Bicycle Mechanics - Star nut?

How do you install a Star nut into a steer tube? Is there much work to installing one? Do you need a special tool?

It's not a difficult job but the devil is in the details.

First of all, if you have a fork with a carbon fiber steerer tube, you want to use a compression nut rather than a star nut.

Assuming that you have a fork with a metal steerer, find a bolt with the right thread to match your star nut. Use that to tap the star nut down into the steerer tube.
1. Make sure that you have the steerer cut to the right length. Deburr the cut edge.
2. Use something like a 2 X 4 under your fork crown so you don't bugger up your fork's dropouts against the floor.
3. Start slow and work at getting the star nut started straight. The biggest advantage of using the proper tool is that it makes it easier to get the star nut started straight.
4. You want the top of the star nut to be 15mm below the top of the steerer tube. Measure your progress as you go.

Assuming that you have a fork with a metal steerer, find a bolt with the right thread to match your star nut.



That's usually the bolt from the old headset you are replacing.

So basicly, all you really have to do is tap it down? I guess if you had a rod of metal, or a tube of metal , slightly smaller in diameter than your steer tube, than you could just use that to make sure it stays straight on the way down? Does a star nut really do all that much? Cause my stem clamps onto my steer tube using two strong bolts. I guess you can never have to much strength.

but now that i think about it, because it has 2 rows of teeth, than it can't be to hard to keep it straight! Am i wrong?

So basicly, all you really have to do is tap it down? I guess if you had a rod of metal, or a tube of metal , slightly smaller in diameter than your steer tube, than you could just use that to make sure it stays straight on the way down? Does a star nut really do all that much? Cause my stem clamps onto my steer tube using two strong bolts. I guess you can never have to much strength.

Yes, a tube with an outside diam slightly smaller than the inside diam of the steerer tube would help align the starnut. The starnut needs to be aligned in order to received the screw.

The starnut is only to preload the bearing (it places a constant vertical force on the bearing system) and is used to adjust the headset. Once you tighten the stem to the steerer tube, the starnut has no function. In fact, I've heard of riders removing the starnut to save weight.

Ok, now I understand. Would I be able to take the star nut out of my old fork , and install it in my new fork. Or would the star nut have lost is retaining abillity? Both of the steer tubes are the same diameter.

I used a wooden dowel. It keeps things from getting dinged up. Also, you can cut the dowel to the length you want for the depth, then go at it with a rubber mallet or a hammer on top of a chunk of 2x4.

I found it hard to get started — that's some stiff spring — but once it was going, no big deal.

This is a $5 job at most from your LBS if it is handy.

Nearest one is a 3 hour drive away! lol!

Ok, now I understand. Would I be able to take the star nut out of my old fork , and install it in my new fork. Or would the star nut have lost is retaining abillity? Both of the steer tubes are the same diameter.
First getting the old starnut out requires removing the front brake and driving it down through the steerer tube and out the bottom. You cannot pull it up. Second, after one installation I would not trust the holding power in a second steerer.

You can get them mailorder if the closest LBS is too far to be worth the trip.

RG's installation procedure is a good one. I like to thread a suitable bolt completely into the starnut to act as the driver, It protects the threads and doesn't interfer with the "pedals" as a full diameter dowel might.

Use caution to keep the bolt centered in the steerer to assure the nut goes in straight. Once the starnut is flush with the steerer, you can remove the bolt, add the topcap and rethread the bolt so the topcap acts as a centering guide as you drive it down the remaining 15 mm.

First getting the old starnut out requires removing the front brake ...

Not if you have disks! :)

Not if you have disks! :)
True.

One thing I neglected to mention is that not all forks have the steerer open at the bottom. I have a Kestrel EMS carbon fork with a Cr-Mo steerer and the steerer tube is completely closed at the bottom. I also have a Kinesis Al fork with a Cr-Mo steerer and the fork crown has only a small vent hole under the steerer. In either case the starnut couldn't be removed from the bottom.

I have a Kestrel EMS carbon fork with a Cr-Mo steerer and the steerer tube is completely closed at the bottom. I also have a Kinesis Al fork with a Cr-Mo steerer and the fork crown has only a small vent hole under the steerer. In either case the starnut couldn't be removed from the bottom.

Is there any way to remove the starnut, or do you just drive it to the bottom?

Is there any way to remove the starnut, or do you just drive it to the bottom?

No practical method I know of for this type of fork. If you have to fit a new one, you just drive the original one down out of the way.

Cool guys! Thanks alot!

I use a threaded rod for this purpose.

No practical method I know of for this type of fork. If you have to fit a new one, you just drive the original one down out of the way.

I've seen forks with multiple starnuts in it :)

I've always found it pretty hard to get it to go in straight at the beginning. When you whack on the bolt, one side always tends to go in first causing it to cock sideways. I usually resort to using a punch on the other side to get it past the lip. Once you've got it fully in around the entire circumference, it's easy to drive it straight down. (Maybe more chamfer on the steerer lip might help.) It's always worked out, but it's surprisingly hard. If a LBS is close, I'd just have the LBS do it (and install the crown race as well). They've typically got tools that make this sort of thing unbelievably easy and foolproof.

- Mark

Just don't be a ****** and try to figure out how to do without a star nut. Buy a new one for the new fork (think about it: the old fork is useless without it) and don't try to remove it after the headset is adjusted to save weight.

If I was on a ride with someone crying about their headset coming loose and not being able to adjust it because they removed the starnut to save weight...I'd laugh and leave them for the bears.

Sorry to bump this thread, but to continue on the 'star nut' question:

I've got a full CF fork that, I've recently found out, was installed - stock - with a starnut.:eek:
I'm going to be changing out the headset, as the current one is shot, and I thought this would be a good opportunity to switch over to using the Tune Gum Gum in place of the starnut once the bearings are set.

Now - full CF steerer + starnut. Any good, recommended ways to take out the star nut with out totally killing the fork's steerer?

Drill

Carefully. You are trying to get the starnut to collapse without grabbing the drill and spinning inside the fork which will do more damage.

This is a $5 job at most from your LBS if it is handy.

More like $35 around here.

Sorry to bump this thread, but to continue on the 'star nut' question:

I've got a full CF fork that, I've recently found out, was installed - stock - with a starnut.:eek:
I'm going to be changing out the headset, as the current one is shot, and I thought this would be a good opportunity to switch over to using the Tune Gum Gum in place of the starnut once the bearings are set.

Now - full CF steerer + starnut. Any good, recommended ways to take out the star nut with out totally killing the fork's steerer?


A few manufacturers, notably Cannondale, use a special starnut for CF sterers. Totally legit. If that's the case, no worries. I'd be cautious of pounding down a starnut through a CF steerer. Was it installed by a shop? If so it is either a) legit or b) their bad. Need more info.