Question about Compression bolt and fork

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4/28/2017 2:44 PM
Edited Date/Time: 4/28/2017 2:45 PM

Just for piece of mind and safety sake, About how many turns of the compression bolt into the thread of the forks is enough for you guys to call safe when adjusting stem height etc, I only ask because I want to add a few more spacers but am unsure if going much higher will be catastrophic once i take her for a few dirt runs... Right now I would say i have at least 10 solid turns before shes tight. so maybe a 1/2" between fork and compression bolt if inside the stem ? Should i shorten that shit up?

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4/28/2017 3:15 PM

Well, if you shorten the thread engagement area, it's less safe. Not monumentally un-safer, just logically less safe. It makes virtually no real difference as the important thing is getting the stem fully touching the steerer tube of the fork since that's what holds it in place, not the compression cap.

Also, it depends on what cap, stem, and fork you're using.

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Scooter kid trying to ride a bike.
@scootereyn

4/28/2017 3:39 PM

You want the top of your steerer as close to the top of your stem as you can get without the compression bolt bottoming out. If you have your stem too high, you'll crush your steerer, risk cracking your stem, and it'll be more likely to slip

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4/28/2017 6:17 PM

readybmxer wrote:

Well, if you shorten the thread engagement area, it's less safe. Not monumentally un-safer, just logically less safe. It makes ...more

Running Colony MVP forks with a Colony screw compression bolt and a S&M shredneck.

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4/28/2017 7:07 PM

grumpySteve wrote:

You want the top of your steerer as close to the top of your stem as you can get without the compression bolt bottoming out. ...more

I don't think it should be as close to the top of your step as you can get it, because things can compress together a tiny bit and once you tighten things up it might end up bottoming out anyway. My rule is no more than 2-3mms. Definitely agree with that second part though.

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4/28/2017 7:57 PM

You can run the stem without a comprehension cap. Not the best thing to do, but if you have the stem bolts tight you can do it.

I always have 1 3mm spacer under my stem. Most times it's about exactly 1mm of stem without steerer, the rest of the stem has steerer in it. The purpose of the compression bolt is mainly to adjust the bearings. Only once you have them right will you know how much steerer is in the stem. Running Fit Blades and a Stolen Convict stem I have about 5 turns after my bearings are right to snug the compression bolt down. So what you want to do is not over tighten the bearings (steerer unless used/cut should be all the way in the stem) be sure that you tighten the stem 1st after your bearings are set. Then tighten the compression bolt up. Be sure you put a bit of grease on the threads. If the steerer sticks out of the stem you will need to trim the steerer or put spacers on top of the stem.

I have really only seen a handful of forks need more than 3-5 turns. Most times they are the old/stock pressed in star nut. A picture would be great to be sure that you are good to go.

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4/28/2017 9:07 PM
Edited Date/Time: 4/28/2017 9:24 PM

^^^ I'm pretty sure you always want to tighten up the compression bolt first (just until there's no play in the headset) and then align your stem and evenly tighten your two clamping bolts. If your headset becomes loose after that, redo everything in the order above, but snug your compression bolt just a tad more (if already bottomed out add another 1mm spacer under your stem).

2.5mm from the steerer tube to the stem is the least amount of space I'd personally go.

3mm-4mm is the sweet spot.

Not advisable to go lower than 1-2mm above your top pinch bolt on your stem (that's if you really have to).

*Edit: Dans Comp's how to says approximately 1/4" (6.35mm), but that seems a little excessive. lol

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4/29/2017 10:56 AM

Bryan91 wrote:

^^^ I'm pretty sure you always want to tighten up the compression bolt first (just until there's no play in the headset) and ...more

Yea I always tighten compression bolt first then stem... I think I am ok, Ill let you know if I eat shit soon.

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4/29/2017 1:10 PM

grumpySteve wrote:

You want the top of your steerer as close to the top of your stem as you can get without the compression bolt bottoming out. ...more

sundaybmxRR wrote:

I don't think it should be as close to the top of your step as you can get it, because things can compress together a tiny bit ...more

Hence why I said as close as possible without the compression bolt bottoming out :p

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