I am looking to run 2.8 or if possible 3.0 inch wide tires on my 2019 stumpjumper 27.5. Any recommendations on rims/rim width and tires, or if I am fine to stick with the rim it currently has, which is stock with 2.6 inch wide tires.
You didn’t mention which model stumpjumper you have; the basic model has 29mm inner width rims. That could be on the narrow side for some wider tires. All tires are different in regards to the actual measured width vs stated width. You would have to find out what brand and model of tire you want to run and see if you can find someone who’s measured it. Mounting a wide tire on a narrow rim will generally make it balloon more, which makes it measure wider then if it were mounted on a wider rim. You could run into clearance problems on the frame and fork and it might just be something you have to try before knowing if it will work.
It is a 2019 Specialized Stumpjumper Alloy comp with 150mm front and back suspension. I talked with specialized and they say it can run 2.8 in wide tires. Though their site says it can run 3.0 in so I am not sure.
I’m assuming that your bike has i30mm (i=inner width) rims which can reasonably mount up any tire from 2.3-3.0in wide. An i30 rim makes an excellent mount for 2.8 tires. Rims in the i30-35 range can span from Narrow to Plus tires, 2.3-3.0. Obviously, i30 rims will perform a little better on Narrow tires while i35 rims will perform a little better on Plus tires. If I had to pick only one rim and tire width, I would pick an i32 rim with a 2.8 tire which I think is the ideal traibike wheel. The i32/2.8 rim/tire provides all the advantages of a Plus wheel while still being reasonably light-weight and is also able to use a wide range of other tire widths if you so desired.
It is a 2019 Specialized Stumpjumper Alloy comp with 150mm front and back suspension. I talked with specialized and they say it can run 2.8 in wide tires. Though their site says it can run 3.0 in so I am not sure
So what you need to do is measure the tires you have with a caliper (a cheap plastic vernier is more then fine) and measure how much room you have left at the tightest points on your frame and fork. Then find the tires you want and see if someone has posted up measurements of those (keeping in mind the rim width will affect tire width). Then roll the dice and see if it works out.