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Ride Instigator
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I'm looking at a frame to ""upgrade" my current rig, specificially a Yeti ASR-5. Spec sheet says 1 1/8-1 1/2 tapered HT. So....does this mean my oldfangled King HS won't work with this frame? What do I need a 1 1/8 TOP HS half with a 1/ 1/2 BOTTOM with an adaptor to go down to a 1 1/8 steer tube. I iz reel confoozed:confused:
 

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Discussion Starter · #6 ·
wyatt79m said:
I think the whole thing is dumb, and looks terrible. I really hope it just goes away.
Yeah, I agree...stupid! It sounds like I need a 1 1/8 cup for the top and a 1.5 for the bottom, what do I have to do, buy 2 freakin headsets???
 

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taper headsets will become readily available standard items (if they're not already).

changing anything, even if its better, is a challenge. im all for stiffer, better steering fronts, i think the taper tube idea isnt all that bad.
 

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Vaginatarian
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the tapered head tube allows more room to attach the top and down tubes so the frame will be stiffer, I really don't think the fork being tapered adds much if anything as far as stiffness, it only makes contact at the upper and lower bearings, so in my opinion an adapter and a 1 1/8 fork will be just as good for all intents and purposes
 

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dan0 said:
the tapered head tube allows more room to attach the top and down tubes so the frame will be stiffer, I really don't think the fork being tapered adds much if anything as far as stiffness, it only makes contact at the upper and lower bearings, so in my opinion an adapter and a 1 1/8 fork will be just as good for all intents and purposes
The idea is that the majority of the force (at least in regards to stiffness and strength) is going to be at the lower race, and running larger ball bearings and larger diameter steer tube at that juncture reduces weight and increases strength. Whether that will be noticeable to the average rider may be questionable, especially since these forks are typically run in aggressive/freeride applications, where many of the 1.125 steer tubes are 1/4" in tube thickness at the base of the steerer anyway, and most of the afforementioned aren't too concerned about saving a few grams of weight.
 

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Trek claims that going to a tapered head tube on their Fuel EX gained them 30% more stiffness in the frame, regardless of fork, and then another 10% with a tapered steerer tube fork. IIRC, that was only in reference to front-rear stiffness (so deflection under hard braking, etc.) I don't have their testing protocol and I can't vouch for how accurate their claims are, but they also claim that the bigger interface lets them use less material so there's not a significant weight penalty. You also get to use the myriad options of 1 1/8 stems instead of the handful of 1.5 stems.
 

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Jim311 said:
The idea is that the majority of the force (at least in regards to stiffness and strength) is going to be at the lower race, and running larger ball bearings and larger diameter steer tube at that juncture reduces weight and increases strength. Whether that will be noticeable to the average rider may be questionable, especially since these forks are typically run in aggressive/freeride applications, where many of the 1.125 steer tubes are 1/4" in tube thickness at the base of the steerer anyway, and most of the afforementioned aren't too concerned about saving a few grams of weight.
you only save weight over a full 1.5", you gain weight over a traditional 1 1/8"
a tapered tube with an adaptor uses the same bearings as one with a tapered tube
the lower race is bigger to fit the 1 1/8 " fork tube, so really what you have is a larger diameter tube and a slightly larger crown area. I will agree that they are stronger, but I dont think anyone can feel it and I dont think the average rider is ever going to break the crown under normal conditions. the fork legs are way more flexible than any fork tube or crown
 

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dan0 said:
you only save weight over a full 1.5", you gain weight over a traditional 1 1/8"
Right, but it's a compromise of strength/weight characteristics that makes it desirable. But when you think about it, these tapered forks are being run on bikes where an extra 50 grams isn't going to make a damn bit of difference. I think I'd rather go full 1.5 steer, as the options for tapered headsets, and tapered forks, is much smaller than 1.125.
 

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Jim311 said:
the options for tapered headsets, and tapered forks, is much smaller than 1.125.
for now. That is always true of every new technology or standard

I'm not excited about tapered setups over 1.5" for any technical reasons at all. What I am excited about is this: tapered forks are showing up on many bikes that would have never had a full 1.5" setup. Bike companies never wanted to put 1.5" forks on anything but big hit bikes. Apparently they didn't think that much stiffness was necessary or they didn't think they could market it properly. Now companies are starting to put tapered on a lot of bikes, all the way down to super light XC race carbon hardtails.

Similar story with the more obviously unnecessary Fox 15QR thru-axle that Marz has also adopted. It has at least helped start a new trend to finally put thru-axle forks on bikes that don't qualify as AM or DH

The idea that my next XC/trail hardtail could come stock with a tapered thru-axle fork is an awesome one:thumbsup:
 

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eric1115 said:
Trek claims that going to a tapered head tube on their Fuel EX gained them 30% more stiffness in the frame, regardless of fork, and then another 10% with a tapered steerer tube fork. IIRC, that was only in reference to front-rear stiffness (so deflection under hard braking, etc.) I don't have their testing protocol and I can't vouch for how accurate their claims are, but they also claim that the bigger interface lets them use less material so there's not a significant weight penalty. You also get to use the myriad options of 1 1/8 stems instead of the handful of 1.5 stems.
hmmm, bigger tube and less weight = thinner tube . dont see how you can have it both ways ( stronger/ heavier lighter /weaker) regardless , I think the difference between a tapered fork tube and a regular fork tube with adapter is not much
 

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dan0 said:
hmmm, bigger tube and less weight = thinner tube . dont see how you can have it both ways ( stronger/ heavier lighter /weaker) regardless , I think the difference between a tapered fork tube and a regular fork tube with adapter is not much
The tube is larger but you can get away with running thinner walls.
 

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given the same weight, a larger but thinner tube will be stronger in resistance to bending, weaker in resistance to impact. vise verse with a thick smaller tube.
 

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dan0 said:
hmmm, bigger tube and less weight = thinner tube . dont see how you can have it both ways ( stronger/ heavier lighter /weaker) regardless , I think the difference between a tapered fork tube and a regular fork tube with adapter is not much
You can have it both ways, lighter and stiffer. If you don't believe me, come back and discuss it after you've taken a first-year engineering course (sorry, but it's very obvious that you have not). If you draw very simple free-body and shear and moment diagrams, you'll see that the bending moment applied to the fork is highest at the lower head bearing. Adding bending stiffness to that area is beneficial, adding it elsewhere is wasted material.

Bending stiffness increases with the section moment of inertia, which for a tube, increases with the fourth power of the diameter. The weight of the tube increases linearly with the diameter. For example, a 1.5" OD tube with a wall thickness of 0.125" is the same weight as a 1.125" OD tube with a wall thickness of 0.18", but the 1.5" tube is more than twice as stiff in bending. You could also make the large tube lighter, and still stiffer, than the smaller tube. This is the reason for over-sized tube aluminum frames (Klein and Cannondale were the first, IIRC), with the limit in that case being the wall thickness for desired dent or buckling resistance.
 

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Ricko said:
Yeah, I agree...stupid! It sounds like I need a 1 1/8 cup for the top and a 1.5 for the bottom, what do I have to do, buy 2 freakin headsets???
Um...why don't ya read the answers given again...thoroughly

emtnate said:
King also makes a reducer cup if you don't want a tapered fork. It's part of the devolution line, if you're in luck, they'll sell just the bottom cup.

http://www.competitivecyclist.com/mo...548.462.1.html
crisillo said:
correct, if you plan on running a 1 1/8" fork you will need a reducer cup in the bottom.
Chris King said:
Already have a Chris King headset?
Because Chris King headsets share the same cups, a conversion kit is available to transform your current King headset into a Devolution™. We even offer kits to convert a Devolution™ to a NoThreadSet™, a 2Nut™, or a GripNut™.
Or; I guess if you really want to you can go buy two headsets :rolleyes:
 

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I haven't ridden a mountain bike with the new head tube yet. But I can say its a huge improvement with my road bike. I got a Ridley a few yeas a go with it. They were one of the first to offer it. And OMG that bike is fun on twisty descents. So I would think it would be much the same on a mountain bike.
 
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