Strange crunching sensation when pedaling - MTB

[TedMaul]

Kona Blast, 2nd bike about 6 months old so doesn't get much hard use, mainly dossing about with kids

Last week or so there is a really horrid crunching sensation when pedalling, no real noise to speak of but you can really feel it. Doesn't vary much depending on gear selection, worse under heavier load

Feels like someone is emptying gravel on to the cassette as I'm going along. Mech, cassette and chain are clean and lubed, doesn't feel bad pedalling backwards or coasting

Ideas?

[WinstonWolf]

BB?

[TedMaul]

That's all I could really think of as well, hoping something less hassle I guess as I'm very time poor over the next few weeks, don't even have time to drop the bike anywhere and have it done for me. Need to sort out dropper post on other bike too as its lost pressure and bloody nightmare trying to get more in... Guess its about time I bought a 3rd bike as back up to the other two

[scottri]

Drop the chain off the front rings and spin the cranks by hand. If the BB is broken you should feel it. You could also spin each pedal by hand and feel for roughness.

[leyorkie]

Pedals more likely than BB but always a chance to upgrade. XT range is around £12.

[leyorkie]

Pedals more likely than BB but always a chance to upgrade. XT range is around £12.

[Mr Gearchange]

Knees?

[Watchman]

Having just gone through a trial-by-error to counter a load-sensitive noise from my bike, I checked out:

1. pedals
2. BB
3. hubs (both - although it wasn't speed-sensitive, so ruled out the front hub quickly)
4. seat post (well, it seemed to creak when I moved)
5. head set (as above)
6. chain interface with front and rear sprockets, and derailleur
7. cassette - this was the culprit - the lock ring wasn't done up very tightly so the whole lot squirmed as I applied torque)

Good luck.

[ALawson]

Mr Gearchange said:

Knees?

Beat me to it.

[Pablo16v]

ALawson said:

Mr Gearchange said:

Knees?

Beat me to it.

[JodyKTM]

is it mainly at top and bottom of stroke? more on one foot that the other?

If so almost definitely pedals

As above new aren't that expensive but you may need a slim spanner to fit them (might be allen key bolt though)

[TedMaul]

ALawson said:

Mr Gearchange said:

Knees?

Beat me to it.

They click rather than crunch

Thanks for the problem determination tips everyone. The feeling is constant throughout the rotation, the chain is clearing the mechs and the pedals felt smooth. Didn't think to drop the chain and check bb, bloody obvious, thanks

Gut 'feel' makes me think its at the rear of the bike so am liking the idea of loose cassette.

Been thinking about what I could have done to it, its Kona Blast that's seen nothing more than a blue trail with the kids. From memory, the last time it was smooth was before my son used the bike wash on it at Sherwood pines so I wonder if its pushed some crap into the bb or pushed some grease out