Redback Motorcycle Smash Repairs - 1/ 9 Collie St, Fyshwick. Ph: 6280 5433

What do you use to inflate your tires?

Jun 9, 2014
What do you use to inflate your tires?
  • Originally posted by @Exonoesis

    I figured that would create an instant emotional response to get your attention!

    Street riders will get air from anywhere usually. Track riders from the track day service provider and racers from either their own supply or from the race tire service brand provider at the event.

    Has a percentage of water vapor in it naturally. When we get compressed air it may have a lot more water vapor in it. Why? The compressor will retain more and more water in it daily. If that compressor hasn't been emptied and dried in weeks there will be a lot of standing water in it. Think that's odd? Go to the local petrol/gas station and see how much water vapor runs out of the nozzle in spray form. That's what you are inflating your tires with.

    Why is this a problem? Water vapor can produce pressure spikes of 10-12 psi when hot giving you a completely false reading. I've seen this at Nationals, Club racing etc so taking control of your air source is critical in making sure carcass temps are true readings not influenced by water vapor content.

    Before you get air from a third party source, ask them when their compressor was last emptied out of air and drained completely. Ask them if they have a water separator in line and check to see how full it is. Finally blow air out of the nozzle to see how much water vapor is visually present.

    Dry air:
    Best source for that is a scuba diving shop. You need to buy your own tank and regulator, but the air is high quality for obvious reasons. Is it worth the investment? For the street, perhaps not. For track days and racing most certainly but that's an individual choice that everyone must make. The question of the moment is how quickly can the investment pay off? If you ruin a tire in 2 sessions at $300, it already paid for itself. The downside is that you have to check the tank regularly and top it off which means a little planning prior to the track day or race weekend.

    Serious racers all use nitrogen as it is an inert gas. That means minimal pressure gains from cold to hot of 2-3psi. Right away you immediately ask the question "What pressure do I start with?" and that of course is all based on a slew of variables. The correct answer is based on pressure and carcass temps, so you have quite a bit of work to do in R&D to find out what pressure gets the carcass to correct temps for that rider, that day, that track time, that lap time, that tire carcass and compound.

    Given what you learned here, how will you apply this knowledge? Is it worth the effort to make the investment of time, energy and some cash or are you happy to stay where you are with the system and or source you use?

    Does it hurt to ask if the dealership or tire vendor if they emptied the compressor yesterday or this week? No it does not, and those who care do it regularly.

    Tires are our biggest consumable item, so wouldn't it be worth the effort to get the best return on investment? Race tires last a couple of hundred miles/kilometers so for me, it is worth it all. Why? Optimal carcass temps give maximum grip and wear. My tire bill would be 5 times what it is now if I didn't take a few extra minutes to pay attention to the tire carcass temps and wear and all the tire test data at supports this.
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