Dusty Bin
Guest
ok - let's simplify it. You said you use the rated maximum as a guide to how much air to put in the tyre. I said that is not good practice.
Fitting tyres aesthetically on a road bike
- Thread starter StuUngar
- Start date
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ok - let's simplify it. You said you use the rated maximum as a guide to how much air to put in the tyre. I said that is not good practice.
OP
OP
StuUngar
Active Member
Not sure if you are being serious or not - lol?
Why is it not good practice to read the max PSI recommendation, adjust the gauge to the max and then pump the tyre to within those tolerances?
Works for me...
Dusty Bin
Guest
This is bizarre. Seriously, have you not read any of my replies? It is NOT A RECOMMENDATION. Just because your car speedo goes up to 140mph, does not suggest that is the recommended speed you drive at. Please go back and read what I wrote. The number on the side of the tyre does NOT help you establish what your ideal tyre pressure might be.
Dusty Bin
Guest
Don't try this at home, kids....
youngoldbloke
The older I get, the faster I used to be ...
deptfordmarmoset
Full time tea drinker
- Location
- Armonmy Way
I always wear a rather fetching red number when I fit my tyres. It's definitely easier on the eyes.
OP
OP
StuUngar
Active Member
I'm not from the Fry / Norton / Liberace camp like you so am looking at the wheels and tyres, not myself.
deptfordmarmoset
Full time tea drinker
- Location
- Armonmy Way
But style, my dear chap, begins with the person not the bike. Rule #273b
I like Skol
A Minging Manc...
- Location
- Sunny Ashton-under-Lyne
Sounds like a very liberal website, You'd be shot, hung, drawn and quartered in front of your young children around here!
OP
OP
StuUngar
Active Member
Sounds like a very liberal website, You'd be shot, hung, drawn and quartered in front of your young children around here!
I tempered it somewhat. Kitten drowner seemed less intense than what I was actually treated like, a kitten or baby rapist!
I wasn't expecting PSI tyre police to turn up. Still unsure whether he was joking...
Which has made me very paranoid with the method I have been using.
Let me tell you, it's not nice to be told that by following the manufacturers recommendations, and staying within them I am doing it all wrong.
Very tempted to contact Continental & Schwalbe & get in an argument with them!
Dusty Bin
Guest
I'm doing my absolute best to make this as clear as possible, but I seem to be failing. Let's have one last go...
The number printed on the tyre is the maximum safe limit, beyond which the manufacturer believes (as a result of its own testing) that the tyre may fail. It is not a 'recommendation' that you run the tyres at that pressure. If anything, it is the exact opposite - it is a recommendation that you do NOT run the tyres at that pressure.
Let me give you an example. On the side of my Conti GP4000S the max rated pressure is 120psi. In other words, it is effectively a warning not to inflate the tyre beyond that pressure. In actual fact, I run those tyres at around 80-90psi for regular road riding, because that is the pressure that suits me best. There is no 'recommended' pressure for any bicycle tyre - because any tyre pressure has to take into account your own weight, the volume of the tyre itself and the type of roads you may ride on.
You've really got to get it out of your head that the number on the side of the tyre is a 'recommended' pressure - it is not.
If anyone else thinks they can make that any clearer for the OP, then be my guest...
sreten
Well-Known Member
- Location
- Brighton, UK
Hi,
The best tyre pressures are not the biggest number on the sidewall. They depend
on rider weight (mainly, unless touring with loads of kit). Usually the front is 10%
to 20% lower pressure than the back depending on the type of bicycle.
I weigh about 75kg and the right tyre pressures on my bike for me would
be too low for someone who weighs 125kg, though the right pressures
for that rider might still be within the pressure ranges on the tyre.
If ~ 100psi works for you on 23mm tyres then ~ 70psi is about right
for 28mm tyes, irrespective of the 28mm tyres maximum pressure.
http://www.bikequarterly.com/images/TireDrop.pdf
Outlines the principles. Pressure depends on tyre width and weight.
Skinny tyres tend to be underinflated, fat tyres overinflated.
Heavy types should avoid skinny tyres. Big numbers on sidewalls
for the tyre width mean they can handle heavy types / heavy loads.
The fastest lightest tyres will not have big numbers for their width.
Blindly inflating tyres to the maximum pressure on the sidewalls
means you don't really understand your optimum tyre pressures,
that give good rolling and maximise comfort on bad roads, making
you faster. Hard tyres on bad roads feel fast, but they simply are not.
e.g. my folder has a lower max rated rear tyre than the front.
Whilst the rear is run a bit lower than its maximum the front
is run nowhere near its maximum, 20% lower than the rear.
(Small wheels are run harder than bigger wheels, for the
same tyre width, i.e. less tyre drop, to improve rolling.)
47mm tyres, 45 psi rear and 35 psi approximately
e.g. My road bike has a 30mm rear and a 32mm front.
The rear is run nowhere near maximum and the front
is about 20% lower (normally about 10% for most) but
the front is fatter and therefore needs less pressure.
Again the front is rated higher than the back tyre,
and I typically run it a way below the maximum,
around 50 psi whilst the maximum is 85 psi.
(Rear is about 65psi.)
rgds, sreten.
Schwalbe ? They tend to go higher than the above link, see page 30 :
http://www.schwalbe.co.uk/_webedit/uploaded-files/All Files/Technical Info.pdf
Fact is optimum pressure depends on the quality of the roads you ride on,
the worse the roads on average, the better you are with lower pressures.
The best tyre pressures are not the biggest number on the sidewall. They depend
on rider weight (mainly, unless touring with loads of kit). Usually the front is 10%
to 20% lower pressure than the back depending on the type of bicycle.
I weigh about 75kg and the right tyre pressures on my bike for me would
be too low for someone who weighs 125kg, though the right pressures
for that rider might still be within the pressure ranges on the tyre.
If ~ 100psi works for you on 23mm tyres then ~ 70psi is about right
for 28mm tyes, irrespective of the 28mm tyres maximum pressure.
http://www.bikequarterly.com/images/TireDrop.pdf
Outlines the principles. Pressure depends on tyre width and weight.
Skinny tyres tend to be underinflated, fat tyres overinflated.
Heavy types should avoid skinny tyres. Big numbers on sidewalls
for the tyre width mean they can handle heavy types / heavy loads.
The fastest lightest tyres will not have big numbers for their width.
Blindly inflating tyres to the maximum pressure on the sidewalls
means you don't really understand your optimum tyre pressures,
that give good rolling and maximise comfort on bad roads, making
you faster. Hard tyres on bad roads feel fast, but they simply are not.
e.g. my folder has a lower max rated rear tyre than the front.
Whilst the rear is run a bit lower than its maximum the front
is run nowhere near its maximum, 20% lower than the rear.
(Small wheels are run harder than bigger wheels, for the
same tyre width, i.e. less tyre drop, to improve rolling.)
47mm tyres, 45 psi rear and 35 psi approximately
e.g. My road bike has a 30mm rear and a 32mm front.
The rear is run nowhere near maximum and the front
is about 20% lower (normally about 10% for most) but
the front is fatter and therefore needs less pressure.
Again the front is rated higher than the back tyre,
and I typically run it a way below the maximum,
around 50 psi whilst the maximum is 85 psi.
(Rear is about 65psi.)
rgds, sreten.
Schwalbe ? They tend to go higher than the above link, see page 30 :
http://www.schwalbe.co.uk/_webedit/uploaded-files/All Files/Technical Info.pdf
Fact is optimum pressure depends on the quality of the roads you ride on,
the worse the roads on average, the better you are with lower pressures.
Last edited:
I like Skol
A Minging Manc...
- Location
- Sunny Ashton-under-Lyne
I do refer to the Max pressure when inflating tyres. Not so much for my bikes as I know what I run them at (and some of them are set OVER the recommended max!) but with a family fleet of bikes with varuious tyres I can't possibly remember all the possible combinations and it isn't unusual to find kids tyres especially with really low max pressures in the region of 35-40psi
There fore, for someone with less experience or less technical knowledge, I think consulting the max recommended pressure is a good starting point before attaching the pump!
Dusty Bin
Guest
Sorry, that doesn't make any sense. The max rating of the tyre gives you absolutely no indication of what an individual's ideal road pressure should be. How could it?
