The real reason that clincher PSIs top out at 120 is...
 

...companies are afraid of rim failure:eek: (according to an ebay bike store mgr).
Is this true?

Looking for a clincher that can go up to 130-140 psi, if this is possible...

Any tire rated for 120psi will do 130-140. The problem is with the rim sidewall.

Yes, many lightweight boutique wheels cannot handle 140 psi. However, I've never heard that as a excuse for limiting tire ratings. For example, the popular Vred TriComp is rated for 145 psi: http://www.biketiresdirect.com/produ...il.asp?p=VR4FO

Unless you are riding on a polished wood track, I do not see any reason for using 145 psi.

Only a matter of time before someone posts a photo of a double-clyde in response to that assertion.

I've got the cheapest Vittoria Zaffiros (700x25C) on my commuter. They're rated for 130 psi.

My dad runs 130psi with ksyriums, 5k miles and no problems, I usually stick with 110-120 with my ksyriums though

Vredestein Fortezza Tricomps, rated to 175, I wouldn't ride'm at that though. Campy rims are only rated to 145.

Why?

+1

My reynolds dv carbon clincher rims go up to 160psi. :eek:

I usually ride at 120 psi. Why go higher?

+2

I float around 200lbs. and usually leave mine at 100psi. I never go past 120.

Because it is there.

I ride my Zipp 404 tubular wheels with Conti Sprinters @ 160lbs all the time.

That's total BS from the 'expert' manager at your LBS! Find another shop!!!
Run Maxxis Courchevels on Topolino wheels @ 130 lbs.

Bontragers carbon clinchers are rated to 120psi. High end Mavics say not to go higher than 138psi.

Different rims are rated for different PSI levels. But, assuming a 140 PSI tire is the perfect width for a given rim, it probably is going to stay mounted without problems.

However, who NEEDS a PSI over 120 pounds? The best PSI level for a tire is the one that yields 15% deflection of the sidewalls under the rider's weight. With the 23mm tires popular with guys who pretend to race bikes, 15% deflection can be obtained at 70 PSI for light riders, and 90 PSI for average riders. A rider over 180 pounds might need to go as high as 120 PSI to get 15% deflection.

That depends on how the tires are constructed. Some of them are so soft and supple that 140 psi feels like 110.

Color me skeptical that 2mm of "supple" rubber is going to make a "140 psi tire feel like 110".

- Mark

It's not the 2mm, it's how they're constructed. Replace 2mm of "supple" rubber with 2mm of 90 A shore rubber and 110psi's gonna feel like 140.

Yes, at 15% deflection, some tires feel more supple than others. Continental tires tend to feel less supple than most until you get to about 20% deflection. Vittoria makes some tires that feel supple at 10
% deflection.

But, at 140 PSI, NO tire feels "supple", unless you weigh over 250 pounds, because the sidewalls have ZERO deflection...they are functioning as blocks of wood under the weight of a 160 pound rider.

If a 160 pound guy rides at 140 PSI, any tire is gonna feel like riding on wooden tires. If a tire is over-inflated and has ZERO deflection of the side walls, it feels absolutely identical to every other tire that has ZERO deflection...it feels like every bump is going directly to your hands and to your rear.

To get a tire's best shock absorption and feel, the sidewalls must sag (slightly) and flex under the rider's weight and in reaction to pavement conditions. For very light riders (110 pounds or 120 pounds) it can be necessary to ride at 70 PSI or 75 PSI to get the amount of sidewall flexing that a 180 pound rider obtains at 120 PSI.

An interesting experiment for 180 pound guys who ride at 120 PSI is to ride for a week with the front tires at 95 PSI and the back tires at 100 PSI. The first day, they think "my tires feel heavy...my bike feels slow". After a week at 100 PSI, they go back to 120 PSI. Then they think "Who tore up the concrete on these streets...I'm getting beaten to death out here".

Hell I have a pair of michelin PR3's right now on a spare wheelset being "stretched out" @ 130psi and I can easily deflect the sidewall by pinching on it with my fingers. I've had 145 psi on my reynolds wheels and vittorias and I've been able to see the sidewalls bulge at the contact points as I ride. I don't need a caliper to tell me that they deflect... but I have a pair of calipers that measure down to 0.0005", a very accurate pressure gage, and I'm north of 150. Are you willing to put money on that?

Ata boy.

My neuvation r28 wheels seem to hold 125-130 psi fine. The wheelset that came stock on my langster(alex r500) went BOOM anywhere past 120 with the same tires and tubes. It's definately the rims.

In most cases, going higher than 100 psi will increase your rolling resistance
-Of course that depends on the riders weight, but unlike the steel drum and 30kg
load during 'rolling resistance testing', where actually a steel wheel would preform
good, we can benefit from a little deflection.

A wider tire (same preassure) would decrease rolling resistance even more