Tyre pressure wisdom

[Gwylan]

I have Schwalbe, Green Marathon, recently fitted

I find the lowest pressure listed on the tyre (50 psi) really too hard. It makes for a bumpy and unsatisfactory ride
Do I choose the tyre pressure that I'm comfortable with or go by the guidance on the tyre?

 

[Alex321]

50psi is pretty low for a tyre with inner tube. You will almost certainly get pinch punctures if you go any lower.

The puncture protection of the tyre works against penetrative punctures, but doesn't do much to help avoid pinch punctures. It does have a stiffer sidewall than many tyres, which helps a bit, so you probably won't get many at 50psi - you would with most tubed tyres.

 

[Tigerbiten]

How badly do they deform when you bump up a curb. If not a lot then you could probably run a little softer.

I've found the softer/more flexible the sidewalls are, the better the tyres are at absorbing road buzz.
I have a section of bad chip and seal road that I always test a new tyre on.
I start at a to low pressure and ride over it many times upping the pressure each time.
I try to feel when the road buzz increases to a bad level.
Then start high and lower it again trying to feel when the road buzz softens.
Then try riding up a few curbs at what I feel is my ideal pressure, just where the road buzz starts to ramp up.
If it doesn't deform to badly that the pressure I try to stick around.

 

[raleighnut]

I have Schwalbe, Green Marathon, recently fitted

I find the lowest pressure listed on the tyre (50 psi) really too hard. It makes for a bumpy and unsatisfactory ride
Do I choose the tyre pressure that I'm comfortable with or go by the guidance on the tyre?

What is the frame material ?..................Sounds like an Aluminium frame to me.

I run a similar tyre on my Ridgeback 'Adventure' hybrid* but in 28mm width at 85 front 95 rear and that rides like silk.

* Tange CrMo frame.

 

[Dan Lotus]

What width is it?
I run the 40mm tyres (Schwalbe Marathon Supremes) on my gravel bike at around 55/50, and that's for predominantly road use - zero issues, and run tubes.

 

[Tigerbiten]

I also run Schwalbe Marathon Supremes (42-406) on the front wheels of my bent trike at around 60 psi.
Running at the same pressure I find them more comfortable than Schwalbe Marathon Racers (40-406) due to softer sidewalls.
I also run a Schwalbe Big Apple (50-406) at a similar pressure on the back. They also pass slightly more road buzz but the thicker rubber in the tread means they last longer and puncture slightly less.
I also tried Schwalbe Kojak (28-406) but had to run at a higher pressure to stop the risk of pinch punctures and could never get them comfortable.

 

[N0bodyOfTheGoat]

I'm running Marathon Supremes on my electric gravel bike, 35mm front and 40mm rear for the aero gains.

I'm ~94.5Kg; ebike with two 750ml bidons ~16.5Kg; kit and bits in jersey ~2Kg {so ~113Kg total, ~60% load on rear wheel}

Typically ~60psi front, ~65psi rear.

I presume we are talking the 700x40mm variant...
https://www.schwalbe.com/en/Green-Marathon-11159394

Great for a commuter that can't really afford to risk punctures, but awfully heavy at 810g each, they will feel a bit "wooden." iirc my 40mm Supreme is ~450g.

 

[Gwylan]

Thanks for the wisdom of experience.
I have a bicycle that I ride quite a lot. It's my first choice for transport.
But as you see I don't know too much about tyres etc

The bike is an alu frame, EBuyer, weighs in at about 18kg.

How do people measure the pressure in their tyres? I use a Makita battery powered pump. I don't know how accurate the pressure is, but I can compare successive readings.

I've noted the hints and questions. I will be slightly more scientific in data gathering on my rides.

I've dropped the pressures to 50 on the front and 55 on the rear. On account of the heavier wheel. 65, the previous setting was like riding wooden wheels.

Over my relationship with this bike I've dropped my weight from mid 90 to early 80 kg. Suppose 10 kg is a bit of a difference .
I'm only superstitious on one matter so I do not mention that. But so far so good.
A Gaadi tube for the rear is on the agenda.

 

[wafter]

The ideal pressure will depend enormously on the tyre size and total bike / rider mass.

The green tyres run a fat rubber puncture-resistant strip at the centre which will inhibit flexibility and for a given pressure make the tyres seem harder / behave like they contained higher pressure.. so you may just have to suck this up as a consequence of the added protection.

Be aware that dropping the pressure too much will cause excessive sidewall flex which can fatigue the tyre over time and cause it to delaminate over time and eventually fail.

I always find the Chinook tyre pressure calculator pretty much on the money if you want a reality check

 

[Tigerbiten]

How do people measure the pressure in their tyres? I use a Makita battery powered pump. I don't know how accurate the pressure is, but I can compare successive readings.

I've noted the hints and questions. I will be slightly more scientific in data gathering on my rides.

I've easily got around a 15 psi range I can run the tyres on my bent trike.
Above about 65 psi the rod buzz starts to get to harsh and below about 50 psi then I feel the risk of pinch punctures start to go up to much if I hit a pothole at speed. I also know I can drop to around 40 psi if going off road.
Then maybe once a month or so, I pull the pump out and find out the actual pressure in the tyres on the attached gauge, adding more air as needed.
How accurate the gauge is I've no idea, but because I work on how the ride feels I just pump the tyres up to a pressure that works for me on that gauge.
Before each ride I tend to give all 3 tyres a quick pinch just to feel how hard they are, if hard then good for the next ride.
If one feels a bit soft then it's pull the pump out to find out the pressure and add air as needed.
A very very slow puncture that takes over a week to go down may or may not be fixed. A slow one that takes a couple of days to go flat will be fixed.

 

[Psamathe]

I also run Schwalbe Marathon Supremes (42-406) on the front wheels of my bent trike at around 60 psi.

Front of my bent tadpole I use Marathon Plus at 3 bar (43 psi) (Marathon's min pressure for the tyre is 3.5 bar (51 psi). Tried 4 bar but too hard for me.

How important is rider weight to the best pressure. I'm 60 kg.

I don't have the experience to make any recommendations for others, just post my own experiences.

Ian

 

[wafter]

Front of my bent tadpole I use Marathon Plus at 3 bar (43 psi) (Marathon's min pressure for the tyre is 3.5 bar (51 psi). Tried 4 bar but too hard for me.

How important is rider weight to the best pressure. I'm 60 kg.

I don't have the experience to make any recommendations for others, just post my own experiences.

Ian

Worth noting that the recommended minimum pressure is probably based on a worst-case scenario (on the back of a bike carrying a heavy rider) - in your case I suspect you could probably go a lot lower since the tyre is on the front, there are two reacting the load so potentially half what there would be on a bike, while you're also lighter than average..

 

[presta]

For a year or two I ran my front tyre with the pressure low enough to be able to ground the rim by bouncing my weight on the bars, but I didn't have any punctures, rim damage or any other problems.

How do people measure the pressure in their tyres?

For most of my life I didn't, I was 54 before I first got a pump with a gauge (Topeak Turbo-Morph). I use 65psi on 35-700 tyres, with an all-up weight for touring of 106kg, arrived at by matching what I normally used by feel (the tyre is 55-85psi, and the rim 88psi max) .