F1 engineering double speak translation please

[nostatic]

“The outer clamp surface of the wheel was given a clear lacquer coating,” explained a statement from McLaren. “As a consequence of this fault, the clamp load that attached the wheel was not to specification. In running, the consequent loss of load caused the wheel to fret and distort, leading to its eventual failure.”

does that mean, "too much armor-all on the tires"?

[Jim Richards]

think of it like a paint build up on your lug holes (at the mating surface with the lug nuts) and you can't get the proper torque on the lugs. It's better to maintain that mating surface as raw metal to ensure you get the proper torque.

And in case this isn't clear enough, Todd...if you paint or laquer that surface, coyotes will jump out in front of you.

[Moses]

Probably. But I'll bet they were jet fokkin' black.

[Jim Richards]

Moses, that would then imply that they were toit!

[nostatic]

fokkin' A!

lacquer coyote. check.

[Tim Hancock]

I have an aircraft engine I am building up that had "thrown" a cylinder due to something similar.... a previous mechanic had sloppily put sealant around the cylinder base studs which squished onto the mating surface of the cylinder base and the crankcase. Over time, this allowed a very slight flexing condition which led to fretting, which led to fatigue of the studs, which led to the cylinder leaving the engine in flight, which led to a forced landing in a field in New York state.

[Zeke]

This would seem to be what happened to Danica's car in the last race in Kansas. However, I don't buy this completely because even though they have those air guns at the precise pressure to give the correct torque value, I have to believe that there are variances from wheel to wheel and pit stop to pit stop.

Duplicate the failure several times and I'll eat my words.

[island911]

What they are saying is the springyness in the stack-up was eff'ed up by the paint. It is not clear, in the description but I'll guess that this was due to an unexpectedly high friction on the paint surface (torque of nut stops short of providing needed clamping pressure)

[John Rogers]

If they had paint on the wheel in the wheel nut area, center lock type of wheel attachment of course, I'll bet the paint melted and the wet paint acted like lube and the nut over tightened causing a distortion of the wheel center area. That's why I never ever use center lock wheels on my 2L vintage class 914!

[BertBeagle]

My guess is the paint sandwiched between the nut and wheel (acting like a shim or gasket) gave up the fight when things got hot, creating clearance where none existed when the paint was good, and the result was a loose nut (wheel).

Did the wheel come off in this case? They have safety devices in the nuts to prevent that. Could be something else went wrong.

Probably not to well known but a Pelican Parts neighbor (in the same neighborhood) http://www.metalore.com/ makes most of the wheel nuts and sockets used in F1 (or did the last we spoke which was a few years ago). If still in the business, he would know what happened.