In garage was at 20.00 on front and 28 on the back with temp 79 degrees, 20 minutes later with weather being low 90's it showed 21.4, 21.6 on front and 29.6 on back at temp 91. Should I be lowering pressure a bit in garage in this hot weather?
I don't have FOBO, but tire pressure is always measured cold because it is going to increase as the tires hear up, even in cold weather. Cold tires perform differently than warm/hot tires. What you have to do is decide how the Spyder feels/performs with the tires at some normal operating temperature. I seriously doubt that in everyday road riding one is able to really tell as about the only way you can do so is to ride a closed course of some kind at some performance percentage and measure lap times and feel of the Spyder. When you have a day wherein everything feels "perfect" to you, you measure the tire pressure(s) at operating temperature. Let them cool and repeat measurement. Then comes tomorrow when everything changes...
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Thing about those gadgets is that if your say a detailed person they will drive you crazy. If you adjust for all the changes during your Ryde you will never get there... set it forget it and check back in a couple of days...
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Want some more info to drive you crazy?? Or maybe improve the way your tires work & last for you?? Just answer me this - Was that pressure increase after ryding it a bit, or just from sitting still in the garage as the temperature of the day climbed?
The funny thing about tire pressures is that if you want to stop or reduce the pressure increase that generally occurs when you ride, you need to INCREASE their cold/start pressure a little!!
As your tires roll & flex while you drive or ride, the tire tread & carcass gets warmer & the air inside the tire increases in temperature & pressure. You actually need SOME increase in temp & pressure in order to get the tire tread compound up to its ideal operating temperature so it can provide optimum traction & ride etc.... generally, most tire manufacturers recommend that on passenger vehicle tires, you should aim for a 4psi increase after about 30-60 mins of riding/driving.... any more increase than 4psi in that time & the pressure increase is telling you that your cold/starting pressure was too LOW & should be a bit higher cos you are risking tire damage, blow-outs, or tire ply delamination, sloppy handling, increased/abnormal tread wear, & less than ideal ride & traction; while any less than 4psi increase & its telling you your cold/starting pressure was too HIGH & you are risking less than ideal traction & a harsh ride, with a different pattern of increased/abnormal tread wear & an increased chance of punctures due to the inability of the tire to absorb impacts & a bunch of other stuff....
So if those pressure changes occurred after you'd ridden for 20 mins or so, I'd suggest your starting pressures were a touch HIGH for what you are doing/the way you're ryding & you could probably drop them one psi or so before you start ryding next time. But if those pressure changes occured while it was just sitting in the garage & the temp increased as the day progressed, then I'd leave them exactly as they are FOR NOW, and check them again after 30-60 mins or so of ryding!! If they haven't gone up to at least about 24 up front & 32 in the rear, then your initial starting pressures are too high & you should drop them a bit to get the best/ideal traction, ride, and tire life!
Last edited by Peter Aawen; 05-29-2018 at 10:43 AM.
Do you change your car's tire pressure?
Short answer - NO!
AJ
Originally Posted by Tyris
In garage was at 20.00 on front and 28 on the back with temp 79 degrees, 20 minutes later with weather being low 90's it showed 21.4, 21.6 on front and 29.6 on back at temp 91. Should I be lowering pressure a bit in garage in this hot weather?
2014 RT-S Akrapovic Exhaust & Cat Bypass
Bajaron Sway Bar w/links / Sena SM-10/Garmin 660
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I set my pressures at around 17/18 psi all the way around and watch them go up and down all day long. If you're riding southbound in the morning you can have as much as 2+ psi more in your left tire than your right tire. Then when you head back in the afternoon it will be the same. Have fun and enjoy the ride. The FOBO's are a safety device to inform you if you have a small problem you need to correct. If you have a catastrophic blow out you're not going to be looking at your FOBO, you're going to be looking for a place to land.
Yep, FOBO says they have air in them, and the fronts are equal - TIME to RYDE
As long as they suit your style of riding and as Pete says, aren't too sloppy and risking damage, you're good to go. Dont remove air from a hot tire.
It is fun for someone who enjoys the physics of Charles Law to see how energy input can change temperature and pressure. Its interesting that the rear tire heats up more than the fronts probably due to more flexing and energy input...now back to paying attention to the road ahead
Last edited by AeroPilot; 05-29-2018 at 01:27 PM.
07 Shadows, Aero, Spirit gone but not forgotten
03 Harley Sportster, 07 RK moved on
11 RT- 76,000 mi, 15 RT-S- 44,000 mi, traded for current 15 base RT and 16 F3T
Want some more info to drive you crazy??
The funny thing about tire pressures is that if you want to stop or reduce the pressure increase that generally occurs when you ride, you need to INCREASE their cold/start pressure a little!!
Yep.....running my rear Kuhmo pressure at around 22psi, I got a 1psi increase after an hours riding. When I dropped it to 19psi, I got a bit over 3psi increase after an hours riding. (according to FOBO)
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Goodyear Duragrip 165/60 fronts (18psi) - provides extra 1/2” ground clearance.
Kenda Kanine rear.
2021 RT Limited , Brake pedal rubber removed for ease of accessing pedal with size 15 boots. Red
I have had mine for 3 years now.
the temp will increase pressure.
the fronts will go up 2 lbs
the rear 3lbs
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Tires warm up on the road and I always get about +2-3psi readings on the FOBO. I run 18 front 28 back like most (COLD), so I set the FOBO to 20 / 30 (+2psi). I want the FOBO to warn me about pressure while tires are warmed up, in case of a rogue nail, etc.!! If the phone buzzes I know somethings up. Hasn't so far, knock on wood!
Yep.....running my rear Kuhmo pressure at around 22psi, I got a 1psi increase after an hours riding. When I dropped it to 19psi, I got a bit over 3psi increase after an hours riding. (according to FOBO)
Pete
That sounds about right: The lower initial air pressure allowed for more tire flex; thus raising the tire's pressure by a greater amount!
FOBO Air pressure
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set it forget it and check back in a couple of days...
Originally Posted by Tyris
