Tyre pressures.

[FROSTY:Me]

well its a bit of a black art --grip/tyre roll/longevity --all come into play

[TwoSeven]

I run my tyres a few (2-3) PSI below the manufacturers recommended pressure. I find it improves the handling on my bike.

I assume thats the sidewall pressure youre talking about.

I usually find road tires for me work best in the mid 30s (34/36) being about the average. Its enough to keep the tread pattern open and not use the tire as suspension, but not too hard as every single bit of grit on the road shows thru the bars.

I think everyone has their different preference, but I'd suggest dont make the tires so soft that they deform around bumps rather than lift the wheel over them.

[Pathos]

How do you check the pressure?

i just use the pumps at the station but they are useless.

I probably rode all the way home from palmy with the wrong pressure for all I know.

[bugjuice]

I assume thats the sidewall pressure youre talking about.

I always took that as being the max the tyre can operate at (safely or not, I don't know). I never run it at that pressure.. it's often like 40psi +!!

[SuperDave]

I run my tyres a few (2-3) PSI below the manufacturers recommended pressure. I find it improves the handling on my bike.

That's interesting as I now run 30 front and 33PSI on the rear after the recommendation of the guys at cyceltreads. My manual says 27 front and 29 rear and after going up to the higher PSI front and back I've certainly noticed improved handling.

Although I guess it all depends on what kind of compound the tyre's are, the size and the bike they are fitted to.

[Flyingpony]

I run my tyres a few (2-3) PSI below the manufacturers recommended pressure. I find it improves the handling on my bike.

Run my tyres 1-2 psi over the bike ownership manual. Handling is better though grip in wet is probably worse, as if it's flash to start with.
Also have difficulty-getting front/rear respectively at 27(25?)/29 psi, so run it at 28/30 psi. Only do short range commuting, so not worried if it's slightly over because tyres never get hot.

[FROSTY:Me]

How do you check the pressure?

i just use the pumps at the station but they are useless.

I probably rode all the way home from palmy with the wrong pressure for all I know.

For road bikes what I used to do is stop at a servo close to home on my way HOME from a ride and deliberately over inflate my tyres by about 5 psi
when I got home I would drape my tyre pressure guage over the seat
next time I wanted to ride I'd just drop the pressure to the pressure i wanted.
Probably one of the best investments you can make for your bike is a good quality tyre pressure gauge.
Mine I bought from Kendle raceing supplies and it cost about $60.00
its got a pressure bleed button and the gauge itself is wrapped in a rubber sheild so it cant get damaged if dropped.

Tyre pressure is a bit of a black art.
if you really want to know the pressures that work for YOU on YOUR bike with a particular set of tyres you need to do some testing.
check the tyre pressures cold then check them hot.
The pressure variation between hot and cold should be around 2 PSI

[vifferman]

I assume thats the sidewall pressure youre talking about.

I usually find road tires for me work best in the mid 30s (34/36) being about the average. Its enough to keep the tread pattern open and not use the tire as suspension, but not too hard as every single bit of grit on the road shows thru the bars.

I think everyone has their different preference, but I'd suggest dont make the tires so soft that they deform around bumps rather than lift the wheel over them.

Y'know, I get the feeeling that tyre pressures have become sort of a combination of "macho bullshit" and weird urban myth. So many sprotsbike riders seem to indicate by the things they say that they believe that if you don't run low, low pressures, then you aint hardcore, and can't cut it in the racing department. So, they end up running low pressures on the road, because someone who does the occasional track day tells them they should, and belittles them if they don't.
Me? I'll start with the manufacturer's recommended pressures, and adjust from there. Incidentally, I've found on my last few bikes that the recommended pressures (or no less than a couple of PSI below) gave the best feel. Anytime the pressure dropped below that, the bike wandered on coarse chip seal, felt unsettled, and - worst of all - sufffered accelerated wear, due to excessive tread flex, as exhibited by cracking next to the tread blocks.

Here's another urban myth: run lower pressures to get better grip in the wet. Nup.
Causes the tread blocks to close up slightly, giving less water clearance. Plus tyres wear faster in the wet, so that's not the time to be further accelerating wear by dropping the pressure.
The tyre's footprint size is the same regardless. All lowering the pressure does is allow the tyre to flex more, and flex causes internal friction, which heats the tyre compound. Ultimately, too much flex/heat wrecks the tyre by causing cracking or delamination.

[Sensei]

Having Shaun Harris at my finger tips in the Naki is excellent to get his point of view about tyre pressures . Put a Supercorsa on the other week & He told me to run it at 29 psi that is what the tyre people told him they are surppose to be not what the bike manufacturer's tell you . Tryed it but was to soft for Road use maybe Ok on the track when you could ride like he can but went back & told him wasn't good for me , He know how fast ride so we worked out a presssure that would help with the suspenion settings we put on my bike . The main thing is that the tyre is getting to its correct heatcycle so it can work correctly like it has been designed too . Track & road differ alot as on the Track the tyre is subjected to alot more heat build up so this has to be taken into count & the road has more varied surfaces which effect the tyres as well . As above a good Tyre gauge is something that is very handy to have on ya bike once you have you own Pressures sorted

[Kickaha]

charlie--you have ready access to nitrogen (he says with his ears perked up)

I know at least a couple of the Firestone stores in Orcland have the equipment for nitrogen filling

[FROSTY:Me]

The main thing is that the tyre is getting to its correct heatcycle so it can work correctly like it has been designed too . Track & road differ alot as on the Track the tyre is subjected to alot more heat build up so this has to be taken into count & the road has more varied surfaces which effect the tyres as well . As above a good Tyre gauge is something that is very handy to have on ya bike once you have you own Pressures sorted

Yup what he said.
From personal experience i can tell ya --a bike set up to handle well on the track is gonna feel like a wheelbarroew full of bricks on the road -and a good road setup feels like a spungy pud on the track.
BUT -even if you run very low tyre pressures ya still gotta check em

[k14]

Lord Bless Google

Do you care to share your source for that info?? Yes I may have been wrong but I find it very hard to believe that 0.02nm difference changes things at all. From my searchings it seems that the reason for using nitrogen in aircraft tyres is due to the fact that atmospheric air has a moisture content, aircrafts travel in temperatures much below 0 thus the moisture in the tyres will freeze at these temps.

Also (as i said in my first post), the atmosphere is made up of around 85% nitrogen anyway so there's already alot of it in your tyres. Pretty sure racing teams use it due to ease of application and nothing else.

[TwoSeven]

The reason given to me many years ago by some factory tire dude guy was that nitrogen keeps the heat in the gas stable, so the heat is only generated by the tire itself. Whereas air, is affected by the heat from the tire and acts to further warm up the tire and so is more unpredictable in what it does. Something like that anyhow.

Don't know the science in it, dont care. I use air and I measure what happens in differing weather and surface conditions - so it doesnt bother me.

Only reason i'd ever consider using nitrogen is in a 45 min race or a long endurance race, and being an unfit, stone broke lazy bastard, there is currently a million to one chance of that ever happening

[FROSTY:Me]

I know at least a couple of the Firestone stores in Orcland have the equipment for nitrogen filling

Thanks kick--its more of a case of--MMMM hes right on my doorstep and hes got nitrogen. I'm interested to see what effect itll have on my tyres whilst racing.

[Racey Rider]

Thanks kick--its more of a case of--MMMM hes right on my doorstep and hes got nitrogen. I'm interested to see what effect itll have on my tyres whilst racing.

Did you experiment with this in the end Frosty?
Are you still using it in your race bike?
Care to share your thoughts if you have any info to add?

Racey