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Correct tyre pressure

MiniMaltsMiniMalts Posts: 266
edited October 2015 in Road beginners
Fairly new to cycling, in fact, before the beginning of August I hadn't been on a bike in 14 years.

I'm aware the tyre pressure is on the tyre but having read some posts on here it's not necessary to inflate the tyres to the max pressure.

Can anyone advise on what would be the best pressure.

I'm 21 stone, have a Ridgeback Speed (hybrid) bike on standard tyres that I use for mainly road cycling..

Posts

  • You have to define "standard tires": On the side of the tire it will tell you what size they are, and the numbers for a hybrid should be something like 700 x 38c. Assuming that's right, the advice below will apply.

    Doing the math in my head since it's been a while since I've thought in stones, that puts you at 294 lbs? Which means your tires should be inflated towards the upper limit of the tires, perhaps 90 - 95%.

    Cheers
  • Sorry, by standard I meant what came fitted with the bike, which is 42 - 622 (28x1.6) Max 85psi

    I'm about 135kg, and on occasion I might need to carry about 8kg in my panniers.
  • BobbinogsBobbinogs Posts: 4,928

    ...except that calculator doesn't have 40mm as an option. Looking at some touring pages (because, let's face it, a laden total weight of ~350lbs is that kind of territory) I would suggest something like 70PSI F and 80PSI R but the quality of tyres could make a difference (something durable like Schwalbe Marathon Kevlars would be ideal).

    What is the OP running at the moment? Tyre deflection/shape is usually a good indicator.

  • ...except that calculator doesn't have 40mm as an option. Looking at some touring pages (because, let's face it, a laden total weight of ~350lbs is that kind of territory) I would suggest something like 70PSI F and 80PSI R but the quality of tyres could make a difference (something durable like Schwalbe Marathon Kevlars would be ideal).

    What is the OP running at the moment? Tyre deflection/shape is usually a good indicator.


    I'm running the stock tyres that came with the bike - "Continental CONTACT SafetySystem" (that's all I can see on the tyre.)

    With regards to the pressure I'm currently running, who knows thanks to the faulty Lezyne pump I have. The bike had its 30 day service at the beginning of September and I think they inflated the tyres to the max. I don't have a tyre pressure gauge that goes above 60psi to check what was in them.
  • wolfsbane2kwolfsbane2k Posts: 2,965

    Thanks for that link, not seen it before.
    Scarily, it recommends I push my tires to 332 PSI on a 23c tyre for the 15% method :)
    Using the second parts

    Even dropping to a 28c tyre which I've got fitted recommends 140 PSI - I don't think I've seen a single tyre capable of that pressure!

    Makes you wonder how a bike shop can recommend a bike and tyres if these aren't suitable :(
    Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
    Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
  • BobbinogsBobbinogs Posts: 4,928

    Thanks for that link, not seen it before.
    Scarily, it recommends I push my tires to 332 PSI on a 23c tyre for the 15% method :)
    Using the second parts

    Even dropping to a 28c tyre which I've got fitted recommends 140 PSI - I don't think I've seen a single tyre capable of that pressure!

    Makes you wonder how a bike shop can recommend a bike and tyres if these aren't suitable :(

    I am not sure about that 15% drop stuff, tbh, but basically the 40/60 part of the tool is saying that riders need to consider tyre size to get a safe/optimum tyre pressure. There is no point moaning about it or blaming the bike shops (let's face it, they don't weigh anyone who enters and say "this range for you fatboy"). The sort of weights that necessitate large tyres and allow them to be run at reasonable pressures (90PSI for example) are pretty heavy by most standards (325 lbs +) and this, in my opinion, needs a rider to think about a few factors (spoke count, tyre model and size, pressure, etc.). Also, something decent for stopping like disc brakes, perhaps with hydro if funds allow. Spending £60 on a carbon bottle cage should help to balance things out though, like buying a diet coke to go with a Happy Meal :)
  • wolfsbane2kwolfsbane2k Posts: 2,965

    Thanks for that link, not seen it before.
    Scarily, it recommends I push my tires to 332 PSI on a 23c tyre for the 15% method :)
    Using the second parts

    Even dropping to a 28c tyre which I've got fitted recommends 140 PSI - I don't think I've seen a single tyre capable of that pressure!

    Makes you wonder how a bike shop can recommend a bike and tyres if these aren't suitable :(

    I am not sure about that 15% drop stuff, tbh, but basically the 40/60 part of the tool is saying that riders need to consider tyre size to get a safe/optimum tyre pressure. There is no point moaning about it or blaming the bike shops (let's face it, they don't weigh anyone who enters and say "this range for you fatboy"). The sort of weights that necessitate large tyres and allow them to be run at reasonable pressures (90PSI for example) are pretty heavy by most standards (325 lbs +) and this, in my opinion, needs a rider to think about a few factors (spoke count, tyre model and size, pressure, etc.). Also, something decent for stopping like disc brakes, perhaps with hydro if funds allow. Spending £60 on a carbon bottle cage should help to balance things out though, like buying a diet coke to go with a Happy Meal :)

    I would agree with your point, were it not the fact that I went into the shop, said I'm a heavy censored at 300lbs, worried about limits etc, and wanting a commuting road bike - They pointed in the direction of the BTwin 500se, and 28C Tyres. The 28C tyres only "Just" fit, but even then can't support the pressures this link recommends.
    Considering that to get the "full" mudguards I had originally wanted needs more clearance, I was going to drop to 25cs, guess i'll not be doing that now!
    It feels like a "not fit for purpose" type argument.

    Given that, apart from the clearance issue, I've not had a problem with the tyres at 100PSI each.
    Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
    Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
  • apreadingapreading Posts: 4,533

    Thanks for that link, not seen it before.
    Scarily, it recommends I push my tires to 332 PSI on a 23c tyre for the 15% method :)
    Using the second parts

    Even dropping to a 28c tyre which I've got fitted recommends 140 PSI - I don't think I've seen a single tyre capable of that pressure!

    Makes you wonder how a bike shop can recommend a bike and tyres if these aren't suitable :(

    The first part is looking at an individual wheel and asking you to input the 'weight at the wheel'. Just bear in mind that you have two wheels and they each carry only part of your combined weight.

    Far better is the second part where they split the weight for you based on either 40% front 60% rear or 45/55.
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