"Ken M" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M. -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
Well normally being a bit over won't hurt anything. Especially in the winter when it is cold outside. But if you have the stamped steel rims, the tire's bead may pop loose at higher pressures than normal causing the bead to come off the rim. These steel rims don't have a sharp defined edge for the tire's bead to lock into good. A sharp rock damaging the tire's cord or plies could lead to a delayed blowout of the tube when you least expect it. Same for sharp edges like uneven road slabs or sidewalk slabs that might damage the internal plies of the tire. In this case a sharp rock doesn't punture all the way through to the tube, but falls short. later the tube's pressure causes the tube to blow out as it isn't supported over the damaged spot on the tire. A tire at lower pressures has more give to it so it suffers less or little damage from the sharp rock. On a hot summer day with hot pavement, the tire's pressure could skyrocket causing a blowout. Really high pressures like 140psi or 160psi or so, could cause the rim's braking surface sides to blow off the wheel, pretty spectacular to experience if you survive the heart attack. Basically the rim's sides get worn down from useage, you put on a new high pressure tire and pump that sucker up to 160psi because the tire's max rating says you can. Boom goes the rim side on you suddenly, because it is too weak now. In track bike racing, they might pump up tubulars to something fantastic like 200psi. But at these pressures the slightest damage to the tire's plies cord could blow them out, sometimes they've blown out just bumping another wheel just waiting for the race start.
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M. -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Since there are other critical variables - rider weight, rim width, etc. - that can have a profound effect on whether a given tire will fail (and how) at a given pressure, I think you'd need a lab, a huge budget, and an infinite number of monkeys to figure this out.
But I bet that there is a very large safety factor built into all these psi ratings, mandated by lawyers. I doubt that a few percent matters.
i blew out an expensive Nokian Extreme 294 studded tire by over inflating, i think. I ran it around 100~110 psi (rated a lot lower), rode 15 miles daily; afer about three months of this, the sidewall seperated from the bead.:-( :-( :-( Thankfully, it happened at the office and not in the arctic bufu.
Painful lesson, cost of tuition: $100.
I now recommend paying attention to the figures on the side of the tire.
"Ken M" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M. -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
I don't think the accuracy of one pump to another would be better than 5 lbs. So I can't imagine that it's a problem. Although, if I were to want much more I'd get something rated for what I want.
What we keep reading about lately are the advantages to slightly under-inflating road bike tires (100 rear, 90 front for most tires). Stated benefits: You get more contact with road, softer ride, better cornering...
What advantages are you after by over-inflating? What's the allure?
-- M Powell
"Ken M" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M. -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
My 26x1.5" IRC Metros are rated to max pressure: 40 psi. I've been pumping 'em up to 60 since I got them (about a year ago) with no ill effects. And that's on several thousand kilometers and some bunny-hopping on a heavily-rigged bike.
Anyways, I notice whenever folks here suggest a list of accessories to tyro or returning-to-the-avocation riders, cycloputers get lots of recommendation. But nobody ever suggests a hand-held pressure gauge.
cheers, Tom
-- -- Nothing is safe from me. Above address is just a spam midden. I'm really at: tkeats [curlicue] vcn [point] bc [point] ca
What we keep reading about lately are the advantages to slightly under-inflating road bike tires (100 rear, 90 front for most tires). Stated benefits: You get more contact with road, softer ride, better cornering...
What advantages are you after by over-inflating? What's the allure?
Well I have read that the rolling resistance is less for a tire with a high air pressure than the same tire with a lower pressure. Lower rr means less energy needed to maintain a set speed. Unless the laws of physics have changed.
Ken -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
My 26x1.5" IRC Metros are rated to max pressure: 40 psi. I've been pumping 'em up to 60 since I got them (about a year ago) with no ill effects. And that's on several thousand kilometers and some bunny-hopping on a heavily-rigged bike.
WOW that seems a bit higher than I might go in my road tires. I was thinking about 10 to 15%.
Quoted message said:
Anyways, I notice whenever folks here suggest a list of accessories to tyro or returning-to-the-avocation riders, cycloputers get lots of recommendation. But nobody ever suggests a hand-held pressure gauge.
I have a nice digital gauge, in addition to the built in gauge on the pump.
Ken -- When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells
I'm a subscriber to RoadBikeRider.com, and also subscribe to their thought that rolling resistance is only one factor, and probably not a very telling one, in tire pressure. Here's a quote: "overinflation causes only bad things on the road -- tread cuts, fast wear, chattering in corners, jack-hammer shocks from road irregularities. As we've often stated, even inflating to the recommended max is usually a mistake. For most riders on typical 700x23C tires, a front pressure of 90-95 psi and a rear around 100 psi will maximize tire life, bike handling and comfort. The only reason to go higher is if the road is so bad or your weight is so high that these moderate pressures allow pinch flats."
Ken M <[email hidden]> wrote in news:FKCdneII3JLcWTveRVn- [email hidden]:
Quoted message said:
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M.
Let me add my voice to the probable chorus of "watch-outs:"
I can't tell you how many tires I blew by overinflating. I'm the kind of guy that viscerally can't stand to look down and see the slightest bit of pudge in a tire. That's both because of aesthetics and rolling resistance, in that order. But finally i learned to accept the reality when a blow-out lost an irreplaceable tire from a rare bicycle.
On Mon, 19 Dec 2005 15:40:39 -0800, [email hidden]
(Tom Keats) said:
In article <[email hidden]>,
Ken M said:
I have a nice digital gauge, in addition to the built in gauge on the pump.
I don't trust gauges that come built-in with pumps. And I figure it's generally good to get a "2nd opinion".
My tire gauge is an old Dunlop No.17. It measures 50 to 140 psi. in ten pound increments. At 70 psi it still correlates with the gauge on my much newer Beto pump.
I usually check tires before riding by putting my weight on the handle bar or saddle and noting the sidewall deflection. With butyl tubes, they need topping-up about once per week. -- zk
I can't tell you how many tires I blew by overinflating. I'm the kind of guy that viscerally can't stand to look down and see the slightest bit of pudge in a tire.
If the tyre isn't squashing, you might as well be riding on solid rubber.
I know that it is not recommended to over inflate your tire, but I have had the tires on my bike inflated up to around 90psi, they are rated for 85psi. So I was wondering is there a "safe" limit to how much you can over inflate tires, or is it more or less a per tire type of thing. Meaning one brand / model of tire may be able to with stand a higher pressure than a different brand / model, even if they are both "rated" for the same maximum pressure.
Ken "pump them till they pop" M.
I had tire problems on a long tour. We were using Continential Top Touring 2000 tires, which have a bit of a reputation for sidewall problems (which I _thought_ had been fixed). Anyway, we had at least two tires get bad bubbles in the sidewalls, and I figured it may have been because I accidentally overinflated.
Michael Warner <[email hidden]> wrote in news:[email hidden]:
Quoted message said:
Andy Gee said:
I can't tell you how many tires I blew by overinflating. I'm the kind of guy that viscerally can't stand to look down and see the slightest bit of pudge in a tire.
If the tyre isn't squashing, you might as well be riding on solid rubber.
Is that a bad thing, if you get the rolling resistance of a solid torus for the weight of one that's hollow?
I notice that a guy that weighs about 150 - 160 lbs, on a light bike with high-pressure tires, bent all the way forward, doesn't squish. I'm 175 with a formerly lightweight bike, usually bent forward, and I pudge out a little bit, but I've learned to accept it.
Anyways, I notice whenever folks here suggest a list of accessories to tyro or returning-to-the-avocation riders, cycloputers get lots of recommendation. But nobody ever suggests a hand-held pressure gauge.
My Silca floor pump gauge is so good, I hardly ever use my hand-held!
(Or at least I guess it is. I've never seen the benefit in comparing one calibration-unknown reading to the reading from another calibration-unknown instrument.)
