I’m in the process of building up a hardtail for ultra distance, multi day races and it seems that in the blurb for just about every component I look at, they claim it’s ‘lightweight’. It’s becoming white noise to me now.
I have no specific target for weight in mind but if I was pushed, I’d say 22lb for a medium frame, 100m front suspension, 20 geared mountain bike would meet my definition of lightweight (and remaining realistically affordable).
Is that reasonable?

Yep.

I’d say so, it’ll be light and reliable at that I’d imagine.

My 19″ framed carbon HT is 10kg / 22lbs with XT 1×11, Crests and Easton Carbon finishing kit.

Depends on what you consider realistically affordable, I think it will take a fair budget to hit that weight

Fairly. Mine fits most of that description, and just a tiny bit over 20 lbs, i’d probably add another lb for something fashionable (29er for instance). Probably on the upper limit of realistically affordable. But there are places i could have saved a good chunk of cash and only take a small hit on weight. I mean, i could save over 200 quid (RRP) on bars/stem/seatpin/saddle and only make it ~150 or so grams heavier. (i didn’t pay RRP, i’m not stupid)

Have had it down to a bit under 19. But wouldn’t fancy multiday or marathons on it. (Mostly done by lighter tyres, wheels, saddle and so on, ok for 2 hours but no fun for much longer. And it gave no performance advantage.)

Total spend is about £3.2k RRP I paid about £2k.

22lbs’d be light- maybe not sprinty XC race diminishing returns superlight but you’ll want reliability, probably full gears, maybe tougher tyres… I’m a weightweenie when I let it but with 29er wheels and sensible kit I’d not mind going up a couple of lbs from there, for the job.

I would say 22lbs is light for all your requirements.
I have 2 bikes that are like this type of build.
I also shopped around for parts a lot.
First:
Haibike 29er carbon, full xt/xtr, carbon wheels, cranks, bar, seatpost. 22lbs cost me £850.
Next:
Ktm Myroon 650b carbon, crests, Lauf Fork (so 60mm travel), XT/XTR, carbon cranks, bar, seatpost.
18lbs £1100.
Both run 1 by 10 with oval rings.
Both very comfy rides.

I’ve got my bike stripped right down just now, rear brake off, rear disc off, lever off, big chain ring off, and front derailer and lever off, and some really light slicks on it. probably brings the bike down to about 24/25lbs (It’s 27.2lbs usually).

Plenty light.

So 22lbs, is extremely light if you ask me!

22lbs (10kg)sounds about right.

My rigid single-speed is just over 8kg and has very reliable components (XT, Thomson, Hope etc,.) and adding a sus fork +800g and mech, shifter and cassette +800g?? would take it to around 10kg.

And that is with a heavyish Ti frame (1600g)

I assume those aren’t new prices?

It’s definitely light for a 29er with “multi day reliability”, what is sensible budget will depend on your definitions!

When I stuck a second bottle cage, tougher tyres etc on to do the SDW I suspect mine went to about 20.5lbs, but that’s full XX1, 1300g wheels, 130g seatpost type territory, albeit on a chunky (real) 1300g frame. Devil’s in the detail, you don’t need to spend the earth, but worth choosing some bits carefully.

I got my simple Rockhopper down to 23lb and that was running 3×9. Running relative light but standard kit without breaking the bank and using parts handed down from other bikes. Carbon bars were the only luxury. To get any lighter would involve a lot more expense or going 1×9.

10kg is a good target IMO. My merida 96 is just over but that’s a full susser 26″. My Orbea that I’d happily race multiday is 23.4lb with dropper post and DT carbon wheels , full sus too but was ££££. ^njee makes a good point “devil is in the detail”.

Absolutely, and it’s probably where you’ll have to make some choices between ultimate reliability and lightweight.

Saddle/seatpost is a good example. I’ve got a 160g saddle and a 130g seatpost. I do happen to find the saddle (Bontrager Evoke XXX Lite) supremely comfy, but many wouldn’t, but the seatpost has an 80kg weight limit on it with barely enough insertion in the frame – would I want something a bit more rugged if I were putting luggage on and riding the Tour Divide? Almost certainly yes!

Conversely it’d be very easy to think “Thomson’s light, and I like this saddle” and it’ll come to 500g more. But that’s possibly worth having if it doesn’t cripple you!

My lightweight HT is a sniff under 20lbs. That’s a 26er, 100m forks and 3×9. Apart from the frame there’s very little carbon involved. Just bars & brake levers IIRC.

If anyone wants to say that lightweight bikes are pointless compared to the weight of the rider – try riding a properly lightweight bike. Granted you might not like it, but it does make a big difference to the feel.

I agree with njee, I had an ultra light carbon saddle that killed my ar**, so opted for a charge.
Most parts I buy are second hand apart from chains and cassettes.
Cycling doesn’t have to be expensive.
Sometimes light weight bikes are not the fastest.

worth making a spreadhseet.
Look at real weights (not just listed weights).
£/g is worth noting but it’s also easy to chase this and not lose big chunks of weight.

Tyres and wheels make the biggest difference to a bike feeling light IME.