Building up my first Fixie/single speed. I happen to come across some forks that seemed like they would be a good fit for the bike. The whole build is made from my parts bin, with very few components purchased brand new. While assembling I noticed that although the top cover screw can find plenty of purchase, the steerer tube falls around a quarter inch below the top of the stem. This is with no spacers. There is no play to be found once it’s all assembled. Everything moves as it should. I’m still learning the ropes, but is this likely to be at risk of failure once I actually put some weight down on it, or am I being overly cautious? Attaching a pic for reference
by Legitimate_Media_446
11 Comments
Way too short. Should be above the top bolt of the stem to be safe. Get an internal extension if you can find one.
there are low profile headset you can buy. which can save your about 1cm, just ok then
Yep
Look for a zero stack headset.
eeh. yeah.
you can try out different stems, and hopefully gain some millimiter. also a different headset might do the same trick. also, steerer extenders exist.
if you want to be unorthodox… the absolute LEAST high the steerer tube needs to be, is *barely* over the higher stem bolt line. that “barely” reads as you will, because it’s obviously highly unadvisable to use this logic, as it is a dangerous one.
[I’ve made things work on bikes through dangerous logics more than once. with no issues, actually. often materials quality is sturdier than needed, ENOUGH to get away with said, unadvisable logic. BUT who knows.]
anyway, your first telltale sign of the tube being effectively too short to even try this shit out (looks so in the picture), except measurements observations, is the higher stem bolt tightening sensibly easier than the lower stem bolt, resulting in the two “faces” of the stem system, not being parallel when tightened (aka, the higher stem bolt definitely more “closed” than the lower one). in other words an inconsistence in the two bolts tightening, leading to the stem slightly warping and only the lower bolt effectively working (=NO GO)
the fork steerer looks alu… that’s less worrying than if it was carbon.
It’s honestly probably fine. Not ideal but you’re still mostly compressing the fork.
Where is the top of the steerer in relation to the top bolt? If it’s above the center of the top bolt you’re probably fine. If most of the bolt is above the steerer it’s no go for me.
Yeeeaaaassssirreebob
You are about 1-2mm shorter than what is ideal (best I can tell, from this angle), but if it’s an aluminum steerer and not carbon, it’s probably fine. You ideally want the steerer to be about even with the top of where the bolt screws in, or higher.
Being a quarter inch (roughly 6mm) below the top of the stem isn’t an issue, as that stem has a built in spacer of sorts that’s probably about 3mm tall but having the top of the steeer 1-2mm lower than the top of the bolt area is the concern. Some stems only have a single bolt, just as a bit of a reality check regarding the stresses here, but there’s definitely a risk of damage if you aren’t careful and you could easily overtighten that top bolt and crack the aluminum stem.
Personally, I’d keep looking for a fork that fits better but I think you could get away with riding this in the meantime, given it’s aluminum(?).
yes
Don’t do any hard sudden braking, but yes. You are what we like to say, clamping air