Shudder after takeoff

[Strappe]

About the time our 2015 RV-12 leaves the ground on take off I feel a distinct shudder. I think that pressing on the brakes stops it, but not instantly, which makes me wonder if it just goes away spontaneously. At the time of this year's annual condition inspection, I replaced the brake rotors, pads and installed new tires (but not new tubes). The tires had significant asymmetric wear, and rather than just switch them R to L (which requires un-mounting the tires), I put on new tires.

On takeoff for the post-inspection and maintenance test flight, the shudder was still there. I'm wondering if the next step is to balance the wheels/tires?

[Piper J3]

Might be nose wheel out of balance. Stick-on lead weights fit nicely inside wheel hub.

[mflander4]

If the brakes don’t stop it I would assume nose wheel also. Balancing would be the fix. I’ve researched a bunch and can’t remember what thread but I’m certain I’ve read about a nosewheel shimmy on the 12 a couple times...

Reason for my post though is to ask if the asymmetric wear on the tires is considered normal or should something be adjusted for that?

[Piper J3]

Originally Posted by mflander4

Reason for my post though is to ask if the asymmetric wear on the tires is considered normal or should something be adjusted for that?

Perfectly normal. Outside edges wear because unloaded gear will change camber angle and as airplane touches down for landing the outside edge of tire makes contact with the runway first.

[Strappe]

Thanks all. Nose wheel is a good bet.

[dwmillsap]

Tap your brakes when it shudders. If it stops, then it's your mains that are out of balance. You can even tap one side or the other to find out exactly which wheel is misbehaving.

[mturnerb]

I had the same problem on my RV-12. Balanced nosewheel, fixed the issue. I ordered a motorcycle wheel balancer - worked perfectly.

[RFSchaller]

Like Turner said. Once I balanced my nosewheel my shudder went away. I got over 500 hrs on my first set of tires and wear was pretty even which really surprised me given the way the plane sits on its gear.