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Correct psi for my tire

Old 07-22-22, 09:13 PM
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travelinhobo
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Correct psi for my tire

I just bought a new tire for my rear and only after buying it looked at what the pressure requires. It's an Ultra Cycle Flamenco, low end hybrid tire and the sidewall reads: Max. Inflate to 40 psi. No range, just that exact number. Any opinions on this? And what would you recommend I inflate it to? I'm on a loaded bike, have a thorn liner in it and I only weigh 120. I felt like I got b.s.ed with the shop's answer and KHS hasn't responded (they make them or own the company). Thanks.
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Old 07-22-22, 09:20 PM
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How is anyone supposed to have an opinion when you haven't bothered to say anything about the size of the tire?
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Old 07-23-22, 05:12 AM
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I assume it's the 26" x 1.95" version. 40psi seems plenty.
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Old 07-23-22, 08:24 AM
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Dear nasty person. There it is. The bikeforums attitude I've missed. I'm sorry I'm not perfect like you - perhaps in my next life. Yes, it's a 26x1.95.
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Old 07-23-22, 08:35 AM
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I’d start with 40 psi and see how it feels and handles. Lower it from there if you aren’t getting pinch flats and you want more comfort.
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Old 07-23-22, 08:41 AM
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Fill the tires until they squish down about 1/4 -1/3 or the distance off the pavement while you sit in your usual position. Ride them. See if you'd like more or less air. (I'm guessing the first criteria will require maybe 30 psi, less in front.) Tires are not an exact science. But too much pressure can lead to the bead lifting off the rim or the sidewall blowing out or the rim sidewall breaking. Any of these events could be very hard on your eardrums.
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Old 07-23-22, 09:35 AM
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https://silca.cc/pages/sppc-form
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Old 07-23-22, 09:42 AM
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Originally Posted by travelinhobo View Post
Dear nasty person. There it is. The bikeforums attitude I've missed. I'm sorry I'm not perfect like you - perhaps in my next life. Yes, it's a 26x1.95.
How was I 'nasty'?
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Old 07-23-22, 10:27 AM
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Originally Posted by travelinhobo View Post
Dear nasty person. There it is. The bikeforums attitude I've missed. I'm sorry I'm not perfect like you - perhaps in my next life. Yes, it's a 26x1.95.
While cxwrench can be a bit blunt at times, he has a point. When asking for advice, giving all the relevant information you have up-front certainly helps the person(s) who might give advice.

Here, you're the one asking for free help (in terms of advice). Seems to me it shouldn't be too much trouble to provide as much info as possible up-front so that the people you're asking for help can, well, help you more easily. Doing that's also IMO likely to increase the quality of the help (advice) you get.

But that's just me. Do what you like.
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Old 07-23-22, 10:38 AM
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Originally Posted by travelinhobo View Post
I just bought a new tire for my rear and only after buying it looked at what the pressure requires. It's an Ultra Cycle Flamenco, low end hybrid tire and the sidewall reads: Max. Inflate to 40 psi. No range, just that exact number. Any opinions on this? And what would you recommend I inflate it to? I'm on a loaded bike, have a thorn liner in it and I only weigh 120. I felt like I got b.s.ed with the shop's answer and KHS hasn't responded (they make them or own the company). Thanks.
My explanation of the optimal tyre pressure (depending on the tyre size and rider+bike+luggage weight).

If you determine the optimal pressure for that tyre size is over its designated maximum pressure, look for a wider or higher-quality tyre (one not excluding the other).
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Old 07-23-22, 11:12 AM
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Originally Posted by travelinhobo View Post
Dear nasty person. There it is. The bikeforums attitude I've missed. I'm sorry I'm not perfect like you - perhaps in my next life. Yes, it's a 26x1.95.
Which would be referred to as a "mountain bike" tire, not hybrid.
Hybrids have a 622mm BSD which is about a 24.5", not 559mm which is 22".
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Old 07-23-22, 02:04 PM
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Originally Posted by Bill Kapaun View Post
Which would be referred to as a "mountain bike" tire, not hybrid.
Hybrids have a 622mm BSD which is about a 24.5", not 559mm which is 22".
I don't completely agree with ISO diameter dictates the bike category. The biggest example are 29ers that have "your" hybrid rim diameter but are considered the MtB way by many. In the shop I still work at (been trying to retire for a few years...) any flat bar bike with a mixed road/dirt tread is a hybrid. This still bothers me as when I see "hybrid" on the bike description I look for a 622 ISO wheeled bike too. But then it was only a decade ago when we would call a drop bar bike with 32ish wide tires that weren't CX treaded a touring bike... (Real story- On one on my first rides with the local club I rode my sew up equipped bike, double crankset, Campy short reach calipers BUT a handle bar bag over my rear wheel on my self made SPT. One guy asked about why I rode a touring bike...)

This description stuff reminds me of how others who don't make their own music seem to want to apply labels to the music they don't make. Andy
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Old 07-23-22, 02:16 PM
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At 120 pounds, there is no way I would run 40 psi. Assuming the bike is around 30 pounds, I would go around 30-32 pounds. Probably a pound less in the front. 31F 32R is what I would do. 40 PSI will jar your teeth.
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Old 07-23-22, 02:26 PM
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Originally Posted by phughes View Post
At 120 pounds, there is no way I would run 40 psi. Assuming the bike is around 30 pounds, I would go around 30-32 pounds. Probably a pound less in the front. 31F 32R is what I would do. 40 PSI will jar your teeth.
"I'm on a loaded bike, have a thorn liner in it" the OP
So, the rider weight is not the only weight the tires are seeing. Wish we knew how much more.

No one has mentioned the tire liner. The most popular brand has a reputation of causing flats if the tires are run with too little pressures for their loads. The ends of the ribbon/liner can act as scrapers against the tube. The less the pressure the greater the squirm that results in the ribbon/liner's end chaffing the tube.

These are two reasons why the "best pressure" question is not formulaic, but experiential. Andy
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Old 07-23-22, 02:28 PM
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Originally Posted by Andrew R Stewart View Post
"I'm on a loaded bike, have a thorn liner in it" the OP
So, the rider weight is not the only weight the tires are seeing. Wish we knew how much more.

No one has mentioned the tire liner. The most popular brand has a reputation of causing flats if the tires are run with too little pressures for their loads. The ends of the ribbon/liner can act as scrapers against the tube. The less the pressure the greater the squirm that results in the ribbon/liner's end chaffing the tube.

These are two reasons why the "best pressure" question is not formulaic, but experiential. Andy
Yes, I added 30 pounds for the bike, but not the load. No idea what the load is. Even assuming another 40 pounds for the load, I wouldn't go over 33 or so for the rear. Even if the OP, bike and load was 250 pounds, it would only need 35 pounds,.
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Old 07-23-22, 02:31 PM
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Originally Posted by Andrew R Stewart View Post
I don't completely agree with ISO diameter dictates the bike category. The biggest example are 29ers that have "your" hybrid rim diameter but are considered the MtB way by many. In the shop I still work at (been trying to retire for a few years...) any flat bar bike with a mixed road/dirt tread is a hybrid. This still bothers me as when I see "hybrid" on the bike description I look for a 622 ISO wheeled bike too. But then it was only a decade ago when we would call a drop bar bike with 32ish wide tires that weren't CX treaded a touring bike... (Real story- On one on my first rides with the local club I rode my sew up equipped bike, double crankset, Campy short reach calipers BUT a handle bar bag over my rear wheel on my self made SPT. One guy asked about why I rode a touring bike...)

This description stuff reminds me of how others who don't make their own music seem to want to apply labels to the music they don't make. Andy
That's how my LBS described the difference, although that was before the introduction of 29'rs. The term "Cruiser" wasn't really popular yet either.
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Old 07-23-22, 05:21 PM
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I like the SRAM calculator. Its easier for me to make adjustments and recalculate. My guess is 29 psi front and 31 psi rear to start. But go try yourself. Its fun 🤩.

https://axs.sram.com/guides/tire/pressure
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Old 07-24-22, 08:29 PM
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Originally Posted by phughes View Post
At 120 pounds, there is no way I would run 40 psi. Assuming the bike is around 30 pounds, I would go around 30-32 pounds.
This.

Required pressure for high pressure road tires is a function of total weight and tire width. Online calculators are available.
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