pre- loading my hope aheadset

OCLV74

Right I've damn near finished my build, the problem that remains is when I hold the front brake and 'rock' the front back and forth, there is a load of play in the headset bearings. I've tried moving the 'head-doctor' (read starnut) further down the fork tube and cranking it up silly tight, and still the play exists.. I'm stumped, so here I am looking like a wally, with the answer most likely staring me in the face.. TY in advance

benpinnick

Do you have enough gap between the top of the steerer and the top of your stem/top spacer?

OCLV74

well i have a 10mm spacer currently, but this leaves the stem about 7 or 8 mm to high for the steerer, I have a 5 mm spacer on order, which should have the stem topping the steerer by about 2 or 3 mm which should be ok. What I can't understand is why even moving the headdoctor down a bit inside the steerer, why the play isn't being reduced

benpinnick

Does it work ok with the stem 7/8 mm too high (even if you wouldnt ride it that way)?

estampida

sounds like the hed doctor is slipping - you can measure if it has moved but -

take out the head doctor

really really grease the inside parts and o rings, and refit

make sure its really tight in the steerer tube

but it needs a gap from the top cap, down 25 mm say (its quite a long bolt for preloading)

and more crazy, the bearings in the right way ? crown race seated right? no seals caught?

Chunkers1980

Even better idea, throw away the expander part, use the top cap and fit an SFN. Lighter, better and cheaper, not many things like that.

cooldad

OCLV74 wrote:

well i have a 10mm spacer currently, but this leaves the stem about 7 or 8 mm to high for the steerer, I have a 5 mm spacer on order, which should have the stem topping the steerer by about 2 or 3 mm which should be ok. What I can't understand is why even moving the headdoctor down a bit inside the steerer, why the play isn't being reduced

Because there isn't a gap between the topcap and top of the steerer tube.

cooldad

Chunkers1980 wrote:

Even better idea, throw away the expander part, use the top cap and fit an SFN. Lighter, better and cheaper, not many things like that.

This but still won't help if there's not enough gap.

OCLV74

wheel brake etc are fine, they are brand new and spin without a rub, I'm thinking maybe I overdid the grease lol, I stuck a load in then squeezed everything together and wiped off the excess, but maybe that has caused the play, in any case it's looking like stripping it down and starting over. Good job I enjoy extra fettling, as liverpool are playing tonight I feel an 8 pack with the bike in the lounge tonight is almost certainly the way forward!

having read what's been posted while I was writing, am I correct in assuming the top cap is what pulls the aheadset together and stops the play? Again sorry for being moronic, but the only other headsets I've had were threaded, shows my age I guess!

cooldad

Not a great pic, but you need a gap between the steerer tube and top cap to preload the bearings. Then you tighten up the stem. Once the stem is tight it holds the whole lot together.

cooldad

ps - you are tightening the top cap before the stem bolts?

OCLV74

exactly the picture that can help my brain see what is going on, ty bud, next trick will be to not stack it on the first ride !

PS, this was also a problem I have since realised.. (regarding your last post!)

oxocube1

I know it seems like pointing out the obvious but is there definitely a crown race on the top of the forks? The amount of times I've had people come in with a similar sounding problem as yours and they have not put the crown race on the forks or it has not been put down flush to the fork crown.

And as for the stem/spacers issue, there should be a minimum of 3mm and a maximum of 10mm gap between the top of the stem and the top of the steerer tube. So the 7-8mm gap you say is currently present should be absolutely fine and adding a 5mm spacer would also be fine making the gap 3mm.

OCLV74

yep the crown race is fitted, mind, it is quite logical that the stem should be above the steerer, for some bizarre reason it didn't seem to click, as I stated earlier, the answer is usually staring you in the face, thank god for the internet, I hate to think how long I'd have taken to work it out. Having removed a bit of grease, (still a ton in there mind) and re-twiddled, headset is super smooth and rock-solid, thanks to everyone who helped out, esp cooldad with the picture that made it all go 'click' for me.

cooldad

No worries. You won't be the first or the last.