Is it possible to upgrade Specialized Tarmac Pro SL3 with the new SRAM Force AXS group set?
I'm guessing a Tarmac Pro SL3 is a slightly older bike, Google search suggest a 2011 model. There's a Specialized web site page but it does not give a model year.
Rim brake versions are offered. Front derailleur comes in braze on and clamp on. Etap is wireless so there are zero cable routing issues. The AXS groups use SRAM DUB bottom brackets which have wide frame compatibility.
The problem comes with the rear hub I think. The bike referenced above is 10 speed so I'm guessing it has a 130mm rear spacing and a 10 speed Hyperglide type freehub body. AXS is 12 speed and uses a XDR cassette driver body. From SRAM's page on XD and XDR 'XDR maintains the same hub spacing and flange locations used for 11-speed road compatible HyperGlide freehub bodies'. I'm fairly sure a wheel with a 10 speed Hyperglide freehub body will not be XDR compatible.