Getting some forks for my sons bike S/H.
Steerer just long enough to reach centre of the top pinch bolt, will that be ok do you think? Bike is for XC... nothing extreme.
I know I can get steerer lengtheners or lower stack stem/ headset but all are problematic for various reasons.
That wouldn't worry me too much as you should still get a secure 'clamp' but to make it safer and for your own piece of mind you could always use a headlock rather than a SFN.
Why are the other options problematic BTW?
Would have to suggest the smaller stem unless it's impossible
Woody, how would a headlock help? Not sure how that would stop the stem from moving (if it were to happen?)
I think he is suggesting it will help it being secure it to the the fork rather than the side to side movement. What's the stack height of the stem and size and I would swap to a shorter stem if possible or play with the stack height of the headset if possible (but you say no to this). The issue isn't so much that the clamping force on the the fork more that you will over stress the stem and break it.
Hiya, the stack height of the stem is 40mm and a length of 80mm. About 7 deg rise I would think.
Ideally, as others have said, you want the top bolt to be entirely below the top of the steerer but at halfway the bolt should still clamp securely and not be at risk of distorting the stem (although I think this is very unlikely depending on stem design).
A headlock would provide a bit of extra security (probably marginal in this case when compared to a SFN) but would ensure there was no risk of the stem loosening or moving on the steerer ie. tighten as normal to ensure no play in headset, nip up the steerer bolts, then tighten up the headclamp again to effectively provide 3 separate stem clamping points.
I think FSA do some stems with very short stack heights. I wouldn't risk it in its current state personally.
Kcnc and kooka race stems have low stack heights but if you want to keep the stem you could also change the headset to a low height one.
[url= http://www.on-one.co.uk/i/q/STOOCNC/on_one_ultralight_cnc_stem ]80mm in gold £19.99[/url]
Stack height 35mm rise 6 degrees.
Problem sorted?
I don't see an issue with that personally although its not perfect
My Whyte was like that from delivery and still is 8 months on no issues the steerer tube is 2-3mm from top of stem clamp so similar to what you suggest.
Ideally it should have a spacer above the stem.Practically 3-5mm is acceptable.Anymore than that I would'nt be keen on.You can always get another son though I s'pose.
Rorschach - Member
Ideally it should have a spacer above the stem.Practically 3-5mm is acceptable.Anymore than that I would'nt be keen on.You can always get another son though I s'pose.
explain why? The steerer should be 2-3mm below the top of the stem - why do you "ideally need a spacer" on top??
I don't know if a small spacer on top is "ideal" but it's how I like to set my bikes up too.
The steerer needs to be 2-3mm below whatever the top cap pushes down on for the pretensioning to work - I just prefer that to be a spacer so the clamp (ok the stem) is as engaged as possible with the steerer. But then I'm big, I break things and that gives me the strongest clamping with the lowest best distributed clamping forces.
I accept that with certain carbon steerer arrangements you can't / shouldn't do what I described.
Would bother me on a bike I was building for myself but I'd be less keen if it was one I was building for someone else. I'd go with one of the low stack height stems in this case.
I have some forks with a short steerer, got a sunline v1 stem which had the lowest stack height I can find (34mm) without getting into super short dj stems.
Used to have Titec stems that only had one pinch bolt, at the bottom. Wouldnt be an issue for me.
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edit: courtesy of google images not mine. The top one looks like it should be on the back of a boat.
The sunline stems are on special at crc at the moment.
The steerer should be 2-3mm below the top of the stem - why do you "ideally need a spacer" on top??
you need something to be proud [above] of the steerer. Either the stem itself* or a spacer or else the cap wont tighthen to compress the headset and will be clamped to the top of the fork.
You can off course use the stem to tension the headset but it is not as easy to do and not how it is designed to be done.
I dont think it would worry me to much ...possibly the headset or stem may be less secure but I doubt anything catastrophic will happen
* the problem is when you use the stem you worry about the top bolt and hwo it clamps the steerer hence for ease you have one above the stem.
I hammered some Pace RC31's around like this for a year or more. I put a small peice of cut steerer in so the top bolt wasn't deforming the stem. Put an Amoeba headlock through the lot & it never moved.I have a Sunnline stem with a very low stack height if your worried, but they are still cheap at CRC I think.
My bike is now set up like what the OP's question.
Last year, I went to a Works Components 1 degree, 1-1/8" headset. The stack height was greater than the original headset, so the steerer only goes to the middle of the upper pinch bolt. Fork is a Fox w/ Aluminum steerer, Stem is Ritchey 4 Axis WCS.
No issues so far...
Have a look on Chainreactioncycles for the sunline xc stem, earlier today they had 80mm ones in stock and they have a 35mm stack hight.