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James R. Davis
 Administrator
14909 Posts
[Mentor]
Houston, TX
USA
Honda
GoldWing 1500
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 Posted - 04/30/2008 : 7:57 AM
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quote:
James - it's the static coefficient of friction that counts!
Why must people take so many tangents?
Yes, we all know that it is the static coefficient of friction that determines when your tire will skid/slide and that it is the dynamic coefficient of friction that determines how fast you can decelerate once you have begun to slide. (That, in my opinion, 'counts', at least if you want to survive over-aggressive use of your brakes.)
The issue was - does contact patch size have a meaningful effect on traction. It does not. |
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albert_tatlock
Junior Member
76 Posts
San Patong, Chiang Mai
Thailand
Honda
XLR250
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Posted - 04/30/2008 : 8:06 AM
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Sorry to be a fly in the ointment, but I have t disagree here about using maximum pressure indicated on the tyre.
Fine if you are driving something that is a heavy machine, but the tyre pressure quoted on the sidewall indicate maximum pressure for a given maximum load.
If I put maximum pressure in my tyres, I will bounce the hell out of the bike, Honda specify 24 PSI rear and 18 front, if I put more than 18 in the front, I will skitter like nobodys business and overwork the suspension.
It depends on weight / load on the bike, I weigh about 60Kg, I do not need the same pressure as someone who weighs 120Kg.
It is exactly the same for my pick up, my tyres are rated maximum pressure of 60 PSI for a maximum load of 900KG, I do not carry 4 x 900 KG, I run my tyres at around 30 PSI, and the car handles fine, if I put 60 PSI in, I would bounce all over the raod! The same for the bike. I am afraid I will side with the bike manufacturers reccomendations on tyre pressure everytime as opposed to the tyre manufacturer, who makes tyres for a wide variety of bikes with vastly different weights and applications. |
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James R. Davis
Administrator
14909 Posts
[Mentor]
Houston, TX
USA
Honda
GoldWing 1500
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Posted - 04/30/2008 : 9:15 AM
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There is no disagreeing - the advice is to keep the pressure ANYWHERE YOU WANT WITHIN the limits stamped on the tire with adjustment for load.
I further advocate tending to use close to max for added tire life, but that is not a rule or requirement.
Finally, be advised that the motorcycle manufacturer's recommendation is relative to the OEM tires ONLY. If you change tires from OEM then surely you would want to pay attention to the tire manufacturer's recommendation over that of the motorcycle manufacture? Well, at least I would. |
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kml
Junior Member
84 Posts
englishtown, nova scotia
Canada
Suzuki
hayabusa
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Posted - 04/30/2008 : 9:56 AM
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quote:
Originally posted by scottrnelson
"I guess we're sufficiently off of the topic of tire pressure now. Do we need a separate suspension adjustment thread?"
Excellent idea!
cheers
ken |
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Speedmaster07
Senior Member
287 Posts
Los Angeles, CA
USA
Triumph
Speedmaster
Peer Review:
Blocked
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Posted - 04/30/2008 : 10:16 AM
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quote:
Originally posted by James R. Davis
quote:
James - it's the static coefficient of friction that counts!
Why must people take so many tangents?
Yes, we all know that it is the static coefficient of friction that determines when your tire will skid/slide and that it is the dynamic coefficient of friction that determines how fast you can decelerate once you have begun to slide. (That, in my opinion, 'counts', at least if you want to survive over-aggressive use of your brakes.)
Sure, but the 99% of the time that I like to think that I'm in control of the bike, it's the static coefficient keeping me in control. 
quote:
The issue was - does contact patch size have a meaningful effect on traction. It does not.
We'll just have to agree to vigorously, yet respectfully, disagree on that one. Obviously your philosophy has worked for you for many miles so it's not a critical difference. Cheers! |
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ananga73
Ex-Member
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Posted - 11/04/2009 : 3:04 PM
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quote:
Originally posted by gdickelman
quote:
The bicycle pump is hopeless even if you could get it attached. Bicycle pumps are meant to deliver a little bit of air at high pressure. You need a greater volume of air at lower pressure.
Hmmm...I have a high quality bicycle pump with a built in pressure guage that works like a charm. It attaches to my valve stems without a hitch, pumps easily, and the pressure that I read on its guage agrees with the auto tire pressure guage that I use to double-check afterward.
After struggling with those impossible gas station air hoses, and paying 50 - 75 cents each time, I decided that the high quality bicycle pump (retail $49.99 pump, on sale for $29) might be a simpler solution than buying a compressor and fittings. In this case, it worked out.
I'm not referring to the portable hand pumps, but rather a floor pump. Mine is a Hurricane Team Floor Pump:
http://www.performancebike.com/shop...fm?SKU=19979
Since I am also a bicycler and shop at Performance Bike, I find many things that are applicable to motorcycles (reflective vests, reflective stickers for the helmet, compact-portable tools, little clocks that you can attach to the handlebars (my Guzzi does not have a clock) and more).
Like you I am a "bicycler" and have one of those pumps however I had doubts it would work for the motorcycle considering the lower pressures on the motorcycle. Will try them this weekend and see if |
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Tire pressure?