So I've never hit trackman outside, but tend to think GC products would be better inside than trackman. I've also never hit on a GC4.I watched a video yesterday where a GC Quad was compared with the Trackman. And the path numbers were about 4 degrees different between units. Some extreme shots off the heel or toe were up to 6 or 7 degrees difference.
But he said he trusted the Quads numbers from what he was feeling in his swing. And toe shots, and heel strikes on the trackman caused all sorts of wild path numbers.
Of course having such big discrepancies in club data between the two best launch monitors isn't a good thing. As you start to wonder if you can trust the data.
But I think I trust the BLP path numbers tbh. I played around on a trackman last weekend, and with driver I was hitting it on the heel some, and I got similar results that he got, heel shots were reading extreme out to in numbers. When I'm generally in to out on the BLP. Granted I was hitting like crap that day.
One positive I guess is pretty much all the other data was the same between the two.
That being said, I experience what you are referring to more on my BLP than Trackman. Trackman, might spit out a weird number from time to time, but I'm almost aware of the type of deliveries and/or the types of mishits that I know are going to give me bad readings. In general, people don't change their path by 5-7 degrees from shot to shot unless they are trying to deliberately work the ball.
I'm wondering if you got the spin numbers w/ driver the same on the two. GC's have supposedly had trouble once you get the spin down near the 2k's. I personally saw it once in a lesson where I wasn't trusting my BLP and brought it to a lesson with an indoor trackman. i got readings at some times 1,500 rpm difference. (BLP reading 900 and trackman reading 2,400)