Weight Kits

Check with a Titleist fitter. I can’t find the online custom catalog to see if the part number(s) changed.

No, TSR and GT have different weight design/systems so none of the models weight will carry over to GTs. All new weights.

With the GT3 track being towards the face, is increasing the weight likely to decrease spin and forgiveness as less weight placed further back (less MOI etc)?

GT weights are different, and unfortunately, retailers don’t want to bother with ordering them for customers. For generations of drivers, I’ve been told “They’re not available” or “They’re out of stock”.
Maybe one day Titleist management will learn, and will make them available through Titleist.com.

I ordered a driver weight through Golf Galaxy

I have a weight kit at work and can order any weights, most big box places probably don’t want to deal with ordering them as they are not a high ticket item and can easily get lost in the receiving area, I have no idea if that is a reason, just guessing.

Should be able to order the kit, which would be your best bet if you are one to tinker with your driver. The sku is GTWEIGHTKIT. If you belong to a golf club and they have an account with Titleist they can order it for you. If you already have the wrench, it will work. I order it thru a local golf shop who I get my Titleist gear/clubs thru. In that you can order clubs on line, check with customer service below at their 800 number and see if it is possible to order thru them. They can only say no.

I asked about getting some weights when I ordered my GT driver / fairway, and was told then that they didn't have any available for sale. Mind you, that was at the beginning of July when they were just rolling the GT lineup out, things have probably changed since that point...

The GT are new weight kits and do not work with TSR.

You can order through your local Titleist retailer.