Measuring and cutting steerer tube.

disgruntledgoat
disgruntledgoat Posts: 8,957
edited December 2008 in Workshop
My name is Goat and I'm a mechanical dunce. However, duncery nonwithstanding I'm going to build my new bike next weekend.

First order of business, once my stem arrives is to chop the fork down to avoid the unsightly bit sticking out the top of my Cervelo's steerer. Can anybody give me an idiots guide ot chopping my steerer down?

In the spirit of a GCSE paper... Your answer should include the following:

If i measure the Cervelo from the bottom of the headtube to the top of the stem, should i simply get the same stack height on the new forks and then mark it? Or do i need to cut slightly lower?

What can I use to keep the forks straight whilst I hack at them, and whats the best tool for the job? (marks off for the first person to say "a saw")

How far into the forks to I need to hammer the star fangled washer and what should i place on top of it to acheive this?

Thanks in advance.
"In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"

@gietvangent

Comments

  • whyamihere
    whyamihere Posts: 7,708
    Firstly, is it an alu steerer or carbon fibre?
  • Monty Dog
    Monty Dog Posts: 20,614
    The top of the fork column needs to be 2-3mm below the top of the stem (plus spacers) to enable you to tighten up the headset bearings. Assemble the fork to the frame with headset, all spacers and stem in position - mark this highest point - your cut should be 2-3mm below. You should find a decent step-by-step guide on www.parktool.com. As with all these things, measure twice and cut once! Wrap tape around the steerer to help with marking and stop loose strands breaking off.
    A hacksaw fitted with a tungsten-carbide 'ceramic tile' blade is reckoned to be the best for carbon steerers and use the underside of an old stem as a saw- guide to get it nearly square. Use fine sandpaper to smooth-off the sharp edge of the carbon after.
    For metal steerers, a heavyweight plumbers pipe cutter is best - do not use on carbon!
    Make mine an Italian, with Campagnolo on the side..
  • keef66
    keef66 Posts: 13,123
    Advice will depend on whether it's a carbon or an alloy steerer.

    Much more caution required with the former, and whatever you do, don't go hammering any star-fangled nuts into one
  • It's alu.

    Duncery, you see?
    "In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"

    @gietvangent
  • nielsamd
    nielsamd Posts: 174
    I'm in the same position as you. Cervelo. Alu steerer.
    FWIW, this is one job I'll be carting to the LBS........
  • 6288
    6288 Posts: 131
    nielsamd wrote:
    I'm in the same position as you. Cervelo. Alu steerer.
    FWIW, this is one job I'll be carting to the LBS........

    +1 for LBS

    take your frame & stem with you ... get them to do the necessary measurements and buy spacers from them as well as stuff u need like bottle cages, tyres etc ... most shops (ie. all the ones i have ever used) will always do you a quick job for free if u r buying something from them as well ... what takes you time and alot of worry can be done by a proper mechanic in about 2 minutes ... even if u have to pay £10 it's worth it ... new bike + error with cutting tools = much swearing and likely holding back tears!!!
  • wilwil
    wilwil Posts: 374
    The LBS will use a proper clamp that they hold in a vice and guides the saw exactly straight.
    After seeing this being done I would not cut my own steerer without this equipment because I would be pissed off it wasn't straight as I am when my wife cuts the bread.

    The mechanic I watched used copious amounts of saw lube but it was a carbon steerer.
  • I was erring on the side of the LBS to be honest... The dude i bought it off loves working on my bikes as they are a mechanical disaster area. It's also the only road frame he's ever sold!

    However, my pa has just bought a workbench with vice for cutting tubes and a mitre saw. Think this could work...
    "In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"

    @gietvangent
  • 6288
    6288 Posts: 131
    ffs ... if the shop sold you the frame then get them to cut the steerer for you ... christ, what a waste of time ...
  • John.T
    John.T Posts: 3,698
    If you have not finalised your position yet you should get it cut so you can leave some spacers above the stem. This will give you some adjustment to get the height right. You can always trim it a bit more later. I leave room for 10mm spacer above my stem permanently. Means I have a bit to play with.
  • 6288 wrote:
    ffs ... if the shop sold you the frame then get them to cut the steerer for you ... christ, what a waste of time ...

    Sorry to have wasted your time.

    I just wanted to build my own bike in an effort to improve my skills.
    "In many ways, my story was that of a raging, Christ-like figure who hauled himself off the cross, looked up at the Romans with blood in his eyes and said 'My turn, sock cookers'"

    @gietvangent
  • giant_man
    giant_man Posts: 6,878
    6288 wrote:
    ffs ... if the shop sold you the frame then get them to cut the steerer for you ... christ, what a waste of time ...

    Sorry to have wasted your time.

    I just wanted to build my own bike in an effort to improve my skills.
    And I would be exactly the same! This particular job seems to be the most challenging for the average joe working on our bikes.
  • redddraggon
    redddraggon Posts: 10,862
    I wouldn't say it was the most challenging, it's pretty easy really......

    ........but if you screw it up, you'll probably need a new fork.
    I like bikes...

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  • Monty Dog
    Monty Dog Posts: 20,614
    I always get pangs of anxiousness when I take a saw or pipe-cutter to a fork and I've done dozens. It is not a difficult job if you know what you are doing - familiarise yourself with the aforementioned instructions and you won't go far wrong. TBH, the saturday lad in your LBS has a greater-chance of F-ing it up - there are plenty of stories on here confirming the same.
    Make mine an Italian, with Campagnolo on the side..
  • giant_man
    giant_man Posts: 6,878
    That's why it's challenging red!
  • "measure twice, cut once"