PSA, Inflate tire to 80% psi
05-18-23, 08:40 PM
#1
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PSA, Inflate tire to 80% psi
For longevity and "I know what psi my tires need to be...." I meant 80% of max psi. Refers to car tires as well..
4 of
4 of
Last edited by rc5781; 05-18-23 at 08:45 PM.
05-18-23, 09:41 PM
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Huh? So front and rear tires should get the same pressure. Wet and dry don't matter? Neither does rider weight? Or does one swap tire sizes ride to ride to meet these conditions and stay at that magic 80%?
If you were going to go by a magic percent, a given percentage of "squish", ie sidewall deflection would probably be better. (I'"d stick to my 5 psi difference front and rear. I like enough surplus air in front to cover hitting that pothole braking hard with all my weight on the front wheel. A moment where I would rather not suddenly blow the tire or wreck the rim.
If you were going to go by a magic percent, a given percentage of "squish", ie sidewall deflection would probably be better. (I'"d stick to my 5 psi difference front and rear. I like enough surplus air in front to cover hitting that pothole braking hard with all my weight on the front wheel. A moment where I would rather not suddenly blow the tire or wreck the rim.
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05-18-23, 10:22 PM
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for cars you follow the manufacturers recommendations other wise you risk loss of control and handling and increase risk of blowouts with under inflation
for bikes there are any number of calculators that will give you a range based on weight, tire size and type there is not standard for all much less some vague 80%
Please don't post uninformed, dangerous crap when you don't know what you are talking about
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Last edited by squirtdad; 05-18-23 at 10:25 PM.
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05-18-23, 10:25 PM
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05-18-23, 10:26 PM
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05-18-23, 10:40 PM
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We can agree that the o.p. misses the mark, but ... I have been riding since 1967 and I have never tried to maintain a differential between f/r. I have never used my weight to compute optimum psi. I do NOT take precipitation or lack of it into consideration. At zero dark thirty when I am heading out on the outbound commute there is only one thing I want to know: do the tires have air? A squeeze of the sidewalls (can't thumb the tire: fenders) tells me all I need to know. I've been doing it this way for too long to stop now.
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05-19-23, 05:46 AM
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Folks can do stuff wrong for years and suffer no ill effects. One of the satisfactions of a hobby is taking the time to learn and do things right. 
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05-19-23, 06:58 AM
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Thanks
05-19-23, 07:02 AM
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I just stretched an assumption to bicycle tires.
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05-19-23, 07:13 AM
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Lee Abel
30+ Yr Senior Master Automotive TechnicianAuthor has 1.9K answers and 1.9M answer views3yAs a 30+ yr auto tech AND front end specialist I have long held factory MINIMUM air specs are just that. MINIMUM.
I was given advice many years ago and it really holds true in what I witnessed over the years. If you take your tires max inflation and use 80% of that your going to get much better results in my opinion.
I like running small to medium cars at 40 psi. If it's auv/cuv try 42.
If it's too stiff/rough try dropping to 38 psi.
But try to keep the 80% , your tires will hold up much better.
I watched a lady with older car that came with actual 32–35 psi tires, door said like 28. With 51 psi tires that half flat.
She went to 40 and loves her new tires.
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30+ Yr Senior Master Automotive TechnicianAuthor has 1.9K answers and 1.9M answer views3yAs a 30+ yr auto tech AND front end specialist I have long held factory MINIMUM air specs are just that. MINIMUM.
I was given advice many years ago and it really holds true in what I witnessed over the years. If you take your tires max inflation and use 80% of that your going to get much better results in my opinion.
I like running small to medium cars at 40 psi. If it's auv/cuv try 42.
If it's too stiff/rough try dropping to 38 psi.
But try to keep the 80% , your tires will hold up much better.
I watched a lady with older car that came with actual 32–35 psi tires, door said like 28. With 51 psi tires that half flat.
She went to 40 and loves her new tires.
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05-19-23, 07:14 AM
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That's a stretch for sure.
Here's a better idea Silca PSI Chart
Here's a better idea Silca PSI Chart
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05-19-23, 07:15 AM
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https://www.quora.com/What-is-the-re...0to%2045%20psi.
I just stretched an assumption to bicycle tires.
I just stretched an assumption to bicycle tires.
Why would you extrapolate from some dude that posted on Quora like it is coming from a useful reference?
05-19-23, 07:17 AM
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The advice in that link is stupid. Most passenger cars use a pressure closer to 30psi, not 40. 40 will increase gas mileage at the sacrifice of breaking and turning traction.
Why would you extrapolate from some dude that posted on Quora like it is coming from a useful reference?
Why would you extrapolate from some dude that posted on Quora like it is coming from a useful reference?
05-19-23, 07:20 AM
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How long have you been driving around in a car with the tires 30% overinflated? Have you noticed the additional centerline wear? How's the emergency handling?
05-19-23, 07:24 AM
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here is what a large reputable tire manufacturer says for their tires.
https://www.toyotires.com/media/pxcj...s_20200723.pdf
https://www.toyotires.com/media/pxcj...s_20200723.pdf
05-19-23, 07:30 AM
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That's a stretch for sure. Here's a better idea Silca PSI Chart
Here's a better idea Silca PSI Chartor this one. curiously enough the if I average the RH soft and firm I get really close to the Silca psi..
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05-19-23, 07:42 AM
#19
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I must admit that I'm getting a little nostalgic for the simplicity of the days when thin was in (are there still 19mm tires?) and max pressure was a must to avoid pinch flats. Not missing the pinch flats though.
05-19-23, 07:50 AM
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I imagine if I tried I might be able to find some 19mm tires. I wish they were more readily available, and slicks would be even better. I still run my tires at the max (140 psi), and stating so usually triggers a large portion of BF folks.
05-19-23, 07:53 AM
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Wouldn't solid rubber tires be a better choice?
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05-19-23, 08:16 AM
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05-19-23, 08:19 AM
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05-19-23, 08:20 AM
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05-19-23, 08:23 AM
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I miss the road surfaces that permitted one to ride with tires less than 38mm wide.
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