Stem to steerer pinch bolts gap issue

buder

Hi All,

Recently taken delivery of a new Orbea Orca and I cannot seem to get equal gaps between the top and bottom stem pinch bolts on the carbon steerer. I am using a torque wrench to 4nm.

The expander plug is 68mm long and extends way below the bottom stem bolt so unless its bulging at the top slightly more than the bottom I cant understand whats going on.

The stem looks fine with the bolts removed gap between the top and bottom looks equal. The stem is an FSA energy stem.

I thought about flipping the stem but dont really want to start taking the bars off.

I am concerned that this is potentially causing a safety issue, any thoughts ??https://farm5.staticflickr.com/4397/36765006660_b3a1e148f2_m.jpg

cooldad

Do them up alternatively little by little.

Can't see the pic as I don't have microvision.

keef66

Are you tightening them alternately a bit at a time or doing one up to 4 Nm then the other?

Is the expander bung supporting the steerer in the same way and to the same degree at both points?

Or is the expansion part so far below the bottom bolt that the steerer is unsupported there?

Is the expander bung tightened to the torque required?

buder

Hi all,

Thanks for replying, sorry about the pic loks fine on flickr so dont know why its launching so small.

Ive tried again using the URL function:
https://flic.kr/p/YkhfyG

I am alternating both bolts in small increments.

The expander is supporting the steerer to the same degree at both bolts. I have had it out and tested this, I am doing it up tight enough for it not to slip, not beyond max torque.

cooldad

Just try it by hand. Don't use too much muscle and it should be fine.

Matthewfalle

That's fine, flip away.

keef66

Now I can see it better it looks OK to me. Maybe they'll be the same when the stem's flipped...

buder

If I do it up by hand and make the bolts appear to have an even gap the lower stem bolt has less torque applied. I can do this but in my mind it would be better to do them both up to the same correct torque (4nm) than to make the gap even etc.

My obvious concern was that the expander was not supporting the inside of the steerer correctly but I have tried two expanders and its the same for both. They definitely extend below the bottom bolt by some margin and seem to function properly, so am not sure whats going on. Most importantly I want it to be safe and not have to worry about it.

cooldad

4nm is not a lot of force, just a finger twist really. A slightly tight screw could throw a measurement like that out.

For that I'd be tempted to trust my fingers more than a basic, non calibrated wrench.

What sort of torque wrench are you using (in terms of quality/range)

buder

cooldad wrote:

4nm is not a lot of force, just a finger twist really. A slightly tight screw could throw a measurement like that out.

For that I'd be tempted to trust my fingers more than a basic, non calibrated wrench.

What sort of torque wrench are you using (in terms of quality/range)

Do you mean just do it by hand making sure the bolt gap is even ?.

I am using the Icetoolz Ocarina beam type torque wrench, incidentally Bike radar reviewed it quite well. I have also used my pals Park tools click type torque wrench at 4nm and it produces the same gap top and bottom.

flasher

I wouldn't worry.

buder

I'll try not to worry about it just seems odd to me. If I go into a bike shop every bike I look at looks alright !

webboo

I have an old model Orbea Orca on which if you tightened the stem to the recommended torque the headset would come loose. The shop tried a different stem which made no difference, so just ended up tightening till it didn't move and the gap looked even.

buder

I done a test in terms of torque required for each bolt to get the gap even.

With the top bolt torqued to 4nm the bottom would have to be torqued around 3 to get the gap even.

The other option would be to over torque the top bolt to match that of the bottom when it is torqued to 4nm but this is obviously not something I will be doing.

dj58

Could be a problem with the stem manufacturing tolerances, if you have a spare stem lying around try fitting it and see if you get the same effect when you tighten the bolts up.

lesfirth

buder wrote:

I done a test in terms of torque required for each bolt to get the gap even.

With the top bolt torqued to 4nm the bottom would have to be torqued around 3 to get the gap even.

The other option would be to over torque the top bolt to match that of the bottom when it is torqued to 4nm but this is obviously not something I will be doing.

You are doing far too much thinking here. Just tighten the bolts. B0llocks to the gap. Now ride the bike,smell the flowers and give your brain a rest.

Matthewfalle

lesfirth wrote:

buder wrote:

I done a test in terms of torque required for each bolt to get the gap even.

With the top bolt torqued to 4nm the bottom would have to be torqued around 3 to get the gap even.

The other option would be to over torque the top bolt to match that of the bottom when it is torqued to 4nm but this is obviously not something I will be doing.

You are doing far too much thinking here. Just tighten the bolts. B0llocks to the gap. Now ride the bike,smell the flowers and give your brain a rest.

This.

Les, Sir, you have hit the nail on the head. Hat.

buder

Thank you all.

I will try not to worry about it and just ride the bike !

Matthewfalle

Get rid of those spacers above the stem though - ugly and you don't need them.

buder

Matthewfalle wrote:

Get rid of those spacers above the stem though - ugly and you don't need them.

The steerer extends 3mm above the top of the stem. The spacer is around 5mm to allow proper preload.

It is ugly to be honest but I would rather not have it 2/3mm shorter than the top of the stem as in my mind it adds a bit of safety and strength even though the expander is the lip variety and arguably doesn't need the steerer to extend above.

svetty

buder wrote:

Matthewfalle wrote:

Get rid of those spacers above the stem though - ugly and you don't need them.

The steerer extends 3mm above the top of the stem. The spacer is around 5mm to allow proper preload.

It is ugly to be honest but I would rather not have it 2/3mm shorter than the top of the stem as in my mind it adds a bit of safety and strength even though the expander is the lip variety and arguably doesn't need the steerer to extend above.

Fair enough if it gives you psychological comfort but it would be no less safe 5 mm shorter without the spacer

Matthewfalle

buder wrote:

Matthewfalle wrote:

Get rid of those spacers above the stem though - ugly and you don't need them.

The steerer extends 3mm above the top of the stem. The spacer is around 5mm to allow proper preload.

It is ugly to be honest but I would rather not have it 2/3mm shorter than the top of the stem as in my mind it adds a bit of safety and strength even though the expander is the lip variety and arguably doesn't need the steerer to extend above.

I feel you're happy with it then cool, leave it - it's your bike - but you don't need it and it ugggerrrly. So long as both bolts are clamping on steerer then you could have 9 miles of steerer exposed and it won't do anything.

buder

Matthewfalle wrote:

buder wrote:

Matthewfalle wrote:

Get rid of those spacers above the stem though - ugly and you don't need them.

The steerer extends 3mm above the top of the stem. The spacer is around 5mm to allow proper preload.

It is ugly to be honest but I would rather not have it 2/3mm shorter than the top of the stem as in my mind it adds a bit of safety and strength even though the expander is the lip variety and arguably doesn't need the steerer to extend above.

I feel you're happy with it then cool, leave it - it's your bike - but you don't need it and it ugggerrrly. So long as both bolts are clamping on steerer then you could have 9 miles of steerer exposed and it won't do anything.

Completely agree but this does seem to divide opinion based on the gap from top of steerer to stem.

I kind of get why you would want 2/3mm above so the stem is clamping completely on the steerer but equally so with the correct expander this is negated.

to be honest I am more pissed at the stem to steerer pinch bolts gap than the spacer on the top !, I will get it cut though at some point !.

Just an aside does anyone know if its possible to repair a carbon steerer ?

Matthewfalle

Anything is repairable by the right person but would you really want to ride on a repaired one?

to tell the truth, by the time you've sourced the right person, paid postage/petrol to get there, paid the person, postage/petrol to pick it up and then the fact that its a repaired steerer you may as well have a look in the sales and get a new fork massively discounted.

Do a quick search on here for carbon repair people and give them a shout.

keef66

I suspect it would depend on the fork construction and the nature and location of the damage.

If repaired externally it won't then fit headset components or the stem. If repaired internally near the top it could affect your ability to install a bung.

You might find somebody prepared to bond an alloy tube inside it and then you could use a star nut...

Matthewfalle

wouldn't even need to bond one in - I had a cheap (£9) carbon seat post snap on me so I got a length of plumbers copper pipe, smacked it up there and it worked perfectly - so long as you match internal&external diameters it'll be perfect.