I think its probably better to measure things with tube/tire of choice mounted, and then measure again with the combo aired up. I mean what you be more realistic than that. all these rim and tire makers can suck d1ck imo, they have absolutely not goddamn clue whatsoever wtf theyre talking about.
Originally Posted by NYrr496
I'd say max allowable tension measured at your operating tire/tube pressure, obviously with the tires and tubes mounted. but hey wtf do i know?
I retensioned and retrued my old wheel by pumping them up to 3.0 bar and then do all the tensioning. and now 5 years after that they are still true. gho figure.
Rule #9 // If you are out riding in bad weather, it means you are a badass
Originally Posted by iheartbicycles
I have found an enlightening web page dedicated to the bicycle wheel and wheel building where they touch on this issue. It seems to concur with the theory of rim deformation along the spoke bed.
Rims, especially aluminum, are built to be rigid. Loaded with 20 to 32 tensioned spokes, they become an amazingly firm, almost brittle structure. But to look closely, rims elastically deform in dramatic ways.
When spokes are attached, a huge compressional force is applied to the rim hoop. It can be 600lbs, measured at a rim joint. Due to the small mass and density of the rim, the hoop actually becomes temporarily smaller. Clincher tire pressure pushes rim beads outward. You can use calipers across the brake track to see those surfaces change. With pressure, parallel brake tracks become angled more than one degree.
Inflation pressure spreads the rim at the brake which affects the rim ďbellyĒ below. For many rims, the change to the belly is enough to increase spoke length and change tension over 20%. Deflate the tire and brake track springs back and spoke tension rises.
With riding, all these elastic deformations combine to define wheel behavior. Itís not just the tire thatís in constant elastic motion. A structure as light as a standard bicycle wheel is a complex, dynamic structure. No wonder there are so many opinions and observations about the zillion combinations of components, spoke tension, tire pressure, and riding.
The more I learn about wheels, the more secrets are revealed. I discovered the elastic properties of spokes while studying them at Wheelsmith in the 1980ís. Now itís clear that all wheel components have elastic properties that affect their neighbors and wheel performance. This elasticity is substantial and you should bear its contribution in mind whenever designing, building, or riding these magnificent structures."
Elasticity - Wheel Fanatyk
I dont know if the article had been mentioned or cited here before.
Tire Pressure and Spoke Tension
We're lucky to have both Hjertberg brothers' contributions to the cycling community.
Originally Posted by abelfonseca