RDC and Tyre Pressures

[SauRoN]

I'm just wondering with winter here in SA meaning tyre pressures read much lower when cold do you guys try and match your tyre pressures near exactly to the RDC values so it compensates for the temperatures?

Or do you always fill up cold levels to whatever values and then just ignore the RDC values reading higher treating it purely as a puncture warning?

This morning I opted to ignore the RDC and filled up to 2.6 F and 2.9 R at the pump but the moment bike was warmed up I was at 2.8 F and 3.2 R.

Usually I just keep it to reading 2.6 and 2.9 when warmed up, but even that is incorrect as the manual recommends pressures for cold tyres.

[Duccrazydave]

Was just reading the RDC section of the manual. It says that actual inflation pressure will rarely match the display, as the display temp is based on a set point of 68F/20C.
Actual cold pressure levels are more important, for sure.
Cheers, David

[Grumpy Goat]

I typically check and inflate the tires when "cold" and ignore the display, since as David said, they are compensated to 68 deg.F/20 deg.C. If they go down a couple-three psi I re-inflate when I get around to it. I know I am a bit of a slacker, but the bike soaks it up in stride and it appears to make little difference during my commuting rides.

As for the concept of "cold" … here in Houston we are presently in a heat wave and actually for the first time in a long time I chickened out and drove the truck in to work today rather than sit in 100 deg.F traffic going home. In my garage it can be in the 80s in the evening/night so goodness knows what is the temperature of the air inside the tire. So if I inflate to recommended 36/42 psi at that time, it means that if I were to take it out for a ride just after to see what the RDC would say (which I never did) I expect it would read lower initially as its readout predicts what the pressures would be at 68 deg.F and as the tire warms up the display (and actual) pressures would rise but would likely never agree. The only time I think that gauge and RDC pressures would agree was if the bike were sitting in a 68 deg.F garage for some time before being filled to gauge pressures - the initial readouts should agree. But as the tires warmed up the RDC reading would rise but still be predicting pressures as if it were 68 deg.F while the real pressures may be higher (or lower) depending on ambient and other factors. If the ambient temperatures stayed at 68 deg.F then the readouts should continue to nominally agree.

I rely on the TPMS for pressure loss warnings and a hand gauge for pressure setting.

[SauRoN]

Was just reading the RDC section of the manual. It says that actual inflation pressure will rarely match the display, as the display temp is based on a set point of 68F/20C.
Actual cold pressure levels are more important, for sure.
Cheers, David

Yup this is exactly why I asked the question as I wondered how other people compensate for it.

Then again it was about 20C this morning when I filled them up.

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I rely on the TPMS for pressure loss warnings and a hand gauge for pressure setting.

I was a die hard for carrying my own gauge until I figured that it's surely also compensating for a particular pressure at which it's calibrated so the two would fight each other either way and therefore the RDC seemed like a more reliable constant.

Now the local garages all have these digital gauge setups where you enter the pressure first and then plug it in so it over inflates and then drops down to the level and I've just thrown chaos theory at it without questioning what it's compensating for.

However in summer they seem to be within .1 bar of what the RDC says so figured it was good enough. Now in winter it's about .3 out (higher) once I'm rolling.