riding under recommended pressure
 

so my frame pump goes up to 90 psi... my tires requre 115-125. is the 90psi just to get me home or to a pickup point or can i finish a ride on 90 psi? I purchased a new frame pump that'll go up to 160 and has a gauge today but it's really not a smart purchase financially... i am trying to decide if i should keep it... i have had 3 flats in 4 days... 2 of them have been ride ending tire cuts... needless to say, the purchase was part retail therapy for my frustrations

The pressure recommended by who?
If you're going off the printing on the tire's sidewall, that's the maximum recommended pressure. In other words, the manufacturer doesn't want you to go over that amount because the tire wasn't designed for it. Running under that amount is just fine. Unless you're a heavy rider on very narrow tires, 125psi is overkill.
Anyway, I consider a frame pump to be useful only in emergencies. If it gets the tire to a useable pressure, that's fine. I use a floor pump at home to a proper job of it.

fwiw i am 220lbs on 25c tires i believe that the tire pressure is the 'recommended pressure' i cannot say that it is max

OK, you're a heavy rider on narrow tires.
As I said, as long as the pressure the frame pump can achieve will get me home, I'm not worried. But if that bothers you, get one that can do better.

You need to get a floor pump -- buy it at a bike shop, as the ones sold at chain stores are often not very good. You can get a very good pump for around $30 (about the cost of a decent tire, so well worth it).

Also, check the last post in this thread for a "starting point" for setting your pressure. I find it works for me!

http://www.bikeforums.net/showthread...pressure+guide

i have a floor pump at home... a very nice one... i was talking about my frame pump for flats while on a ride

take a look at the topeak road morph G.

++
I bought one because people on my rides were getting flats all the time and carrying these tiny little pumps that would tire anyone out trying to get enough psi to get home. Apparently I either do not ride enough or my tires really are bombproof, because I have not gotten a flat since I bought my current bike this time last year.
The road morph G is a great pump, and has a lot of features that I find indispensable when inflating a tire on the side of the road.

Ok, so the REAL question was whether 90 lb from a frame pump was ENOUGH pressure. The writing on the tire, max pressure, blah, blah, blah were all just red herrings.

Alright. Here we go.

90 lbs is about as much as most of us can get from a typical frame pump, unless it's something like a Roadmorph or Lezyne Micro Floor Drive HP. 90psi will get you home or to the next stop where you can top off your tire with a "real" pump. Since you're a big guy, you do need to be careful if your pressure is low.

The pressure listed on the sidewall is the max pressure. Use the psimet's guide I referenced earlier to determine what pressure you should be using based on the tire width and weight. You may want to use least 25mm tires given your weight.

If the pump you bought is one of the two that I listed, then it's probably a good investment. There are many pumps with gauges that go to 160 but actually getting above 100 with them can be nearly impossible. The Lezyne and the Roadmorph are both proven performers.

I've finished rides (as much as 30 additional miles) with about 90 psi in my 23s (max PSI 120) and I'm heavier than you are. Just be careful riding over places where you might pinch flat (driveways, potholes, etc.) and you should be OK.

The tire pressure printed on the side of the tire is MAX pressure -- it's the usual lawyer warning not to exceed manufacturer limits. There is no 'recommended pressure' printed on any tire that I've ever seen. Some have minimums, as well, but most are just max.

Tires are tested at double the pressure listed on the sidewall. It's safe to go over, though there is a point of diminishing returns.

At 220, I recommend 120 psi in the rear tire.

When I began riding over 25 years ago, our tires weren't rated for that much pressure, usually more like 95 psi. They can be ridden at less pressure under emergency conditions, certainly better to ride home with low pressure than to walk.

I've ridden different brands of tires and tire sizes vary from brand to brand. The tires I bought back then that were called 700x25 actually measured 25mm wide. The tires I'm riding now are called 700x20 but they still measure 25mm wide. (I'm getting heavier though so I might need something a bit bigger now.)

Last I knew, the width rating came not from the width measurement but the bead-to-bead measurement, divided by 2.5. Not sure why, but there you go.

I see this from a different perspective to all of you. I pump my tires (700x28) to about 120 psi and over a period of about a month or two they slowly go down to about 90 psi. If I let them get lower than that there is a risk of rim damage if I hit a pot hole or manhole cover with an edge. Now - if I only pump them to 90 psi I would have to re-inflate them every week at least. So it seems to me the maximum pressure is all about how long you want between re-inflation. On the other hand, the minimum pressure is all about how good the roads are. You could get home on 40 psi if the pavement is quite good and you ride carefully.

I weigh 140lb and have ridden 23s at 90psi without problems. You weigh 80 lbs more than me. Make of that what you will. My guess is that you'll get pinch flats at that pressure.

Sidewall pressure is 1/2 the pressure to blow the tire off the rim. Here is a good chart for pressure and the reasons.https://www.adventurecycling.org/res...SIRX_Heine.pdf

90 psi should be enough to get you home. Just be careful going over RR tracks and don't go off any curbs otherwise you'll get a pinch flat.

check pressure before every ride, look for em-bedded debris and super glue cuts, don't ride in the gutter and you won't get flats.

I recommend getting either the Road Morph mentioned above or some CO2 with 16g cartridges. If the latter, carry your 90 psi pump with you in case you run out of cartridges (to get you home).

The Road Morph is the only frame pump I've seen comfortably go up to 120 psi. Every other pump rated that high is only rated that way because it won't blow out a seal, but it takes a body builder who can bench 250 to actually get it into a tire.

For what it's worth, as an actual frame pump, the Topeak Master Blaster will put out a genuine 120 psi without much struggle. Mine, in the 54-59 size, does a measured 120psi into a 23mm tire with 120 strokes.

A 16 gram CO2 will do 100 psi in the same tire.

90 in a 25 should be fine. I run 90 as a preferred pressure in that tire size (I'm a tad lighter than you). I don't trust pump gauges a whole lot, though...

the pump that i picked up is in fact a topeak road morph. i de-boxed and mounted it tonight... i guess i am not comfortable with the 90 psi... ill just have to cut back an expense somewhere to offset the cost (only about $45, so not too bad). Am headed out for a ride, hopefully this is the first of the past 4 rides without a flat