I've never owned a nice road bike. Im 57 and in my younger days--prior to 40--I was mainly a distance runner everything from 5k to marathon. I did some biking, but never bought a nice bike. I did bike Lands End to John O'Groats in 1992 on an old steel frame bike that was way to big for me, but I was young and strong and didn't think anything of it.
In August of this year I bought the best, and most expensive, bike I've ever owned--a 2017 Trek 520 touring bike. I'm training on it and have put a little over 1,000 miles on it since September. I'm starting to really enjoy riding. I've lost 20 pounds since September and am beginning to feel fit again. I want to make this a lifestyle change and continue biking for a long time. I bought the Trek with the plan of doing the TransAmerica next year and am still on track to do that barring some major life event that keeps me from it.
I ride mostly along, but have done a few rides with a biking group and there are a lot of other bike riders on the trail where I ride. On my normal rides of 20 to 35 miles, I generally average between 13.5 to 14.5 mph. I know it's better to measure power or effort, but I'm more of an mph kind of guy.
Now to the point of my post and question. I seem to notice that when I ride with others, whether in a group or just passing them (or them passing me) on my rides, the other riders who are on carbon fiber road bikes--and most other riders I encounter are on road bikes--I seem to be working harder on my touring bike than some of them are on their road bikes. Now I know some are a lot fitter than I am and I'm not talking about those individuals. But some people who I think I am just as fit/strong as they are, or maybe even fitter/stronger, some of them (a lot of them) seem to have an easier time maintaining 15mph on their road bikes than I do on my 520.
So, I guess my question is, would I see a noticeable difference in the level of effort it takes to ride at a given speed, say 15 mph, on a carbon fiber road bike vs doing that on my Trek 520 steel frame touring bike? For example, in Oct I did a 20 mile ride with members of the local bike club and we averaged about 17 mph. I was on my Trek and was worn out when I finished. If I was on a carbon fiber road bike instead of the 520, would I have been able to do that same ride with noticeably less effort? I am thinking about investing in a relatively nice road bike--something in the price range of a Trek Domane SL6, but honestly, if riding it wouldn't be noticeably different than riding my 520, then there isn't much point. Regardless I'm keeping my 520 for touring and will be using it on the TA ride, but would be nice to have a "faster" bike for when I do more organized training rides with the bike club. I do know I can get faster and ride at a given mph with less effort by getting fitter and stronger--and I plan to keep building my fitness and strength. But, all else being equal, if a nice carbon fiber road bike would help I am up for the investment.
Thanks in advance for any advice.