Tyre pressure wisdom

[N0bodyOfTheGoat]

I run upto 40 PSI in my 38c gravel tyres if that helps, including when 'loaded' for touring. 85 PSI in the 28c road tyres.

What system weight, you and bike all ready to head out? I suspect a lot lower than ~112Kg for me and my light ebike that very rarely rides anything worse than rough tarmac!
What tyre model?
Tubeless, latex tubes, TPU or butyl tubes?

 

[Pat "5mph"]

I have Schwalbe, Green Marathon, recently fitted

I find the lowest pressure listed on the tyre (50 psi) really too hard.

Those are the tyres I have been using on my (heavy) bikes for years.
35/38 whatever I find cheaper, 35 at the moment on my commuter.
I run them at 70psi, the max is 85.
I am under 60Kg, the bikes are over 12Kg, plus the kitchen sink in the panniers
Maybe your pressure gauge is incorrect?
I think 50psi is very low, should you run into a pothole you're guaranteed a puncture imo.

 

[Gwylan]

Those are the tyres I have been using on my (heavy) bikes for years.
35/38 whatever I find cheaper, 35 at the moment on my commuter.
I run them at 70psi, the max is 85.
I am under 60Kg, the bikes are over 12Kg, plus the kitchen sink in the panniers
Maybe your pressure gauge is incorrect?
I think 50psi is very low, should you run into a pothole you're guaranteed a puncture imo.

Never thought to doubt the gauge on the Makita pump. I'll see what the track pump says.

 

[midlandsgrimpeur]

When I had a gravel bike I ran a 38mm Schwalbe one at 40psi and that always felt fine to me. I am around 56kg and the bike was around 9kg loaded up with bidons. Tyre pressure is really subjective though, I always think it best to just work on trial and error as to what feels best for a particular setup as it varies so much.

I would generally try and stick to manufacturer recommendations on max pressure though, 5% above here and there should be fine but if the max pressure is 50psi and you are loading it up to 70+ there could be some issues down the line.

 

[T4tomo]

how wide are the tyres @Gwylan?

People are saying 50spi is very low, risk of pinch puncture etc, but if its a wide tyre then that is horlicks.
Ultimately though, Marathons are a quite hard ride.

 

[Moodyman]

Worth noting that tough tyres like the Marathon are a harsher ride, and even harsher when they’re new. A couple of hundred miles on mixed terrain (preferably gravel) will knead them to more pliability.

 

[Ming the Merciless]

People are saying 50spi is very low

I run that pressure on the front 32mm tyres. All up weight of about 84kg. Run 60 psi on back on 30mm tyres. Fast rolling and nice and smooth on our roads.

 

[Gwylan]

how wide are the tyres @Gwylan?

People are saying 50spi is very low, risk of pinch puncture etc, but if its a wide tyre then that is horlicks.
Ultimately though, Marathons are a quite hard ride.

1.5"

 

[Alex321]

1.5"

That is 38mm. Quite wide, but I still wouldn't like to go as low as 50psi.

My hybrid has 38mm marathon+, and I still usually put 70-75psi in them.

My main road bike, with 28mm, I usually inflate to 80psi.

 

[T4tomo]

A 5psi /6% reduction for going from 28mm to 38mm is off the scale too small.

Google a few tyre pressure charts are you'll see what I mean.

I reckon @Gwylan could safely try 45psi to see how it feels.

 

[Gwylan]

I sort of calibrated the Makita pump.

Pumped a tyre on the car to 35psi, checked it with an old fashioned tyre gauge. Seemed "close enough for navy work".

So I've pumped the bike tyres up to 65psi. Then make an excursion on a few km sample route.
Depending on that I'll make a decision what to do next.
To be continued.