Help with play in Giant Overdrive2 headset

[IBarrett]

Hi all,

I recently bought a Giant Defy that I believe is an 2014 advanced pro but with warranty replacement frame and fork set so there are no decals to confirm this so we might need to do a bit of detective work if we need to know for certain which model it is,
Be that may, the cover over the top bearing and the first spacer both say Overdrive2 on them.

There is distinct movement if I apply the front brake and rock the bike forward and back.
I’ve taken the fork out today and the bearing look ok, so I cleaned regressed and refitted everything but there is still play.

The component parts, working from the bottom up are;
Bottom bearing
Top bearing
Blue split ring
Thin steel coloured ring
Top cover with Overdrive2 embossed
3 plain flat spacers
1 spacer with a lip
===stem===
Stem top cover

I also removed the bolt in the top of the forks. It dropped the nut inside into the forks but I managed to wiggle it back onto the pin inside the fork and replace the bolt.

The only video I can find for overdrive forks is for a TCR and it has 2 of the steel coloured rings, where I have just 1.

So a couple of questions
Is there anything missing which might allow play? It looks like there cound be another lipped spacer on the top of the stem which the top cover then sits on. The cover looks a fraction small.
Or should there be 2 steel rings on top of the Blue one?

What is the purpose of the nut/bolt thing inside the top of the fork - strengthener for the carbon stem?

Sorry for the long winded thread and thanks for looking in.
IanB

 

[Yellow Saddle]

Photos always help.
Having said that, do you understand how the adjustement on a threadless steerer works?

 

[IBarrett]

Thanks for the quick response @Yellow Saddle

I’ll get photos tomorrow if they help. And I’m happy to dismantle it all again.
I may show my ignorance here, so please feel free to tell me if I am wrong, but the way I thought it all bolted together was to fit the stem loose, fit the top cap and tighten down then tighten the side bolts on the stem.

 

[Jody]

What is the purpose of the nut/bolt thing inside the top of the fork - strengthener for the carbon stem?

That's the critical item in tightening your headset.

My guess is that you are short of a spacer or one of the bearings is the wrong way round.

As @Yellow Saddle says pics will help.

 

[IBarrett]

Hmm, I didn’t take the bottom bearing out. But I’m sure I checked the chamfer.

 

[Yellow Saddle]

Thanks for the quick response @Yellow Saddle

I’ll get photos tomorrow if they help. And I’m happy to dismantle it all again.
I may show my ignorance here, so please feel free to tell me if I am wrong, but the way I thought it all bolted together was to fit the stem loose, fit the top cap and tighten down then tighten the side bolts on the stem.

OK, that's the correct way, so no problem there. Let's look at those pictures.

Usually the order is like this, from the bottom up.

Fork
Crown race (nowadays some forks have it built in).
Bearing, chamfer side down
Headset bottom cup.
Head tube
Headset Top Cup
Gearing (chamfer up).
Conical, split compression ring
Washer of sorts
Headset top cap with logos and stuff
Spacer, spacer spacer etc
Stem
Top cap.

 

[IBarrett]

I just read up on threadless steerers and don’t think I set the preload correctly @Yellow Saddle
I’ve not come across this bolt underneath the top cap before, having only had an aluminium road bike.
I’ll have another go tomorrow and if I get no joy I’ll photograph all the bits.

 

[Levo-Lon]

I just read up on threadless steerers and don’t think I set the preload correctly @Yellow Saddle
I’ve not come across this bolt underneath the top cap before, having only had an aluminium road bike.
I’ll have another go tomorrow and if I get no joy I’ll photograph all the bits.

If it's not tight they creep and you get play.
Or it needs another shim

 

[boydj]

It's important that your top cap is not touching the steerer when tightening. It should be tightening onto the stem or a spacer above the stem.

 

[IBarrett]

Hi all.

I’m resurrection this thread because I still can’t get the fork tight enough to remove the movement I can actually see.

I have the parts in this doc I found, so I think there is nothing missing.
https://dstqaa92re5c4.cloudfront.net/Manuals/Bikes/Giant/Propel Disc/Giant_Propel Disc_EN.pdf

What I do find odd is when I remove the top cap the bolt goes down into the fork and attaches to a chamfered nut. This is such a bloody faff it can’t be right. I have to turn the frame upside down to get the nut to sit where I can get the bolt into it.

Does the top cap fit into a bolt which goes down into the fork?
So the bolt sets the preload and the top cap just lightly screws into the bolt?
I found this idiot guide which seems to show just this in picture 3 - the top cap fits into a bolt in the fork.
https://road.cc/content/feature/167572-how-adjust-your-threadless-headset

If this is how it’s supposed to be is it possible my top cap is pulling the whole lot out so it looks like a single bolt. But I didn’t think of this before putting it together again tonight.

 

[boydj]

Inside the steerer should be a compression bung which is fixed at a height that the top cap can be bolted into. This is what applies the compression that pulls the headset bearings and the steerer into the correct position in the head tube. Sounds like you need a new compression bung, such as
https://www.chainreactioncycles.com/bbb-powerhead-compressor-adjuster-bap03/rp-prod29884

Google "compression bung" to see what I mean. With an aluminium head tube a 'star nut' is used to perform the same function. The star nut is drifted down inside the steerer and can only move in the one direction.

 

[IBarrett]

Ooo, that IS interesting @boydj , thank you

 

[IBarrett]

I’m really happy to report I’ve finally got to the bottom of the problem and fixed it.
There were 2 issues

1. The top cap bolt was siezed in the compression bolt. So undoing the top cap was also undoing the compression bolt and dropping the nut inside the headset into the bottom of the fork.
Even putting the compression bolt in a gently tightened vice wasn’t enough to get the top cap separated from it and I had to use water pump grips which cut into the soft alloy of the bolt and they separated.

I cleaned and greased everything but i I still couldn’t get the stem to tighten everything properly.
So I started to look at the mechanics of the top cap and found the problem.

2. There was a 2mm split washer underneath the compression bolt, making the bolt head stand proud enough to stop the top cap sitting on the stem.

With the washer thrown on the floor in a fit of temper everything went together as it should.
God know what the original owner thought was going on, but it may be the reason he sold it. And I have now got the bargain I hoped for, rather than a pup I was worried I’d got.

Thanks for all your help.

 

[Duffnote]

I have exactly the same issue and was considering doing the same or getting a stem gap which sits on top of the stem rather than sinks into it, like the Kapz OD2 cap. Is it safe to remove the washer as you've done? Any issues so far? Thanks.