How much length to allow when cutting a steerer tube

ricktabor1
ricktabor1 Posts: 272
edited May 2010 in Workshop
Hi guys.

I'm currently putting together a Kona Sutra - bought the frame on ebay. I've bought the Kona Project 2 chromoly forks and i need to cut the steerer down.

The headtube is 135mm, my stem is 35mm, and the stack of the headset is 30.5mm.
I will be putting 4 x 5mm spacers in. This all adds up to 220.5mm.

I was wondering if i should put in 2 more 5mm spacers on top of the stem and cut it to 230.5mm so that I can be sure that I haven't cut the steerer too short in case i want to put the forks on another bike in the future (one that may have a larger headtube).

Is 6 x 5mm spacer too much? Would anyone else bother cutting the extra length or just go for the 220.5mm?

Thanks for reading. Any advice will be excellent as i've never cut a steerer down before.
Got to get up to get down

Comments

  • John.T
    John.T Posts: 3,698
    edited May 2010
    It is usually not recomended to have more than 40mm of spacer below the stem. You can have as much as you like above it. Are you sure how much spacer you need below the stem top. If so them cut at 3mm below the stem. If not leave room for at least 20mm of spacer above and see how it goes. You can always cut it down later when you are sure.
    My Fleet.
  • hopper1
    hopper1 Posts: 4,389
    +1...

    Build it, ride it, then cut the stem, when you know how many spacers you need...
    Start with a budget, finish with a mortgage!
  • ricktabor1
    ricktabor1 Posts: 272
    Thanks for that.

    It couldn't have been put more clearer.

    I'll allow for 20mm above the stem and 20mm below and then, hopefully I won't mess it up bad style!

    So I guess, if the steerer needs to be 3mm from the top of the stem, i need to take 3mm off my original calculation and then add 20mm for the extra spacers above.

    That makes.....237.5mm.... does that sound right?
    Got to get up to get down
  • sturmey
    sturmey Posts: 964
    I would forget about measurements.the most reliable way is to assemble it all with the headset,stem and spacers in place,make a mark on the steerer in line with the top of the last spacer, then cut your steerer 3mm below that. I found that a plumbing pipe cutter went through an alloy steerer easily enough and gave a nice square clean cut.
    Then all that's left to worry about is fitting your starnut!
  • ricktabor1
    ricktabor1 Posts: 272
    Excellent plan nice one.
    Got to get up to get down

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