Psimet's tip of the Day
04-23-08, 01:31 PM
#1
I eat carbide.
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Psimet's tip of the Day
I thought I would create a place to share some of the nuggets I have gotten or given while on BF. I will come back and update this thread when I think about it. Probably no more than once a day though.
Tip 1 - Inflate your tires before every single ride. Know what the proper inflation pressure should be for your tires. Inflation requirements will vary by rider, bike, tires, conditions, etc.
Below you will find equations that you can use to help determine an appropriate starting point using your weight and the tire's size. Adjust from these baselines to suit needs and conditions.
Proper inflation is the easiet way to avoid flats.
Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67
Example: You are 150lbs running 28's
Pressure (psi) = (0.33*150) +33.33 = 82.83psi (rear)
Front Pressure = .9*Rear Pressure = .9*82.83psi = 74.55psi front
EDIT: I added () in order to make the equations make more sense. I think some people are doing the math incorrectly.
Tip 1 - Inflate your tires before every single ride. Know what the proper inflation pressure should be for your tires. Inflation requirements will vary by rider, bike, tires, conditions, etc.
Below you will find equations that you can use to help determine an appropriate starting point using your weight and the tire's size. Adjust from these baselines to suit needs and conditions.
Proper inflation is the easiet way to avoid flats.
Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67
Example: You are 150lbs running 28's
Pressure (psi) = (0.33*150) +33.33 = 82.83psi (rear)
Front Pressure = .9*Rear Pressure = .9*82.83psi = 74.55psi front
EDIT: I added () in order to make the equations make more sense. I think some people are doing the math incorrectly.
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Last edited by Psimet2001; 06-03-08 at 08:42 AM.
04-23-08, 01:37 PM
#2
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My tire doesnt hold enough air, now what??
BTW, do you accomplish ANYTHING at work, thats WORK related?? ALSO... I saw that little comment in the other post about someone descending. Might cost you a few beers this weekend for me to "forget" it.
BTW, do you accomplish ANYTHING at work, thats WORK related?? ALSO... I saw that little comment in the other post about someone descending. Might cost you a few beers this weekend for me to "forget" it.
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and the road becomes my bride
I have stripped of all but pride
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and the road becomes my bride
I have stripped of all but pride
So in her I do confide
And she keeps me satisfied
Gives me all I need
04-23-08, 01:42 PM
#3
Batüwü Creakcreak
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You have a typo, the front pressure should be multiplied by rear pressure not by front pressure 
This should be a fun thread.
This should be a fun thread.
04-23-08, 01:43 PM
#4
grilled cheesus
first i need the freaking tip on how to tell what tire size i have?!@? geesh.
later.
later.
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04-23-08, 01:43 PM
#5
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Can't... get it... to work.
Head hurts. Is it like the sound of one hand clapping?
Head hurts. Is it like the sound of one hand clapping?
04-23-08, 01:44 PM
#6
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Are you sure he works? I just thought everybody posting here during the day didn't work, like me...
04-23-08, 01:48 PM
#7
You Know!? For Kids!
Psimet works at UselessBikeTriviata Inc., a subsidiary of PCadhatesyou Worldwide Holdings Ltd.
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04-23-08, 01:58 PM
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I come in at 109 rear, 98 front. That is about what I use on wet, relatively smooth roads in a race. Seems a little low to me for dry conditions. On bad pavement I'd be risking a pinch flat.
04-23-08, 02:01 PM
#9
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I come out at 99.8psi for my 23s
i think that is a bit low really - according to my gauge on my pump (probably wrong) I put 120psi in often
i think that is a bit low really - according to my gauge on my pump (probably wrong) I put 120psi in often
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i jam my thumbs up and back into the tubes. this way i can point my fingers straight out in front to split the wind and attain an even more aero profile, and the usual fixed gear - zen - connectedness feeling through the drivetrain is multiplied ten fold because my thumbs become one with the tubing.
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04-23-08, 02:02 PM
#10
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Now I have to carry a scale as well as a pump in my bike kit?
No need to reduce tire pressure while riding to compensate for fluid loss; your tires will do it for you.
With a little practice, of course, one should be able to do these calculations in one's head.
No need to reduce tire pressure while riding to compensate for fluid loss; your tires will do it for you.
With a little practice, of course, one should be able to do these calculations in one's head.
04-23-08, 02:11 PM
#11
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Holy crap, I did the math, but the answer I got was
"Pump your tire up as much as you can you fat b@stard. If the tire blows, stop the lesson."
"Pump your tire up as much as you can you fat b@stard. If the tire blows, stop the lesson."
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
04-23-08, 02:14 PM
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Thanks, I havent seen this before.
Ive been trying to dial in my pressures during my last few rides few rides.
Ill try the front pressure=0.9Xrear pressure tonight.
Ive been trying to dial in my pressures during my last few rides few rides.
Ill try the front pressure=0.9Xrear pressure tonight.
04-23-08, 02:15 PM
#13
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04-23-08, 02:21 PM
#14
How much does it weigh?
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Psimet, it doesn't matter how many excuses you want to come up with (tire pressure being one of them), you'll still get dropped and we'll still yell at you.
That is all.
That is all.
04-23-08, 02:22 PM
#15
I eat carbide.
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I fixed the infinite loop 
Yes...I do work...although we did block access to Bikeforums on our firewall here....wonder why.
Not to worry. BF nerds helped me supply my addiction.
I do not currently - nor do I have plans to - work for pcad or any of his subsidiaries. I should though because then maybe I could afford some Zipps...even if they were used and from ebay.
I will forever remain ....off the back...
Kimbercop - You know I was joking *as I reach for my wallet and hail the waitress*
Yes...I do work...although we did block access to Bikeforums on our firewall here....wonder why.
Not to worry. BF nerds helped me supply my addiction.
I do not currently - nor do I have plans to - work for pcad or any of his subsidiaries. I should though because then maybe I could afford some Zipps...even if they were used and from ebay.
I will forever remain ....off the back...
Kimbercop - You know I was joking *as I reach for my wallet and hail the waitress*
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04-23-08, 02:49 PM
#20
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so, 89.6 rear, 80.64 front? that seems seriously... low.
04-23-08, 02:52 PM
#21
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Maybe these values are for charity rides...
04-23-08, 02:56 PM
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Ya those numbers seem low. Here's a useful tip: The easiest way to prevent flats is to buy a pair of Specialized Armadillo tires. Unless you run over a razor blade or an industrial sized nail, you will not get a flat, and they last for ever.
04-23-08, 03:09 PM
#23
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yeah, everyone knows armadillos will prevent pinch flats.
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
04-23-08, 03:15 PM
#25
I eat carbide.
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- *shakes head* - most riders ride with their tires pumped way too high. Seems they all decided to post today.
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