Tyre Pressures

[Ming the Merciless]

I run Schwalbe Big Apples which are fat slicks. I like the higher pressures which roll faster.

How much faster. What are your average speed vs.pressure numbers from when you tested this?

 

[MichaelW2]

How much faster. What are your average speed vs.pressure numbers from when you tested this?

I dont have numbers and use a calibrated thumb for measuring pressure. The Big Apple can be run at alarmingly low pressure: 30-55 psi but I find the lower end very squishy. There is an immediate jump in speed after pumping to max pressure.

 

[Ming the Merciless]

I dont have numbers and use a calibrated thumb for measuring pressure. The Big Apple can be run at alarmingly low pressure: 30-55 psi but I find the lower end very squishy. There is an immediate jump in speed after pumping to max pressure.

Try a bit lower. Max pressure is rarely the fastest and it’s always the one that causes most vibration

 

[rockyroller]

fwiw - I run my front tire 5-10 lbs lower than my rear. on the MTB the difference is smaller, more like 4 lbs lower

 

[Ming the Merciless]

I run 37mm on front and 32mm on rear of my recumbent. I tried running 32mm up front but too much road vibration even at 15% drop pressure. The 32mm up front wasn’t faster. I run the 37mm at 40 psi and 32mm at 60 psi. Combined recumbent bike + me weight is 85kg.

 

[Lazy Fat Vegan]

Thank you for all your replies and advice. Have to admit to being surprised at how high tyre pressures seem to be on everyone's bikes....I'm much more used to car pressures of 30 ish psi

 

[Drago]

Never measured tyre pressure. I just do the finger thumb squeeze thing.

The magistrate has banned me from doing that after the nun reported me to the police.

 

[cougie uk]

You can't guess ftom the tyre size. The MAXIMUM pressure of some 700 x 23 tyres is lower than the MINIMUM pressure of others. The Vredestein Fortezza TriComps needed to be run at stratospheric pressures (they'll take 185psi, and 130psi at the rear is about as low as I'd go) or they are vulnerable to pinch punctures, as my mate discovered last night. Some Schwalbe Duranos have a maximum pressure of only 115psi and will happily pop off the rim at 120psi.

One issue with the wide modern road rims is that they are not rated for much over 100psi.

I had those Vredestein Fortezza tyres - check what your rims are rated to - my tyres were higher than the rims.
They were also the tyres I blew out whilst descending the Alpe d'Huez - thankfully there was a run off at the hairpin or god knows what would have happened. I binned them shortly after. Conti GP4000s much safer - lower pressures.

 

[Ming the Merciless]

Thank you for all your replies and advice. Have to admit to being surprised at how high tyre pressures seem to be on everyone's bikes....I'm much more used to car pressures of 30 ish psi

It is all about volume. The bigger the volume of a tyre the lower the pressure. It’s only once you hit the 2” width of mtn bike tyres that you are in the 30 psi level. Of course if you are very light you’ll also have lower pressures.

 

[Lazy Fat Vegan]

It is all about volume. The bigger the volume of a tyre the lower the pressure. It’s only once you hit the 2” width of mtn bike tyres that you are in the 30 psi level. Of course if you are very light you’ll also have lower pressures.

I'm a long way from being average weight, I can't see me ever getting to being light/very light