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Inflating tires below the recommended minimum PSI pressure

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  • February 13, 2015 at 6:06 pm #23266
    Charles-Antoine

    Hello,

    Last fall I purchased a pair of Specialized Armadillo 700x25mm tires. Their PSI range is 110 to 125. Really good tires, works great of paved road and packed dirt roads.

    But since their minimum PSI is 110, it shakes way too much when riding on a loose gravel road section. Of course I slow down considerably when riding in loose gravel/dirt, but even when riding slowly the ride is still way too shaky.

    Now, what if I inflate them below 110 PSI? Something like 95 at the front and 100 at the rear.

    Is that dangerous? Can they wear down in a way that they will get fragile or unstable?

    Thanks.

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  • February 16, 2015 at 11:01 am #832213
    0
    Izaak30

    Thanks folks
    Thanks folks

    February 15, 2015 at 10:46 pm #832211
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    Charles-Antoine

    Thanks everybody, really
    Thanks everybody, really appreciate it!

    February 15, 2015 at 6:18 pm #832209
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    glynr36

    Simon E wrote:Izaak30

    Simon E wrote:
    Izaak30 wrote:
    Sorry I’m a bit thick and its early this morning so struggling to do the sums. Please help.
    I’m 80kg and ride 25c tyres. What pressures should I be looking at? Thanks

    I’d try 90 psi front, 100 psi rear. If it feels a bit soft add 10 psi.

    It’s not rocket science, even though some people like to make it seem complicated.

    This! People really over complicate it.
    Just give it some trial and error and you’ll soon settle on what works well with how you like the bike to feel

    February 15, 2015 at 5:54 pm #832207
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    Simon E

    Izaak30 wrote:Sorry I’m a bit

    Izaak30 wrote:
    Sorry I’m a bit thick and its early this morning so struggling to do the sums. Please help.
    I’m 80kg and ride 25c tyres. What pressures should I be looking at? Thanks

    I’d try 90 psi front, 100 psi rear. If it feels a bit soft add 10 psi.

    It’s not rocket science, even though some people like to make it seem complicated.

    February 15, 2015 at 11:38 am #832205
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    TheHound

    Izaak30 wrote:Sorry I’m a bit

    Izaak30 wrote:
    Sorry I’m a bit thick and its early this morning so struggling to do the sums. Please help.
    I’m 80kg and ride 25c tyres. What pressures should I be looking at? Thanks

    It’s personal preference depending on what you’re comfortable with and the type of roads you’re on.

    Start off with about 100 psi in each and then take it from there. Add a bit, take a bit. See how it feels to you.

    Just make sure you’re not exceeding the maximum pressure.

    February 15, 2015 at 11:08 am #832203
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    Izaak30

    Sorry I’m a bit thick and its
    Sorry I’m a bit thick and its early this morning so struggling to do the sums. Please help.
    I’m 80kg and ride 25c tyres. What pressures should I be looking at? Thanks

    February 15, 2015 at 11:03 am #832201
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    fukawitribe

    TheHound wrote:I’m using

    TheHound wrote:
    I’m using Vittoria Open CG Paves 27c at the moment.

    The stated range on them is 110 – 130psi.

    I think it’s just the manufacturer playing it safe. I’ve no problems running 90/rear and 85/front.

    Spectacular tyres by the way if anyone is looking for a qualility winter tyre.

    Agree with that, been using the 25s for some months now and at nearly the same pressures and they’ve been superb.

    February 15, 2015 at 10:19 am #832199
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    TheHound

    I’m using Vittoria Open CG
    I’m using Vittoria Open CG Paves 27c at the moment.

    The stated range on them is 110 – 130psi.

    I think it’s just the manufacturer playing it safe. I’ve no problems running 90/rear and 85/front.

    Spectacular tyres by the way if anyone is looking for a qualility winter tyre.

    February 15, 2015 at 12:42 am #832197
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    sergius

    Fairly unscientific, but I
    Fairly unscientific, but I pump front/rear to 90 PSI every couple of weeks, I’ve not had a puncture in the last 18 months since I started riding again. I’m fairly light at ~63kg so that may be a factor – my old boss used to flat every couple of weeks and he was a fair bit larger than me.

    February 14, 2015 at 11:29 pm #832195
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    Charles-Antoine

    185 lbs / 84 kgs
    185 lbs / 84 kgs

    February 14, 2015 at 6:44 pm #832193
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    slam that stem

    It’s not about bulging its
    It’s not about bulging its about bottoming out and you can only feel this by riding on them. Try 85 psi one ride then 80 the next until they feel too sluggish or you bottom out on them.

    How much do you weigh?

    February 14, 2015 at 6:07 pm #832191
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    chokofingrz

    I inflate my tyres according
    I inflate my tyres according to the 15% drop principle – the pdf linked above. For my low weight and 25c tyres that’s about 90psi rear and 60psi front. Shocked? Yes it’s less than the stated range, but the ride is just dandy. No punctures.

    February 13, 2015 at 10:54 pm #832189
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    bikecellar

    http://www.bikequarterly.com/
    http://www.bikequarterly.com/images/TireDrop.pdf
    check this out

    February 13, 2015 at 10:21 pm #832187
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    Simon E

    110-125 psi seems a very
    110-125 psi seems a very narrow range. My 25mm Durano (and Vittoria Rubino Pro before them) work well for me at 60-80 psi, I don’t know what the sidewall says.

    I would try a short test ride at 85 front & 95 rear, see how it feels. The main risk at low pressures is probably pinch punctures.

    February 13, 2015 at 9:30 pm #832185
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    matthewn5

    I run 700 x 23 Specialized
    I run 700 x 23 Specialized All Condition Armadillo Elites on my winter bike. As its dirty and cold I often go a fortnight without pumping them up. They are sometimes at 60psi by the time I get to them. Never had the slightest problem, even with energetic cycling and hard cornering on much less than ideal surfaces. If you really do push it hard on an off camber corner just for fun they start to give way very gently leaving plenty of time to correct. Try 80 front 90 rear and relax.

    If you want to do the pressures by the book, look at this, you’ll be surprised how low the optimum pressure is on 25c tyres:

    Science and Bicycles 1: Tires and Pressure

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