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Discussion Starter #1
This am i went for a 100 mile quick ride. I checked my tire pressure and it was f35 r34. I inflated to f41 r42 i am 6'5" and 290lbs. The air temp is 39 and the rear load setting is a firm 25, off i go, 2 miles later going down a small hill the back of the bike feels like a lowrider and i pull in the clutch and my bike wont hardley coast,i let it run for 10 min putting my gear on, so i know the bike fluids are warm and shouldnt be constricting. I actually turned around and headed home, i thought i had a flat. No flat, no nothing back at home??? I left and ran to the canyons, feeling like i was going to break down, but i have a tire kit and a warranty. 60 miles pass and it still feels low in the back and a little slugish while coasting. I went to San Francisco last year and 3 times i thought i had a flat while my friend laughed at me because nothing was wrong. Is this the way this bike is, do i need a different rear shock because im big. I have a BMW R1200gs and weather never seems to affect the feel of the bike. any thoughts??? my bike is an 06 with 3500 miles, if this makes any diff. :?: :banghead:
 

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You forgot to factor the temps in when reading the tire pressures. As a general rule of thumb, it is easiest to assume 1 psi change for each 10 F of temp. 80 F is the reference temp. With 30something F, the 80-30=50/10=5 variance would put your tires at 41-5=36 psi as the starting point. You should not have added air to your tires.

That said, you didn't mention how many miles are on your bike. My '04 has 40k miles and the rear also feels like it sags. It's time for me to replace/upgrade my rear shock so that's what I'm doing. I don't know all the details, but they have been discusssed on this board before.

HTH.
 

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David M. said:
You forgot to factor the temps in when reading the tire pressures. As a general rule of thumb, it is easiest to assume 1 psi change for each 10 F of temp. 80 F is the reference temp. With 30something F, the 80-30=50/10=5 variance would put your tires at 41-5=36 psi as the starting point. You should not have added air to your tires.

HTH.
HUH?????????? What would that have to do with "not adding air"????
You check you tires cold, so when they warm up they will be OK. The colder the ambient temp the less the tire will heat up, right????????
So if your summer air needs a boost in the winter, you should add air. Then when summer gets here you can let the winter air out, right????
 

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Hey ICEBRU, I don't know about your tire pressures, but,
check the range of adjustment on your 0-25 rear shock.
Start at zero and listen for the pump motor sound to change as it starts to build pressure.
That should happen in a second or two and the bike should start to rise
as the numbers start up from 0-to-1.
My 02 got so bad it wouldn't even start moving until 12-13
and when it got to 25 the back of the bike hadn't come up even half
as far as it did when new.
Fred Harmon has posts and videos about fixing the problem,
which has to do with air in the small hydraulic system for the rear shock.
I went with the Traxxion Dynamics suspension on the new 07
and it's going to be a keeper.
Max at Traxxion can build it for just the weight range you're going to be carrying.
Hope you find the problem and have many happy Wing Miles.
DC
 

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How do I put this? if you have 40 psi at 80F, and you have 35 psi at 30F, you have the SAME AMOIUNT OF AIR in the tire. Do not add more pressure at 30 degrees outside temperature. This is measured before any highway miles at either temperature.
 

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David M. said:
That said, you didn't mention how many miles are on your bike.

IceBru:

any thoughts??? my bike is an 06 with 3500 miles, if this makes any diff. Question

:shock: :D :wink:
 

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David, in theory you are correct. But... one should check the air pressure cold no matter what the temp is outside. If the air pressure reads low, fill it to spec's. In the summer I would re-check the pressure and go from there.

Heated atoms are larger and colder atoms are smaller. I know what you are referring too. But why try and split atoms? If the tire is low....air it up!

Have a nice day!
 

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ICEBRU, Swap bikes with your friend. Let some one who owns a GW
ride your bike when these symptoms are present. Get a second opinion.
Report back. galewing
 

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Wingman, if it's 30F outside and the bike has not been ridden today, then a 36 psi reading IS right. Don't add air. Same is true if it is 110 out; the calibrated gauge should read 44 psi and still be correct.
 

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Discussion Starter #11
Thanks for all the help, the tires where qat 41 and 42, when i got to valencia where it was 70 the tires where 44 and 45, yipp :shock: I would like to ride someone elses wing and let them ride mine, who wants to ride a few days? breakfast is on me. thanks :cus:
 

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Really trying to learn something here.. If ambient temp drops 30*, thats only 3 PSI. With 900# bike and my 225# fat butt, the rolling friction should quickly heat the tires quickly to normal pressure. If my logic is correct, then I think that David M is right on.
 
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