I went 1×10 for just over £100.

KMC 10sp chain, Deore XT cassette, SLX Shifter/clutch mech, and Raceface N/W ring.

…do you really need 40t?

Well assuming you already have a 10spd shifter, 2 of these things are unnecessary. You don’t need a cassette expander just because its trendy. Dont need a NW ring, guide rings are pretty good, or buy the SS one. Don’t have to buy a new rear mech but it does help!

Personally I think you are just pricing yourself out it before you consider the simplicity of it and it looks neater/removes a cable. No other reasons in my opinion.

You lose half a pound plus of weight, and your chain doesn’t come off.

Mech and chain wore out, was already 1×9 so a shifter and cassette were the only expenses on top of what I was going to have to pay.

Wait till you need to do a fresh drivetrain.

don’t bother with the expander, but the real bonus is the simplicity

Don’t buy it all brand new, I’m doing a fresh build for myself and have decided on 1×10 and the only new parts I bought were the N/W and the chain, total spend with Zee shifter and XT block and clutch mech was £100

Doesn’t have to cost that much! I justified it to myself when my 9speed cassette and chain wore out.

£30 – XT shifter. £35 – SLX mech, £25 – on-one chainring. Used some CRC codes too. Also you are left with a pair of 9 speed mechs and shifters which could be worth £30ish depending on spec and condition.

So after all that you are looking at an excess spend of more like £50.

Simplicity, weight saving and less clutter for a dropper remote

Sometimes I do wish I had a 40t but if its too steep I just push now, which turns out to be faster than my mates on their granny rings anyway.

I do love not having to worry about the front mech, chain slipping off and chain suck.

Because it is the latest in thing to do. Next yr it will be 3×7 cos u get better weight distribution, its cheaper, simler, more reliable, ligrhter… Blar blar blar

Is 1×10 (or 1×11) really just this year’s fashion? There have been threads on here about it for two or three years at least.

I’ve a 1×10 setup, 30T on the front and 11-40 on the back. I’ll spend 95%+ of my time in a gear that isn’t one of those two extremes but having them is useful though by the time I engage the 40T I’m close to getting off and pushing. This is for Lakes riding so you do have the range with 1×10 even with steep stuff on your rides. By the time I’m engaging the 11T I’m going at a speed where I might as well be freewheeling so that’s just about right.

To the OP:

Simplicity – even with a dropper seatpost control there’s very little clutter on the handlebars.
Lots of chainring clearance

Downsides – you do think “Why have I got a dinner plate strapped to my rear wheel?”!
Explaining to everyone that you’ll be just fine on the uphills. 🙂