I have a slow swing speed, maybe 80mph
I have a x-hot 13.5 senior flex driver.
I hit it very straight but not very long.
I was thinking of getting a 48 inch shaft for more length.
Is this a good Idea? Whats a good brand?
48" shaft? That sounds like Cobra's Long Tom driver - four feet long and only 269 grams, according to the promo ads.
Long Toms started out at $435 each... more recently, the clearance price is $39.
There's a reason no big-names followed LT to do 48" shafts. The super-super long shafts cause control problems for most golfers.
I'm 62 years old, and play an R-flex 60-gram Aldila RIP.D VD high-launch shaft (stock) in my RazrFit driver. My prior driver was a HyperX Tour R-flex with 68 gram mid-launch shaft. The RIP's extra lift and slightly less weight has helped my driving consistency.
Two things you might do to improve distance: Get some launch monitor data on the shaft you use. If you are launching too high or too low, this will cost you distance. Also, get a ball fitting. There's a lot of variety out there, and switching balls often can deliver 10+ yards per shot.
Also, if you have a pro, you might have him check out your setup - you might have something in there that's costing you clubhead speed and distance. (I know - I got cured last summer).