If I put weight tubes in my 28",55/75 Gold Tip Carbon Arrows will I also be increasing the spine of the arrows?  If so, anyone know by how much?
Thanks!

michigan bill

The spine will increase only slightly. Anytime the arrow is heavier, it will shoot slower. A slower arrow will in effect cause it to shoot stiffer.

I added 3gr/inch weight tubes to my Carbon Express 250's recently. I could not see any difference bare shaft shooting the weighted and un-weighted shafts. Though they added 87 grains to my arrows, out to 25 yds my groups are very consistent with the un-weighted shafts.

Hope this helps, I had the same question and decided to experiment to see what happened. I have decided to add weight tubes to all my shafts.

Brian

I added the 3 gr/" tubes to my Carbon Express Terminator Lite arrows.  I got my arrows up to 10 gr/" and out to 20 yards haven't noticed any difference in the performance of the arrows.  They fly like darts.

Bill

I know I was wondering if the weight tube being pressed up against the carbon wall would essentially act as thickening the arrow wall and thus increasing spine. My tubes fit snug but I see no change in the spine. I have heard of problems when they are glued in, I'm assuming full length. Then I bet it is affecting spine.

I added 3gr. tubes to my Beman ICS. I saw no change in spine. Arrows shoot great, gave me a extra 82gr and at 30 yards, very little difference b/w weighted and nonweighted shafts.
I do have the problem of blowing the nocks off, when I hit something hard (rock, far shoulder on a deer, hard stumps). The weight tube will actually come out the back of the shaft.  I now make sure to carry extra nocks with me.

I added weight tubes to carbon express Heritage 350 arrows and they flew terrible out of my Zipper. Tried to shoot them for 3 months with no luck. Putting HEAVY broadheads up front helped some...

Good luck

Thanks, everyone.
I appreciate your help.

Bill