Rear end wobble (Brompton)

[straas]

Noticed a rear wobble from the rear last week, most noticeable when freewheeling.

Got home and the wheel was slightly out of true laterally and radially but nothing massive - assumed the smaller wheel might amplify things like this so took it in for a true.

True wasn't perfect but better than it was.

Same wobble remained, if anything now more prominent.

The wheel itself doesn't seem to have any play in it.

What should I check? Not comfortable riding it like this.

Cheers

 

[Ming the Merciless]

Rear hinge bushes worn and need replacing ?

 

[Kell]

Could be rear hinge as stated above, but have you also checked the cones?

My hinge has some play in it, but it's not noticeable when riding. Had it checked and was told "That's nothing to worry about"

Cones are far more likely - I'm having a nightmare with my front wheel at the minute. No matter how much I tighten it, it works loose in about a week. Very disconcerting.

Final thing I suppose is ensuring that your wheel nuts are tight. It's easy to overlook the one under where the chain pusher attaches.

 

[T4tomo]

The wheel itself doesn't seem to have any play in it.

What should I check? Not comfortable riding it like this.

So are you saying the wheel has no play in the frame if you try to wobble it from side to side?

does the tyre have a deformation somewhere, maybe a bead coming off the rim?

rear hinge?

saddle issue you think is the rear wheel?

 

[berlinonaut]

Excerpt from Brompton's datasheet "rear hinge replacement" (ds-rhin.pdf)

On used bikes, slight play can be expected at the rear hinge; if the play is unacceptable (more than 2mm in either direction, at the rear wheel axle) the rear hinge bushes need to be replaced.

 

[straas]

So are you saying the wheel has no play in the frame if you try to wobble it from side to side?

does the tyre have a deformation somewhere, maybe a bead coming off the rim?

rear hinge?

saddle issue you think is the rear wheel?

Yes, put the bike upside down and tried to move the wheel from side to side but nothing of note. The tyre doesn't appear to have any bulges and the reflective lines on the side appear to follow the rim profile.

What should I look for in the rear hinge?

If I get the wheel up to speed using the cranks when upside down it appears there's some eccentricity with a slight jump on rotation.

When coasting the whole rear triangle appears to vibrate side to side - hard to see as I had to keep looking up so I didn't crash...

 

[straas]

Think I've found the culprit! My marathon + has started to separate at the sidewall! Didn't notice at first because its just below the schwalbe logo.

Only 10 months old!

 

[ukoldschool]

possibly a brake pad rubbing on the sidewall has caused that?

 

[T4tomo]

does the tyre have a deformation somewhere, maybe a bead coming off the rim?

Think I've found the culprit! My marathon + has started to separate at the sidewall! Didn't notice at first because its just below the schwalbe logo.

Only 10 months old!

Takes a bow...

 

[Kell]

possibly a brake pad rubbing on the sidewall has caused that?

Could be - I had something similar happen when my rear brake was a bit loose. Only under hard braking did it shift enough to put it in contact with the tyre.