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Repeat Tire Pressure Question?
- mzandmz
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New to Family, 1979 KZ440 LTD
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- 650ed
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1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- JMKZHI
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My bike is the 81 CSR w spoked tube-type wheels & the manual states to inflate the oem tires to 25 psi front & 22-25 psi rear (depending upon the load). The Dunlop GT501s are recommended to be run at 32 Fr & 36 Rr on my 650H. The sidewall doesn't really have a Max Pressure. Instead it lists a Max Load (weight) at 42 psi. I keep them at about 32/34 Fr & 34/36 Rr.
FYI: the same tires on a KZ550-Ltd which is a smaller/ligher bike are recommended to be inflated to 30 Fr & 34 Rr.
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- mzandmz
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New to Family, 1979 KZ440 LTD
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- bountyhunter
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Go with the manula, assuming you are running stock tire size. You have to put more air in the rear if you carry a load in the back like an extra person. basically, a tire is like a balloon that needs to be at it's optimal shape to perform best. More weight pushes it down more so it needs more air pressure to force it back to proper shape.What determins your tire pressure? Following the recommended pressure from the manual? Whats stated on the side wall of the tire? Do you fill to the maxx cold pressure? All tires are different. Weight load? Outside Temp? Whats Safe? Helps us Find out the truth. .:huh: .:dry:
I run 32 front and 28 rear on mine. I have found over time I get better rear tread life if I run a little less in the back (don't burn the center strip so soon). Fronts never wear out the tread, they die of old age from sidewall rot.
1979 KZ-750 Twin
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- PLUMMEN
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Still recovering,some days are better than others.
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- OKC_Kent
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Oklahoma City, OK
78 KZ650 B2 82,000+ miles
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- mzandmz
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New to Family, 1979 KZ440 LTD
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- bountyhunter
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Somewhere on the internet I saw a process to determine the optimum air pressure for your motorcycle tires, it involved measuring the pressure cold, then measuring the pressure after hot, maybe a 10 mile rides worth. The difference between cold-hot pressures told you if the pressure cold was correct. If I can find it I'll post it.
That's interesting because like I said earlier: the trick is to get just enough pressure to hold the tire well formed so it isn't "flattening" too much at the bottom where it sits on the ground. Each time the tire rotates, the sidewall flexes how ever much it goes from the top where it's fully extended and the bottom where it is compressed some. The amount it flexes makes heat and that would change the cold - hot pressure range.
Interesting, I never thought of using that for determining best air pressure, but it makes sense.
1979 KZ-750 Twin
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- TexasKZ
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As Plummen and others have suggested, the "right" presure depends on a combination of what a person intendes to do and what the manufacturer designed the tire to do. If you plan to mount some knobbies on a Gold Wing, inflate them to 100psi, and take that rascal drag racing, then you'd better be prepared for some unpredictable and unpleasant consequenses.
Tire manufacturers spend quite a bit of time and money designing tires devising recommended pressures because they want happy customers and no lawsuits. The best place to start is with those recommendations. You can then adjust a little one way or the other to suit your particular circumstances, but deviating very far from that is asking for troulbe and will void the warranty.
My dime's worth (inflation, don't you know.)
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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