Framebuilders - BikeIsland frame/fork stability question
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11-26-08, 01:45 PM
So there has been this debate going on on another forum and I thought I would pose this quesiton to frame builders.
Bike island offers a new lugged frame called the "old school track" it includes an uncut, partially threaded fork, the description reads:
This frame comes with a seatpost clamp and a partially threaded 1 inch fork. You can finish threading it or simply cut it down and run it threadless.
My understanding is that 1" threaded and threadless forks are not interchangeable as the thickness of the steer tube is different and it would be unsafe to run a threaded fork as threadless.
Second, cutting threads into a fork isn't something bike shops just do, correct? My understanding is that it can dull the chasing die and eventually ruin it.
Lastly, if the steer tube wall was thicker, would a standard 22.2 quill still fit?
Could ya'll clear this up?
11-26-08, 02:16 PM
They're telling you that if you want to cut down the steer tube past the threads to make it "threadless" you can do it. However, you don't want to do it the other way around- you don't want to thread a threadless steer tube. Most threadless steer tubes are either aluminum or carbon fiber, neither of which lend themselves to threading or clamping forces, or both.
I'm going on a limb and saying that the steer tube that they are using is steel, and if it'll cope with the stresses of a quilled stem and the offset piece in the steer tube, the clamping of a stem won't affect it. And yes, any bike shop that's worth their salt can cut additional threads. It's no big deal, and eventually, the cutter will wear down. But, slide the quill stem in there first and see if it fits. If it does, and it has threads already, then it's suitable for either.
If anyone tells you different, they are wrong, simple as that.
11-26-08, 02:21 PM
pretty sure both threaded (&most threadless) steer tubes have 1.5 walls up top, and somewheres like 2.2 down by the crown. some have rifle butting too. The kilo TT comes with 2cm of threads because most LBS' thread cutters dont start threads well (straight). It comes with enough steer tube length for you to either have threads cut all the way down , cut to length and use a quill and threaded headset, or cut to the proper length for a threadless set up: threadless headset & clamp on stem.
1.5+1.5+.2 (wiggle for installing the quill)+22.2=25.4mm or 1"
i think some dedicated threadless steertubes have thinner walls, maybe the reason for most bikes going to 1 1/8th, larger dia, thinner walls=smae or better stiffness& lighter.
O have put together 5 of those kilo TT's and the first batch came with 1" threaded forks, pre-cut to your frame size. the second 2 bikes came threadless. and the last one was as you mentioned. The LBS has no problem continuing the threads. But as i recently found out, very few people like to cut threads where no were before, so have the threads cut before you cut the steer tube. Since lotsa shops charge for cutting threads by the inch, you'll be tempted to cut it before hand. then they woln't even try:(
11-26-08, 02:23 PM
If anyone tells you different, they are wrong, simple as that.[/QUOTE]
i wish i was a sure of myself as you. experience has proven there's an exception to everything.
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