I’m just fitting new stem and handlebars and the fork steerer is about 3mm below the top of the stem. The previous stem which has been in since bought is the same height so again steerer ends before top of stem.

I probably wouldn’t have thought anything of it but the instructions for the new stem (thomson) state the steerer should be 3mm above the stem top.

I’ve got a few spacers below the stem so there’s some flexibility but that would make my stem/bars start in a different position wouldn’t it.

Will I die if I fit it as it was before or should I remove a spacer?

Below, as per your last set-up.

It’ll be fine, my Raceface stem is supposed to have the steerer 0-3mm below the top of the stem. Don’t blame me if you die though.

below, or put a spacer on top

hang on hang on, I would say steerer above, then put a spacer or two there so that the steerer is below the top of the spacers. Only because I would prefer to have maximum contact of the clamped face on the steerer. And the edge of the steerer has the potential to cause a stress concentration on the clamped face. This won’t happen if the top of the steerer is next to a spacer.

You read the instructions on ow to fit a stem?

Anywhoo I always used to cut the steerer below the stem, about 3mm, but now I always cut it above. For a combination of reasons really, my HT is quite short and I also run my stem low, with the steerer cut shorter it gives me less scope for possible frame changes. Obviously I run a couple of spacers above the stem.

steerer a few mm above the stem ad spacer to compress it all down when bolt up the top cap
You can do it without anything above iirc one of mine is slightly above without major issue

or of course you can just do this

Steerer needs to be below the top of the stem so that when you tighten the bolt into the top cap, it presses on the stem, not the steerer.

You can put your spacers wherever you like as long as the total height of them and the stem is a few mm less than the length of steerer sticking out of the top of the headtube.

That is so dangerous. If I was a psychologist I would suggest the owner of that has commitment issues.

You read the instructions on ow to fit a stem?

Yep, I’ve no pretensions of being a mechanical know all and I like my face (I’ll admit to being in a minority of one here).

Having got some contradictory responses it seems that either the thomson instructions are unusual or lots of people have been doing it wrong!

I tend to agree with the idea that the steerer is longer so that the entirety of the stem face plate in contact with it. Less leverage. So I’ll try it like that and hope that removing the spacer doesn’t make it feel too weird. I can always swap back as I’ve survived the last two years in the other set-up.

thanks

veedubba is wrong they need to be above to compress for obvious reasons [ they wont touch if it s below if you have few mm the spacers will spin

to install you compress it all then tighten the stem last.

http://www.ehow.com/how_14188_install-threadless-stem.html

http://www.parktool.com/blog/repair-help/threadless-headset-service

video here shows large space above
http://www.parktool.com/blog/repair-help/threadless-headset-service

most folk would allow th whole stem to contact teh whole stem and have a small space above for a steerer spacer ..i think you can live without this but if the stem is belwo the top the headset is not under compression by the top bolt but by the stem…like that pic with HUGE steerer ..it would work but it is not the best method

Pic above he was not sure what size to cut it to it is not like that now

I like the stem to be around 1mm below the top of the steerer to get maximum clamping area, but then add a 3mm spacer above the stem to get the pre-tension on the head doctor / star nut to work.

But that’s just me – and beware on some carbon steerers (Niner) the stem position is mandated as being in line with the expansion thing that isn’t a head doctor but looks roughly like one and does the same job so that the stem doesn’t crush the steerer. Hope that made sense.

Edit: don’t you love it when someone posts a pic that is better than your explanation while you’re typing?