Mono shock adaptation

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

Hi all,
Got a question about rear mono shocks which my mate asked me & I couldn't answer.
So, oem shock has a 45mm bush/mount at bottom which bolts straight onto swingarm (no linkage) & a more normal sized 25mm bush/mount at top.
He was asking if another shock, same length etc obv, but one with the fork at the bottom, could this be adapted to fit?
So basically it would be fitting a fork onto a fork if you like.
Usually the forks are a bit wider so I'm wondering if it's ever been done & why not?

Cheers ,
GAZ

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

So you would be getting rid of the bushed connector at one end and just bolting the fork end of the shock onto the fork-type mounting on the swingarm.

If the bolt isn't just the right size you'll get play in the joint. If the joint is too tight, you won't have things moving smoothly enough. The bush absorbs some noise and vibration, and also allows a bit of side to side flex.

Basically, the bush allows things to move around a bit without putting as much strain on the mountings. If you get rid of that, more chance of breaking something or wearing out the bolt quickly. I would fit the right part, seeing as suspension is at the most chance of breaking when it's under the most load - which is when you need it most. Fast bumpy road, suddenly the seat drops down and the shock tries to jam itself between swingarm and tyre.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Sometimes the bottom unscrews off the shock.

If you put a fork in a fork, there will be no bushing or bearing for it to pivot around which will lead to wear on the bolt and ovalling of the holes. Even small amounts of play at a bottom linkage are magnified enormously in a monoshock setup.

Also, when you tighten the bolt, it'll likely bend the ends of the forks in.
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stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

Hi,
Thanks for the replies & you both have said pretty much what I was thinking.
His idea was to fit the shock with fork at the bottom, with a bush in, then bolt it to the "fork" on the bike (it would fit inside the fork on the bike as it's a slightly smaller width)

cheers,
GAZ

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

In that case the bush wouldn't be doing anything, just filling some otherwise empty space. The shock would still be riding on the forks of the shock and its mount.