Originally Posted by
georges1
700-23c and 700-25c are comfy and some older rims width are not allowing wider tires than 700-23c, I don't like large tires on a road bike 700-28c or 700-32c, 700-25c is the maximum I can accept, also the rear and front tire clearance should be taken in consideration when buying tires and when having a not so new frame. If I want to gravel I have 700-35c schwalbe marathons on my hybrid. The comfort is also due to the saddle you have chosen to ride, the wheels and tires as well as what is the bartape stem and bar combination you have chosen to ride with. I used to ride in my very first road bike on 700-19c and 700-20c tires before switching to 700-23c and some tires are larger than their indicated sizes. Not everyone is into disc brakes , di2, 11 speeds, 12 speeds and large tires.
The rims will generally allow a wider tire, they aren't so picky up a point. It is usually the frames on vintage bikes and older aero bikes that are the problem with wider tires. Going from 19s a 23 is a wider tire but it is 2024 wider tires have been a thing for a while and really have always been a thing but old "knowledge" though that a super narrow skinny tire has got to be faster because you feel the speed (speed in that case being bumps and vibrations that are slowing you down) because aero at that point was lets make it thin and narrow to cut through the wind because they thought that was practical and a lot more testing has been done to find that is all hooey.
Yes there is comfort in other things but I think in terms of real ride comfort tires probably have the biggest impact to the point I would rather have an aluminum bike (which I wouldn't really want) with 700x32c tires than a steel bike (which I would want) with 700x23c tires. I used to be part of the old school club of it's gotta be faster we can feel it and then I went wider and haven't really looked back much I have a vintage race bike that can clear only 25c tires it can fit 28s but it is a super tight fit and caused some rubbing and I don't want to damage the paint. I love the look of vintage bikes and some of them do have proper tire clearance and some are just fun to look at and work on but just putting on some bar tape and a saddle can only do so much with skinny tires. Certainly yes a more supple tire will help as well but it won't be as good as a wider supple tire.
In terms of Di2 or anything else not relevant here. You can have a 2x5 bike with wider tires and be more comfortable on it. In terms of disc brakes there are fewer and fewer draw backs as time goes on. I do have plenty of rim braked bikes and will continue to have them for a while so it is not a treatise against them but they are great for wider tires and other issues.