Tire pressure

General bike chat that does not fit elsewhere
Gabbo
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Tire pressure

Postby Gabbo » Wed Nov 07, 2012 13:20 pm

Set off on a relatively short ride today (about 30 miles) and found it somewhat harder than usual. Was going at a similar speed to usual but my quads were burning and I was breathing a little. I've had a few days off so unsure whether that may have an effect but I've noticed my muscle tone looks to have faded - not sure why either!

Anyway, stopped off at my lbs on way home to find my tire pressure under 40psi. I then proceeded to pump them up to about 115psi and noticed how sensitive everything was. If anything it made the ride incredibly uncomfortable but I suppose this is the recommended pressure for road tires.

What affect could 40psi have on the performance?

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Peat
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Re: Tire pressure

Postby Peat » Wed Nov 07, 2012 13:22 pm

More resistance, but more grip. If you train with tyres at 40, you'll be quick come race day when you pump the tyres up, you just might fall off more.

TakeTurns
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Re: Tire pressure

Postby TakeTurns » Wed Nov 07, 2012 13:28 pm

As you've experienced, you'll go slower at 40psi. However, if you're a light person, you could ride with 100psi without comprimising the speed if you find 115 too uncomfortable. At 40psi, the tyre will wear out a lot quicker and risk folding off the rim while cornering

tiredofwhiners
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Re: Tire pressure

Postby tiredofwhiners » Wed Nov 07, 2012 13:35 pm

......... its tyre.

Tire means to become exhausted ...... just sayin'

night_porter
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Re: Tire pressure

Postby night_porter » Wed Nov 07, 2012 13:47 pm

If you normally pump your tyres up to 115psi and don't notice the problems then I would suspect that your own pump gauge isn't working correctly. When you borrowed the pump from your lbs then the tyres were actually at 115psi instead of what they are normally at, just a thought!

I am not light but I never pump tyres to more than 100psi as I find this is the best compromise between speed and comfort but what suits me may not suit everyone else, just experiment with different pressures until you find the one that suits you.

Beware going too low though as the pinch flats will happen on typical pot holed roads.

keef66
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Re: Tire pressure

Postby keef66 » Wed Nov 07, 2012 15:50 pm

My tyres are typically 60-80 psi, but they are 25's and I'm no Bunter. Above 90 psi and I can feel my fillings loosening over the rough stuff.

It makes me wince when people say they routinely run pressures of 110 psi.

ChrisAOnABike
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Re: Tire pressure

Postby ChrisAOnABike » Wed Nov 07, 2012 15:56 pm

keef66 wrote:It makes me wince when people say they routinely run pressures of 110 psi.

I've been pumping mine up to 115 according to the gauge. Is that too high? The max indicated on the side is 120.

It's a hardish ride, but I quite like the positive feel.
Is the gorilla tired yet?

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zx6man
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Re: Tire pressure

Postby zx6man » Wed Nov 07, 2012 15:59 pm

I would squash my tyres to the rim with 60-80 and then probably damage the rim in the process :-)

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TheFD
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Re: Tire pressure

Postby TheFD » Wed Nov 07, 2012 16:49 pm

tiredofwhiners wrote:......... its tyre.

Tire means to become exhausted ...... just sayin'

So you don't have a 'tyre made from whiners?' :lol:

To the OP - pinch flats will be more prevalent if the psi is 40.
2013 - R872
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Ron Stuart
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Re: Tire pressure

Postby Ron Stuart » Wed Nov 07, 2012 19:23 pm

Peat wrote:More resistance, but more grip. If you train with tyres at 40, you'll be quick come race day when you pump the tyres up, you just might fall off more.


If you descend with hairpin corners at speed on tyres at 40psi that have a recommended pressure between 80 and 120psi for example you are very likely to roll them off the rim and anyway they would handle like a bowl of custard. :twisted:

p7rider
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Re: Tire pressure

Postby p7rider » Wed Nov 07, 2012 19:43 pm

Ron Stuart wrote:
Peat wrote:More resistance, but more grip. If you train with tyres at 40, you'll be quick come race day when you pump the tyres up, you just might fall off more.


If you descend with hairpin corners at speed on tyres at 40psi that have a recommended pressure between 80 and 120psi for example you are very likely to roll them off the rim and anyway they would handle like a bowl of custard. :twisted:

Been there done that got the gravel rash :oops:


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