The on-one carbon frame will apparently have a tapered head tube. Can anyone tell me about the issues / benefits of this?
More stiffness, less weight
A lot of roadbikes have tapered headtubes:
[url= http://www.canyon.com/_en/roadbikes/bike.html?b=1924 ]Canyon[/url].
Trek have got their E2 tapered headtube on their Madonne roadbike, Fuel EX, Remedy, Scratch,...
Gary Fisher, specialized also use a tapered headtube.
It makes the front end a lot stiffer than normal headtubes.
It also makes the steering more precise.
Look at this website: [url= http://treknology3.com/cms/index.php?option=com_content&task=view&id=315&Itemid=535 ]Treknology[/url].
The explanation is on the right hand side.
The flip side being that, to benefit from the stiffer steerer, you are tied to a more limited range of forks.
Surely the only forks you can't use are 1.5" steerer forks?
no, 1 1/2 tapering to 1 1/8 at the top. even fewer options, then.
you just use a reducer cup at the bottom and your old 1 1/8" forks.
[i]Surely the only forks you can't use are 1.5" steerer forks? [/i]
Yes but mtbfix said "[b][i]to benefit from the stiffer steerer[/b], you are tied to a more limited range of forks. [/i]" which is true
I was considering the on-one frame as a race frame. Are there any tapered race forks I could buy?
And what about headsets? I assume the reducer to use a 1 1/8" fork shims the fork rather than the frame - and you need to use a tapered headset. Will this be heavier & more expensive than 1 1/8"?
I'm all in favour of bigger, stiffer front ends (lightweight carbon 1.125" steerers often flex more than old steel 1" ones) but tapering just seems like a crap compromise,just so that people can continue to use 1.125" stems.
Far better would have been to go back to a full top and bottom 1 and a quarter ( or better still- a similar round METRIC bearing size), but so far the accountants seem to be winning over the engineers.
tapering just seems like a crap compromise,just so that people can continue to use 1.125" stems.
no, the loads are greatest at the base of the steerer, so a 1.5 headset here is a good comprimise. also 1.5 stems look a bit daft and weigh too much for racers to be interested.
also, tapered head tubes are good even if your using normal forks, they stiffen up the frame, which is why most WC DH bikes run 1.5 head tubes despite almost no one buying or running RS totems or marzocchi 66's on DH bikes anymore.
1.25 headsets died because they were useless, not much stiffer than 1.125 and nowhere near as stiff as 1.5 .
Sorry, I dont believe that loads are greatest near the base. BEARING loads, well, yes, but lateral/ torsional flex can happen right at the top of the steerer. I just dont think that tapering is as effective for reducing twist as running a continuous increased diameter.
For that matter, I wouldnt be against 1.5" top and bottom even on road bikes.
west kipper, surely bending stresses are greatest at the support of a cantilever, ie where the fork meets the frame at the base of the steerer.
Well, the flex I notice most strongly typically seems to occur with a longish stem and where the steerer is supported by the top bearing. With a so called tapered st. much of the upper part of it is actually a similar diameter as a non tapered steerer, to allow for height adjustment.
The Cannondale system six that I rode did have a certain sense of the lower bearing supporting better, but even with a (slammed) heavy 110mm stem there was still a surprising amount of deflection. I expected better.
On a long stem, how much of that flex is in the stem itself, and how much is in the steerer tube? I'd contend that it's in the shaft of the stem as the height of the steerer protruding above the top bearing is less than the length of the stem in the example you give.... and the stiffness of the steerer plus the material of the stem around it will be much greater than the shaft of the stem itself. I'd be looking to 'blame' the stem itself for the flex you observed, not the steerer tube.
Firstly, the long stem complaint refers to my own bikes with normal steerers. the stem on the cannondale was a fairly average length 110, fairly stiff and very heavy.
I'm not saying that tapering is NO better than 1.125, just that if changes are happening it would have been better still to move to the best possible solution.
We now have a whole range of different 'tapered' standards, and I dont think that its currently a big upgrade.