45mm Continental tire on 42mm max recommended? S-WORKS Turbo Creo SL EVO

You can start by measuring the width of the tire you have (in several places) with a caliper then the tightest clearance between the tire and the frame (probably at the chainstays) using hex (Allen) wrenches.  For every extra mm of tire width the clearance will decrease 1/2 mm.  The tire could also be close to the seat tube, if so measure that clearance with hex wrenches.

 

BRR measures tires mounted on a 18 mm (inside) rim.  If your rims are wider then the mounted tires will be wider by about 40% of the difference in rim width.  For example, a tire which measures 43 mm on a 18 mm rim should measure about 46 mm on a 25 mm rim.

 

BRR measured the height of the Terra Speed TR 45 at 40.3 mm, that won't vary significantly with rim width.

 

Then decide how much clearance you need.  My personal minimum is 4 mm but my wheels are strong and true.  If you expect to ride in mud you'll need more than that.

If your Roval rims are the EVO and measure 30 mm inside then the Terra Speed TR 45 might measure 48 mm or more on them.  Also FWIW a 38 mm tire on a 30 mm rim is outside the ETRTO spec and if it has significant tread it might not work as intended.

Hi. I have my very special s-works turbo creo sl evo bike which I want to upgrade tires for. Official recommendation is limited to 42mm tires but I would really like to go with Continental terra speed TR 45 as they have great numbers according to BRR. So the question -- can I go that bigger? BRR says those Continental tires measure at 43.1mm so am I fine? Otherwise I would go with a second best option challenge gateway 40mm tire.
I really want to go Continental because I mostly ride very rocky gravel + forests so I would like to have as wide tire as possible (also it measures well).