Tire inflation problem

I have a typical bicycle pump, the kind shaped like a T which you operate by hand. It has a Schrader-type connector at the end of the hose, which perfectly fits my tire’s Schrader-type valve stem. I have no problem connecting the hose to the valve stem, and no problem giving it a few pumps to begin re-inflating the tire. (Please, no replies saying I must be using the wrong type of connector for my valve stem [Presta vs. Schrader], or that I must not have established a solid enough connection between the pump and valve stem. It’s a solid connection; air is definitely going into the tire, and without any air escaping. That’s not the issue.)

Here’s my problem. At a certain point, the pump suddenly gives me considerable resistance. In all my years of using bike pumps I’ve never encountered such resistance before, so I assumed this was a new feature in the design of bicycle pumps, a way for the pump to tell the user to stop pumping, because the tire pressure is reaching maximum psi. I’m afraid to force more air into the tire when I reach this stage, because I fear over-inflation and bursting the tube, so this is when I consider the tire “full” and stop pumping. And yet, the tire does seem to have room for a little more air: if I put pressure on the tire with my hand it gives way a little, and people watching me ride are always saying “I think you need more air in your tire.” (This is with every bit of my 200-pound body pushing down on the tire.) I think they’re right, and yet I get that resistance from the pump when I try to further inflate the tire. Should I ignore the resistance the pump is giving me and just force more air into the tire, strong-arm it in, or should I take the pump’s resistance to mean “stop pumping, because your tire has had enough”?

Have you tried to pump another tire?

Or, Check to see if you have dried up green Slime plugging up the valve stem…

You must be using the wrong type of conn… oops!

Maybe you could try borrowing a different pump from a friend and see if it makes a difference.

Have you tested with a gauge the pressure level?

Does your fitting look like this ? If so my guess is you need to tighten the ring on the tip a bit more so it grabs the stem tighter. Sound like you get enough pressure that it’s slipping up the stem until the valve core closes.


With an average tire your can take a chisel and remove the digits before PSI :wink:
No seriously; with tires the quality of Pr1mo or Nokian it should be possible to put double the pressure without any ear damage.
But I guess it wont surprise you when I’d say riding that is a timebomb.

But let’s say you’re doing a 125%

With an overinflated tire then you might (very slowly) damage your rim and lacing, especially when it’s single wall, or worse: when it it’s a trial rim that has suspension holes (but usually then you don’t want super high pressures). And when you’re not inside a hall, keep in mind your spinal cord! As seats that nowadays are common lack decent suspension.

Another point when doing over-inflation: make sure you reliable innertubes. It’s OK if they’re thin, as long the material is good. Personally I would recommend Maxis Ultralight and Pr1mo again, especially when it says “made in Taiwan” (the Chinese batches are -IMHO- of less quality).
Foss tubes are probably no good here, although it depends on what pressure you’re aiming at.

What your question made me realize; you nowadays see only the max.
While before usually you would see a also an under-limit (thus a range).
I start to feel like an old grumpy guy now.

But to get a better impression of what you’re doing; what’s was the max before you took the chisel, and how much are you trying to get in there?
If I understand correct your pump stops before you reached your max?

I should’ve done some research before asking my question. I just discovered my own answer(s). Here’s what I found…

  1. As unicyclists, just one wheel is taking the full brunt of our weight (and some of us are men weighing in excess of 200-225 pounds), so – as many on this forum know – it’s a safe and common practice to over-inflate your unicycle tire, even by as much as twice the maximum recommended pressure.

  2. My tire indicates it should be inflated to 40-65 psi.

  3. My pump indicates it will only inflate to 100 psi, and no more. (This is why I’m getting the “resistance” from the pump; it’s reached its maximum output of 100 psi and won’t go further.)

So what I’ve been experiencing is this: I’m inflating the tire with as much air as I can, until the pump won’t let me add any more. The result is a tire of 100 psi, which is higher than the recommended pressure (40-65 psi) and perfectly acceptable to ride on, but which appears to need still more air when it’s squashed down by my 200-pound body. And it probably does need more air, but I’d need a different pump to bring it there.

Or, you know, I could lose weight. ; )

That’s a lot of pressure! I weigh 190, and don’t put the max into any of my tires, and still don’t feel like I’m bottoming out, or lack control. Riding with a little less than max pressure does make for a little softer ride. This may or may not make a difference to you, depends on where and how you ride.

I don’t think so! :astonished:

Too much pressure could cause the tyre to blow or to bulge outside the rim.

I suggest that you put on a stronger tyre that can hold the pressure.

I don’t know of any unicyclist who would put 100 psi into a 65 psi max tyre.

Hope this helps.

Hey, you’re ahead of the game…the machine’s in front of you…now get to it while the clock is young:D

Fatter and wider rims perhaps? I love mine, Sun Double Wides, Duro 3.0, and im not that heavy, and I run them at 25-30 psi. A good workout indeed.

“So what I’ve been experiencing is this: I’m inflating the tire with as much air as I can, until the pump won’t let me add any more. The result is a tire of 100 psi, which is higher than the recommended pressure (40-65 psi) and perfectly acceptable to ride on, but which appears to need still more air when it’s squashed down by my 200-pound body. And it probably does need more air, but I’d need a different pump to bring it there.”

Darn, your tire’s in pain!!:D:D

Well, according to an older thread on this very forum, everyone who posted said “Yes, yes… overinflate the tire… I inflate by as much as 2.5 times the maximum recommended… etc., etc.”

I think both you and Lance might be reacting to a difference in semantics: MAXIMUM tire pressure allowable vs. maximum RECOMMENDED pressure. My maximum RECOMMENDED pressure is 65, the top end of a recommended range, but the tire can take much more than that. And whoever in that old thread said that he inflates to 2.5 times the maximum, may have meant 2.5 times the maximum RECOMMENDED as well.

Tires sometimes indicate a recommended range, and sometimes (more frequently these days) they indicate the maximum allowable, which is supposedly a line you should never cross.

I think I have this right.

Extreme overinflation is asking for trouble. I’d get a second opinion with a different pump or gauge.

A tire blowing off the bead is no picnic. At best it’s just an annoying sound and a few bucks for a new tube. However, a blowout could easily lead to you solving the problem by buying a new high PSI rated tire when you go to replace the tire. I’ve known of at least 2 instances when people have had to shell out for new 36er tires when they blew off the rim. Yeah, this isn’t a 36er we’re talking about here, but it is a tire and tube.

As stated earlier the wheel itself could suffer damage.

Getting a second opinion on pressure now will be much easier than suffering the fallout if something fails.

Im sure you could cross it a little, but to double it?? super thin roadbikes like my 700x23c run at higher than 100psi, max125 psi.
Way too inflated for comfort, in my opinion. Really, try wider tires, and dare i say, longer cranks, you might find it more fun and a greater work out.

Hello GR, I’ve just been editing my previous post as you were writing your reply. You might like to read it again. For me if the manufacturer gives a max recommendation then that’s where I draw the line.

What size tyre are you using. In the freestyle 20" range you buy a Maxxis Grifter which can be pumped up to 110 psi. I pump mine up to 100psi approx.

I believe my 29" Qu-Ax that I bought used, the original owner probably ran it at or near 100psi. It ran like the shits, all over, no control!:stuck_out_tongue:

Hello UPD. Yeah, when I’m on my freestyle I’m using 75 mm cranks which makes the uni more stable. 100 psi in 29" tyre with long cranks would be a bit twitchy. I use about 45 psi in my big apple tyre which works very well for me. If the wheel is to twitchy then forward momentum is compromised

I have 170" on my 26" 3" duros. At the current moment I enjoy them for muni trails, roads not. I have gotten used to them so theyre not twichy to me…
29er, I have 145" on 2" maxxis beavers. Not liking it for trails. I am thinking of a wider tires like Ardents or High Roller? What do you think for 29" light muni?

Yeah, now I’m embarrassed. :o I have this all wrong. I took a few bits of information which were available to me, and jumped to an entirely erroneous conclusion.

I just bought a pressure gauge, which indicates my tire is currently at about 30 psi. I tried pumping it higher (recommended: 40-65, if you recall), but my bike pump resists further pumping action. Still, I managed to put about 6 more psi into it (36 psi total), and it’s hard as a rock and I don’t dare go further. 40-65, my ass! I can’t imagine going as high as 65! It would blow for sure. I guess 65 is the ABSOLUTE MAXIMUM before it explodes.

This brings me back to the original conundrum: why my bike pump inflates a tire only so far, and then resists further pumping. Does it act as a self-regulating gauge, and knows when my tire has had enough?

And what about that old thread, with everyone recommending over-inflation, and one person even recommending DOUBLE the maximum? That’s crazy!!

In any case, the pressure gauge I bought will help, going forward. Seems 40 is about the maximum I really want in this tire. Rides great!