Tyre pressure check advice help

[raymond]

Guys I know they say to check your tyres cold, but I'm about to do a 10,000km ride and wont have access to a compressor like I do at home. So if I pull up and lay a swag down for the night on the side of the road, get up the next morning, check my tyre pressures with my portable gauge and find that theyre low on air, can I ride another 100k's to a fuel station and just add the difference to what they should be??. Hope this dosnt sound like a stupid question, but I'm about to replace my front tyre with a new PR2 after the oem fitted front was stuffed after 5000k's, but I think it was the last 1000k's that did the damage as I checked the pressures before my last ride and the front was 38psi. Pressure was down to about 32 psi and the edge of the tyre was really chewed out due to the road cambers and rough bitumen roads we have down here. Again hope this isnt a dumb question but I really dont want to chew out another one because the pressure was low. Is there a thumb rule for hot tyres. Any advice appreciated.

 

[Solo]

I can't answer your question, but you can. Get your tires to proper operating temp before setting out, and after your first day's ride, check your temps again. That should give you a rule of thumb to go by.

A lot of us won't ride without tire plugs of some sort and a portable, compact compressor that will easily fit under the seat. That would allow you to check your tires cold in the morning with a compressor at hand if you need to add air.

 

[Ignacio]

The theory of adding a defined amount of PSI once warm after you check cold is sound assuming the hot pressure is close to the cold pressure. Say cold = 38 and you want 40. You add 2 psi to a warm pressure of 45 to make it 47....it's going to be close enough to 40 when it cools down (maybe a bit under).

However, if the warm pressure were say 57...then you'd have to add 3 psi because of the proportionality. The hot psi is 50% more than cold psi...so you have to adjust an additional 50% of air.

But, to me that's all academic. If you're losing that much pressure daily and not it's not because of a major change in temperature or altitude....then you likely have a leak and need to address that. I don't think tire damage isn't going to occur unless you're really far under or over the target range. I'd be more skeptical about a puncture or bead seat issue somewhere.

And even more practical. Get a compressor and silly string plug kit for <$20 USD from Wal-mart (or equivalent that has been talked about many, many times here) and carry it with you. it all fits under the passenger seat in the bike quite nicely.

It takes just one flat in a remote area to realize you're stuck and wish you'd have had it all.

 

[Sagebrush]

Walmart slime compressor, tire plug kit, air pressure guage. All fits under the seat with a tool roll too.

I run 42 psi front and rear checked cold. After two weeks on the road I'm usually still over 40 psi, I probably loose more air by checking. I loose about a pound per week. So, the last three sets of tires needed air every three weeks since I don't run them under 39 psi. Keeping the air above 40 seems to help on tire wear...

 

[raymond]

Thanks guys good advice. I got the tyre plug kit with the throw away CO2 cylinders that go into a canister thingy, thats also a combined hand pump in case of emergency as I would hate to be stuck out in mad max country in the middle of nowhere. How stupid of me, never to think of checking the pressures when hot, as that makes total sense, thankyou. As usual the answers are always found here. I gotta look into that slime compressor, as Ive looked everywhere over here for a small unit, but there all too big.

 

[Pepperell]

Often the large size of these compressors is plastic added

to make them look more impressive. Creative cutting

away can make them much smAller.

 

[James Burleigh]

What's a tyre? :blink:

 

[ShinyPartsUp]

Walmart slime compressor, tire plug kit, air pressure guage. All fits under the seat with a tool roll too.
I run 42 psi front and rear checked cold. After two weeks on the road I'm usually still over 40 psi, I probably loose more air by checking. I loose about a pound per week. So, the last three sets of tires needed air every three weeks since I don't run them under 39 psi. Keeping the air above 40 seems to help on tire wear...

Exactly my riding behaviors. Gunny.

friendly advice to the OP: Riding on a tire (or tyre) at 32 PSI can be very dangerous. Like Ignacio said, check your pressures more often and if you have more than a 1-2 psi drop in a week (without other explanation), have the tire checked. Your life isn't worth the time and effort saved ignoring it. My bike sat for 2 months recently (I know, shame on me) except for one ride. Pressure in the front dropped 7 psi and the rear was down 3 psi. Exactly as one would expect, as tires lose air just sitting. Always check pressures.

 

[raymond]

What's a tyre? :blink:

Yeh I know us Aussies spin the other direction. Now I wonder if the arrow on my tyres are suppose to point to the rear :dribble:

 

[mcatrophy]

...Yeh I know us Aussies spin the other direction. Now I wonder if the arrow on my tyres are suppose to point to the rear :dribble:

Only when the arrow is down under.

 

[yak]

Look at some of the pumps on Motopumps.com.Cheap and small.

 

[Wanderer]

I took a "Slime" brand compressor from Walmart that looks like this. I think it was about 20 bucks.

Unscrew the 4 little screws on the back and the plastic case comes apart to reveal the actual pump:

It curls up nicely in the tool kit pan. Just make sure your fingers are out of the way when its running, the little drive gear is exposed. it also gets a bit warm after running a while so I set it on a small rag kept with the pump. A string style repair kit is kept in the tail section near the rear light sockets. This is actually my second pump. The forst one lasted 3 years and eventually I canned it because the rubber seals started to dry rot from neglect. It was powered by a spliced in SAE plug. This one has the included 12V acc plug to match the socket in my fairing.

 

[crankbear]

G'day Mate -

I had all my tyre pressure theory blown away when I did the california superbike school at Phillip Island last year. I usually maintain tyre pressure quite religously at the 38 / 40 psi / front rear, based on the tyre placard. These are cold temps. However, before we went out on track, the scrutineers were deflating tyres to around 30 psi (hot), and went into an albeit rather sensible ramble about: (1) larger contact point with road; (2) no destabilisation of the tyre based on the inherent strength of the sidewall; bugger all difference in wear (higher PSI makes the tyre slightly more prone to puncture); and (4) making things much easier on my wheel bearings...much easier so they reckon.

None of which explains why the numbers on the tyre placards are as they are. I always ride with a puncture repair kit (plugs), and a few co2 cartridges - which is enough to get at least one hoop back up to pressure if you have to.

Enjoy the 10K.

 

[bang-n-gearz]

I sure appreciate this thread- If you only knew.

Buck

Dls.TX

 

[jacko]

G'day Mate -
I had all my tyre pressure theory blown away when I did the california superbike school at Phillip Island last year. I usually maintain tyre pressure quite religously at the 38 / 40 psi / front rear, based on the tyre placard. These are cold temps. However, before we went out on track, the scrutineers were deflating tyres to around 30 psi (hot), and went into an albeit rather sensible ramble about: (1) larger contact point with road; (2) no destabilisation of the tyre based on the inherent strength of the sidewall; bugger all difference in wear (higher PSI makes the tyre slightly more prone to puncture); and (4) making things much easier on my wheel bearings...much easier so they reckon.

None of which explains why the numbers on the tyre placards are as they are. I always ride with a puncture repair kit (plugs), and a few co2 cartridges - which is enough to get at least one hoop back up to pressure if you have to.

Enjoy the 10K.

Jeez thats interesting , I run 38-40 , a couple more PSI in the rear loaded with a passenger

Do you now run the lower pressures on the road , and did they say anything about pressures for a loaded bike ?

I carry plugs and small compressor and needed them , 2 times in the last couple of months