I have some Reba WC (carbon steerer) forks that need a new steerer tube, now I don't know if you have an idea as to how much that would cost, but lets just say its 'prohibitive' 😉
So, as the carbon has a small split, & is a bit rough/flaking around the top of the steerer, I was pondering on ways to make them more usable & confidence inspiring.
The best I can come up with is to fill the steerer tube with a decent glue like Araldite, then ream most of it out & fit a hellicoil to take the topcap, I know it would add a few (hundred?) grams, but the alternative would cost hundreds.
What would you do?
[i]what would you do?[/i]
i would not by suspension forks with a carbon steerer, they'd worry me and this is the reason i'd not want carbon stem or bars
I'd buy new forks and I have same thoughts as rocketdog on carbon.
As an aside I enquired as to the cost of a new steerer for some Pikes it was eye watering and over £200
I've ridden with carbon bars on my two hardtails for the last six and a half years, and I have no qualms about them, but carbon steerers bother me. Ok when you have sponsors to pick up the tab, but not otherwise. Cost implications alone, as you've found, would put those forks out of the picture. Oh, and I've got rigid carbon forks on my SS, but they do have an alloy steerer, which gives me confidence in them.
the carbon has a small split, & is a bit rough/flaking around the top of the steerer
Do you have a death wish or want to remove all your front teeth in one easy go. Then by all means carry on it will provide your friends with hours of amusing anecdotes of the day your forks snapped off on that fast downhill.
Fill the steerer tube with a mix of two part epoxy and carbon fibre rods.
Use PVC electrical tape to seal the bottom of the steerer.
I used this method on some steel tent poles and they are stronger than new.
Of course its up to you to assess whether this is suitable for your application, but a steerer jammed solid with various diameter carbon rods and two part epoxy will be friggin strong.
I bought rods from model shop, and two part epoxy from there two.
I squirted both syringes of epoxy into a 50ml syringe to mix it. This way you waste none of it.
Cut your carbon first. Work out best combination of diameters to fill the steerer.
If you need a good dentist...tough, mines NHS in Rothwell.
CHB, there is no 'bottom' of the steerer tube to worry about, it's solid.
The carbon rods sound interesting, not thought of those before, but the theory seems good.
Re the 'dentist', compared to the carbon seatpost that failed on me the other week sending the big ring into my leg, I'm not sure what I would choose 😉
I still think an epoxy filled steerer tube would be stronger than standard alloy.
Whereabouts is the "small split"? If it's near the top of the steerer I'd cut them down a little bit and sell the forks on ebay! Than I'd buy some new forks. 🙂
FWIW I had SID WC forks (with the carbon steerer) for years with no problems but the new SIDs are all alloy steerers and they're still very light.
Crazy-legs, at the top, but to make good the steerer would then be about 170-175mm long, not much use to most folks.
Cheers.
As CHB desribed, & I'd suggest using one of the West System epoxy's. It's incredably strong & durable, it's used in boat manufacture & repair. I think you can get small repair kits. You can also add filler powders & microfibres to both lighten & strengthen the repair.
[url= http://www.westsystem.com/ss/ ]West System Here[/url]
You'll get it from a decent boat or yacht chandlers. Not cheap but far better than using something like Araldite.
Is it possible to fit a cheaper, alloy replacement crown/steerer? This would add as much weight as the botch you detailed and might offer more peace of mind.
there is much more force through the bottom of the steerer(witness 1.5 > 1.125 head tubes). I say bodge the top with a bit of epoxy and keep an eye on it.
DEAR GOD NO!!!!!!!!!!!
Epoxy is just plastic, you may as well melt candlewax down the steerer tube to fix it!
As for putting carbon rods through it, its a better idea, but not by much. Comparable to asking a builder to build the bottom half of your house out of dry bricks then the top half out of concreet. ok, bad example, concreet and bricks have similar properties (strong in compression but rubbish in tension, hence why walls crack but wont crumble, whereas CF and epoxy are opposites (CF is strong in tension, epoxy in compression) its the combination that makes composites so strong.
Nothing suggested on this thread even aproaches what i'd considder good advice.
Bin them and buy new ones.
Get an Easton bung for EC90 road forks. It's an alloy sleeve with pre-fitted star-nut that is designed to be bonded (with supplied epoxy) inside carbon steerers. It both holds the star-nut and helps with the stem loads...
at what degree is the crack on the steerer (ie front 0 degrees rear 180 degrees) i would second aluminium bung but would also epoxy the crack i would also make sure the bung goes further in to the steerer than the crack (at lease 25%)
This is not a spoon is correct (ish!)...epoxy is not great in tension.
Using CF rods with epoxy is like a hi-tech version of re-enforced concrete.
You take two materials with contrasting properties and together they are much stronger. I am sure if James May or Richard Hammond were here they could point you to a youtube interweb link to explain the theory.
nope, im competely right,
CF rods aren't just CF, they'r carbon fibers bonded into epoxy (the same as the steerer already) And as they'r straight they wont grip with the epoxy like the (comparitively) random weve in CF composite.
And glueing the two sides of the crack together with epoxy won't solve the problem, the two sides of the crack will always be in tension with each other (hence why its a crack) and you'r filling the gap with the component thats no good in tension!
For your own sake bin them, buy some new forks,
SH Reba's - £160
Dentist's bill £1k ++++++
Funeral costs (covered by your life insurance so irelavent)
The only place i can think of that could potential fix this are various ice hockey stick repair shops, although they'r never the same again, hockey sticks are not going to kill you when they fail, and im not sure if the repair them from the inside or the out.
So how about gluing a steel tube to the inside of the steerer?
At least it would bend after the CF had failed 💡
**** it, £350 on a new set of forks sounds like a good idea 🙂
is the steerer pressed in or is it bonded to the crown? if its pressed why dont you get a new steerer fitted??
The steerer & crown are one unit, last time I asked it was about £500 plus about £100 to fit & service 🙁
How small is the split? and if it's right at the top, wouldn't it be all together by the stem clamping around it anyway?
Stick them on eBay, either cut them down first, or let people know that there's a crack and they may want to cut them down.
How did you crack it!? I've had 3 pairs of MTB forks with carbon steerers (SID WC, Reba WC and Specialized E100s) and never had a problem with any, in fact I'm not sure I've ever seen anyone crack a steerer, the top's not exactly under much strain!
Can we get some pics? Then we can all decide on the best method of repair and then make bets on how long it'll last.
I'll try & do a pic when I get home later.
Whats the shortest usable steerer length anyway? Ebay's not a bad idea.
Nick, not sure, but when I bought them they had a SFN fitted so I cut down the steerer.
there's a guy in last months 220 tri magazine who repairs carbon bike frames, I'll look up the details tonight and you could get his opinion - he's done a lot of carbon fibre work over the years by the sound of it!
here's the guy from the mag article (copied an pasted from another forum):-
Carbon repairs. Darren Bancroft:
07767 766063
01530 835771
djbancroft@btinternet.com
seen frames replaced by him - does very good job , not sure on the technicalitys of his repairs but my mates riding a Giant TCR once that got trashed when the "peloton" binned it and his bike got ran over - at 3 weeks old !
now im sure you can appreciate how old it must be to be an once ....
Can you get a new alloy steerer fitted?
Stick an alloy shim down inside it - jobsagoodun.
have people never seen a carbon steerer - crown combo .... a vast majority of these replys suggests not ....
personally it sounds like the steerer clamp on the stem has been over tightened.
id just cut the damaged portion off ebay em and buy some others with the right steerer,- people with short headtubes need forks too !
i have generally steered clear of carbon steerers on the mtb - yep they are flash but seen more than my fair share of steerer damage from badly designed headsets to innocuous crashes doing more than meets the eye ...
i have generally steered clear of carbon steerers on the mtb - yep they are flash but seen more than my fair share of steerer damage from badly designed headsets to innocuous crashes doing more than meets the eye ...
when I bought them they had a SFN fitted
Please tell me someone didn't bang a SFN into a carbon steerer. No wonder they're cracked. Even if you cut a good inch or two below the SFN, the tension from the SFN expanding the tube from the inside could still have done some damage.
A bond-in bung/sleeve as mentioned above (EC90, Cervelo 3T/Wolf) might be ok if the crack is less than 10mm long, any more than that and I reckon it's toast.
OK, just got home, can't be arsed with pics tonight TBH, maybe tomorrow.
Does anyone have a link to the easton bung, or any other suitable bung, google is pants for looking for stuff like that 🙁
Cheers.
forge197 - Member
I'd buy new forks and I have same thoughts as rocketdog on carbon.As an aside I enquired as to the cost of a new steerer for some Pikes it was eye watering and over £200
I recently got a new steerer for Fox 32's and it was less than £100 from Mojo 🙂