Not sure why I’ve only just noticed pit lane officials randomly checking tyre ‘pressures’ as bikes enter the pit lane although I did know minimum tyre pressures are mandatory and enforced at most levels of racing. I’m guessing they point an infra red temperature monitor at the tyres to get a temperature, which can be related to a pressure. Surely it can’t be an exact science but obviously accurate enough for initial checks. Having raced scaled Buggies and Truggies at club level years ago, I just happen to have a temperature monitor which I’d like to try out at Almeria. Google found a temperature range 70° to 90°C which seems pretty wide so I’m hoping someone on here will be able to point me at a more typical tyre temperature range for an intermediate level track rider ? Ambient air temperature is looking around 28°C. Pretty happy I understand Metzeler Racetec RRs pressures and cold/hot tear tyre wear patterns but using a temperature seems a nice and easy check. Andy
Difficult to answer. Never heard of them checking pressures. race tyres don’t like track temps below 15 degrees. I would imagine 80 ish would be about average in terms of operating temp for a race tyre. I usually check my pressures straight after each session. someone like Bob would probably know some correlative figures for specific tyres and compounds. Others will only likely know what they have experience of
Thank you for your take on it. Noticed it during the Moto3 coverage at Jerez, bikes randomly pulled over entering the pits and 2 officials waving temperature monitors at the tyres. My current thought is it’s a nice to have, not a substitute for using a gauge. My perceived issue, is the amount of time it takes me to get out of my kit before being able to check the pressure. If I can relate a temperature to a pressure, it’s something I can do before putting the bike up on stands and getting my kit off. Andy
Easier for them I guess as they’re all on the same tyre and bike. Which will have shed loads of data. In that instance, yes, I reckon they will know
Yep, ~80 deg C. I’d imagine there is a correlation between temperature and pressure but you’d have to be sharp with your IR temperature gun as the surface of the tyre will cool quite quickly when you come off track. At a hot track (Brno) I’ve seen an 8psi increase from out the warmer to end of session. That was 19psi out the warmer and 27 psi after reapplying the warmer at the end of the session. As a % that’s a lot!
We had a dunlop delaminate at brands in Bemsee powerbikes and the dunlop guy g came and checked out our warmers and said they were only getting to 70 degrees. He said the tyre working range of min 90 degrees so needed to try and get the blankets off them at 90 so that at the end of the warm up laps he’s got somewhere near tht temp
It is pretty exact actually , thanks to the work of Mr Charles and Mr Boyle , and the Ideal Gas Law PV = nRT If no air is added or removed , the comparison of pressures at different temperatures is a simple linear relationship ..... Pressure x Volume = "a constant" x Temperature You could argue that the volume of the tyre might change with pressure , but I don't reckon it would be very much ....... ....... but just my dos pesetas worth ..... https://www.calculatorsoup.com/calculators/physics/ideal-gas-law.php
PV=kT where k is a constant (nR). Pressure is directly proportional to temperature. Just do a very slow in lap...
Way too technical folks, Advikaz and Fairy have given me the ball park figure I was looking for. It’s an experiment on my part, in the hope of getting my head around needing to let a bit of air out of the tyre (cold tear) or needing to put a bit more in (hot tear) a little easier, nothing more technical or complicated than that. @bootsam, sadly don’t have the luxury of a supply of nitrogen, it’ll be Tabernas air, through my bicycle track pump Andy
Those laser temp sensors only give you teh surface temp of what they are pointed at. They do not provide you with the overall weighted average mass temp of the tyre and its contents. If, for example you rode over a fag end and the laser hit the hot bit then thats what youd get. Use them with that in mind.
True, but without going all E=MC squared, before my first session I set my warmer to 90degC and leave for ~45 minutes. If the rims get warm to the touch, jobs a good un
Its only the laser pointer temp thing Im mentioning as theyre not as useful as they pretend to be. How you guys warm your tyres will be better known by yourselves than I. I'd use a probe temp sensor for reliability.
For track dayers playing on their motorbikes, like me, it doesn’t have to be exact. Warm your tyres, have a steady outlap and off you go. If you’re off racing it would be wise to be a bit more particular with temperatures and pressures. I do check pressures after the first session just to make sure it’s not all out of whack. I may check again in the afternoon… if I remember Usually too busy gassing…
