Every now and then someone spins their VascuVive wheel, takes their hand off, and notices a small wobble as it coasts down. They reach out asking if their wheel is defective. The short answer: it almost certainly isn’t. The wobble is a side effect of the crank handle, and it disappears the moment the wheel is doing its job.
The Crank Handle Is Offset On Purpose
Look closely at the wheel and you’ll see the crank handle sits off-center. That’s not a mistake — it’s the only way a crank handle can work. To spin the wheel quickly with your fingers (or a drill), the grip point has to be away from the axis of rotation. A handle mounted dead-center wouldn’t crank anything; it would just twist in place.
That offset mass is what creates the wobble you see when the wheel is unloaded and spinning freely. The handle is heavier than the air on the opposite side of the wheel, so the center of mass sits slightly off the rotational axis. Physics does the rest.
Remove the Handle and It’s Perfectly Balanced
Here’s the proof. In this video I take the same wheel, remove the crank handle, and spin it. With the offset mass gone, it spins true:
The wheel itself, the bearings, and the threaded shaft are all balanced. The wobble you see in normal use is the handle, not the wheel.
You Won’t Feel It In Use
This is the part that matters: the wobble is not noticeable when the wheel is pressed against your member. The contact pressure damps out the small offset oscillation completely. The handle is also moving in your fingers (or in the drill chuck) during a session, so the wobble isn’t free to express itself the way it does when the wheel is coasting in mid-air.
If you’ve been using your wheel and it feels smooth in session, your wheel is working exactly as intended.
When It IS a Real Problem
I want to be straight with you: roughly 1 in 100 wheels can slip past QA with a slightly bent threaded screw or a heat-warped plate. When that happens, the wobble is bigger, you can feel it during use, and it’s not the offset-handle effect described above — it’s an actual defect.
If your wheel:
- Wobbles dramatically, not just a small oscillation as it coasts
- Feels rough, grindy, or off-balance during a session
- Has visible play, warping, or a shaft that doesn’t sit straight
…that’s a support issue, and I want to know about it. Contact me here and I’ll get a replacement out to you ASAP. No hassle.
TL;DR
- The crank handle has to be offset from center — that’s how a crank works.
- That offset mass causes a small visible wobble when the wheel coasts unloaded.
- Pressed against the body, the wobble disappears and doesn’t affect the session.
- If your wobble is severe or you feel it in use, reach out and we’ll replace it.
