What About Tyre Pressures?

[RiderInBlack]

What about Tyre Pressures? How do you guys workout what is best for you for:

1. Racing. Before and in between races. For different conditions (dry to wet, etc)
2. Road (Normal, Commuting, Pillion, Packs, etc)

With the VFR750 and the CBR1000FL I've been told that Front 36psi and Rear 42psi (cold) are fairly standard, but after getting the P-Diab's fitted at Leading Edge I have been told that this varys in relation to bike usage and road conditions. For Track they told me 32-34psi for the front and 35-38psi rear, and for Touring 38psi Front and 42psi (44psi with pillion) Rear for my CBR1000FL. I am experimenting with tyre pressures now to see what feels right for me, and am interested to what you feel for when setting the tyre pressures for your bikes.

[vifferman]

Dunno about track (never had my bike on one, although I've ridden a few bikes at Pukekohe), but on the road I've found that sticking with 36F/42R on the VFR worked best, and it seems the same for the VTR.
The previous owner of the VTR ran much lower pressures with the Pirelli Dragons (EVO/GTS), and the tyres were shagged. I eventually removed most of the squaring off - which I believe was caused in part by too low pressures - but they never felt good.
Running lower pressures allows the tyres to heat up quicker due to the carcase and tread flexing, but a tyre has a limited number of 'heat cycles' in it, and once this is exceeded, it's done, even if there's still tread left. For a race tyre, this may be only a handful of races, and is why using race tyres on the road is not necessarily a good idea. Also even though the flexing/heating makes the tyre stickier, it wears the tyre out faster, and may cause cracking around the tread blocks. It may also make the tyre a little more prone to damage from potholes and the like (but not here - we have such perfectly maintained roads, eh?)

It's largely a subjective/personal thing. F'rinstance, the Azaros I've now got on the VTR (luvly tyres) apparently don't like to be run at lower than recommended pressures. Then again, I don't like lower pressures, because of the 'squirmy' feeling it induces.

What you need to do, is record the pressures before and after a ride, and see how much the pressure has gone up. It should rise by no more than about 5-10% of the cold pressure.

[MikeL]

It may or may not be a coincidence, but I've found with all four bikes I've had that sticking to the recommended pressures within 1-2 lb/sq in feels best. When I put air in I set the pressure to 1 over the recommended figure (don't know how accurate these things are). In most cases I can ride for about 2 weeks before it starts feeling a bit different, and when I check the pressure has usually dropped to 2-3 lb/sq in below the recommended figure.
When I went on the track i didn't change the pressure and was quite happy with the way it felt.

[Hitcher]

I work on the assumption that the manufacturers must know what they're talking about, and run my tyres at their recommendations, maybe plus 1psi.

For the Zrex that's 37psi front and rear.

Mrs H's Marauder runs 29psi up front and 33psi rear.

There's a great fitment guide on the Dunlop UK web site that will tell you recommended pressures for the make, model and year of your ride. It doesn't go into subtleties such as track or road, wet or fine, sweet or sour, over and under...

[Hitcher]

According to the Metzeler online fitment guide, your Honda VTR1000F should be running Rennsports, at 2.5 BAR front and 2.9 BAR rear.

[aff-man]

the zxr has 32psi in the front (mtr01) and 35psi at the back (gp80) normally and i usually drop it 1 to 2 psi when riding 2 if it's a hot day 1.5 is warm ect...

[RiderInBlack]

Last Bike-only Day @ Puke I tried 36psi front and 40psi rear set after riding from Barry's Point to Puke (had been set at 36psi and 40psi @ Leading Edge that day and was showing 40psi and 48psi on arrivial), which seemed to stick well. Just curious as to what feedback you use to judge the "right" psi for you.

Have read this Thread on Tyre Pressure (http://www.kiwibiker.co.nz/forums/sh...Tyre+Pressures), which has been good (especially the bit by WKO), but feel I need more info.

[vifferman]

According to the Metzeler online fitment guide, your Honda VTR1000F should be running Rennsports, at 2.5 BAR front and 2.9 BAR rear.

Is that so?

What's a BAR?

What's a Rennnnnnnsports?

[svs]

Is that so?

What's a BAR?

What's a Rennnnnnnsports?

1 bar = 14.5037738 pounds per square inch

Kind of tyre http://www.metzelermoto.com/product_...D=168&idCat=15

[vifferman]

1 bar = 14.5037738 pounds per square inch

Kind of tyre http://www.metzelermoto.com/product_...D=168&idCat=15

So I need to run my front tyre at 36.2594345 psi, and my rear one at
42.06094402 psi.

Hmmm... So where am I going to get a tyre pressure gauge that reads that accurately?

I don't reckon them Rennnnssssportz - they appear to be made from elephants.

[White trash]

30 front, 32 rear.

So there

[pete376403]

1 bar = 14.5037738 pounds per square inch

Kind of tyre http://www.metzelermoto.com/product_...D=168&idCat=15

I Bar = atmospheric pressure at sea level (can also mean Browning Automatic Rifle)
(OMG I've introduced guns to the thread)

[Jackrat]

I set my pressures to what the book say's.
If I alter from this it is up, not down.Set right an the bike rolls in nicely,let the front end get low and it front becomes very slow, heavy,and hard to change lines plus I can feel the fork flex a lot more.Let the rear get down and it feels like I'm towing a trailer plus it will weave in corners.With firm tyre pressures and the suspension set firm the bike handles a lot better than legend would have it.

[vifferman]

Y' know - what this thread needs is:
Bike model
Type of riding (commuting, touring, etc.)
Laden weight (rider weight, passenger? luggage?)
Type of tyres (make, model, size)
Riding style
Tyre pressures.

So for me, it's:
VTR1000
Commuting in all weathers, try to stick to backstreets
87 kg, plus 10kg of backpack, plus gear, rarely a passenger
Avon Azaro AV49-SP 120/70-17 front, AV46-ST 180/55-17 rear.
Mostly careful, but with some hooning (wheelies, stoppies, etc.)
36 F/42R

[madandy]

RF400
Commuting in all weather, open road plus weekend blasts
94kgs + sometimes a pillion
Metzeller MeZ4 120/70ZR17f 160/60ZR17r
cruisy, high speed riding
34psi (f) 40psi (r)cold.