Originally Posted by bikebikebike

I have several sensors mounting with Orings and they break over time. When going to a Hardware store I am seeing a lot of variability in oring elasticity/stretch, which is a big deal in sensor mounting.
Does anyone have a resource for targeting stretchy orings , rather than the thicker Buna rubber ones more directed towards sealing?
I really need robust rubber bands, not seals. more a bike mount band kit
Either a discussion of this or a source . Onesies and twosies are more expensive and hard to reproduce results.

Most of mine came with sensors from China and OEM is not a good source.

Sources state:
"To provide an effective seal, the O-ring's inside diameter (I.D.) must be smaller than the piston groove diameter, so that the O-ring is slightly stretched, fitting snugly in the groove.
This stretch should be between 1%-5% with 2% as the ideal in most applications. A stretch greater than 5% is not recommended."
"With the O-ring calculator, engineers can specify the groove dimensions for a specific O-ring or a specific groove.
The O-ring calculator calculates the most relevant size O-ring for any given groove and includes O-ring inner diameter stretch and the desired Polymer Group or Seal Hardness. ."
Examples: Garmin Bike mount band kit (replacement) 6 for $15.77,CatEye CA5447010 Rapid X Spare Bands- 2 for 8.95,Ascher Bike Silicone Mount Band, Cycling Bicycle Rubber Straps, Pack of 4 $6.99
All seeming less than ideal