I’ve decided that I’d like to have a go at TTing but have no clue where to start.
I currently ride a Scott foil in a 54, does TT bike sizing work in the same way? Are there particular models to look out for or avoid? Im probably looking at used so feedback on older models would still be valid.
Thanks in advance
Hi there!
Sizing can vary considerably between manufacturers so I’d always recommend consulting a professional (or a geometry chart for that specific model, if you know your measurements.) My road bike is a 52, but my Canyon TT bike is a 48.
I can’t say any particularly awful models spring to mind, but standard caveats apply- fit comes first, check the wheels are true and there’s no faults in the carbon (might pay to bring a friend if you’re not sure what to look for), and get it checked out by a bike shop after purchase- though preferably the prior owner has done that for you already.
Also the Scott is pretty aero anyway. I’d be tempted to dip a toe in the water by buying a good pair of aero tri / ski bars to fit to the Scott. If you hate you’ll have splashed c£ / $ 100 rather than £ / $ 1000-3000.
And if you buy good bars you’ll be happy to drop them onto your new aero TT bike when you’ve been bitten by the bug, along with the pointy hat, one piece human condom (skinsuit), over socks, deep section rims long aero-socks etc!
Careful it’s a cash blackhole! 
That is the exact route I wouldve gone except I fitted some zipp sl-70 aero bars to it when it was new so unfortunately there’s no spare claiming space 