Cobbling together a 1x gravel drivetrain

Spa cycles would be my starting point to look for bits.

Easily as long as you buy from China.

Eg. https://www.aliexpress.com/item/1005003466730236.html &
https://www.aliexpress.com/item/1005005780941464.html &
https://www.aliexpress.com/item/1005003103122796.html

If you want mainstream then judging from the price of bikes it's spec'd on Sram Apex 1x11 should be available OEM for about £300-£400

Nearly.

https://sportandleisure.com/collections/groupsets

Without shopping around (or checking stock levels) you can get Adventx brifters, mech and cassette for about £225.
https://www.sjscycles.co.uk/search/?term=microshift
That leave 175 for brakes, cables, chain, etc. Should be able to get Avid BB5 in that budget, maybe BB7 if you get deals on other parts.

Or if you can raise another £80 you can have a whole bike.

https://www.ultimateoutdoors.com/16245370/calibre-lost-lad-gravel-bike-16245370/3751138

@midlifecrashes that's 2*8 

@slowol all out of stock

10 speed does seem to be in short supply.
9 speed all available at Kids Racing:
https://kidsracing.co.uk/
Bikeinn seem to have stock as do Bike24 if ordering from Europe is an option.
Good luck with the build.

I haven’t done the exact maths . But if you happy swapping to longer hoses you might get shifters and brakes for £200.

https://www.wiggle.com/p/shimano-grx400-1x10-speed-hydraulic-disc-brake?color=black&partLength=850mm&position=Right+%7C+Front+%7C+850mm&utm_source=google&utm_term=&utm_campaign=WGL_UK_GGL_PMX_SMA_MAN_CYC_ALL_NA_NA_NA_TIER0_NA_NA_Endgame_Newstructure&utm_medium=base&gad_source=1&gclid=CjwKCAiA04arBhAkEiwAuNOsIi4SZE-ETZYnojcxqY6A_YZUeM1rARLsOpy1pEMIKgStKojmgH0yGBoCbGoQAvD_BwE&gclsrc=aw.ds

https://www.wiggle.com/p/shimano-grx400-1x10-speed-hydraulic-disc-brake?color=black&partLength=1500mm+&position=Left+%7C+Rear+%7C+1500mm&utm_source=google&utm_term=&utm_campaign=WGL_UK_GGL_PMX_SMA_MAN_CYC_ALL_NA_NA_NA_TIER0_NA_NA_Endgame_Newstructure&utm_medium=base&gad_source=1&gclid=CjwKCAiA04arBhAkEiwAuNOsIu3z2Mriav-rXUVjTLtVW8-T5JlCgrqqyhi7EPmQxosS9hq3wOiAXBoC_ZIQAvD_BwE&gclsrc=aw.ds

I just paid £35 for the derailleur. So that leaves loads for the block and chain

Been looking at something similar myself.

I think you could get close to that price with Deore 1x11 and a Microshift bar end shifter, TRP Spyre calipers with Tektro levers and whatever rotors are available for a good price.

Ribble are doing 10 speed tiagra 4700 levers/brakes for £90 each.

So you could do

Tiagra brakes (Ribble) £180

Grx 600 chainset (eBay) £80

Grx 400 mech (chainreaction) £37

Deore 10 speed 11-40 cassette £50ish

Which takes you to just under £350, which levers enough for a chain.

You could get wider range by using a 11 speed MTB mech, but then you'd need a wolftooth tanpan to adjust the cable pull

Use a cheaper MTB crank with a large ring to get the cost of that down. I used a set of RF turbines I had as CRC were selling the 42t cinch ring for about £15.
Or this 1x11 lot for £264
Microshift sb-m110 which use a Shimano MTB mech. £110
https://www.ebay.co.uk/itm/165992150461
Deore mech £34 Merlin
microSHIFT XLE 11 H113 11 Speed MTB Cassette £24 CRC
Chain £10ish
Clarks CMD-22 calipers (they do cheaper ones but these are the dual mechanical piston version). £50
Shimano CUES FC-U4000 CUES chainset; for 9/10/11-speed; 170 mm; 40T, Bikeparts.co.uk £36

Slackboys option could be made cheaper with the £19 11-46 deore cassette from CRC and the cues crank above, maybe even cheap enough to swap tiagra fro grx400 brifters.

Ribble are doing 10 speed tiagra 4700 levers/brakes for £90 each.

wiggle are doing brakes and shifters at that price (grx 400)

I’ll admit not budgeting for a chainset. Spa cycles square taper? Or a low end shimano MTB one. Like a triple and take 2 rings off

I've got a pair of 1x11 Shimano GRX RX600 disc brake STI's & RX400 flat mount calipers I'm about to sell.  I would be looking for about £200 but open to sensible offers.

They've only done one 50 mile ride before I remembered how much I hate drop bars and converted the GT Grade to a nice  carbon flat bar.

I've got SRAM CX1x11 mech and shifters you could have got a lot less than £400. Good as new.

Merlin do a full 2x10 GRX 400/600 groupset for £440 but I don't think that there's a 1x10 option in GRX. Both Merlin and Wiggle do some good deals on GRX components though but I'm not sure how much a 1x11 grx would cost you.

I complete bike might not be a bad idea. Wiggle have some silly deals on Vitus gravel bikes. This one is £599 (additional 10% off with OUTLET10) with a 1x9 groupset, there are probably other. It would be a bit of a risk with the market as it is, as to whether you could claw back a couple of hundred quid selling the frame, forks, wheels etc., but it might be worth thinking about.

Vitus Substance VR-FB Gravel Bike | Wiggle

Get in quick OP

https://www.ribblecycles.co.uk/shimano-rs505-sti-hydraulic-disc-brake-set-w-rs785-calipers/

That's 2x11 and postmount.

Ugh, didn't even check the detail.  <br /><br />

2X isn't an issue, you just don't cable (I use Ultegra with GRX) but didn't  notice the callipers.

However some one on hear has post mounts and was looking to upgrade to hydraulic brakes 🙂

It will mean 2 new 11 speed cassette’s. But that’s fine as one is really worn

I have microshift 1x11 using Gevenalle cable cantis. They also convert TRP Spires, and as stated, go bar end instead. Shifting is just fine. Rear derailleur was £25. It’s
currently set up with road tyres and a 38T SRAM Red carbon crankset with 11-28 cassette. Reasonable range for road and cross duties. But hard up some hills and you’ll be coasting down others, but a decent range.

Apex 1 groupset that’s been ridden once round the block before being swapped out any use to you?

Cable brakes with Spyre flat mount.

Do you mean just drivetrain or full groupset, including calipers?

If you need the lot, I'd say get secondhand GRX400 or Tiagra brifters & calipers, then add:

GRX812 mech
Deore 11-42t cassette
10sp chain of your choice

Or get the items linked by Ampthill above, then add the other bits.

The 812 mech works great with 10sp Tiagra and GRX400.

Tonnes of adapters for using Post mount brakes on Flat mount frames and forks. Just one example: https://www.merlincycles.com/trp-flat-mount-to-post-disc-brake-adaptor-89957.html?utm_source=PHG&source=PHG&utm_medium=Affiliates&utm_campaign=genieshopping

And again, ignore 1x specific just don't cable up the LH brifter. That should all open up more options.

L-Twoo GR 7 1x 10 on AliExpress for £167.

Hydraulic disc brakes levers and rear mech.

I'd snap up those Microshift 11 speed MTB drop levers above at that price. Link. I got some a year ago rather than e.g. Advent X bits because I wanted cross compatibility with the drivetrains I run on the MTB and commuter. I like being able to easily swap stuff about. FWIW their brake cable pull works well with the BB7 road calipers that Spa are knocking out for £59 (incl rotor and post mount adapter); much prefer them to Spyres.

That might work as I've got a few 11 speed rear mechs slx and deore kicking around

Just need a cassette then and a suitable crank

Second hand crank with 104bcd symmetric spacing - fill your boots with <£10 NW chainrings off eBay that'll work with any chainline with a handful of spacer washers.