Just leave what you have on the bike already. There’s very few bits that you could ride with lower gearing. It’s ridable then it’s walking very quickly !! Not much in between.

The first two bits you can’t ride up. The only one where it makes a difference is Pen y ghent. Try and get as close as you can to 1:1. Even then if you’ve been riding and running at your limit for a few hours then you’ll find there are sections you need to walk. That and if it rains it is slippy.

Last time I did it I used 34:32 which was the lowest I could get on my CX. Rode most of the last climb and got round in 3h42.

I’ve got a triple on my CX which gives me 26 at the front x32 at the rear. Unfashionable but suits me for the 3 Peaks.

It depends on your fitness. Have you ridden before/got a time ?

I guess if you’re able to get a 1×11 setup, you’ll be able to go as low as you want, although you’ll sacrifice higher gears for the road sections, which might then outweigh the advantage of having low gears. Having said that, the podium riders were all on 1x11s so I guess it didn’t bother them. My CX is my only ‘road’ bike so I would be missing certain gears if training with a 1×11, hence I prefer my ‘old’ double 10spd groupset. Incidentally, in case you’re wondering why a few of us have 34 x 32, and not lower, it’s because road derailleurs generally don’t support anything bigger than a 32, hence we’re ‘stuck’ with road cassettes such as 12-32.

As jonba said, it’s Pen Y Ghent that matters. The surface is all rideable right up to about 100 mtrs before the big right-hander where you turn onto the shoulder of the hill. By this latter part of the trail, it’s so steep that twiddling a low gear isn’t quicker than running. But if you’ve managed to pedal all the way before that without putting a foot down, you’ll have saved time compared to running.

My bike has a 34 x 32 lowest gear. Last year I struggled to do Pen Y Ghent. But this year I was fitter (25 minutes faster), and 34 x 32 was just about OK for a 4 hour ride. I’d have preferred a lower gear on certain bits, but it wouldn’t have made me go much quicker (we’re talking seconds, not minutes). And besides, I’m aiming to do a faster time again next year, and if I fit a lower 1st gear, it won’t necessarily mean I’ll do a faster time, only that I won’t be grinding so much on the steeper sections. In other words, my guess is that the riders doing 3:45 or less are probably riding a 1st gear ratio similar to 34 x 32 – certainly no lower than 1:1. Of course, if you’re aiming for something like 4 and a half hours, which is still very impressive, you might be better off with something less than 1:1, and focus on pedalling as much as possible – unless you’re a fell runner !

I’m not sure if this makes much sense, but hope it helps 🙂

22/32/44 with 11 /34 cassette on the 3 peaks for me it helps me ride most of PYG if I don`t cramp first

Never done 3 peaks but I can confirm a short cage 105 mech will do 11-36. I found chain length critical, one link too many or too few and it didn’t work, took me alot of fettling before I figured that out. I run mine with a 38t ring