gatorskins @ 110psi)

[andrelam]

I don't believe in over-inflating tires. I don't want to test the limits. :D

+1 on that. I made that mistake this Winter. It was cold and dark one morning. I was adding some air. Somehow my brain did not engage properly and I miss read the tire pressure on the sidewall and thought it said 6.5 bar it should have been 4.5 bar. The bike was pretty cold from staying in the garage all night (it was in the single digits outside). The ride to work was prefectly uneventfull. I was sitting in my office around 4:00 PM, and all of a sudden there was a loud explosion. It shocked the cr@p out of me. My ears were ringing. After some investigation I found that my front tire bead had let go. The tire was beyond use and the inner tube actually schreded. I guess between the over pressure and the extra 15 or so PSI gain from the temperature increase from around 20 F to 75F (very warm office) was enough to put the tire over the edge.

I now fill the tire EXACTLY to max pressure, and am a bit more careful to make sure I have some light in the garage to see what I am doing.

Happy riding,
André

[flip18436572]

I run mine at 110 psi, but that is what the tube and tires are rated for, or actually more. I will usually lose up to 5 pounds of air a week in my tires, don't ask me why, but some weeks it is more in the front and some weeks it is more in the back. I close the presta valve the same way each time, but it still different each week and yes you can really tell the difference and I can tell the difference when I am riding on my rollers also as it is much tougher.

[Caincando1]

I need to top off every couple days. I don't thumb test because I can't feel the difference between 100-120 with my thumb, but I sure can feel it when I ride. I just make sure they are at 120 before every ride.

[WonderMonkey]

I suppose I should say that my tires were not UNDER the lowest range of the tire so I was still within what the manufacturer stated. I was just way lower then the max and felt I could feel it.

[Halthane]

I run very high pressures nearly all the time. If it's really wet I'll let them down a couple PSI, but I tend to check before pretty much every ride. Just got a new (old) specialized crossroads that I commute on that has 700 x47c Slicks that go to 100psi. They rule... supper comfy and fast fast fast.

[Bill Kapaun]

Rate of air loss depends a lot on tire size and pressure.
Higher pressure = faster loss.
A "skinny" tire is affected faster because it has a low volume. A slight air loss has a greater effect on pressure than losing the same amount of air in a "fat" tire.
I "think" lightweight tubes also lose air faster than thicker ones. Tubes are "porous" and a thinner tube is bound to be "more porous".

If your pressure rating is 40-65 psi you probably have "fatter" MB tires? My tires have the same pressure rating and I top them off at 70 psi. They roll noticeably easier than when at 60 psi. I'm not a bit worried about 5 psi over max. How many tire gauges are really that accurate? If you didn't spend a lot of money on your gauge, it's probably better to consider it to be an "estimate" of psi!. Manufacturers have to allow a safety margin!

I'll give my tires a "squeeze test" about once a week and really don't need to top them off but every 3 weeks or so. I may top them off if going for a "longer than normal" ride however, if I think it'll make a difference. Most my trips are <5 miles, so I don't get too anal about it.

[fc_]

I have a smaller version of that style. However when I tried to use it yesterday all I did was lose air in my tire.

You may want to try one of the Topeak Morph series, I have the predecessor "combo master blaster", and the current Road Morph (http://www.topeak.com/products/detail/239). Great pumps for the road, much more like using a standard floor pump.

[Wogsterca]

How often is "normal" to add air?

The main reason I didn't add air is all I had was my emergency pump which sucks. I brought in my full sized pump today and plan on getting a different emergency pump for my bike.

It's normal to lose some pressure every day, typically around 3% of the total pressure, some will be a little less, some will be a little more, depending on the composition of the tube material, and manufacturing tolerances in the material and the tube itself. If your losing more then 5% though, you probably have a slow leak somewhere.

Everyone has a different idea of when to add air, some people are positively anal about it, they have digital pressure gauges and check them constantly, if it's down half a pound they add air. Most people are more tolerant though, some will get on, and if the tire "looks" flat they add air, others use the bounce or thumb test, still others know that they generally add air every 3 days, so they dig out the pump every 3 days and top them up.

Emergency pumps are just that, you use it in an emergency to put in enough air to get you to a floor pump, there are some pumps designed to work as both, they have a fold out "foot" that lets them operate as a floor pump, but are small enough to fit on a bicycle, I believe the Topeak Road Morph is one of these. I don;t have one, so I can't say how well it works though......

[CACycling]

I top off the tires on all 7 bikes every Friday. I run everything at max (65, 100, 105 or 115 depending on the tire). Rarely have anything down more than 5 psi. I have a small electric compressor with a guage on it and with all the bikes hang in the garage I just go down the row and hit them all.

[v1k1ng1001]

I top off before every ride, even if it's just riding into the office. I do it mostly to protect my wheels.

If you're mountain biking it is a good idea to experiment with tire pressure. As clydes, you want to keep the tire inflated to protect your rim, but you also have to realize that a high pressure tire is a liability on slow, gnarly single track or in mud. I usually start an off road ride at 55 psi and then let out air as needed.

[DieselDan]

I know better.

[WonderMonkey]

Rate of air loss depends a lot on tire size and pressure.
Higher pressure = faster loss.
A "skinny" tire is affected faster because it has a low volume. A slight air loss has a greater effect on pressure than losing the same amount of air in a "fat" tire.
I "think" lightweight tubes also lose air faster than thicker ones. Tubes are "porous" and a thinner tube is bound to be "more porous".

If your pressure rating is 40-65 psi you probably have "fatter" MB tires? My tires have the same pressure rating and I top them off at 70 psi. They roll noticeably easier than when at 60 psi. I'm not a bit worried about 5 psi over max. How many tire gauges are really that accurate? If you didn't spend a lot of money on your gauge, it's probably better to consider it to be an "estimate" of psi!. Manufacturers have to allow a safety margin!

I'll give my tires a "squeeze test" about once a week and really don't need to top them off but every 3 weeks or so. I may top them off if going for a "longer than normal" ride however, if I think it'll make a difference. Most my trips are <5 miles, so I don't get too anal about it.

They are Town and Country style for a mountain bike. Slight inlaid tread.

[WonderMonkey]

You may want to try one of the Topeak Morph series, I have the predecessor "combo master blaster", and the current Road Morph (http://www.topeak.com/products/detail/239). Great pumps for the road, much more like using a standard floor pump.

I like that. Thanks for the point.

[jaxgtr]

I'm really anal about this stuff and check the pressure at every ride and do a safety check as well. I guess that comes from my military days and doing pre-flight checks.

[themetalman]

i use 700x23 tires and i keep them at 120 psi, i check them everytime i go for a ride.

[speedxl]

Even though I was never in the military I attended aviation maintenance school while in High school and have a CDL drivers license, I always do a pre flight (trip) inspection. You only got two wheels and my safety is #1. I check religiously my air psi, especially here in Florida where ambient temperature cause drastic changes in psi. I also check my cars tire every fill up ( trust me you'll notice with increased mpg's ).

[Luke1511]

700x23 tires here. I keep the psi at 110 and check every ride. It's a habit now, only takes a second and the difference between 95 or 100 psi and the regular 110 is noticeable.

[chainsaw5vent]

HEY! i checked the air pressure in my sienna's wheelset. all less than 36 psi. took them all up to 44 psi and noticed an immediate increase in estimated miles to go til empty....

oops..wrong forum

more air pressure means less rolling resistance = less effort wasted on flat tires. and less pinch flats.