Are threaded forks tapered inside?
09-01-17 | 07:50 PM
#1
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Bikes: Dave Kirk Custom, Clockwork Bikes Custom, Batavus Course Specialized HardRock x2 Trek 700 MultiTrack 1991 Trek 950 SingleTrack. Miyata Three Ten
Are threaded forks tapered inside?
Hi,
I have a big tall dirt drop stem going into a 1 inch threaded fork. I want it to go another inch in, and looking at the inside of the tube, there is at least 2 more inches it could go, but it won't. I'm guessing the inside of the steerer column must be tapered? I was hoping to avoid cutting the stem. Thx.
I have a big tall dirt drop stem going into a 1 inch threaded fork. I want it to go another inch in, and looking at the inside of the tube, there is at least 2 more inches it could go, but it won't. I'm guessing the inside of the steerer column must be tapered? I was hoping to avoid cutting the stem. Thx.
09-01-17 | 08:02 PM
#2
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From: Sacramento, CA
Bikes: old ones
Steerer tube diameter
...this refers, if I'm not mistaken, to the outside diameter of the steerer, but you do run into a number of issues trying to drop a stem all the way into many threaded steerer forks, either because they are butted at the bottom, or because there is some obstruction in the lower section. If it looks like straight wall tubing, you can ream it out with the proper tool, but most people choose instead to reduce the lower stem diameter by sanding or grinding.
There's no good universal answer. If it won't go down, don't force it.
When sizing a fork to a frame, the diameter of the fork steerer or steer tube (1" or 1⅛" or 1½") must not be larger than that of the frame, and the length of the steerer tube should be greater than but approximately equal to the head tube length plus the stack height of the headset. Adapter kits are available to enable use of a 1" fork in a frame designed for a 1⅛" steer tube or a 1⅛" fork in a 1½" frame.
Manufacturers of high-end bikes, both road and mountain, have started to use tapered steerer tubes. While there are purported advantages, there are not any standards yet developed, with each manufacturer following its own conventions. This makes replacement parts difficult to come by, only available from the original manufacturer.https://en.wikipedia.org/wiki/Bicycl..._tube_diameter
Manufacturers of high-end bikes, both road and mountain, have started to use tapered steerer tubes. While there are purported advantages, there are not any standards yet developed, with each manufacturer following its own conventions. This makes replacement parts difficult to come by, only available from the original manufacturer.https://en.wikipedia.org/wiki/Bicycl..._tube_diameter
There's no good universal answer. If it won't go down, don't force it.
09-01-17 | 08:12 PM
#3
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Joined: May 2012
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From: Atlanta, GA
Bikes: Dave Kirk Custom, Clockwork Bikes Custom, Batavus Course Specialized HardRock x2 Trek 700 MultiTrack 1991 Trek 950 SingleTrack. Miyata Three Ten
Steerer tube diameter
...this refers, if I'm not mistaken, to the outside diameter of the steerer, but you do run into a number of issues trying to drop a stem all the way into many threaded steerer forks, either because they are butted at the bottom, or because there is some obstruction in the lower section. If it looks like straight wall tubing, you can ream it out with the proper tool, but most people choose instead to reduce the lower stem diameter by sanding or grinding.
There's no good universal answer. If it won't go down, don't force it.
...this refers, if I'm not mistaken, to the outside diameter of the steerer, but you do run into a number of issues trying to drop a stem all the way into many threaded steerer forks, either because they are butted at the bottom, or because there is some obstruction in the lower section. If it looks like straight wall tubing, you can ream it out with the proper tool, but most people choose instead to reduce the lower stem diameter by sanding or grinding.
There's no good universal answer. If it won't go down, don't force it.
09-01-17 | 08:47 PM
#4
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From: Appleton WI
Bikes: Several, mostly not name brands.
Steer tubes are often butted, meaning that the lower end of the tube has a thicker wall than the upper end of the tube. This can prevent your quill stem from fully inserting into the fork.
09-02-17 | 05:29 AM
#5
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From: Roswell, GA
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Here is an article on butted steerers and the danger of trying to clamp a quill stem too far down in them. https://www.sheldonbrown.com/handsup.html#danger
09-02-17 | 08:23 PM
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From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
the steerer tube on the fork may have a seam where the tubing was joined during manufacture... it may not have been reamed out all the way through...
https://www.metalsupermarkets.com/di...seamless-tube/
note how the ERW tubing is dressed after welding only on the OUTSIDE diameter... a fork steerer made of this tubing would then be reamed to allow a good fit to the quill type stems... that process may not have been done all the way down through the tube... time is money during manufacturing...
https://www.metalsupermarkets.com/di...seamless-tube/
note how the ERW tubing is dressed after welding only on the OUTSIDE diameter... a fork steerer made of this tubing would then be reamed to allow a good fit to the quill type stems... that process may not have been done all the way down through the tube... time is money during manufacturing...
Last edited by maddog34; 09-02-17 at 08:29 PM.
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