How can I tighten pivot bolts on a Woosh Zephyr B and why is it loose in the first place?

[topographer]

Given that Woosh observes the Sabbath, I'll try my luck here.

There is quite a lot of movement at the point where the seat stays connect to the rear sus triangle (I don't know what you call that thing). Rather than one bolt going right through, there are two short ones with allen key heads on each end of each bolt. The snag is that the gap between the two bolts is narrower than the short leg of the allen key so I can't get anything on the inside end of the bolts. How am I supposed to tighten these? Sadly, Woosh's manual gives a fair bit of info about maintenance but nothing on rear sus. Snooping around the internet hasn't helped me much. Could the problem even be something other than bolt looseness? Could there be a bearing problem? I flipping hope not. I've only done 170 miles.

 

[Deleted member 4366]

They're pivot bolts. Surely if they were tight, your suspension couldn't work?

 

[topographer]

Yeah, probably knackered bushes or bearings. There seems to be some lateral or diagonal movement when I lift the back of the bike at the saddle which wasn't there when the bike was new. This is the only bike I've ever owned with any kind of suspension. It's beyond my ken. It's just occurred to me that I didn't check to see if there was any side-to-side movement. I'll check that tomorrow.

 

[Woosh]

hello Topographer,

You may need longer allen keys.
From memory, you only need one 5mm allen key, one side is locked to the frame.
would you contact support@wooshbikes.co.uk , Andy should be able to help.

 

[topographer]

No, the ones at the top of the seat stays just spin when only using an allen key on one end. I think it's only the one just in front of the seat tube that tightens with a single allen key. A longer allen key isn't going to work; the gap is too narrow (see pic). I need a key with an extremely short short end. Conundrum.

I'll make sure to email andy before Monday morning.

 

[Woosh]

I need a key with an extremely short short end. Conundrum.

Jim can probably cut down an allen key for you. It won't take him long.

 

[D C]

I need a key with an extremely short short end

I think you've answered your own question
Allen keys are quite hard metal, it's difficult to shorten them with a hacksaw but they can be filed part way through then snapped off easily in a vice or with two sets of pliers, wear safety glasses or shut your eyes.
If you have a disc or bench grinder or know someone who has then it's an easy job.
I keep several shortened ones as I've come across these sort of problems several times.
Nice of Woosh to offer.
Dave.

 

[johnc46]

Remove the bolt that is easy to get to, that should increase the space to get a standard Allen key in or use the long leg through the hole, then refit the other bolt and tighten.

 

[daveboy]

Have you got a Allen key head (the type that fits in a screwdriver) hold one of these in an adjustable spanner or pair of pliers.

 

[argoose]

Have you got a Allen key head (the type that fits in a screwdriver) hold one of these in an adjustable spanner or pair of pliers.

or fit it into adapter on ratchet wrench

 

[topographer]

Jim can probably cut down an allen key for you. It won't take him long.

That'd be good.

 

[topographer]

I can't remove one of the bolts to make more room. The whole thing including both heads spins. I doubt a ratchet would take up less room than the short leg of an allen key. Daveboy's pliers holding a bit idea might work. I'll give it a go.

 

[topographer]

I think you've answered your own question
Allen keys are quite hard metal, it's difficult to shorten them with a hacksaw but they can be filed part way through then snapped off easily in a vice or with two sets of pliers, wear safety glasses or shut your eyes.
If you have a disc or bench grinder or know someone who has then it's an easy job.
I keep several shortened ones as I've come across these sort of problems several times.
Nice of Woosh to offer.
Dave.

Been meaning to get a dremel for months but never got around to it.

 

[Woosh]

The arrangement of the hinge bolts is that the fixing is internally threaded on one side, so they tighten to each other but don’t clamp the frame tightly as such. The slack is taken up with a nylon washer. A similar type of bolt arrangement is pictured below.:

If you can email Andy a picture of the state of the nylon washer, it'll give him a better idea how to fix it.
He's got an allen key for you should you need it.

 

[MikelBikel]

Don't know if it will engage securely enough for your bolt but there are ball-headed allen key spanners that can work at an angle.

Threadlock on the bolts should stop them loosening again.

As the pivot moves, the steel bolt wears thru the alloy, and the nylon washer may need renewing (thicker). To remove all slack in the pivots they would have to be shimmed/sleeved. If the bolts have bottomed out, washers under the heads might take out all but the inline slack.

 

[topographer]

I emailed Andy at Woosh. Sent him a couple of pics and a couple of vids...and asked to be sent the shorter allen key. Daveboy's idea didn't work. Even the hex bits are too long for that narrow gap. Which probably means the ball-headed allen key idea won't work either. Thanks MikelBikel and Woosh for the above info about how those linkages work. That's what I failed to discover on my internet searching. Sounds like it won't be too complex if I have to start unscrewing them. Hope I don't have to start messing about with shims or sleeves though. Oh, there was a slight side-to-side movement in that area, but tightening a bolt further forward fixed that.

 

[topographer]

I added two very thin nylon washers as per advice from Woosh support and it solved the problem.

 

[argoose]

I think the manufacturer should fit the nuts with flats so an open ended spanner can be used to hold them when removal/installation is required

 

[argoose]

 

[topographer]

The outside bit has a bush and a strange rim that sometimes rubs against the edge of the bolt head.

The inside is just a hole

I put washers on the outside

Maybe this will create some friction that hampers the suspension slightly and maybe the thin washers will rub through fairly quickly. After two rides I'm happy with it though.