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Old 01-23-2006, 12:04 PM   #1
jonnyluck
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Default Re: Tire Pressure Query

no such thing as a stupid question, eh?? 1st Post
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Old 01-23-2006, 12:04 PM   #2
Redd_Dawgg
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Default Re: Tire Pressure Query

The instructor is right. I run 31 front and 29 rear for track use on my FZ1. I don't run those pressures on the street because of pot holes, bricks, etc. Low pressures will result in bent rims on the street.
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Old 01-23-2006, 12:10 PM   #3
maladg
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Default Re: Tire Pressure Query

Hmmm....35 yrs of this and first time I've ever heard such a thing.



I don't buy it. Not at all.



My "Fat Lady" would wallow like the hog she ain't. In fact, a couple of years ago I had a local dealer mount a set of nice, fresh, tasty Metzlers on the old girl. My wife dropped me at the dealer...I paid (and paid then paid again)...then I pulled out onto HWY 41 (of Allman Bro fame) and dang. Felt ALL wrong. I went direct back to dealer, got service mgr. Ft and rear about 12-15 psi down from ST11 spec of 36/42.



Nope...10 below spec ain't right. And that "dealer" is off the list and I went running back to the arms of my fav independent...
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Old 01-23-2006, 12:12 PM   #4
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Default Re: Tire Pressure Query

And I've never had a track day (yes, on my list!!). I have NO direct personal knowledge of that environment.
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Old 01-23-2006, 12:20 PM   #5
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Default Re: Tire Pressure Query

Thats a tip that wont work for a Kawasaki KLR 650 where recommended pressures with 215 lbs or less is 21.8 psi front and rear. I increased my rear tire to 28 because I'm just over the 215 limit with all my gear on. NFL linebacker type.
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Old 01-23-2006, 12:22 PM   #6
wilro09
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Default Re: Tire Pressure Query

I have ridden for about 20 years. First I heard of it. My VFR800 feels like it is falling over in corners if my pressure is as low as 32. I run 38 front and 36 rear normally.



Not only would I not run lower but you can increase control in the rain by running 5 or 6 lbs. above normal. This increases the speed at which your tires will hydroplane. Motorcycle police do it and so do airplane pilots.
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Old 01-23-2006, 12:42 PM   #7
Mike_L
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Default Re: Tire Pressure Query

Doesn't sound like a good idea to me.



In general, lowering tire pressure will increase traction, but also increase heat and wear while decreasing steering response. This is good for the track, but not for the street. Also, even on the track a 10psi drop is a bit much.
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Old 01-23-2006, 12:45 PM   #8
gbrummett
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Default Track day pressure

I only have one day at the track, but they suggested I start out much lower then my street riding pressure. I ended up running something like 29 - 30 psi front and 32 psi rear.



The manufacturers recommended tire pressure is probally what you would need on the street as you are riding in a much rougher enviroment then a track. Like was said above, there are pot holes to consider, longer tire wear life, heavier loads etc etc etc etc.
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Old 01-23-2006, 12:48 PM   #9
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Default Re: Tire Pressure Query

Reducing tire pressures is standard fare for track days. Get track-specific advice for your bike from one of the tire reps at the track or an instructor that doesnÂ’t limp too badly.



As noted earlier, you definitely donÂ’t want to run these low pressures on the street. But that begs the question, what pressure SHOULD you use on the street?



For bias-ply tires, a good rule of thumb is that a properly inflated tire should gain about 10 percent pressure when warmed up to operating temperature. For example, if you start with 40 psi cold and end up with 44 psi hot, you were right on target. If it only got to 42, your starting pressure was too high. If it got to 46, your starting pressure was too low. With a little trial and error, you can get the ideal starting (cold) pressure for any condition of ambient temperature and loading. With this kind of info you can head out of the garage with the smug satisfaction that you have exactly the right tire pressure, whether you intended to blast down the freeway two-up with luggage on a hot summer day or carve the twisties solo on a cool autumn morning.



Now that IÂ’ve said all that, I canÂ’t find anyone that recommends using a similar rule of thumb for radial tires. Dealers, manufacturers, answer-guys at motorcycle magazines all say, "follow the ownerÂ’s manual" for street use. My VTR 1000 calls for 36 front, 42 rear. I find it hard to believe that this is the best pressure for all ambient temperatures and all vehicle loadings. Somebody in this forum has got to have the right answer for this one.

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Old 01-23-2006, 12:53 PM   #10
The_Aerodynamic_Head
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Default Re: Tire Pressure Query

A lower pressure would yield a larger contact patch. At the track, this is good. Also, at race pace, tires get much hotter, and the internal pressure difference between cold and hot temps. is greater. Thus, if you start with reccomended cold pressure, once you reach operating temperature of the tire, it could be WAY over-pressured, making you more prone to blowout. Also important is the converse thinking...that a lower tire pressure, ceteris paribus (all things being equal), allows more flex, and thus greature temperature, which is, to a certain extent, good for a race tire, it being designed to stick better at higher temps.
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