Tyre pressure?

[Paul_C]

Hey Guys (and Gals),

In a lot of the reading i've been doing I've seen that everyone recommends checking (and filling) tyres when they're cold, so that the heat doesn't interfere with the pressure. I don't have a compressor at home, so pretty much everytime I want to fill my tyres I'm going to have to pop down the road at least 2km to the nearest servo - thus heating the tyres and spoiling my readings.

I have a handy dandy tyre pressure gage that I can apply to find the true cold pressure, but in order to fill I'll have to heat the tyres up.

Does heat in the tyres make _that_ much of a difference?

[MSTRS]

Yes <kuhybkukuyh>

[Sully60]

Depending on your bike, riding style, load it's carrying etc. you could get up to 6 psi increase pressure, this also depends on how far you've ridden. (if it's just around the corner you're probably ok)
Buy a good quality gauge,(Accugage all the way for me!) a cheap footpump from the warewhare if you live too far away from the gas station.

[short-circuit]

Depending on your bike, riding style, load it's carrying etc. you could get up to 6 psi increase pressure, this also depends on how far you've ridden. (if it's just around the corner you're probably ok)
Buy a good quality gauge,(Accugage all the way for me!) a cheap footpump from the warewhare if you live too far away from the gas station.

+1 Check at home with tyre pressure gauge and get yourself a footpump at Repco or supercheap for $30. TOO EASY

[Ralph]

+1 Check at home with tyre pressure gauge and get yourself a footpump at Repco or supercheap for $30. TOO EASY

What he said plus by doing this it gives you a regular consistant reading rather than using those crap ones at the servo where eveyone will give you a different result.

[vifferman]

Yep, what they said. I also carry a pen-type gauge with me (checked against my more expensive Accugage), as if you need to check your tyres away from home, service station gauges are often inaccurate.
BTW - having owned a VFR or two, you will find that for many tyre types running the front tyre at more than a couple of PSI lower than the recommended 36 psi pressure will cause the bike to be somewhat "wandery", due to steering geometry / weight bias. The rear tyre isn't quite so picky, so you can run that up to 4 psi lower. Note that if this is too low, this may lead to uneven wear or 'squaring off'.

[dipshit]

http://www.autoexpress.co.uk/products/products/208103/michelin_singlebarrel_footpump.html

One of these from supercheap will be the best $35 you will have ever spent. (plus a separate gauge)

[xgnr]

FWIW

I use a cheapish gauge and top up with a Push bike pump (cos I ride a pushy eh ...)

However, last time I was down south I was talking to a guy who has a lot of experience and he was of the opinion that you need to check the change between cold and hot.

If the change from cold to hot is greater than 10% then the pressure (cold) is too low.

If it is less than 10% then too high

Logic being I guess that there are lots of variables about absolute values BUT the change is what is important with that tyre.

Cheers

Stu

[dipshit]

However, last time I was down south I was talking to a guy who has a lot of experience and he was of the opinion that you need to check the change between cold and hot.

Yep, but once you have worked out what pressures to run... you then still want to check and set them when cold.

[xgnr]

Yep, but once you have worked out what pressures to run... you then still want to check and set them when cold.

errr yes a logical next step

[Jerry74]

BP down this way at Rolleston has the computerised air meter, very accurate.

I just pop another 2 psi in each tyre for any long distance stuff.

[Owl]

I have a handy dandy tyre pressure gage that I can apply to find the true cold pressure, but in order to fill I'll have to heat the tyres up.

You could always take a cold reading at home, take your pressure guage with you and check pressure again at servo. Note the difference and adjust accordingly!

[Rodney007]

what tyres are you using to start with.......

[discotex]

It's simple really... Overfill them by a few psi on the way home.

Leave the bike overnight then check and lower using your gauge in the morning.

Or just use the same servo every time. If it's always after 2km warmup of gentle riding you'll at least be consistent if not 100% accurate. You're unlikely to gain more than 2psi if you ride like a nana.

Or just get a foot pump.

[Paul_C]

BTW - having owned a VFR or two, you will find that for many tyre types running the front tyre at more than a couple of PSI lower than the recommended 36 psi pressure will cause the bike to be somewhat "wandery", due to steering geometry / weight bias. The rear tyre isn't quite so picky, so you can run that up to 4 psi lower. Note that if this is too low, this may lead to uneven wear or 'squaring off'.

Yes, I've definitely noticed this one. It almost seems that depending on the day/weather/tyre pressure the front will want to go its own way by various amounts.


what tyres are you using to start with.......

I've got a Metzeler Z6 on the back which is probably at about 75% and a Michelin Macadam 100X on the front with maybe only 500km left. I'm going to get it replaced with a matching Z6 this payday.

By all accounts a foot pump is a way to go. I always thought that due to the size of the tyre a foot pump wouldn't provide enough pressure. But then again I have a road bicycle which push past 50 so 36 shouldn't be a problem.

Cheers for all of the advice!

[xgnr]

By all accounts a foot pump is a way to go. I always thought that due to the size of the tyre a foot pump wouldn't provide enough pressure. But then again I have a road bicycle which push past 50 so 36 shouldn't be a problem.


I use a "Joe Blow" pump (one of the stand up type ones.... pedestal?) for pushbike, car and motorbike. Easier than a hand pump and I suspect easier to use than a foot pump.

Amazing how much tyres lose air over just a week hmmm

[NZJONESY]

I highly rate these little buggers.
What you do is kind of estimate the pressure with any old shitty pump, but pump a bit more in before you disconnect the pump.

Then grab one of these and stick it on the valve for a perfect reading.
They have a tiny little clicker/valve release so you just click and release tiny amounts of pressure until its perfectly where you want it.

I think most release a quarter or half a psi per click.

The super fancy one
http://www.torpedo7.co.nz/products/TPPUGN8SG/title/TOPEAK-SmartHead-Digital-Tyre-Gauge

Not so fancy, but still fancy
http://www.torpedo7.co.nz/products/TGPUGN8DG/title/TIOGA-Dual-Valve-Digital-Pressure-Gauge

[imdying]

No, it doesn't matter, so long as you always check them when they're either hot or cold, then all your readings will be relative to one another, and you'll soon learn what pressures you prefer. Do check them both hot and cold though, then you'll know exactly what the difference really is (and thus how much it actually matters).

[Mr Triple]

You could always take a cold reading at home, take your pressure guage with you and check pressure again at servo. Note the difference and adjust accordingly!

I do the same as Owl, or sometimes I will put 3-4 psi at the servo at the end of my ride when tyres are hot and adjust next morning when cold.:msn-wink:

[rocketman1]

If I have 33psi in my tyres it feels like-yuk ( at speed) but with 36psi feel like its on rails, so much so that I know if the tyres are down by the way it rides.
Very important to stick to the right pressure.

[NZJONESY]

Most bikes have a recommended pressures for them right?
For example on my 250 it states the front should be 28psi and the rear 32psi.

How important are these numbers?
Do you have to stick with them religiously??

[Cajun]

Most bikes have a recommended pressures for them right?
For example on my 250 it states the front should be 28psi and the rear 32psi.

How important are these numbers?
Do you have to stick with them religiously??

different tire brands often require different tire pressure settings.
Often the recommended settings are also for getting the best milage out of the tire.

Recommended pressure is a good starting point, have a play go up and down a 1-2 psi on the tires and see if you prefer it or not.

[NZJONESY]

different tire brands often require different tire pressure settings.
Often the recommended settings are also for getting the best milage out of the tire.

Recommended pressure is a good starting point, have a play go up and down a 1-2 psi on the tires and see if you prefer it or not.

Say if you didn't care about mileage, more performance and grip, Would you run them harder or softer generally??

Logically that makes total sense why kawi would place those numbers, I was wondering if it was something like that.

[Racin Jason]

Say if you didn't care about mileage, more performance and grip, Would you run them harder or softer generally??

Logically that makes total sense why kawi would place those numbers, I was wondering if it was something like that.

If you wanna go really fast lower the pressures, (this is because the greater heat will cause greater pressure), if you want tyres to last for touring or pillion riding raise the pressures.


Tyre pressure are funny. they depend on type of bike, type of tyre, and suspension settings. Touring tyres work better with high pressures and race tyre dont work at all with high pressures.

Lower pressures means more grip, but its a fine balance between lowering pressure to provide greater grip, and lowering them to far to the point that the tyre deflects excesively.

My advice for road riding is start with manufactures specs. If you go for a stickier tyre and ride faster - lower pressure a bit (a few psi only). If youre gonna tour on harder tyres, raise them a bit.(about 6 psi rear for pillions and a couple clicks of compression dampning and preload).

if you ride on the track you will need to adjust pressures so that the front is higher than the rear. Ask the tyre distribitor as they have the benefit of lots of riders/racers testing their product.

On the track we run conti race attacks no higher than 26 psi in the rear, or they slide. Similar for pirelli, dunlop etc.

ALWAYS measure tyre pressures when cold. Hot pressures are only applicable when racing, and even then tyre temperature is much much more important.

Hope this helps guys

PS. i bought a foot pump from M10 mega for $9. It has never let me down

[3umph]

You could always take a cold reading at home, take your pressure guage with you and check pressure again at servo. Note the difference and adjust accordingly!

yip thats one of the best ways:2thumbsup

[lanci]

Should you factor in summer vs winter road temps???

[Laxi]

i always check mine at the local on the way home. i always fill them 7psi bellow the recomended that way they are always perfect for me