al vs carbon steerer

[rparedes]

I'm evaluating several carbon bikes and one item that I don't know about are headsets: the advantages/disadvantages of a carbon fork with carbon steerer tube vs a carbon fork with aluminum steerer tube. All the bikes I'm looking at seem to have an integrated headset- which i guess is the only way to get a full carbon bike?

BUT I've also read from a headset manufacturer's website that integrated headsets are not the way to go

The bike will be used for more serious training-faster more intense workouts- mostly on asphalt roads with lots of patches mostly flat with a few steep hills.

 

[kytyree]

Speaking in generalities the carbon steerer will be lighter than an Al one. There is a limit to how long a carbon steerer can be above the headtube, generally this shouldn't be too much of a concern assumming you aren't of unusual proportions and have a frame that fits you.

Both are very durable, with the carbon steerer you do need to be more careful with properly torquing stem bolts and so on but other than that they work well.

Personally I would rather build a bike with a carbon steerer just because I find it easier to work with and less trouble to cut than a metal one. If a bike fits you well, rides well and the price makes sense I wouldn't let the steerer material be a concern. You can always change a fork out later anyway.

 

[artemidorus]

I'm evaluating several carbon bikes and one item that I don't know about are headsets: the advantages/disadvantages of a carbon fork with carbon steerer tube vs a carbon fork with aluminum steerer tube. All the bikes I'm looking at seem to have an integrated headset- which i guess is the only way to get a full carbon bike?

BUT I've also read from a headset manufacturer's website that integrated headsets are not the way to go

The bike will be used for more serious training-faster more intense workouts- mostly on asphalt roads with lots of patches mostly flat with a few steep hills.

As far as I know, carbon steerers can be used with traditional threadless and integrated headsets. The only sort they can't be used with is a threaded headset. Chris King's concerns about longevity have not been born out by published longevity data or even general opinion. This may be because many/most enthusiasts and most pros replace their frames frequently. A carbon steerer is lighter, but less easily inspected or trusted after a big hit.

 

[531Aussie]

I'm evaluating ........

In general, I prefer alu steerers because the whole fork is usually stiffer due to the alu crown. The weight 'penalty' is anywhere from 80g to 100g upward, although a lot of full-carbon forks have more 'sophisticated' blades, so if a 'fancy' full-carbon weighs <300g, it's not just due to the steerer material, it's due to the overall design of the fork. Vice versa for an alu-steerer fork.

An alu-steerer fork will weigh anywhere from ~470g to ~570g, and a full-carbon fork will be ~450g, right down to <300g for expensive ones

'Word' on the street is that carbon steerers aren't as strong as alu -- and I tend to agree -- but, like a lot of this stuff, we're not seeing a bazillion carbon steerers snapping all over the place.

I've got rid of a few full-carbon forks and replaced them with cheaper forks with alu steerers because the full-carbons were a bit flexy. I've got rid of a Columbus Muscle, two Mizuno full-carbons, a Specialized FACT, and an old LOOK HSC. The only full-carbon fork I really like is an oldish Columbus Carve.

Stiffer forks obviously don't flex as much when you get off the saddle to mash, they're generally more stable at high speeds, and they generally corner better. The downside is less comfort and a tiny weight penalty.


In theory, integrated headsets put more stress on the head-tube, but, once again, we don't see a trazillion cracked or distorted frames. I reckon they're a bit of a toss, and mostly done for looks, but they're becoming difficult to avoid on new frames. I said I'd never get one, but then I got a good deal on an alu Cervelo Soloist frame, so...... Columbus make a semi-integrated head-set, but I dunno how compatible they are with all frames.

http://www.columbustubi.com/eng/4_3_7.htm

 

[alienator]

In general, I prefer alu steerers because the whole fork is usually stiffer due to the alu crown. The weight 'penalty' is anywhere from 80g to 100g upward, although a lot of full-carbon forks have more 'sophisticated' blades, so if a 'fancy' full-carbon weighs <300g, it's not just due to the steerer material, it's due to the overall design of the fork. Vice versa for an alu-steerer fork.

An alu-steerer fork will weigh anywhere from ~470g to ~570g, and a full-carbon fork will be ~450g, right down to <300g for expensive ones

'Word' on the street is that carbon steerers aren't as strong as alu -- and I tend to agree -- but, like a lot of this stuff, we're not seeing a bazillion carbon steerers snapping all over the place.

I've got rid of a few full-carbon forks and replaced them with cheaper forks with alu steerers because the full-carbons were a bit flexy. I've got rid of a Columbus Muscle, two Mizuno full-carbons, a Specialized FACT, and an old LOOK HSC. The only full-carbon fork I really like is an oldish Columbus Carve.

Stiffer forks obviously don't flex as much when you get off the saddle to mash, they're generally more stable at high speeds, and they generally corner better. The downside is less comfort and a tiny weight penalty.


In theory, integrated headsets put more stress on the head-tube, but, once again, we don't see a trazillion cracked or distorted frames. I reckon they're a bit of a toss, and mostly done for looks, but they're becoming difficult to avoid on new frames. I said I'd never get one, but then I got a good deal on an alu Cervelo Soloist frame, so...... Columbus make a semi-integrated head-set, but I dunno how compatible they are with all frames.

Okay, I'll disagree on a few points.

A lot of "fork flex" actually comes from the steerer, and using simple geometry you can see how a little steerer flex results in a lot more movement at the dropouts. The steerer has to flex. For it to have as little flex as possible, it'd have to be supported along its entire length with roller bearings or summat.

There is some flex at the crown, but of possibly greater concern is adding another joint--a glued joint at that--at the crown. Granted, bonded joint technology is mature, and it's rare for bonded joints to fail. However, for those people that insist on worrying over every little thing, well, they can worry over joints unbonding.

Aluminum is stronger? Well, that's an ill-posed question, especially when posed in the context of composites. You first have to determine what strong means. If you mean "strong" as in "less likely to fail," I think your claim fails. George Hincapie might disagree with you, but then that was only one instance. The fact is that CF can be made to have a lifespan much greater than an aluminum steerer. In real terms, though, both are sufficiently sturdy that no one should really worry.

Given the new CE standards for forks, people ought to be a bit less worried about full CF forks. And as long, now, that full CF forks have been around--and at least Look, if not some of the other makers, have been making them a long time--and with the rarity of failures, I think they've been proven to be reliable.

I'm about to test a Reynolds Ouzo Pro Lite on a descent of a nasty fire road/motocross road as soon as my Vittoria Pave tubies get here, so I'll let you know how that goes.

In the end, go with what helps you sleep better. No matter what you choose, it'll be more than durable enough for you on the road.

 

[531Aussie]

Okay, I'll disagree on a few points.

A lot of "fork flex" actually comes from the steerer, and using simple geometry you can see how a little steerer flex results in a lot more movement at the dropouts. The steerer has to flex. For it to have as little flex as possible, it'd have to be supported along its entire length with roller bearings or summat.
.

I also reckon steerers flex, but someone once challenged me on here (or on Bike Fourms) to explain exactly how, and I couldn't, so i balked, and started 'attacking' the crown.

 

[alienator]

I also reckon steerers flex, but someone once challenged me on here (or on Bike Fourms) to explain exactly how, and I couldn't, so i balked, and started 'attacking' the crown.

I understand. One of the lower order bending modes for a fork is one where the lower headset bearing is the fulcrum. In that mode the fork bends on both sides of the bearing, i.e. in the steerer and the crown/legs. Bending modes/vibration modes (they're really the same things) are a bit complicated in a fork, but all that really needs to be realized is that the fork is only supported at three places: the dropouts, the lower HS bearing, and the upper HS bearing. A fork is free to bend and does so in every other place. It has to or it would break with the first load.

As a result of being an optics guy, I also have to be a bit of a vibrations/bending guy. Light is just a harmonic energy form, and when we're measuring things to silly small precisions, controlling vibrations can be mucho important. See, it's not all fame, fabulous wealth, and Playboy parties like you might have thought.

 

[OldGoat]

All the bikes I'm looking at seem to have an integrated headset- which i guess is the only way to get a full carbon bike?

My Aegis Aro Svelte is full carbon, and has a Chris King non-integrated headset.

 

[Peter@vecchios]

I'm evaluating several carbon bikes and one item that I don't know about are headsets: the advantages/disadvantages of a carbon fork with carbon steerer tube vs a carbon fork with aluminum steerer tube. All the bikes I'm looking at seem to have an integrated headset- which i guess is the only way to get a full carbon bike?

BUT I've also read from a headset manufacturer's website that integrated headsets are not the way to go

The bike will be used for more serious training-faster more intense workouts- mostly on asphalt roads with lots of patches mostly flat with a few steep hills.

Integrated headsets make the head tube larger which make assembly easier(read cheaper). They color it as some sort of performance advantage but it really isn't. As long as the bearings are available, it really is no big deal but if they disappear, you may have to replace the frame because of a $20 set of bearings. Carbon steerer forks are lighter, not better than aluminum steerer carbon forks. PLUS you are generally limited to how many spacers you can put under the stem on carbon steerers(I use a max of 4cm), not so with aluminum. BUT if ya gotta put lots and lots of spacers under the stem, fit of the frame may be an issue.

 

[531Aussie]

^ Crikey!

 

[rparedes]

The fact is that CF can be made to have a lifespan much greater than an aluminum steerer. In real terms, though, both are sufficiently sturdy that no one should really worry.

OK.
How about the "integral head set" issue? Any concerns that the carbon head tube will not last due to the wear of the bearings?

Thanks!

 

[rparedes]

As long as the bearings are available, it really is no big deal but if they disappear, you may have to replace the frame because of a $20 set of bearings.

So... the bearings can NOT be replaced in an integrated headset? or does it mean that they have caused wear on the internal surface of the head tube and you have to trash the frame? any life expectancy (bearings or head tube wearing surface) in terms of miles?

 

[artemidorus]

OK.
How about the "integral head set" issue? Any concerns that the carbon head tube will not last due to the wear of the bearings?

Thanks!

The concerns with regard to integrated headsets relate to the possibility that the cartridges will wear into the sockets they sit in within the headtube, not that they will eat into the steerer. I don't think that Chris King's paper made any reference to steerer damage.
I'm running a carbon steerer with an integrated headset, so I'll post in a few years' time and let you know!

 

[artemidorus]

So... the bearings can NOT be replaced in an integrated headset? or does it mean that they have caused wear on the internal surface of the head tube and you have to trash the frame? any life expectancy (bearings or head tube wearing surface) in terms of miles?

The bearings can be replaced very easily if they can be obtained. As far as I know, noone knows whether premature headtube wear is a real process, yet.

 

[Peter@vecchios]

So... the bearings can NOT be replaced in an integrated headset? or does it mean that they have caused wear on the internal surface of the head tube and you have to trash the frame? any life expectancy (bearings or head tube wearing surface) in terms of miles?

Schwinn Fastbac..no more bearings. Trek 5500(maybe 5200) with unique to that fork bearings..no mas. They can be replaced as long as the bearing maker makes 'em. Internal/integrated HS can cause wear to head tubes of aluminum frames..if that happens, frame is adios....

 

[PeterF]

Schwinn Fastbac..no more bearings. Trek 5500(maybe 5200) with unique to that fork bearings..no mas. They can be replaced as long as the bearing maker makes 'em. Internal/integrated HS can cause wear to head tubes of aluminum frames..if that happens, frame is adios....

I don't see the trend going back to external headsets any time soon. I'm seeing more and more tapered steerer tubes which will require even quirkier set ups. I have a 2004 Pinarello with an internal headset. I was able to replace the bearings, but not sure how much longer they will be available (hopefully it won't be an issue). The crown race doesn't seem to be available, so I need to be carefull with the one I have if I need to switch forks again. BTW the design of the Pinarello was pretty basic. Just two bearing cartridges pressed into the frame and a top retainer ring. Easy job replacing.