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Thread: Why most head tubes on Ti bikes are straight not tapered?

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    Default Why most head tubes on Ti bikes are straight not tapered?

    I've noticed most Ti bikes use straight HT (either 1-1/8'' or 44mm) but rarely tapered HT (only a couple of custom builders has it as an optional extra), much less so than on steel and carbon bikes.

    Is this because Ti tubes supply are straight and few are bothered to invest in the tooling to make tapered ones? Or is it because welding/fabrication with tapered HT is significantly more challenging and mistakes can be costly (for both builder and customer)? Or is it tapered HT simply doesn't make a functional/performance/ride feel difference on Ti?

    Any experience or insight to share?

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    From what have been told, itís mainly a cost thing. I suppose as a technical matter, a straight tube is stiffer, but I donít think I could tell the difference. For taller headtubes, I think a tapered tube looks better:


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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    FWIW, Lynskey only uses tapered head tubes now. I actually prefer the look of a straight head tube but thatís just me.

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    I agree. The Firefly transition is much smoother and looks pretty good to my eye, but I much prefer the look of a straight 44mm head tube to the Lynskey and Paragon tapered head tubes.

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Tapered head tubes only look decent on large sizes. I guess the mitering process is easier on straight tubes.
    --
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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Any noticeable difference between tapered and 44mm in terms of front-end ride feel and handling? Had 44mm and 1-1/8'' HT bikes and 44mm feels quite a bit stiffer, wonder what it's like for tapered

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by amaro View Post
    I've noticed most Ti bikes use straight HT (either 1-1/8'' or 44mm) but rarely tapered HT (only a couple of custom builders has it as an optional extra), much less so than on steel and carbon bikes.

    Is this because Ti tubes supply are straight and few are bothered to invest in the tooling to make tapered ones? Or is it because welding/fabrication with tapered HT is significantly more challenging and mistakes can be costly (for both builder and customer)? Or is it tapered HT simply doesn't make a functional/performance/ride feel difference on Ti?

    Any experience or insight to share?
    I feel like I can speak to this directly because I created the 1.5" lower cup for 44mm head tubes.

    There are several reasons really and you hit on pretty much all of them.

    When I came up with the idea, if a ti builder wanted to use an available headset for tapered steerers, we had to machine or have machined a tapered head tube from 6/4 rod. It was a big investment in both time and cost. The 44mm cup skirt allowed us to use a straight tube or pipe (pipe size was 1.5" sched 40 IIRC) in 3/3.5 ti. At the time, the tubing was harder to come by, but it was still out there as 2" hollows (a "hollow" is an unfinished tube that hasn't been swaged or rocked to size yet). The pipe is slightly undersized on the OD to look really good with the upper cup, but it was still a solution that worked. To the builder, the benefit is that we can buy 8ft sticks of material and as long as we have a lathe, we have a cost effective way to make about a couple dozen head tubes of exactly the size we needed, relieved how we want them with pre-finish tolerances where we want them, we can cut the miters with off the shelf hole saws AND the reamer already existed...win, win, win, win.

    Of course the "tapered steerer fad" (as I was told by the person to whom I first pitched the idea) stuck and as fork makers went, the market for frame building supplies went as well. Relatively recently, Paragon Machine Works (which really is the paragon of readily available frame parts) started offering tapered head tubes of several varieties and you'll see them out in the world but not as often. The builder has to cut the down tube to fit a conical-ish shape and that's going to be a pain in the ass for most builders. I don't know how Firefly does it, but they are DIALED AF so I'm sure it's great. I do know how other builders around me do it and they are not dialed so I'll just say that I personally would not be happy with the fitup that they're tolerating. There's also the matter of post-weld machining. The headtube goes a bit oval when you weld it, no matter how good your fitup and heat control might be and this is where the importance of the post weld processing really comes into play. If you're using drop-in bearings, how do you get the tolerances right without the chatter that is sometimes present with hand tool use? There are a few ways to solve that particular problem, but smaller builders are less likely to spend the time to do it when an easy solution exists and is easier to implement.

    As for the ride feel...the head tube on its own shouldn't make a noticeable difference but the bigger headtube makes it easier to use bigger tubing, which does make a big difference.
    Sean Chaney
    www.vertigocycles.com
    a peek behind the curtain

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by VertigoCycles View Post
    I feel like I can speak to this directly because I created the 1.5" lower cup for 44mm head tubes.

    There are several reasons really and you hit on pretty much all of them.

    When I came up with the idea, if a ti builder wanted to use an available headset for tapered steerers, we had to machine or have machined a tapered head tube from 6/4 rod. It was a big investment in both time and cost. The 44mm cup skirt allowed us to use a straight tube or pipe (pipe size was 1.5" sched 40 IIRC) in 3/3.5 ti. At the time, the tubing was harder to come by, but it was still out there as 2" hollows (a "hollow" is an unfinished tube that hasn't been swaged or rocked to size yet). The pipe is slightly undersized on the OD to look really good with the upper cup, but it was still a solution that worked. To the builder, the benefit is that we can buy 8ft sticks of material and as long as we have a lathe, we have a cost effective way to make about a couple dozen head tubes of exactly the size we needed, relieved how we want them with pre-finish tolerances where we want them, we can cut the miters with off the shelf hole saws AND the reamer already existed...win, win, win, win.

    Of course the "tapered steerer fad" (as I was told by the person to whom I first pitched the idea) stuck and as fork makers went, the market for frame building supplies went as well. Relatively recently, Paragon Machine Works (which really is the paragon of readily available frame parts) started offering tapered head tubes of several varieties and you'll see them out in the world but not as often. The builder has to cut the down tube to fit a conical-ish shape and that's going to be a pain in the ass for most builders. I don't know how Firefly does it, but they are DIALED AF so I'm sure it's great. I do know how other builders around me do it and they are not dialed so I'll just say that I personally would not be happy with the fitup that they're tolerating. There's also the matter of post-weld machining. The headtube goes a bit oval when you weld it, no matter how good your fitup and heat control might be and this is where the importance of the post weld processing really comes into play. If you're using drop-in bearings, how do you get the tolerances right without the chatter that is sometimes present with hand tool use? There are a few ways to solve that particular problem, but smaller builders are less likely to spend the time to do it when an easy solution exists and is easier to implement.

    As for the ride feel...the head tube on its own shouldn't make a noticeable difference but the bigger headtube makes it easier to use bigger tubing, which does make a big difference.
    Thanks for the great, informative post. At least one deft turn of phrase you have there, too, compliments.

    Looking at Paragon's site, I notice that there's little difference in the weights of a straight 44 (3/2.5) headtube and a conical (6/4) headtube, so no penalty if you prefer the aesthetic of a straight tube, hooray.

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    I just caught that "3/3.5" in the first paragraph...it should read 3/2.5. my apologies
    Sean Chaney
    www.vertigocycles.com
    a peek behind the curtain

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Thanks very much for the informative reply.

    Digging into this a little further:

    Quote Originally Posted by VertigoCycles View Post
    "I do know how other builders around me do it and they are not dialed so I'll just say that I personally would not be happy with the fitup that they're tolerating"
    How do other builders do it? And is this more of fitup jig/equipment issue or welding issue?

    Quote Originally Posted by VertigoCycles View Post
    The headtube goes a bit oval when you weld it, no matter how good your fitup and heat control might be and this is where the importance of the post weld processing really comes into play. If you're using drop-in bearings, how do you get the tolerances right without the chatter that is sometimes present with hand tool use?
    Would it be correct to assume this is less an issue if the HS cups/bearings are external style (both upper and bottom)?

    Quote Originally Posted by VertigoCycles View Post
    As for the ride feel...the head tube on its own shouldn't make a noticeable difference but the bigger headtube makes it easier to use bigger tubing, which does make a big difference.
    Take a 44mm straight HT and a EC34/EC44 tapered HT, I assume 44mm straight is bigger hence allowing bigger tubing more easily, so in this case there may be appreciable difference in ride feel (e.g. front-end stiffness). Stiffer than the tapered?

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by sk_tle View Post
    Tapered head tubes only look decent on large sizes. I guess the mitering process is easier on straight tubes.
    I have tapered head tubes on both of my Fireflys (-ies?)...I think they look pretty good and nobody would describe the 125mm head tubes as large.
    "I guess you're some weird relic of an obsolete age." - davids

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by Matthew Strongin View Post
    I have tapered head tubes on both of my Fireflys (-ies?)...I think they look pretty good and nobody would describe the 125mm head tubes as large.
    In fact they look great.

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by amaro View Post
    Thanks very much for the informative reply.

    Digging into this a little further:



    How do other builders do it? And is this more of fitup jig/equipment issue or welding issue?
    A fitup issue is a welding issue. I want to be really careful and state that my opinions about this are mine and apply to me. Other builders can and should decide for themselves how they want to do things and what's acceptable. With that out of the way, a generalization would be that if you can fuse it (weld with no filler) then it's good to go. The first pass as a fusion pass isn't very tolerant of fitup issues. You CAN close gaps that are a few thousandths wide, but it pulls pretty hard in my experience and you have to work harder to straighten the frame through the rest of the process. Some folks I know, miter through with a smaller hole saw and then part of the way through again with a large one to rough out the shape. Then they snip the ears and file it the rest of the way

    Quote Originally Posted by amaro View Post
    Would it be correct to assume this is less an issue if the HS cups/bearings are external style (both upper and bottom)?
    The head tube going oval is expected and planned for. The OTS head tubes from Paragon have an undersized I.D. just for that reason. It allows a builder to easily make it round and square with a reamer/facer once they're done putting heat into it. No matter what kind of bearing is being used, if the builder can make concentric holes with parallel faces (or chamfers for the drop-in bearings) there's no problem. As I see it, the "problem" is that if a builder is able to purchase a head tube that's already prepped for drop-in bearings, they may feel like they don't need post-heat machining. A lot of builders know better and create the necessary processes to do what's needed but some don't. As a consumer, the hard part is weeding them out. If I weren't already a bike builder and I was looking for a new curly bar bike, I'd buy a Firefly. That crew is doing phenomenal work

    Quote Originally Posted by amaro View Post
    Take a 44mm straight HT and a EC34/EC44 tapered HT, I assume 44mm straight is bigger hence allowing bigger tubing more easily, so in this case there may be appreciable difference in ride feel (e.g. front-end stiffness). Stiffer than the tapered?
    I see your logic, pre 2009 I built plenty of bikes with 1.75" (44.45mm) down tubes. You just give it a bit of a squish. I used to make eccentric 38mm head tubes with a little weight relief on the front half, I used to also turn the 38mm tubing down to 37mm to relieve the whole thing for lighter riders but you can still get a 44mm downtube stuck to it with a little persuasion. Same sort of concept for BSA BB shells. You can offset the miter so it's tangent to the bottom of the tube and leave it round, but you've got a hell of a long point to weld between the ST and DT or you can give it a squish, cut it on center and make the afternoon with the torch a little easier.

    Anyhow, bikes can be build with bigger down tubes if you want them and they can still be manipulated to work with whatever HT and BB you want to use without too much trouble so you can have more stiffness than you might ever want.
    Sean Chaney
    www.vertigocycles.com
    a peek behind the curtain

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by VertigoCycles View Post
    A fitup issue is a welding issue. I want to be really careful and state that my opinions about this are mine and apply to me. Other builders can and should decide for themselves how they want to do things and what's acceptable. With that out of the way, a generalization would be that if you can fuse it (weld with no filler) then it's good to go. The first pass as a fusion pass isn't very tolerant of fitup issues. You CAN close gaps that are a few thousandths wide, but it pulls pretty hard in my experience and you have to work harder to straighten the frame through the rest of the process. Some folks I know, miter through with a smaller hole saw and then part of the way through again with a large one to rough out the shape. Then they snip the ears and file it the rest of the way



    The head tube going oval is expected and planned for. The OTS head tubes from Paragon have an undersized I.D. just for that reason. It allows a builder to easily make it round and square with a reamer/facer once they're done putting heat into it. No matter what kind of bearing is being used, if the builder can make concentric holes with parallel faces (or chamfers for the drop-in bearings) there's no problem. As I see it, the "problem" is that if a builder is able to purchase a head tube that's already prepped for drop-in bearings, they may feel like they don't need post-heat machining. A lot of builders know better and create the necessary processes to do what's needed but some don't. As a consumer, the hard part is weeding them out. If I weren't already a bike builder and I was looking for a new curly bar bike, I'd buy a Firefly. That crew is doing phenomenal work



    I see your logic, pre 2009 I built plenty of bikes with 1.75" (44.45mm) down tubes. You just give it a bit of a squish. I used to make eccentric 38mm head tubes with a little weight relief on the front half, I used to also turn the 38mm tubing down to 37mm to relieve the whole thing for lighter riders but you can still get a 44mm downtube stuck to it with a little persuasion. Same sort of concept for BSA BB shells. You can offset the miter so it's tangent to the bottom of the tube and leave it round, but you've got a hell of a long point to weld between the ST and DT or you can give it a squish, cut it on center and make the afternoon with the torch a little easier.

    Anyhow, bikes can be build with bigger down tubes if you want them and they can still be manipulated to work with whatever HT and BB you want to use without too much trouble so you can have more stiffness than you might ever want.
    Another fine post with lots to learn from. Thanks. On the last HT point, besides making it easier to have a larger DT, I was also thinking if the straight vs. tapered makes a difference in terms of HT itself. Reading your replies, you seem to suggest there's probably little difference. However, considering a straight HT paired with a 1-1/8''-1-1/2'' tapered fork and a tapered HT paired with 1-1/8''-1-1/4'' fork, would that make an appreciable difference in the front-end ride feel?

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by amaro View Post
    Another fine post with lots to learn from. Thanks. On the last HT point, besides making it easier to have a larger DT, I was also thinking if the straight vs. tapered makes a difference in terms of HT itself. Reading your replies, you seem to suggest there's probably little difference. However, considering a straight HT paired with a 1-1/8''-1-1/2'' tapered fork and a tapered HT paired with 1-1/8''-1-1/4'' fork, would that make an appreciable difference in the front-end ride feel?
    I think you can remove the headtube out of the stiffness equation, regardless of the diameter. It's a short tube, constrained at both ends, although its main axis is fairly free to wiggle with respect to the centerline of the bike the tube itself, if it's flexing (bowing) I doubt any one can feel it...or test for it. The other main tubes make a huge difference in the feeling of stiffness, as do the chain stays.

    As for the fork, I can't honestly say whether you'd be able to feel the difference between a 1.125/1.5 and 1.125/1.25 fork, I've never ridden a bike with the 1.125/1.25" taper. My gut tells me that it depends on your weight, how you ride and what kind of brakes you use. I'm a bigger guy and there's absolutely a difference between a straight steerer and a 1.124/1.5 steerer in all aspects of riding for me. The biggest immediate bonus for me was on my CX bike when I was still racing and using canti brakes. The whole cable system for canti brakes when a cable stop is on the upper part of the steerer is a recipe for brake shudder and the bigger steerer did a lot to combat this. I could feel it on my road bike too when braking hard before entering a corner and on mountain bikes it was a total game changer, especially as you get into longer travel forks. The added stiffness under a brake load, while cornering and in high speed sections helps in numerous ways. I can't imagine ever going back to a straight steerer on a single crown suspension fork.

    Distilling it down to a road bike...I'm not the guy who can tell you the intricacies of that comparison.
    Sean Chaney
    www.vertigocycles.com
    a peek behind the curtain

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    Default Re: Why most head tubes on Ti bikes are straight not tapered?

    Quote Originally Posted by VertigoCycles View Post
    I think you can remove the headtube out of the stiffness equation, regardless of the diameter. It's a short tube, constrained at both ends, although its main axis is fairly free to wiggle with respect to the centerline of the bike the tube itself, if it's flexing (bowing) I doubt any one can feel it...or test for it. The other main tubes make a huge difference in the feeling of stiffness, as do the chain stays.

    As for the fork, I can't honestly say whether you'd be able to feel the difference between a 1.125/1.5 and 1.125/1.25 fork, I've never ridden a bike with the 1.125/1.25" taper. My gut tells me that it depends on your weight, how you ride and what kind of brakes you use. I'm a bigger guy and there's absolutely a difference between a straight steerer and a 1.124/1.5 steerer in all aspects of riding for me. The biggest immediate bonus for me was on my CX bike when I was still racing and using canti brakes. The whole cable system for canti brakes when a cable stop is on the upper part of the steerer is a recipe for brake shudder and the bigger steerer did a lot to combat this. I could feel it on my road bike too when braking hard before entering a corner and on mountain bikes it was a total game changer, especially as you get into longer travel forks. The added stiffness under a brake load, while cornering and in high speed sections helps in numerous ways. I can't imagine ever going back to a straight steerer on a single crown suspension fork.

    Distilling it down to a road bike...I'm not the guy who can tell you the intricacies of that comparison.
    Ah, brake shudder. Yes, I suspected that with a slimmer steerer. In my case, it's an all-road bike with disc brakes and the rider is fairly light at ~145lb. 1.125/1.25 might make a difference?

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