speedlever

That sounds high for a 32c tire. What does it say on the sidewall? I'd guess 85psi for the max on those tires... but I could be wrong.

And yes, per the formula, your math is correct. See the example Psimet posted at the end of his post.

Of course, YMMV.

More info:
https://sheldonbrown.com/tires.html#pressure

beowulf7

Thanks, that site has some useful info.

What confuses the heck out of me is that my tire inflation recommendation is extremely different. My bike is a Trek 7.3 FX with 700x32c tires. The link says I should inflate to 67 PSI given my weight of 150 lbs. Yet the sidewall of my bike's tires says to inflate to a max. of 110 PSI. That's a huge difference.

I know this is the Internet and no one can be trusted. So for anyone who thinks I'm lying or am blind, I took a couple pics of it w/ my phone and can post it here once I offload those pics.

speedlever

You could modify the formula with Sheldon's advice. Air up to 67/60 psi then check to see if you have a slight bulge when you sit on the bike. If so, that's probably about right. If it seems low, add 10 psi and check again.

Running the formula to see what rider weight it would take to get to 110 psi for a 32c tire comes up with a 402 lb rider! Yowza.

As always, YMMV.

michelinmike

Purchased a Schwinn Air Driver 1100 at a local Target out of necessity when my high end brand new pump died on me. The manufacturer of the high end has been very nice and has offered to replace the pump but cannot tell me what went wrong with it. While I'm waiting for the replacement I still need to ride--hence the 1100. I learned a bit about so called high end pumps and it seems the majority of them come out of the same 3 factories in the Far East. Depending upon who the brander is the pumps are made to different specs but Chinese manufacture has come a long way. The Schwinn 1100 is no exception. For $17 I can't believe the quality I got. A solid well painted steel barrel and a 5-in-1 switchblade head that works just fine on my presta valves. Took the tires right up to 105 psi ( a bit short of 116 optimum) once I learned how to properly engage the solid and weighty aluminum lock. You can disassemble the rubber and plastic components of the washer head and reassemble it to handle presta without any adapter, even though the pump comes with the standard brass screw on adaptor. The gauge is accurate and the rubber tubing has joints that can be adjusted. Pump build is excellent. I don't think you can say "cheap Chinese junk" and be accurate anymore. Holy cow.

beowulf7

Wow, apparently a great product and at a excellent price. I don't see that pump on target.com, so I'm tempted to go to my local Target to see if they sell the Schwinn Air Driver 100 there. Thanks for the info.

Edit: I just found that product on Wal-Mart's site for $12 with so-so reviews. Hmm ... : \

Also, on Amazon's site for $18 with a 2/5 rating.

Darkrider23

That pump is pretty much a hit and miss. I've read about the pump actually popping off the valve once it hits 90 PSI or so. Thought about buying it because I need one, but I think I'll wait and save up money for a better one.

beowulf7

I (thread starter) bought that Schwinn 1100 Deluxe bike pump from Target for $20. It comes w/ a Presta tire valve adapter (small brass piece). I hate it! The pump won't stay on the adapter. Every time I start pumping it, it falls off. It's a 2-man job - one to pump and the other to hold.

I'm going to return this and find another bike pump that has a built-in Presta adapter. It's a PITA dealing w/ multiple parts. Terrible design. The Amazon reviews where 2 people rated it 1/5 are completely correct. Lesson learned.

socalrider

The Joe Blows work fine and good bang for the buck.. Pedros Prestige works great.. Easy getting to 120-130psi..

https://jensonusa.com/store/product/P...tige+Pump.aspx

beowulf7

^ Yeah, I'm leaning toward Joe Blow. It's a bit of a hike to get to PB's store (half hour drive), but I'll just go w/ that, it seems.

I'm not familiar w/ that Pedros pump, but one of the reviews said it's a PITA to work w/ Presta valve (which is what I have). : \

socalrider

I only use presta valves and it works fine.. I use a few times a week with no issues..

varuscelli

Are you sure you're locking the lever in the correct position? This pump locks with the lever up instead of lever down. If you're pressing the lever down, you're not locking it in place. That seems to be the most common mistake with the 1100 pump. Or does it not work the same way with the Presta valve?

michelinmike

Hey Beowulf, you don't need to use a Presta adaptor with the 1100. The trick is this: unscrew the plastic cap on top of the pump head. There is a small plastic insert underneath. Take that out and reverse it. Reinsert it into the head. Carefully screw the cap back on, the threads are fine make sure you don't damage them. You now have a presta head. Just push the assembly onto the presta valve and close the lever. Pump. It will not fall off. I get 120 psi out of mine. These pumps will drive you crazy. I now have a very expensive one and a very cheap one. They both work equally well. The only time they might come loose is if you happen to have nonthreaded valve stems. Still I am able to pump almost to capacity even when the pump head shoots off one of those.

beowulf7

Thanks for the feedback, guys. var, I was not aware that the locking position was vertical and not perpendicular. I will try locking it the other way around. michelin, hmm, that's an interesting idea. I did try to mess w/ the cap on the pump, but it wouldn't unscrew. I didn't try very hard, so I'll try it again.

datlas 

Sorry about the hijack, but I have a pump-related issue....the joe blow holds onto the valve well, maybe too well....so every couple of months my tube fails at the valve....are you supposed to lube the head??

StanSeven

I've gone through two Joe Blows as well as sveral others including the Park shop. The best pump I've found is the lowest price model from Specialized. It sells for $30-$35.

thebeatcatcher

What PSI are you getting out of that thing?

beowulf7

(I didn't realize I forgot to reply to this post.) Even trying to lock it like that causes the bike pump to still pop out after a certain PSI (which is nowhere near the 110 my tires require). Therefore, I'm going to get rid of this Schwinn and probably get the Joe Blow or something else that my local bike store carries. I don't want to deal w/ adapters either. That's a PITA and something that can get lost easily.

beowulf7

I think I finally got a bike pump that will keep me happy for a while. I bought the Bontrager TurboCharger from my LBS. It's got a smart head that locks in place. It takes a little bit of effort to get my hybrid tires to 100 PSI, but it's a good forearm workout.

beowulf7

Too bad the Bontrager pump I got can't be used to pump car tires. I still have my old cheap pump that I used for it, but it took quite a bit of effort. Are there any smart head pumps (i.e. those that auto-fit Presta and Schrader) that can also be used for car tires? Just wondering, not that I plan to return my Bontrager.