I use the Vise IT.

Yes, I have an IT in my spare ball as well. I don't change it back and forth with my strike ball though. The one in my spare ball is more of a "spare" in case I need one and am away from home. It doesn't get lost, misplaced or messed up in anyway and I k ow the fit is perfect if it's needed.

I have all my balls including my spare ball the same and I use the one out of my strike ball in my spare ball so I have the same fit. I use Grip Loc system the only difference in price when I drill a new ball is $7.00 extra for the outer , as compared to a thumb slug.The whole idea is to have the same fit from ball to ball on any given day.I used to tape all four of the balls in my bag up each day so I had the same fit if I needed to change balls now now I just move the thumb from ball to ball. Same fit every time.   

Yes I have it in my spare ball. Why wouldn't you? Don't you want the same fit and feel when shooting at spares?

This is the whole idea behind interchangable thumb systems and spares are just as important as strikes. More important on tough conditions.

Yes I have it in my spare ball. Why wouldn't you? Don't you want the same fit and feel when shooting at spares?

This is the whole idea behind interchangable thumb systems and spares are just as important as strikes. More important on tough conditions.

Agreed.

Switch grip in strike balls, normal slug in spare.  Because I keep a looser feel in the strike shot and need a tighter fit to be able to break my wrist back without squeezing on a spare ball

Another thing you could do is to use a second interchangable thumb and make it slightly bigger or smaller if that's what you prefer for spare shots. That way if your thumb changes size due to weather or other circumstances you'd have another option ready and waiting to attack whatever situation arises.

Thanks for all the responses guys. I'm just coming back after being off about 7 months due to surgery, I've dropped my ball weight and went to the IT system. Don't have a spare ball drilled in the new weight yet (still just practicing timing), still not sure if I'm going with or without in that ball. I've thought a lot about it and all your responses had valid reasoning with them. Thanks again to all....

Another thing you could do is to use a second interchangable thumb and make it slightly bigger or smaller if that's what you prefer for spare shots. That way if your thumb changes size due to weather or other circumstances you'd have another option ready and waiting to attack whatever situation arises.

Quote from: 300 dan on January 30, 2013, 09:23:12 PM

Thanks for all the responses guys. I'm just coming back after being off about 7 months due to surgery, I've dropped my ball weight and went to the IT system. Don't have a spare ball drilled in the new weight yet (still just practicing timing), still not sure if I'm going with or without in that ball. I've thought a lot about it and all your responses had valid reasoning with them. Thanks again to all....

I have 3 Switchgrips with me at all times. Normal, smaller, and a slightly bigger and oval milled thumb. I rarely have to mess with tape and almost never have a bad feel in the ball.

Definitely the way to go in my opinion. And damn the cost....fit is the most important thing to bowling better. Instead of buying the next latest greatest ball (that is probably just a parts ball from the previous latest greatest ball) go have your best 6-8 balls professionally fitted and converted to interchangable thumbs. You will thank me later.