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Mohawk · May 27th, 2018, 12:56 PM

OK, regarding Tyre pressure, there are some things you need to now.
First all tyres are specified with a maximum cold pressure on the side wall, but remember COLD means 20dgrees Celcius or 20C.
Next all tyres when used generate heat in the tyre due to flexation of the carcass, this will increase the pressure in the tyre. The heat generated is proportional to ambient air & road surface temps & to the use cycle. So on a cold day on a cold damp road, you don't get much heat in your tyre & this directly affects the grip level of the rubber compound. Conversely a trackday or race on a hot dry sunny day will add a lot of heat to your tyre due to the hard acceleration & braking, plus cornering loads.

Thus if you set max pressure on a cold damp day then it will be like skating on ice. By comparison if you did the same on a hot day at the track, you would quickly over heat the tyre & its max pressure levels, leading to a skating feeling in a few laps.

So manufacturers specify a pressure front & rear based on the expected nominal loads the bike is expected to experience, across a wide temperature range & varied use. So unless you fully understand the variables, then you should always use the Bike manufacturers recommended figures, UNLESS the tyre manufacturer has a specific recommendation for a certain model of tyre on your model of bike.

Now track day riders & racers will use much lower pressures, to allow the tyre to operate at the optimum pressure once heated in use. Likewise smart road riders will work out the best pressure for their use on their bike based on local ambient conditions & rider use models. So a gentle rider in a cold place would generally have better grip with pressures below the bike manufacturers recommended pressure. But a harder riding rider may use higher pressures than the gentle rider in the same conditions, due to the harder flex applied to the tyre by more agressive riders.

But remember pressure also affects handling, so a low front pressure will give a distinctly poor feeling until the pressure is corrected by heat. If the heat can't be generated the bike will handle like crap. So be careful what you do & adjust by a maximum 2psi either way when finding your sweet spot.

YMMV & YOU are responsible for YOUR own & all other road users safety when playing with safety settings !

If you don't know what you are doing, DON'T do it !

May 27th, 2018, 12:56 PM	#34
Mohawk ninjette.org guru Name: Chris Location: Bristol, UK Join Date: Feb 2016 Motorcycle(s): ZZR250, VFR800 Posts: 478	OK, regarding Tyre pressure, there are some things you need to now. First all tyres are specified with a maximum cold pressure on the side wall, but remember COLD means 20dgrees Celcius or 20C. Next all tyres when used generate heat in the tyre due to flexation of the carcass, this will increase the pressure in the tyre. The heat generated is proportional to ambient air & road surface temps & to the use cycle. So on a cold day on a cold damp road, you don't get much heat in your tyre & this directly affects the grip level of the rubber compound. Conversely a trackday or race on a hot dry sunny day will add a lot of heat to your tyre due to the hard acceleration & braking, plus cornering loads. Thus if you set max pressure on a cold damp day then it will be like skating on ice. By comparison if you did the same on a hot day at the track, you would quickly over heat the tyre & its max pressure levels, leading to a skating feeling in a few laps. So manufacturers specify a pressure front & rear based on the expected nominal loads the bike is expected to experience, across a wide temperature range & varied use. So unless you fully understand the variables, then you should always use the Bike manufacturers recommended figures, UNLESS the tyre manufacturer has a specific recommendation for a certain model of tyre on your model of bike. Now track day riders & racers will use much lower pressures, to allow the tyre to operate at the optimum pressure once heated in use. Likewise smart road riders will work out the best pressure for their use on their bike based on local ambient conditions & rider use models. So a gentle rider in a cold place would generally have better grip with pressures below the bike manufacturers recommended pressure. But a harder riding rider may use higher pressures than the gentle rider in the same conditions, due to the harder flex applied to the tyre by more agressive riders. But remember pressure also affects handling, so a low front pressure will give a distinctly poor feeling until the pressure is corrected by heat. If the heat can't be generated the bike will handle like crap. So be careful what you do & adjust by a maximum 2psi either way when finding your sweet spot. YMMV & YOU are responsible for YOUR own & all other road users safety when playing with safety settings ! If you don't know what you are doing, DON'T do it !