steerer: how short is too short?

General Help
1

I know the principles in question, but i’m after some input from engineering types:

I have a 3T funda fork that i really want to use on a light road build, but the steerer is cut a bit short for the frame. I’ve already replaced the top of the headset with a 0.3mm thick (or thereabouts) naked carbon cover from veloflyte, saving a few mm, and i have a stem (sunline xc-one) stem with a 33mm stack height, but there’s still 5.5mm between the top of the stem and the top of the steerer, a couple of mm shy of the desired 3mm gap. The centreline of the top bolt of the stem is below the top of the steerer, but only by about 1mm. The steerer is carbon with an alloy sleeve bonded in it (and a standard starnut).

So, safe to ride, or not?

Or: does anyone know of a stem with a 30mm stack height? (the sunline at 33 is the shortest i’ve found)

thanks in advance!

2

It sounds a bit risky.

3

Shave down your stem? Drop a piece shaved off another steerer to make up the gap to stop the stem from putting weird pressure on the steerer??

I don’t really know… I don’t own anything carbon (related to bicycling) so my input is pointless.

4

Yup.

I wouldn’t use that particular combination. Unless you can find a super short stem or headset, go look for another fork.

5

so how much steerer do you have there?

6

yep, it’s risky. i already have another fork, new, that i can cut for this frame, but the funda is nicer. (and i have another frame that i could use the funda with, but i don’t really have a use for that build…) i think i probably have to accept that the combo won’t work.

Captain, i’ll measure the steerer tomorrow. why do you ask?

thanks all for the replies so far.

7

Funn do a stem called the mx light with a 10mm stack height and one call the Funndura or ssomething stupid like that which is a 30mm stack height but both come with a max reach of 45-50mm - which probably not helpful for you, unless you’re are a t-rex.

8

thanks lorday. but, yep, i should have mentioned that i know bmx stems and mtb dj type stuff with super low stack heights, but am after something high-end, light, 90 or 100mm for OS bars.

9

Having the stem slammed is less than ideal in all but the most extreme of cases. That said, this is a light road build, so practicality probably isn’t high on your list. If you have a backup fork, maybe give it a go and if you feel it’s jackass, just change it out.

10

Get a crankbrothers headset. Super low stack height (20.56mm inc. crown race for the cobalt)… Otherwise, buy a new bike.

http://www.crankbrothers.com/directsets_cobaltsl.php

11

Thanks Dice, I also neglected to mention that it’s an integrated headset.

I reckon I better play it safe and use the other fork. The funda’s just so cool, dammit.

12

flat cap?

13

whassat?

14

^ flat top cap on the top of the headset?

15

Do you have a crazy tall conical bearing cover like on most stock bikes or a low profile bearing cover. Think ‘slam that stem’.

16

Yup, i mentioned in the first post that i have a veloflyte dust cover already. Thinner than the ‘slam that stem’ equivalent, i think, although i like the STS attitude! I have a new-fork-based solution to this problem, but, for the archives:

I can totally recommend these:
Veloflyte - Carbon Fiber Integrated Headset Upper Dust Shield

And, at 33mm stack, beautifully machined, and lighter than a Thomson X2, everyone should stock up on the seemingly discontinued sunline xc-one:
Sunline XC-1 Stem | Buy Online | ChainReactionCycles.com

thanks all for the replies.

17

oops. sorry, next time i’ll read the whole thread.

18

if you tighten just one stem bolt on any fork, you’ll notice that it takes a considerable amount of force to move the fork out of alignment. Unless you’re putting some serious torque, not just talk, through the bars i wouldn’t hesitate to ride it.

As a precaution i’d put some some 243 Loctite (blue) on the bolt so it can’t unintentionally come loose. Some friction paste wouldn’t go astray either.