Installing forks with carbon steerer

[AndyTheBikeGuy]

Hi all,

I've just purchased a set of Lauf TR29s and I've only ever used star nuts, I believe the solution for carbon steerers is a bung and there are plenty online, but just looking for any advice on which one to go for and anything to look out for on installation?

All advice very welcome!

Cheers,

Andy

[redefined_cycles]

I just go with anything thats got some branding on it.... I try to make sure the grippy bit is properly seated/held in place before tightening the bolt that pulls the bung back into it (the grippy bit)...

I also try to take it easy and ensure that I dont get into tge situation that the grippy bit rotates/slips (ie. Dont want it to inadvertantly grind the carbon as I always felt (for some reason, cant remember exaclty) that once it swivels and makes the inner of the steerer tube any smoother, the grips not gonna be there...

Once you know its dug into the steerer tube then I just torque it snug (obviously dont overdo it) enough that its properly held in...

Sorry for making it seems complicated. Its not really but you know

[johnnystorm]

Main thing is to get the right size for your steerer's internal diameter. Beyond that it's just installing an expanding wedge with the appropriate hex key.

[pistonbroke]

The wall thickness of carbon steerers can vary and getting the correct diameter insert is important.
Can Lauf tell you the nominal internal diameter?
Unless you have experience and a proper cutting guide, I'd advise taking it to your LBS for steerer cutting, if they look blank and get a standard pitch hacksaw out of the toolbox WALK AWAY. You need a shop used to cutting carbon tube with the appropriate fine pitch saw blade and cutting guide, sure there will be those along here who have done it with a rusty penknife but I'd not be risking a £700 fork with a novice. Also measure several times with the correct stem, spacers, headset, the stem should clamp all of the steerer and not sit above the top of the carbon.
Expander wedges should be at least 40mm long to grip the inside of the steerer, the stresses on road bikes are lower than off road.
This one works well if it's the correct diameter.
https://www.planetx.co.uk/i/q/FSPXFBUMK ... -bung-mk-2

[redefined_cycles]

Just remembered... Dont forget that gripping carbon steerer at the end isnt same as gripping standard alloy ones... therefore before making your (perfectly square cut using correct tools to hold it tight and if you need the saw then Screwfix does and Irwin that takes a special carbon cutting blade which they also sell) cut, make sure you consider that your not to have the stem sitting at the very end (with the 5mm gap etc etc on inside if yph know what I mean for a standard stem clamping...

Ie. Make surw you lwave room to have at least a 5 or 10mm spacer above the stem so its not putting pressure on the end/edge pf the steerer but rather on the main body of it

[ScotRoutes]

I always ensure that the wedge is within the dimensions of the stem.

You can buy fine-pitched hacksaw blades at B&Q and an old stem bolted on makes an adequate cutting guide.

www.carboncycles.cc sell a wedge.

[AndyTheBikeGuy]

Thanks all, really helpful as always. I'll speak to the LBS as I need them to look at my susser so 2 bird one stone.

Cheers,

Andy

[jameso]

Make surw you lwave room to have at least a 5 or 10mm spacer above the stem so its not putting pressure on the end/edge pf the steerer but rather on the main body of it

Yes.. do this ^

[Cheddar Man]

Definitely get some LBS advice on this, especially if you have to cut the tube. This could be a really expensive learning curve for you

[AndyTheBikeGuy]

Thanks all, so after a quick fit test yesterday, I don't need to cut the tube down (they're second hand, so already cut). There's enough space for a spacer or two above the stem so that should be fine. I've measured internal diameter and found a compression plug that's the right size. Is it just a matter of fitting and seeing how I go or anything else that's a risk?

[redefined_cycles]

Thanks all, so after a quick fit test yesterday, I don't need to cut the tube down (they're second hand, so already cut). There's enough space for a spacer or two above the stem so that should be fine. I've measured internal diameter and found a compression plug that's the right size. Is it just a matter of fitting and seeing how I go or anything else that's a risk?

Just fitting left now matey... The only risk I found (or was it in my head) is the plug not gripping. Ensure (its not PX) its a decent plug and looks a bit textured on outside. No harm adding bit of carbon paste for extra grip...

Essentially though, just a matter of fitting really and ensuring its as close to the steerer edge as poss and gripped in there. No harm finding a torque spec online but I've never really needed it... Don't swing on it whilst tightening (that might bw a bit much )