Is my steerer length safe?

HollisHarri

I discovered that flipping my stem would let me take 20mm of spacers away. This would have meant that I had a whopping 25mm of spacer above the stem clamp.

I decided to take 23mm off the steerer but because I'm lazy/terrible at cutting and measuring I ended up taking 30mm off.

Now it looks much better BUT now I have a 7.5mm gap between the top of the steerer and the top of the stem (well, the top of the fork bung). The centre of the top bolt is 6.5mm from the top of the stem.

There's a 10mm spacer under the stem but I can't afford to lose any stack now. I've also got the top cap sitting directly on top of the stem without a spacer.

I've taken some terrible pictures of it here.

extrusion

Remove the spacer ...

BillyMansell

If I understand you correctly with the bung removed the end of the steerer is ~10mm below the top of the stem which would mean you've only got one stem bolt holding the stem onto the steerer.

If that one stem bolt should fail it would be catastrophic but even if it doesn't fail catastrophically you are putting a lot of your weight on a lever (the stem) that isn't properly or adequately fastened to the steerer so it may just be a matter of time until it does fail in some way.

As a remedy, and for your own safety, reduce the 10mm spacer to 5mm but ideally you only need a couple of mm below the top of the stem for the top cap to be flush fitting.

wishitwasallflat

+1 looks like the top bolt of the clamp is tightening down on nothing! No way I would ride that.

HollisHarri

Actually remeasured it and the bung cap was 1mm below the stem bolt so yeah it was grabbing onto nothing. Urk.

Stuck the 5mm spacer on and it looks much better. I guess I'll have to do some core exercises now!

Still, I guess it'll look more pro when it's leaned up against the cafe wall.

me-109

HollisHarri wrote:

Still, I guess it'll look more pro when it's leaned up against the cafe wall.

Actually, it would only look 'pro' with a flat(ish) stem, not one pointing up.

simonj

Still looks weird and wrong, I'd flip the stem back down to normal to start with, then remove the 5mm from below and put it on top, so the forks protrude above the stem slightly - safer more solid grip and less likely to damage fork, but the 5mm spacer is enough to go above the bung again before putting top cap on.

simonj

http://www.cyclingnews.com/features/pho ... mod/130342

HollisHarri

Your solution, while admittedly making the bike look super-pro, would reduce the stack a further 25mm so I would no longer be able to ride it.

As it stands it's -5mm from my ideal stack height so I can't reduce it any further and still be able to ride it.

simonj

Ha ha, or buy another fork and next time measure twice, cut once! Honestly though, cutting the steerer to look like a pro, whilst having your stem flipped up (which doesn't look like a pro) kind of defeats the point don't you think. I personally can't talk as am not very flexible, so have quite a high stack on my relaxed bike, but it doesn't bother me if it looks good or not as I can't see it when I'm riding along. Ideally people say put a spacer on top, but your second picture will suffice and looks a hell of a lot safer than your first. I'd personally stop worrying what your bike looks like whilst up against a wall and just go out and ride it.

HollisHarri

I'm not having a go, I'm just being sarcastic which I realise hasn't really come across well now.

I didn't cut it to look pro (the pro comments are just tongue in cheek since people seem to have missed my comment in the first post about not being able to lose any stack height). I cut it because I had a 45mm stack under the stem and flipped the stem to get rid of 20mm worth of spacers in the hope it'd make the front end less flexy (It's a PX Pro carbon which are a bit noodly anyway). I'm honestly not fussed over how it looks which is why I'm fine flipping the bastard in the first place.

simonj

Sorry I didn't see the comment about trying to make it less flexy just the one about how it was looking. Anyway now at least it looks safer to ride.

ugo.santalucia

get a shorter spacer, easy

g00se

1. You could get a stem with a greater angle, and remove the spacer (or use a 2.5 mm one - as some recommend at least one spacer below and one above on carbon steerers).

2. You might be able to find a stem with a smaller stack height - I think 38mm is about the smallest. Though your's already looks about 40mm at a guess.

3. New fork

PS - personally, If you don't want to slam a stem, it will look better to have 25mm of spacers below the stem, rather than inverting the stem. If 25mm of spacers are causing flex, I would suggest there is an issue with the stem or steerer.

Eg - this looks OK:



this doesn't have the same aesthetic:

HollisHarri

Had my first ride out on it today with the 5mm spacer under and no top spacer and it felt solid and my back was fine with it so I think it'll just stay like that (maybe put a 5mm on top if I can find it). I'll probably wait until the forks are on sale at PX again, buy a new set and then whack these ones on my singlespeed which takes a much shorter steerer.

Goose, I don't deny that a straight stem looks nicer aesthetically but there was a tapered top cap (15mm) with 30mm of spacers on top of that, plus the 40mm of stem so it looked like I had a boat tiller stuck to the front of my bike.

The flex isn't massive, and it's known that the front end of the Pro Carbon's not the stiffest. I was just trying to tighten it up as much as possible. Not sure if cutting the steerer has made any actual difference to that or I'm just getting the benefit of the placebo effect but I felt a lot more planted on tight corners today.

simonj

It may also have been the pre-load on the bearings that were creating the flex rather than the fork itself. I sometimes find I have to preload a little more than I thought I would to stop the fork moving.