Tyre Pressure?

Tyre Pressure?

Bike tyre pressures seem to be dragging out a thread on the VC Melyd Facebook group at the moment.

Through the medium of waffle we have managed to ascertain that people are either all over their tyre pressure, or its a general ‘that will do’. Other things came to light such as it would very much depend on other factors, such as tyre type, tyre size, weight of rider – the latter being the one that seemed to define whether this was some or all of the air. All very scientific.

It turns out that Vittoria – manufacturers of great tubulars and so-so clinchers have written an App to make such troubles go away – or at the very least give you a line in the sand in a ‘bloke down the pub said’ third party opinion to compare your findings against. While I was unable to find it on my phone – I was able to find a working version on-line. Now this makes NO ALLOWANCES FOR TYRE SIZE – however lets assume that this is great if you don’t want to over complicate things.

VITTORIA TYRE PRESSURE LINK

Sure – if you don’t know what the weather is going to be, or how many TPI your tyres are (it’s usually plastered all over the outside of racing tyre boxes – as an indication of suppleness)… however really does make no allowances for 23c or 25c tyres. Wider tyres are now not only just for winter – 25c and 28c rolling more efficiently than 23c in more recent studies … just come with friends and club mates silently pointing wide eyed at your delicate racing rims with balloon tyres on.

  – Bigger riders, more air;

  – Wider tyres, lower pressures;

  – Wider tyres, deeper profile, more protection;

  – More air in the rear than the front usually around a 60/40 spilt;

  – Wetter weather, slightly lower pressure.

Too low, tyre off in a corner, rim on road, snake bite punctures – too high, vibration, jumping off road in corners, e’splode!

The rest it would appear is an art, done by feel, which kinda goes along with everything I love about riding.

The most well rounded responses thus far being unsurprisingly Darren:

Everyone needs a digital pressure gauge in their life. There is no definitive answer to your question, the variables are so many. Time of day, temp, road conditions, bike weight, type of tube, width of tyres, road surface etc.. You’ve got to start somewhere though and trial and error will get you there and the numbers you’ve been given are a great start. Wet roads on a cold day you’ll need less for example I’m 69kg and on 25s in the winter I run 80 front and 85 rear, if it’s wet I may run a little lower. It just suits me. On 23s in the summer using latex tubes I will ride 90 front and 95 rear. If though just pounding up a few hills I may go higher. If the roads are crap slightly higher is better to avoid pinch flats.

— Darren Wareing (Road Race Secretary)

Join the conversation over in the VCM FB group (and I will get this updated if we ever get back on topic again).

Oh, and just on the off chance you wanted some more people telling you something you already knew – here are a bunch of other random graphs with crucial bits of information missing or just seemingly wildly wrong (my particular favourite was one that suggested according to their graph at 25C I should be running at 180psi… it is not included for health and safety reasons).

Enjoy…

12nov-table UdRE3

Not that we have to really worry too much about tyre rubber temperatures and the like – it is worth considering that pressure is relative to air density and temperature… so here is a little something to take that pain away also.

Bontrager-Fat-bike-pressure-chart1

Now… we have ‘some’ air in our tyres – can we go out riding now?