Mountain Biking - How Long Is Steerer Tube On New Forks?

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BigBlueToe
12-09-07, 10:35 AM
Greetings. I bought a used Rockhopper frame I want to build up. The first order of business is some suspension forks. I'm wondering about the length of the steerer tube. I'm looking at a set of forks on Ebay that has a 9" long steerer tube. I'm wondering if that's enough. The length of the head tube on my frame is about 6 3/4" http://www.bikeforums.net/attachment.php?attachmentid=60435&stc=1&d=1197221636 With the headset and the stem, I'm wondering how long of a steerer I need.
I'm also wondering if there's a standard length steerer length when you buy a new fork. I'd like it as long as possible so I'd have options for how high I could mount my bars. I'm 6'4". One of the criticisms I have of my old Stumpjumper from the 80's is how much lower my bars are than my saddle. I think the salesman sold me a frame that wasn't quite big enough for me. I want to make sure my "new" bike fits better.
Thanks!
kenhill3
12-09-07, 10:44 AM
Wow. That's a LONG head tube! Do I see that this is a 23" frame?
I've got 2 1/4" of steerer and three 5mm spacers, so you ought to be ok unless you have to jack up the stem..
Even then, you can sort out bar height with risers and stem length/angle. But you probably knew that already.
BigBlueToe
12-09-07, 04:11 PM
Wow. That's a LONG head tube! Do I see that this is a 23" frame?
Good eyes, Grasshopper. Yup, it's a 23".
Standard uncut length on a threadless steerer tube is 265mm.
Your 170mm head tube length + the stack height of the headset (roughly 28-30mm) and the clamping area of the stem (maybe 40mm) means you'd need at least a 240mm (9.4") long steerer tube.
Looks like you can add in a few spacers and forgo cutting the steerer at all.
kenhill3
12-09-07, 07:24 PM
Standard uncut length on a threadless steerer tube is 265mm.
So, SVR, just to confirm here for those of us like myself just picking up this info for the first time- 265mm is THE INDUSTRY STANDARD supplied uncut length for threadless steer tubes, all rigid and suspension forks. Thanks, I'm here to learn.
265mm is THE INDUSTRY STANDARD supplied uncut length for threadless steer tubes, all rigid and suspension forks.
That is correct -- but I'm sure there may be a few exceptions out there. I'd verify the uncut length with the fork manufacturer to be sure.
BigBlueToe
12-10-07, 07:55 AM
Standard uncut length on a threadless steerer tube is 265mm.
Your 170mm head tube length + the stack height of the headset (roughly 28-30mm) and the clamping area of the stem (maybe 40mm) means you'd need at least a 240mm (9.4") long steerer tube.
Looks like you can add in a few spacers and forgo cutting the steerer at all.
Thanks Svr. I had two main reasons for replacing my old mountain bike. One was being able to have front suspension. My old Stumpjumper has a 1" threaded headset. Finding suspension forks for it would be difficult, and I don't know if the frame geometry would make it suitable. The second was because the handlebars were so much lower than the saddle. I think it's partly because the frame is a little small. The seatpost is pulled way out, but the stem is maxed out. I think having an uncut steerer on suspension forks will help with this, as will the 23" frame, as will the ability to mount a stem with some rise and some riser handlebars. I'm looking forward to dialing in the handlebar height so that it feels just right!
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