Give when pedalling

[shouldbeinbed]

Bought a 2nd hand road bike the other week, 105 groupset. First roadie for quite a while and never had 105 before. I've already replaced the rear hanger and derailleur as they were out of whack, it has been shifting fine on the new one albeit on a clearly worn cassette and chain. There was a slight give at the top of each pedal stroke which confirmed this wear to me and told me they were past their useful life.
I've ridden it lightly and in easy gears waiting for payday to change these components out.

*payday* I replaced the cassette and chain last night, had a little check over and tighten up of anything that felt like it needed it and my test ride was spot on, super smooth shifting and a solid feel throughout the full pedal rev, uphill, down, on the flat and in both front chainrings

Commuting in on it this morning (7am, subzero all the way) again felt as new, no give and silent click perfect shifting but after about 7 miles the slight give in the pedal stroke reappeared (again in both front rings and across all of the rear cassette) and persisted for my last mile into work. Nothing feels loose or give-y whilst poking and prodding it at work

What is Plan B?

bottom bracket
rear hub
front chainrings
faulty new kit- nothing visibly obvious
operator error - again nothing obvious on looking this morning and these are fittings I've done plenty of times before without issue.

 

[lpretro1]

Check pedal bearings?

 

[Graham]

Worn splines on the non-drive side crank giving rise to a bit of play? Maybe try standing over the bike and then pull up and down on the pedals at same time - see if there is any movement.

 

[shouldbeinbed]

cheers guys. Ipreto1 they're near new pedals and they were fine on the other bike

Graham, interesting one, my perception is that the give is more pronunced on that side. could well be Plan A. there doesn't feel like there is any play, now I've tightened everything up a bit more than it was but still something not right when I actually pedal on it.

I think it's going to be a weekend job to take it more to bits than I'd hoped to do when I got the bike. hey ho.

 

[Graham]

Good luck, let us know how you get on!

 

[mrandmrspoves]

Most likely to be wear in the crank, if so you may get away with tightening it up a bit....

Differential diagnoses..... play in the bottom bracket. - Slip the chain off and rotate the crank feel for resistance and lateral play.
........play in rear wheel bearings - take the rear wheel and try wobbling it sideways. If there is play check
that the QR lever/wheel nuts are tight, if they are tight , adjust cones.

Other possibility.......play in your knee/hip/ankle

 

[HovR]

What bottom bracket system does the bike use? If it's Hollowtech I believe that having the bearing preload not tightened enough could cause some play or give in the pedal stroke. Another thing you might want to check is if the cassette lock ring is nice and tight. If it wasn't tight enough it could have worked its way loose on the commute.

If that's not the issue I'd be buying a new bottom bracket next.

 

[martint235]

Pawls in the freewheel not biting properly? Although I don't think it would feel like give, more the chain skipping.

 

[shouldbeinbed]

Graham wins the nearest prize. The chainrings must have been off or seriously loosened. The splines weren't engaging properly onto the BB and were full of crud and oil. I'm fairly happy they're not overly worn everything has been given a good clean and put back together properly and is riding like it should. If it goes soft again it'll be a new double on the front.

Thanks for all the replies and suggestions

 

[Graham]

Ah, glory!!! The best thing that's happened all morning!

 

[eck]

Glad you got yours fixed. My old Marin has been suffering for a few weeks with the freehub pawls skipping before engaging: potentially painful.
It's an ancient (1996) Shimano STX hub. Most of my stuff is Campag (quiet at the back there!), and I'd never stripped a Shimano hub, but it was fairly straightforward: I got the freehub body off, flushed it with Magic Spray then dribbled some oil in. It all went back together well enough, and seems to have done the trick.
So, tell me: have I done anything wrong, and will I die a horrible Shimano-death?

 

[Cyclopathic]

It does appear to be a fairly hard and fast rule that no matter what one sets about fixing something else will always present itself. I don't think I can remember doing a job that did not throw up something else that needed attention.