I’m wondering what people’s thoughts are on what’s going to happen with carbon steerers. We’ve already seen fork recalls from Cervelo and Isaac. It looks like Isaac chose to add a longer expander plug (similar in length to the Alpha Q) to strengthen the carbon steerer. I’m not an engineer, but I’d imagine that the longer plug helps reinforce the steerer around the stem clamp and headset area. Most top cap expanders are relatively short. Are more manufacturer’s going to return to aluminum steerers, even with the weight penality? Or does titanium offer a better solution? Hincapie’s steerer that broke during Paris-Roubaix a few years ago was alumnium. Is any material ideal for this area of the bike?
Correct me if I’m wrong, but the expansion plug doesn’t function to keep the structural integrity of the steerer tube intact… it functions to give your topcap something to compress the bearings/headset with. If someone wants to argue that the little rubber o-ring and aluminum inserts are ‘key to the integrity of the steerer tube’ I suggest you don’t buy their product.
4 Simple truths:
Carbon breaks
Aluminum breaks (e.g. Hincapie…).
Carbon breaks a lot: Examine all the examples and horrible pictures on this board which happen during everyday use. I have personally had carbon handlebars break during an ‘everyday’ ride.
Aluminum breaks ‘not a lot’: While I’m sure other examples exist…the only example I can think of is Paris-Roubaix…itself the most punishing course in road cycling.
I would love to see the total weight of a carbon steerer with one of these metal inserts for ‘reinforcement’ compared to a well designed fork with an alloy steerer. Both in grams and $$. If this is done for our own dorky curiosity & comparison, and the lawyers are consulted, I’m guessing you wouldn’t see 100% carbon forks anymore for good reason.
A quick note on Hincape’s crash, he had crashed earlier in the race and not changed bikes. It’s likely that the steerer was cracked during the first crash (damage that was not externally visible), and the pounding of the cobbles led to the catastrophic failure (and some cool crash footage).
Carbon’s issue is that it needs to be treated with care. It’s not the best material for the masses (in a fork), since the masses don’t own a torque wrench. Long term I’m bullish on carbon. I look at how Zipp has already worked to make their carbon rims more impact resistant; there are issues to solve, but they will be solved.
The expander plug is to keep the steerer from cracking when the stem is clamped (the resin used to hold the carbon is fairly brittle). It does serve to load the headset bearings, but once the stem is clamped you could then remove it if it was just for preload.
It is like with everything. Some of the superlight forks were simply poorly designed.
Apart from that, if you do not pay attention to stressloads, any expander plug, even the long ones, can potentially be dangerous (just imagine the long steerer people might be tempted to install with the “long and safe” expander)
Problem is: There are no “matched” components out there (like fork + stem + expander) and the manufs are not specific enough what you can or can not do with their components (probably calculated, since they want to sell more units).
I have seen my share of cracked/mangeled steerer tubes (assembled by retailers) and it makes me shudder that there are no real control mechanisms/training in place to prevent suff like the Alpha Q debacle.
I’d like to see some standards on this kind of stuff in the future (when using component A, you should be using component B, but only up to XY mm…)
What you mostly get right now is either some mumbling or some scary disclaimers… neither is helpfull.
