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Typical "steerer cut too short;" possible solution?

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Typical "steerer cut too short;" possible solution?

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flag dvfflebagboy
Posted: Jul 28, 2020 at 22:37 Quote
photo
steerer comes up 5.6mm short of the top of my stem. stem has a 30mm stack height.

steerer comes a couple mm above the highest stem bolt's centerline.

ohlins rxf 36 so steerer and crown are one piece and it would be cheaper to just buy another secondhand fork.

I don't wanna run it as is. has anyone ever considered running small grub/set screws, through drill through the side of the stem and steerer, on one side or both?

I'm sure this area sees a ton of force (torque) and the failure point is possibly too small diameter of a screw/pin being easily sheared between the stem and steerer. however I figure I can run a fairly large set screw/through-pin, as plenty of stems have no material at all in that area, and "lock" the stem from rotating around the steerer at all.

I don't want to rely on this as holding the stem straight but maybe as a failsafe if the stem can't grip the steerer in a high-load scenario.
don't be scared to tell me this is stupid, it sounds too easy, but I'd like to hear why you think it's a dumb one!

on an unrelated note I snapped the topcap bolt when I was test fitting without the torque wrench using a screwdriver style torx driver. I can't believe it snapped so easily? I reached out to cane creek but it is a slamset so I won't be able to easily find a replacement bolt...
[/PI]
flag Branmuffin
O+
Posted: Jul 29, 2020 at 6:21 Quote
Hard to tell from the picture but is your steerer tube slightly above the top clamping screw on the stem? If so I would say you are golden. I run the same stem, and my steerer is just a hair above the top clamp screw and never been any issue.

I would just run it unless you are having issues with not being able to torque the stem clamp to spec or the bars are twisting, which I highly doubt they are.
flag muddytreker
Posted: Jul 29, 2020 at 7:20 Quote
Ive had this one a couple of times.

For the 10 -15mm short steerer I had, opted for a
stem extender, its a 1 1/8" alloy round tube, 6mm wall thickness, with a step down
at one end, it drops neatly into the top of the steerer, seats in about 30mm
into the steerer and adds 20mm extension,
note: the step down mantains the 6mm wall thickness as it steps internally to
compansate, also a tight friction fit which had to be tapped in using a nylon
hammer.

Used an alloy lower steerer plug that goes up into the bottom of the fork steerer
( blocks off and prevents mud getting in from the front wheel ) and used a full
length partial threaded M6 x150mm allen bolt that threads in from the top cap,
and down through the steerer into the lower alloy steerer plug,
instead of a stem cap bolt and star fangled nut.

Fitted the stem as normal and added a 5mm spacer on top, fit the stem cap
and push the 150mm allen bolt down through the stem cap, and thread into the
lower steerer tube plug, torque up to suit headset bearings.

Alternatively you could use a 10mm steerer off cut and drop it in to help
even the force applied when doing up the stem bolts, bike shops have parts bins,
I tried a few shops and got lucky with one who had 3 steerer offcuts from recent
fork fittings.
flag dvfflebagboy
Posted: Jul 29, 2020 at 10:36 Quote
here is a more telling picture from behind the stem with the top stem bolt removed, about as straight as I could get the camera, what appers to be a silver ring in the gap is the top of the steerer's filed bevel.

photo

bran muffin, you think this is okay?

muddy taker, I like your idea, could you point me in the direction of where you got your stem extender? all I can find are quill stem style.

I might try out the steerer cutoff trick but I feel like that might take some clamping force away from the real stem... and if they aren't cut completely square, creating a "leaning tower of Pisa" situation, it could make more of a mess than it was in the first place.
flag Branmuffin
O+
Posted: Jul 29, 2020 at 12:04 Quote
dvfflebagboy wrote:
here is a more telling picture from behind the stem with the top stem bolt removed, about as straight as I could get the camera, what appers to be a silver ring in the gap is the top of the steerer's filed bevel.

photo

bran muffin, you think this is okay?

muddy taker, I like your idea, could you point me in the direction of where you got your stem extender? all I can find are quill stem style.

I might try out the steerer cutoff trick but I feel like that might take some clamping force away from the real stem... and if they aren't cut completely square, creating a "leaning tower of Pisa" situation, it could make more of a mess than it was in the first place.

I would run it. I even looked at mine, which I have been running for the last 6 months and it’s maybe 1mm higher than yours. As long as you are above the top clamp imo, you are good. You are cutting it close for sure but I would not be worried about it.
You still have 85% of your stem clamping the steerer, I would also bet 99% of that clamping force is directly behind the bolts. I don’t see anything catastrophic happening, worst case scenario would be in a hard crash your stem may be more likely to slip and force you to re align your stem and wheel. That being said, it’s you riding it not me, so if you just don’t feel comfortable with it then look into another fix but I would be more hesitant running any type of extender than just running it short.

photo

photo
flag gazmoose
Posted: Jul 31, 2020 at 0:47 Quote
you could get a machine shop to turn you a 'top hat' spacer and press it into the top. smother it in Loctite bearing retainer.
flag Davec85
FL
Posted: Jul 31, 2020 at 13:41 Quote
It's marginal that is. DMR Defy stem has 27mm stack, might just be what you need for peace of mind.
flag wickedfatchance
Posted: Jul 31, 2020 at 14:50 Quote
No problems,I have run with that short and shorter with zero issues.
flag whattheheel
Posted: Jul 31, 2020 at 15:08 Quote
What about taking the bottom of your current stem to the belt sander for a little bit of "weight loss"?
flag Falcon991
Posted: Jul 31, 2020 at 15:15 Quote
Take a shim out and go with a taller handlebar?
flag whattheheel
Posted: Jul 31, 2020 at 15:21 Quote
The OP's stem is slammed, the pic you see is for reference from another user.
flag rahrider
Posted: Jul 31, 2020 at 21:34 Quote
DMR defy stem has a 27mm stack. May do the trick for you.
flag muddytreker
Posted: Aug 3, 2020 at 9:06 Quote
@ dvfflebagboy

Having tried to find them again it seems they are know longer availabe.
I bought them from a private Ebay listing some years back for my
Fox 32 Vanilla's.

The simplicity of them is easily turned on a lathe, a solid T6 round bar of suitable size can be got
on Ebay, perhaps aproach a machine shop who may be willing to undertake
the simple task, some drawings with tolerances for them to go with, or just take the
fork CSU in with you for them to see.
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