as to "suitability", Tire manufacturers often mention tires for Harley Davidsons specifically. Or, best, consult Harley Davidson. You should not run out and put on just anything that "fits" and pump it up to suit Harley's owner's manual. You should not run at or very near the tire's marked maximum cold pressure.
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Coincidence?
- Thread starter Rob S.
- Start date
as to "suitability", Tire manufacturers often mention tires for Harley Davidsons specifically. Or, best, consult Harley Davidson. You should not run out and put on just anything that "fits" and pump it up to suit Harley's owner's manual. You should not run at or very near the tire's marked maximum cold pressure.
They are the original tires that came with the bike. That make any difference? (They have 3k miles on them).
Are you at all worried about the high mileage ruining your resale value?
Datsa Noydb
Forum Mentor
I was kinda noticing that, too. But, ... at 100 mph every time out, it wouldn't take very long.
Agemax
Forum Guru
100MPH........... on a Harley???????
just sayin' is all. Your Michelins that are on are "Harley badged" so how can they be wrong?( I guess it's a pretty heavy bike...)
The coincidence I'd guess is that the Harley and the Suzuki weigh the same , having same tire pressure to hold them up is not so suprising.
It'd get more complicated as a comparison where the two bikes had different footprints entirely...the Harley wanting a big wide contact patch at the rear (wider,+ lower profile maybe) versus...something else. Which gets me back to the Harley-Intended refrain... I don't have a Harley but I think I'd be leery of putting Sport Demons on. Don't know about Michelin "Scorchers" either.
I hope your tires aren't worn out with 3k miles on em. Hot streets where you are or it's your own fault!
fbody_mike
Forum Mentor
Just to follow up on the 10% rule. My 82 XJ650LJ (turbo), had specs for 28 psi front and 28 rear from the factory. Now add a passenger or high speed riding, it said to go to 32 psi on the rear only.
With 28 in the front, I got a 10% delta after a nice spirited ride.
The rear with 32 psi, I got a 17% delta. Which should mean it was too hot and needs more air pressure. So I went up in 2 psi increments until I found a 10% delta which turns out to be 38 psi.
It is interesting because a while back Avon had a lookup program on their website that would suggest which of their tires to use and how much psi to use with it. I think it was on their UK site, but for this bike, they recommended 33 psi front and 40 psi rear. I run Michelin Pilots on it now, but the more I compare notes and measurements the more I like this 10% rule for inflation.
Now for the 550 with its Sport Demons, once I get it back together.
With 28 in the front, I got a 10% delta after a nice spirited ride.
The rear with 32 psi, I got a 17% delta. Which should mean it was too hot and needs more air pressure. So I went up in 2 psi increments until I found a 10% delta which turns out to be 38 psi.
It is interesting because a while back Avon had a lookup program on their website that would suggest which of their tires to use and how much psi to use with it. I think it was on their UK site, but for this bike, they recommended 33 psi front and 40 psi rear. I run Michelin Pilots on it now, but the more I compare notes and measurements the more I like this 10% rule for inflation.
Now for the 550 with its Sport Demons, once I get it back together.
Perfect understanding and application for this method. Funny that years ago I did the same thing with my GS1000 which is about the same weight and probably power as well and runs the same tires sizes. With the Dunlop GT501s that I used for years I settled on 32/38. I switched to Battleaxes last year so just for giggles I should rerun the tests to see if there is a different result.
Steve
GS Whisperer
If you look back to your post #13, you mentioned that some believe the rear should have a 20% delta, and your 32 psi starting point put you pretty darn close.
Getting the EXACT correct pressure is a bit difficult, but how do you KNOW what is correct? If you don't have enough pressure, the tire will run hot and wear out quicker. If you have too much pressure, it won't deform enough and will tend to wear out in the middle, due to a smaller contact patch. Only religious pressure checking over the life of the tire will tell you what was correct, so you can make adjustments on your next tire.
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Where's Posplayer when you need him? I'm sure he's got the formula somewhere in his head on how much heat is needed to expand the air in a tire by 20%. LOL. I certainly don't know but then I've never run a tire low enough nor loaded enough to find out. Pyrometer anyone?
Steve
GS Whisperer
I contacted him a couple of weeks ago and pretty much asked him that same question.
He said he is working on a project at work and decided to take a break from GSR.
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Ok. Found some stuff on the net. Yeah I can be a bit OCD at times. A tire starting at 68?F would have to reach a temp of 122?F for a 10% increase. Sounds pretty reasonable. For 20% increase the tire would have to reach a temp of 176?F. Probably way too hot.
Formula is in C with totals converted to F.
50c+273c/20c+273c = 1.10 or 10% increase
80c+273c/20c+273c = 1.20 or 20% increase
20c = 68f, 50c = 122f, 80c = 176f
Google ......making dumb people seem smarter everyday. LOL.
Formula is in C with totals converted to F.
50c+273c/20c+273c = 1.10 or 10% increase
80c+273c/20c+273c = 1.20 or 20% increase
20c = 68f, 50c = 122f, 80c = 176f
Google ......making dumb people seem smarter everyday. LOL.
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