# Tyre pressure - massive wheel load difference!?

#### beany_bot

##### Über Member
So I am trying to figure out my optimal tyre pressure (28C tyres on a cross bike used for roads). I am 85Kg

I read the most accurate way was to weight each wheel as you sit on the bike (wheel load).
But I have a much bigges disparency than I see anywhere else online.
My weights were 58Kg on the back wheel and 38Kg on the front wheel. Which would (by most graph) give me a rear wheel PSI of 100Psi!! on 28C tyres! and a front PSI of only 60....
100/60 seems a bit weird? anyone try this wheel load thing?

#### ianrauk

##### Tattooed Beat Messiah
You're thinking too much about it. Check the tyre walls. There should be 'inflate to min/max'.
Go for somewhere inbetween, ride and adjust for comfort.
It's as simple as that.

#### raleighnut

##### Legendary Member
So I am trying to figure out my optimal tyre pressure (28C tyres on a cross bike used for roads). I am 85Kg

I read the most accurate way was to weight each wheel as you sit on the bike (wheel load).
But I have a much bigges disparency than I see anywhere else online.
My weights were 58Kg on the back wheel and 38Kg on the front wheel. Which would (by most graph) give me a rear wheel PSI of 100Psi!! on 28C tyres! and a front PSI of only 60....
100/60 seems a bit weird? anyone try this wheel load thing?
You need to weigh both wheel weights simultaneously unless the bike weighs 31Kg your figures don't add up. Position on the bike alters weight distribution.

I'd say 100 rear 80 front was about right on 28s but I'm a touch heavier than you.

#### Crackle

##### ..
25's 90/100 front/rear. Seems about the right blend for me and my bike after some experimentation.

#### derrick

##### The Glue that binds us together.
90 and 100 sound's a bit high for 28c tyres.

#### raleighnut

##### Legendary Member
Just check for any loose fillings before setting off .
Nah that's on the 20mm Continental Grand Prix 'Supersonic' 160psi or I get snakebite pinch flats (max is quoted at 170)

#### Vantage

##### Carbon fibre... LMAO!!!
What @ianrauk said. Inflate to max recommended pressures and then go for a couple rides. Let the air out a little each ride till they roll comfy but not enough to cause significant rolling resistance and bottoming out on bumps.

#### Venod

##### Eh up
85 psi rear 75psi front would be my starting point for your weight and tyre width, go for a ride and adjust as required, 100psi for 28 mm seems a bit high to me.

#### gbb

##### Legendary Member
Ive never checked what actual pressures i run at....and i'm 61
Inflate until hard using a press of the thumb into the tyre as a guage.. On rare occasions ive found the ride jarring, deflate a little.

#### CXRAndy

##### Guru
You could start with recommended max tyre pressure, then keep lowering 5psi until tyres feel just a little squishy whilst cornering. Then just add a couple of PSI

You could go upto 30/32mm for greater air volume and run lower pressure. Also tubeless is a fair bit lower too, see above method

I run 40 mm tyres at 50R 45F. but run 25mm at 90R 85F. My 40mm G Ones are so nice to ride and only slightly slower, I much prefer them