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!
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!
I would be questioning the accuracy of the new gauge.
(: (darnit, I have a terrible habit of putting plurals in front of the (one) tire. 
It’s normal for pumps to get more difficult to use as the pressure increases. On a Shrader you are pressurizing the whole system, tube, hose, gauge… So, at some point during inflation if you want to add any pressure to it you have to overcome the pressure currently in the line. If you are using a high volume/low pressure pump it can get to this point under much lower pressure than a high pressure/low volume pump. Since your built in gauge stops at 100 psi, it would suggest a low pressure/high volume pump. Consider that if the piston in your pump is 2sq. inches you will have to put 130 lb’s of force into the pump to compress 65psi (pounds/sq. inch). Now consider that the piston in a lot of hv pumps is bigger than 2sq. inches and the effort increases by a bunch.
Just because the gauge reads up to 100psi doesn’t mean the pump can get there. Most gauges are more accurate in the middle of their range, and so pumps that go up to 65psi may have gauges that read to 100psi.
Then the last thing, your new gauge. It is probably a better read, and more accurate than the one built into the pump. If you know someone who has a calibrated gauge that you could use to verify yours it would be the best. Otherwise, actual pressure is a bit of a shot in the dark. I have two floor pumps, same model different pump ends (SKS/Zefal Husky), and the gauges are off by about 15psi between them. My handheld gauges are within 2lbs of each other and show both of my floor pumps to be off by 7-8psi in opposite directions. I trust my hand gauges (accugage).
Anyway good luck.
Something is fishy here. I weigh 210 lbs. If I had a tire with 100 psi and got on my uni, I doubt the tire would deform at all.
If your tire is ‘squishy’ there is no way it’s over inflated.
Have you tried pumping it while holding the pump head onto the valve stem? It’s an awkward movement, but sometimes I have to do that as the tire pressure pushes my pump head off sometimes (I’m using very old crappy pump).
Depending which market the product was targeted… …with a security factor of 2 before it explodes.
Ehm, could it be the pump is not really meant for high pressure?
Usually pumps for high pressure have the gauge “onboard” (unless it’s a hand-pump or so).
In bicycle racing nobody would drive less than 110, unless you’re featherlight.
Exactly; a timebomb.
If that’s good for you, then stick with that. Mind my spinal cord remark, I’m very serious about that.
My own digits:
Over the years I went with tiny steps each time a bit up. I have 4 unicycles. 20", freestyle. Two almost identical, so I use 3 different tires:
Pr1mo - The Wall: 85 PSI max
Odyssey - Path: 90 PSI max
I’m skinny and 155 pound, but usually put 75 to 80 PSI in them, and keep constantly track of of it (with a warning at a underlimit of 70).
Then I have and a slick Spanish/Japanese flatland tire:
Suelo - Silkworm: 110 PSI max (doing 200% in that one for sure will deform it).
That one is very thin and flexible, and so I put about 80 in that one. But riding that in a smooth clean studio will give so much contact with the concrete that it makes you nervous.
Once you’re used to higher values you don’t want to go back (it responds slower at steering). But in fact I do want to go lower (because of my back, when using the unicycle in traffic).
Fishy indeed - I was in error, and corrected myself in a later post. The tire did NOT have 100 psi; I assumed it did only because my pump (which has a maximum output of 100) was resisting my efforts at pumping more air into the tire. I figured it was giving me resistance because it had reached its 100 psi maximum output, but I was wrong. Checking it with a pressure gauge last night, I found that the tire only had 30 psi, and I then pushed a little more into it, bringing it to 36 psi, where it actually feels very hard and not squishy at all.
To everyone: any idea why, in an older thread here, everyone recommends over-inflation? The comments in that thread and the comments in this one (“DO NOT overinflate!”) are at complete odds. Here’s the old thread, from 1999:
http://www.unicyclist.com/forums/showthread.php?t=9360
The folks in that thread routinely ignore the recommended ratings on their tires and considerably overinflate them. Could it be that the ratings on tires are more accurate today than they were then, in 1999? Some selected quotes:
“I usually inflate my 40 psi tires to about 80 or 100 psi.”
“I generally will inflate a tire which suggests 40 pounds to about 60 pounds. Tires which suggest 40-65 pounds of pressure… will usually hold 75 pounds.”
“Over-inflation is the norm on unicycles.”
“On my unicycle I go up to about 2.5 times what it says sometimes. Generally I’m a bit under twice.” [A bit less than twice the recommended pressure.]
“I use a 50psi tyre and inflate it to approx. 80 to 90psi.”
My favorite story of overinflation happened over the Christmas season a few years ago.
A local church had a plan to get disadvantaged children some holiday cheer. They had the kids each make a wish list and matched the list with members of the congregation (who they didn’t disclose to the kids to keep it more Santa-like).
One of the kids wanted a bike. Their secret santa bought the bike at a local department store and placed it by the tree in the church.
Midway through the 8:30am Sunday service, during a time of silence, those in attendance were treated to a BLAM! Several people panicked as they thought someone had shot a gun inside the building. The older gentleman in the chair next to the bike just sat there calmly as confetti rained down on him.
I was called in to try to fix the bike. It took me a bit to get to the bottom of the story, but once I did I found out that when the bike was purchased the front tire was soft. The well-meaning secret santa took it out to the garage and filled it with an air compressor- not checking the pressure. Most likely it was inflated to well over 100 psi. It was rated for 40-65 psi. They brought the bike to the church and placed it beside the Giving Tree.
It just so happened that the tire detonated at an opportune time. When it did, the tags on the bike were turned to confetti, and that’s what showered the older gentleman sitting calmly in the chair beside the tree.
Hilarious.
Unfortunately, the whole front wheel was destroyed as a result of the over inflation. The wheel went from round to taco shaped and couldn’t be trued. They ultimately got a new front wheel for the bike and the child was as excited about getting a pedal-powered machine as we all are.
Happy ending, and (I think) a great story.
It really depends on what you’re doing. If you’re doing freestyle tricks on a gym floor (which is most of what was happening in 1999), over-inflating is fine. If you’re riding outdoors, you definitely don’t want a typical uni tire at 80+ psi. And if you’re riding on bumpy stuff (dirt, or most sidewalks), you probably want it to be on the low end of the range, or even below for real MUni with a real MUni tire.
The thing with your pump is probably that the Schaeder valve stem isn’t being properly engaged, so you’re having to pump against the spring pressure of the valve as well as the air pressure of the tire. That happens with a lot of valve/pump combinations. Push the pump valve further onto the stem and see if it can engage better, or try a different type of tube. (Or try a presta tube).
Hello Unigoat, I enjoyed reading that story. I think the moral of the story is… follow the manufacturers instructions.
That’s easy. In 1999 the unicycle market was very different. Most unicycles came with tires that indicated a max. of 40-45 psi, which would be insufficient for unicycling. Remember, in 1999 there were no Trials unicycles, or fat-tire unicycles of any kind unless you made them yourself. I used around 60 psi on the 1.75" tires of the day.
In your pump situation I would tend to blame the pump. Have you tried it on any other wheels? My floor pumps of recent years, when they died, all seemed to develop the same problem. They seemed to get worse and worse at being able to attach to Schrader valves while holding the valve open so you could pump. I had several pumps get to that place where no matter how much I screwed it back and forth over the stem to try to get it on there, they would simply not be putting air into the tires.
While this is not the problem you’re describing, it still sounds to me like the pump is where the problem is. If you weigh 200 lbs and have less than 40 psi in your tire (assuming a 1.75 tire or similar, not a Trials or Muni tire), it’s not enough. It should ride pretty crappy with way too much friction. Beyond that it depends what type of tire you’re working on. Fatter tires use lower pressure.
But if your pump is crapping out after 30 psi, question the pump itself. Is it old? Is it made for bikes? Your description seems to say yes about that. Is it a cheapie, or something that cost enough to not be crappy?
Try pumping up something else. Also, if you can, get a second pressure gauge so you can have a second opinion. Tire pressure gauges are not necessarily very accurate either (except compared to tire pump pressure gauges). 
BTW, having a tire pump that stops at a certain pressure is only useful if it lets you set the amount. And even for a car you wouldn’t want to limit it to 30 psi.
Totally agree. First time I used it, I was miffed it wouldn’t let me pump as much as I wanted. And to discover it begins to resist at just 30 psi? WTF?!
All good advice.
It IS a 1.75 tire, 24", with recommended pressure of 40-65.
If you think 40psi or less is too little, then I question the accuracy of the gauge I bought, because it’s reading 30-36 right now, and the tire is a solid, unsquashable rock.
What brand of gauge do you have? is it well reviewed?
200lbs on a 30psi tire should have a contact patch of close to 7sq. inches if my math isn’t totally screwed up. On a 1.75" tire that should be a noticeable deformation under load.