Having trouble identifying the source of some clunking on my 2018 Mega.

There’s a small amount of vertical play and a bit of a clunk if you lift the bike up and put it down. All of the bolts are tight – nothing is loose. The last time I had this was when one of the shock bolts was a bit loose, but this is obviously not the cause in this case.

There’s no lateral play anywhere, but the bearings are still original, so could probably do with being replaced.

Any ideas?

Cheers,

JP

Shock bushings probably

Are the headset bearings properly loaded?

Northwind

Subscriber

Shock bushings probably

Do you mean the bearings? I don’t think it has any bushings, but I may be wrong.

JP

speedstar

Subscriber

Are the headset bearings properly loaded?

Yeah – there’s no movement at the front of the bike.

JP

It’s got a bearing at 1 end and a normal bush at the other.

Check the chainstays very carefully. A friend’s broke the driveside chainstay right where it joins the pivot. Was difficult to spot.

dhrider

Member

It’s got a bearing at 1 end and a normal bush at the other.

At each end of the shock itself?

Cheers,
JP

At each end of the shock itself?

Yep, only a bearing on one end.

Either side could be worn and will cause a clunk. I’d guess that’s your problem if all bolts are tight.

I had an older mega and that sounds like the symptoms of a worn shock bushing to me, as Northwind says. You can pick up a tool to change them pretty cheap on ebay.

OK – thanks. I’ve got a bearing kit but I don’t think it includes any bushings. Can’t see any bushings on CRC either, so not sure what to do.

I’m riding at Wind Hill tomorrow – I guess I’m not going to die if it’s the bushing?

Cheers,

JP

Shock bushing. I had the same on my bike, when I picked it up there was a slight knock. 10 mins at TF Tuned (in Westbury, I assume you live fairly close if you’re riding at Windhill) and it was sorted.

OK – thanks. I’ve got a bearing kit but I don’t think it includes any bushings. Can’t see any bushings on CRC either, so not sure what to do.

Mega bearing kit is frame bearings only, it doesn’t have the shock bearing.

According to the manual, the hardware sizes are
F: 8mm x 25mm
R: 8mm x 30mm

Worn hardware will be fine to ride tomorrow but I’d replace ASAP.

I think you’ll need https://www.tftuned.com/rear-shock-bearing-kit-deluxesuper-deluxe/p3689

Plus RockShox hardware which is 8mm x 25mm for the other end

Then the DU bush is 12.7mm

I’d replace it all if you aren’t 100% sure to try and make sure you sort it in one go.

Brilliant – thanks all!

JP

Have you tried the 2 X 2mm Allen key bolts at the rear of the shock that hold the bearing casing in? That’s where the knocking was coming from on my Bronson.

My old Mega 290 used to eat shock bushings (DU bushings) for breakfast. Mainly the rear one.

I’d try that first.

When I’ve had this before (Mega and a Stumpy), it was the shock itself that needed servicing.

With the bike static, wheels on the ground, hold the shock shaft with one hand whilst you lift the bike up slightly by the saddle – don’t lift the wheels off the ground, but lift enough to tell if there is a bit of free travel of the shaft into the air can – thats what it has been for me.

Just a check, but you might also need to do your bearings.

For future reference, (as so many of these sorts of thread come up on searches and most have no final resolution) it was the bearings. All were shot apart from the Horst Link pivot. Shock mount bushes/bearing and shock were fine.

It was interesting to see how bad the old bearings were – it was almost impossible to turn them – yet the suspension still felt fairly supple.

JP

I had that on my jeffsy.

Suspension felt absolutely fine, just an annoying clicking noise occasionally.

When I actually removed all 11 bearings, most of them were shot. Totally dry and full of rust.