RV-7A tire wear (toe in) Gear Mount error
I first flew my RV7A in August 2010. It was soon painfully obvious there was something wrong with either the main tires or with the alignment.
I contacted Vans in December 2010. It was suggested that I raise and level the airplane to measure the toe-in, which should be about zero to ? degrees. The measured toe-in was about 3 degrees inward on both left and right main gears. I sent to Vans and received many emails from Vans that "investigated" the legs and mounts for manufacturing accuracies, as well as re-measuring the toe-in another time.
By October 2011, after about 23 emails back and forth, I received an email that basically said, "Toe in may be too much; however, the measured tire wear is something you can live with." In the meantime I also acquired Desser Monster retread tires (great tires), since the Vans kit tires are not quite average for wear and durability. I also spoke with the gear leg manufacturer (Harmon) and learned the legs are drilled by Vans, not the leg manufacturer.
Then in February 2013, I heard about a gear leg issue that was resolved by Vans. That RV-7A also had about a 3 degree toe-in. I received the contact information for Ken at Vans. I called and he transferred me to Sterling, also at Vans, who had created a rather well done test tool that allowed for a simple check of toe-in.
That tool took less than 30 minutes to mount, activate, and evaluate the gear leg mounts in my 7A. The tool showed my legs both had excessive toe-in. Once Sterling heard my test tool results, he shipped out two purposely drilled (new) gear legs. The drilling was to account for the error in placement angle on the gear mounts when they were drilled at Vans (in about 2007). The gear mounts had been created for an RV7A but the 1/4" alignment / pilot holes were drilled for an RV9A ? thus the 3 degrees difference leading to excessive toe-in. Virtually impossible to detect during aircraft assembly. Also, why would one check toe-in during assembly, since these were pilot holes?
I guess it just took Vans a long time to realize their error. They went from "We haven't seen that before" to "Here is a test tool that will determine if the problem is with an improperly drilled pilot hole at Vans". In 2011, part of their assumption was that I must have done something wrong. My guess is there are a few more RV7As with too much toe-in and excessive tire wear.
Bottom line, if there is an issue you should stick with it and stay in touch with the Vans user groups. Two Vans Air Force users got me there once Vans owned up the issue (unbeknownst to me otherwise). The plane now taxis easily using rudder (not brakes) and is pretty easy on tires.
Took awhile; but, all is well now.
Francis
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