Anyone switched for fatter winter tyres? Switching from 28mm to 35mm tyres?

I've got a whyte glencoe. Really nice bike and a great commuter. Has 650b wheels with 47mm tyres. Nice and comfortable and grippy but draggy as hell above around 18mph.

Recently tried normal 700c wheels with 28mm tyres...added an extra 2mph or so for similar or less effort.

For cruising speeds wider is better, if your pushing it a bit then it's bloody hard work. What made me switch was taking the fat tyres on a club run...

On a previous cx bike I found similar (though smaller speed difference) when going from 35mm to 28mm, though part of that may be the actual tyres involved. So for me, wider is harder work when trying to push it, else not much in it.

I’ve only recently got my winter/adventure bike out of the shed. It has 35mm Schwalbe G One Allrounds on it and feels fast enough that I still feel quick on the road, but I’ve been having a lot of fun pointing it at muddy paths, through the woods, through massive puddles on farm roads and across fields. There are lanes that I’d happily take a bike with narrow tyres on in summer that the bad weather has completely transformed, with new cracks opening up and washes of muck and gravel across them, and the 35mm tyres just give me more confidence and mean I spend less time worrying about my line. I was worried they’d feel slow, especially as the bike is much heavier than my “summer” bike, but I’m having a great time, so for anyone in two minds, yes go for it!

I have 40 mm G Ones, which I prefer to any other tyre I have on other wheelset.  They're fast over most terrain.  The only downside is that after a fast club run >19 mph you know there is a little extra drag, whether aero or rolling resistance, this is when I start to tire.  I have done 100 mile sportives over 17 mph with the 40mm G's

I'd have thought it more likely that the smoother ride (at lower pressure?) is allowing you to maintain power delivery more smoothly with less accommodating tiring road buzz/bumps. And a wider tyre's rolling resistance is often better - check out www.bicyclerollingresistance.com

There was an article by someone comparing a superlight Cannondale and his old steel tourer a few years back - he found the same result as you (but I can't find the article).

It probably depends on the nature of your routes too - all other things being equal (which they aren't!) the lighter tyres probably accelerate faster and feel faster when you're looking for a response but the fatter heavier ones may roll better when up to speed and you don't really sense the differences.

A bit like weight-v-aero gains - we feel the former more viscerally (like when trying to drop someone with a vicious acceleration on a climb) but the latter is more significant objectively.

I find that bigger tyres run at a lower pressure are quicker on everything except smooth tarmac. currently running 700x32 but been as big as 650x48 without materially affecting my average speed around the lanes. they're much more comfortable too.