Where the hell is that weight coming from?

[Slowman]

I just weighed my carbon gravel bike and it's 10.11kg and yet my carbon hard tail 29er (Spec Stumpy) is 10.24kg and that's with a RS Reba 100mm suspension fork, that's just 120g more. Please help me this an existential crisis for my gravel bike

I figure some of it is because of things like spares and water bottle (which are in the camel back for the MTB). As well things like center lock rotors seem to be heavier. The only way to get real lightweight rotors is to use standard ones with a 6 bolt to center lock adapter.

 

[teK--]

common areas usually sight unseen are the cassette, hubs, and rims that can add up to several hundred grams difference.

also are you running tubeless in one but not the other?

plus yeah, pull off all the accessories so you are comparing apples with apples

 

[Freediver]

If you're weighing it with a full water bottle, that would be your answer.

 

[caad9]

Gravel bikes are becoming very similar to a hardtail MTB in purpose and are built accordingly.

Wheels and cassette will be the lowest hanging fruit

 

[Calvin27]

You really need to list specs to figure this out.

Accessories add a lot of weight as well. Tube kit and bottle is easily half a kilo. Do you have a FD and double?

Other main big ticket items are:
- Cranks
- Saddle
- Drop bars /tape grip stem combo (much easier to get ligther in mtb than road/gravel imo)
- 1x shifter plus brakes is lighter than the full sti setup

I'd not worry about rotors, there are probably many weight savings you can do before you get to that. Top of the list is put that donut down lol.

FYI my gravel bike is 9.8kg with a not particularly lightweight focused build:
- GRX600 double
- 1800g XC wheels, tubeless and 38c
- Alloy cockpit stuff
- Bolted on top tube bag.
- Titanium which is not very light compared to carbon.

 

[Slowman]

just some interim notes/comparisons:
hard tail v gravel bike
frame: carbon c-works (~1200g) v Flyxii carbon frame (1250g+/-50g) let's say heavier 50g
fork: Rokshox Reba SL 29 (1600g) v Flyxii carbon fork (500g+/-20g) lighter 1100g
shifters: X0 grip shift (246 x 2 = 492g) v STI R7000 (500g) heavier 6g
bars: carbon riser (~175g) v carbon gravel drop bars (305g) heavier 130g
cassette: SRAM PG990 9sp cassette (11-34T) v ZTTO 11-36T 11sp not much in it but say heavier 30g
wheels: Stans ZTR Crest Mk3 29 (~1650g) v Carbon CSC 38x28 (~1650g)
tyres: Schwalbe Racing Ray 29x2.25(625g)/Ralph(630g) v Tufo Speedero 700 x 40c (2 x 445 = 890g) lighter 350g
cranks: Shimano XT 770 175mm 44/32/22 (820g) v GRX FC-820-2 48/31 175mm (721g) lighter 100g
pedals: crank bros candy v candy
extras on the gravel bike:
pump 200g
750ml water bottle full about 750g
extra bidon cage 40g
spares bag with levers 3 x TPU tubes, let's say 200g
looks roughly about right without going down to every bolt that would mean the hard tail weighs 184g more

 

[birddog69]

Gravel bikes are becoming very similar to a hardtail MTB in purpose and are built accordingly.

Wheels and cassette will be the lowest hanging fruit

Agree. My Chameleon with ligher wheels and tires works perfectly.

 

[teK--]

11.8kg for my alloy gravel with suspension forks and dropper post. Dunno what you're whinging about

 

[Calvin27]

Few things to check:
- Do you really have dual grip shifts and not running 1x?
- Frame weights are sometimes based on a smaller size - check this.
- Check actual for weight, 500g is normal but seems on the lighter side.
- 750ml water bottle is more than 750g, more if it's overfilled.
- Rekon casette weight is going to be higher for the ztto one, Never used it but chinese cassettes have been heavy in my experience.
- Bag with tube might be more than 200g i rekon, you got tools and levers in there etc.?
- Pedals? Spd can weight a lot more than a good composite flat pedal.

You need to take all the bits off the bike to get an accurate representation.

 

[Slowman]

Few things to check:
- Do you really have dual grip shifts and not running 1x?
- Frame weights are sometimes based on a smaller size - check this.
- Check actual for weight, 500g is normal but seems on the lighter side.
- 750ml water bottle is more than 750g, more if it's overfilled.
- Rekon casette weight is going to be higher for the ztto one, Never used it but chinese cassettes have been heavy in my experience.
- Bag with tube might be more than 200g i rekon, you got tools and levers in there etc.?
- Pedals? Spd can weight a lot more than a good composite flat pedal.

You need to take all the bits off the bike to get an accurate representation.

Frame weights already determined and I am looking for weight savings on the gravel bike not the hard tail. However, I am a RetroMTBer I still ride 3x 10/11. With 1x the weight you save on shifter and front derailleur you add to the cassette and you still don't have the range.

I changed the centre lock disc rotors to an old favourite; Alligator Aries with a light alloy 6 bolt to CL adaptor. After taking just the water bottle off it's weighing 9.48kg. Next will be the handle bars. The current funky ones(350g) will be swapped for some Chinese 3T Ergonova copies(185g), saving around 150g or more. Around 9.3kg sounds respectable enough for a gravel bike I think.