Trackday tyre pressures

[aspad]

Sorry to hear about your off Mike - sounds like a bad un. Did you land on your ankle when you came down?
Can you learn anything from it?
Heal well.

 

[Mikef]

Thanks for the good wishes

I was hanging right off the bike with knee down (or almost) it highsided and I suspect my foot got stuck under the right hand pot as I was flicked over the top hence the dislocation and damage (I fractured the lumpy bits either side of the ankle and right through)

I remember flying over and looking down on the bike and thinking 'jeeezzzz my ankle hurts' I didnt land on the ankle I landed on my head and split my AGV in two

Plenty to learn from it ...
dont try and go so quick so soon,
I am 46 not 16 calm down,
the GS will out brake anything anywhere but really it isnt suited to the track, I really need an R6 If I am going to ride that hard
GSs crash really really well

And the biggest learning is that I have fantastically supportivefamily/friends/employer

 

[Micky]

Errrrr !!!! I dont think you read right through the thread

Errrr!!! sorry, my mistake then. Your initial thread was on tyre pressures, and I still stand by what I said about them being lower than the manufacturers!

Sorry about your off, but don't be too eager to place the blame elsewhere. I highsided my 1150 GS at Oulton Park, into the chicane, a personal dice with three sports bikes, no one else was on the track to all intents and purposes. I was beating them in the corners, outbraking them, diving under and over them, but they had me on the straights... so it went on for several laps. I was in front into the chicane and on my arse on the exit... my fault entirely!

Hope you're on the mend Mike, and all goes well.



www.adventure.gs

 

[vfxmark]

Sorry VFXMARK. Disagree completely with you re putting more pressure in the tyre.

 

[(RIP) Kaister]

next time use nitrogen in the tyres - that doesn't expand with heat and this whole thread might have been avoided - and you might not have fell off....



http://www.bridgestone.com.au/tyres/products/car/care/nitrogen.asp

 

[vfxmark]

First - Sorry to hear about your get-off, Mike...no fun in that . 'fraid I did the same a few years ago...broke the bike worse than myself in that case, but no fun either way.

Sorry to jump back in to the middle of a thread so late, but...

Sorry VFXMARK. Disagree completely with you re putting more pressure in the tyre.
(end quote)


Actually, I wasn't advocating raising the pressures on the track...we lower the pressures on our S bikes when we go to the track ourselves. What I was describing was the physics...The target pressure is the one that gives you the best handling... and in the olden days, one way to judge it was to find the low pressure that yielded 5 psi higher when hot...

Lowering the pressures a little, can actually yield higher running temps from the temp increase due to sidewall flex. I tested this with bias belted tires back in the day - while the dynamic might be a bit different with modern radial tires, especially the low profile ones on our sportbikes, the principle should remain the same -a significant amount of tire temp increase (and therefore pressure increase) comes from sidewall flex.

Lowering more than a little bit will still yield lower running pressures, but might yield higher operating temps. If you are running race compounds, which are designed for high temps, you will be fine, but if you are running street tires, which, contrary to popular belief, are designed to be sticky at lower operating temps than track tires, running them at too-high temps may not be the best idea...
...and one really easy way to get too high temps is to run at too low pressures.

The track we play at is in the desert and the combination of really hot ambient temps (often near 100 degreesF) and hot black tarmac radiating heat means we might want to run slightly higher pressures than we would if it were a more bearable temperature or a cloudy day, or...(once a year) raining.)

If I were going to the track on a cold day, I would probably run slightly lower pressures so that the tires would get up to operating temp a bit faster...

Mark

 

[vfxmark]

next time use nitrogen in the tyres - that doesn't expand with heat and this whole thread might have been avoided - and you might not have fell off....

Not true...nitrogen expands with heat...believe me, for reasons that have more to do with marketing than anything else, a major tire replacement outfit here uses nitrogen to fill their tires, and I had two sets of tires from them (for two different trucks) inside of a month.

Nitrogen does expand...80 percent of compressed air is nitrogen already.... The advantages of running nitrogen include no water vapor in the tire (so you get less of a pressure change as the tires heat up and less corrosion) less oxidation of the tire rubber inside (a very questionable difference) and most of all, less likelyhood of a tire fire (no oxygen inside), which, frankly, has not been that much of a threat in my life

 

[aspad]

Nice one Mike.
Glad to hear that you are being well looked after.
Good observations about the off - can relate to all of them.
You'll be posting more on this site in the coming weeks then....

Thanks for the good wishes

I was hanging right off the bike with knee down (or almost) it highsided and I suspect my foot got stuck under the right hand pot as I was flicked over the top hence the dislocation and damage (I fractured the lumpy bits either side of the ankle and right through)

I remember flying over and looking down on the bike and thinking 'jeeezzzz my ankle hurts' I didnt land on the ankle I landed on my head and split my AGV in two

Plenty to learn from it ...
dont try and go so quick so soon,
I am 46 not 16 calm down,
the GS will out brake anything anywhere but really it isnt suited to the track, I really need an R6 If I am going to ride that hard
GSs crash really really well

And the biggest learning is that I have fantastically supportivefamily/friends/employer

 

[Rushy]

to run at too low pressures.

The track we play at is in the desert and the combination of really hot ambient temps (often near 100 degreesF) and hot black tarmac radiating heat means we might want to run slightly higher pressures than we would if it were a more bearable temperature or a cloudy day, or...(once a year) raining.)


Mark

Willow Springs?

 

[vfxmark]

yup...Streets of Willow, which is the smaller tighter track, not the big track, for which I have neither the horsepower, nor, I suspect the reproductive equipment

Mark

Lost Angeles

(Great riding weather, except when your favorite two roads are closed for a couple of weeks due to a ginormous forest fire : -( )

http://inciweb.org/incident/475/