I ended up changing them to tubes with 700c x 32 for winter riding (I'm in UK)...Do you think it will make life easier, i.e. get more miles in per day for the same time if I swap to 700c x 28's ?
In a word..."No".
In my experience, the wider tires will have you ending each day less fatigued because the larger volume tires can be run at reduced pressure for greater comfort. In any case, I don't think they will hold you back.
I use the Android Berto Tire Pressure app to adjust my tire pressures for load and riding position (the app extends the work of the late US petroleum engineer and bike magazine technical editor Frank Berto. In numerous interviews with bicycle tire engineers, he found the "sweet spot" between rolling resistance and comfort came from tire pressures that allowed a 15% drop in rim height under load). It works well for my needs and has indeed resulted in a measured 15% rim drop for me under stated loads. For comparison, here are some figures for identical loads and on-bike position for 25mm vs 28mm vs 32mm tires (by actual measured mounted width):
25mm: F: 84psi R: 105psi
28mm: F: 70psi R: 87psi
32mm: F: 58psi R: 71psi
Wrt to reduced vibration helping with increased comfort and endurance, I fitted my two primary randonneur bikes with Thudbuster ST suspension seatposts and found myself ending my 300-400km day rides feeling more refreshed. Completion times were about the same for similar conditions, but I
felt better After -- less achey and fatigued -- especially if the roads were rough/chip-sealed or included gravel.
For reference, I'm nearly at my 61st birthday. Impressions from a 321km ride in January 2020 as almost no riding after 1 February due to Covid and restrictions for same. Still haven't recovered my pre-Covid breathing capacity and have ongoing symptoms.
Best,
Dan.
