My tires are making me nuts!

[RedNigel]

OK
I go to the garage, check my tire pressure before leaving and I am 1-2 lbs low front and rear
After I ride half a mile and get to an air pump, my pressures are either spot on or a pound or two high
Question:
Do I call it good and ride on?
Do I remember how low I was at the house and add the pound or two I was missing half a mile ago?

 

[RedLdr1]

Do I remember how low I was at the house and add the pound or two I was missing half a mile ago?

Yes, just add the difference...

 

[Mellow]

If you ride your bike to a pump at a gas station the friction will cause the internal air temperature and pressure to rise. It can get up to 8-10lbs higher on a ride.

If you're checking it cold then do as Wayne said and just add how much you were low and you'll be fine.

 

[tawilke46]

Which reminds me, I have yet to use the portable pump in my saddlebag. May rain tomorrow, so it will give me something to do.

 

[DirtFlier]

As Mello said, tire pressures are always stated as "cold." If you check air pressure somewhere along the way, it will always be different depending on ambient temp and the distance you've ridden so making adjustments at this point is incorrect as you have no idea where it'll be when cold.

 

[charlie b]

Just NEVER let air out of your tires when warm.

 

[DirtFlier]

There are plenty of 12-volt mini air compressors on the market for under $25 so you don't need to spend hundreds for an air compressor just to add air to your tires. I've been carrying one around with me for 12-13 years and it still works fine. It was a Campbell-Hausfield unit that I stripped out of ts plastic case making it much, much smaller and easily packable with the tools I carry on the NT at all times.

 

[skiper]

I agree Bob , the simple bicycle pump is useful in some circumstances and might not occur to everyone. I just recently found out that the new car tires are much more reactive to tire pressure. MY new Bridgestones got all feathered and cupped from being overfilled ten pounds. MY gauge was off and I was running em high. After more careful attention on the NT tires and more cornering - rather than only straight runnin - the cupping went away. .. keep the rubber side down.. and make a good day

 

[charlie b]

FYI, tires don't lose air with change in temps. As temp lowers the pressure will lower if you don't change anything else. And when temps increase again the pressure will increase.

Something I had thought to research at one time is if we should change the cold tire temp in cold weather. In the old days we'd decrease tire press in winter to give better grip in the snow, like running in sand.

 

[charlie b]

Rick, that's why I added "in the old days".

Modern car tires can run with a range of inflation pressures from about 20psi to max for the tire and most people (passenger cars) won't see any difference. The steel belts are so stiff these days that the air pressure serves mainly to keep from 'bottoming out' the tire. Truck tires are a much different story and their air pressure should be managed by the load they are carrying (yes, even on pickup trucks).

Motorcycle tires are a bit different. The radial belt is there but is not as stiff as for cars. There is still a lot of leeway in tire pressure with bike radials and a couple psi either way won't make that much difference. If you run bias ply then the pressure is a bit more critical and you can feel the difference of a few psi in tire pressure.

Concrete vs asphalt. Not sure. If pushing in corners then there might be or if the concrete is 'textured' for wet traction. Asphalt is pretty rough on tires. I guess I'd look at it this way. How fast can you take a corner on that surface. If you can go just as fast on asphalt than concrete then they are about equally abrasive to the tires.

 

[charlie b]

I have to say I have been guilty of running low pressures as well. After having the bike serviced one time I didn't follow up and found mine were at 25 and 35. I caught it because it felt a bit mushy.

Most of the time I check the pressures monthly and rarely need to add any air. The Guzzi right now I check weekly because the tires are getting a bit old and it is very sensitive to pressure for handling. I can feel a couple psi difference on it where I can't on the Honda. But, I also rarely need to add any air to it either.

Me being the lazy type, I'd like to have a TPMS with readout on the dash. Next time the bikes get tires I will add it.

 

[Chuck 500]

There are plenty of 12-volt mini air compressors on the market for under $25 so you don't need to spend hundreds for an air compressor just to add air to your tires. I've been carrying one around with me for 12-13 years and it still works fine. It was a Campbell-Hausfield unit that I stripped out of ts plastic case making it much, much smaller and easily packable with the tools I carry on the NT at all times.

+1 on inexpensive pumps. I have a "no name" Chinese pump I use for the car and in the garage. It even has the feature to read pressure and pump to a set pressure. It has proved accurate so far, and I've had it maybe 15 years. The chuck is starting to show signs of wear though. I also have a small Slime pump in the bike. It works well but slower than the old pump. You have to watch it and turn it off at the desired pressure.

I generally check tires weekly. Sometimes bi-weekly. Have not had them more that a lb or three out so far.

Keep the pressure up and the tires down,

Chuck

 

[JQL]

Having just had a puncture I read the info on the side of my Bridgestone Rear tyre (BT023) and it says the pressure should be checked when cold.

When I did a mechanic's course (at a Ford Main Dealer) I was told that tyre pressures MUST be checked when cold as the pressure will vary by as much a 10 PSI when warm depending on the type of driving.

I have a 12v tyre pump which I got from Mercedes Benz about 10 years ago and it fits nicely in my panniers.

 

[Rmcapozzi]

Things to consider when calculating "cold" tire pressure.

Is your bike in an attached garage? The temp in the garage will be warmer than the outside temp in the winter and cooler in the summer.

Is the sun shining on your tires? The sun can rise the temps in your tire by a few lbs. Ideally, the tires would be in the shade before checking them so consider that when taking pressure readings.

General rule is 1 lbs of air pressure for every 10F of temp change. That means a 10F temp increase = about a 1lb increase in tire pressure. If it is a really cold morning but I know the temps will be significantly increasing later in the day, I'll take that into account. So if it is 20F in the morning but I know the temps will be increasing into the 70s (an unusually large temp spread), I'll let my tires be 2lbs (~5%) under my target pressure in the morning to help offset the +5lb natural pressure gain the tires will see throughout the day. A few lbs +/- isn't gonna make a huge difference in wear/performance. The important bit is to keep an eye on them and actively manage them so you don't unknowingly wind up with under inflated tires. I believe the NHTSA considers a tire that is 25% below the recommended cold pressure as under inflated.

I keep my pressures within 1 lb of my target. Managing this is made easier with an on-board TPMS with real time pressure readout.

 

[tawilke46]

It would be nice if tire pressure monitor systems came standard on motorcycles.
Especially since the correct air pressure in mororcycle tires is more critical than car tires.

 

[charlie b]

Ditto

After many years of riding and experiencing several tire failures/flats I am not so anal about pressures.

I have found that I can 'feel' a tire that is at the dangerous pressure level. The bike 'wanders' or 'wiggles' and feels less responsive. This pressure level is 10-15lbs under inflated on modern tires.

You aren't in any danger of killing a tire just because you're a couple pounds under in pressure.

 

[Rob]

It would be nice if tire pressure monitor systems came standard on motorcycles.
Especially since the correct air pressure in mororcycle tires is more critical than car tires.

i agree. you shouldn't have to pay $15k or $20k on a bike to get this. and there's really not much to them.
i know i love having it on my bike as it makes it easy to see changes in pressure while riding.