ED & other dual Gates belts users ( including myself ) at our last chapter fly-in two gyro planes came in & the owner/designer/builder was telling Greg & I about a company that makes heavy-duty  "matched "  v-belts for his gyro drive sys., point is they are matched, one of our belts is stretching differently than the other ( one is loose other is tight ). Greg is going to purchase a couple of belts for our 13B stock 70A  Mazda Alt. with under-drive dual v-belt sys., will let you know as soon as we know.  David R. Cook  RV6A  Rotary  last rivets now installed ( Data plt. ) slapped in the face by the economy so moving very slow.

Uncle Sam buys thousands of matched belt sets each month for big Diesel trucks. They are replaced as sets, and are quite pricey. Belts small enough for this application might also be pricey. Matched sets usually come from the same drum. Belts are molded on a form or tube and cut apart when completed.

So belts from side by side on the drum are more likely a matched set.  Just buying two of the same part number might get you belts manufactured hours, or months apart. Gates and Good Year make most of the Government belts.

 

I use Gates on the racer. Never lost one. I have one Gates to run the water pump with no idler. Perfect fit.

 

Lynn E. Hanover