Measuring / Cutting Carbon Steerer Tube

steve2021

I am about to start building my new bike (Pedalforce RS2).

I would like some advice on measuring and cutting the steerer tube. I am intending to have 1 spacer above the stem in case I want to put my bars up in the future.

I have read that the tube should sit 3mm below the top of the spacer. Is this correct? Does it have to be 3mm exactly? It seems easier to measure this 3mm than to try and measure the required length from the bottom of the steerer.

I dont have a vice - is it difficult to do it on the bike? Presumably I could just clamp everything down with the stem which would hold it tight enough to then cut.

Is this a job anyone does themselves or is at an LBS job? I'd rather do everything myself if poss.

Any thoughts or tips would be greatly appreciated.

topdude

Ok, this is easy to do yourself if you are careful.
With the forks fitted to the bike and all the spacers you want plus the stem assembled on the steerer mark round the steerer to give a starting point.
Remove the forks from the frame and fit the stem plus one old / spare spacer to the steerer.
Clamp the stem in place with the spacer above it approx 3mm below the mark on the steerer you made earlier. Recheck this several times before you start cutting.
Lay the forks on a towel / blanket / cushion on a bench / workmate / worktop and using the spacer as a guide saw the excess steerer off gently with a hacksaw.
Tidy up the cut end with emery cloth or a fine file and refit to the frame.
Assemble the spacers, stem and expanding bung and tighten the top cap to remove all play from the headset bearings (no need to over tighten).
The extra 3mm you cut off means the top cap will tighten down on the spacers and stem to preload the bearings before finally tightening the stem bolts to hold it all in place.
Job done

PS don't breathe in the carbon dust or you will die horribly :twisted:

maddog 2

3mm sounds about right. As long as you have a small gap it'll be fine.

I'd fit the stem+spacer (and check you stem doesn't have a very short stack height, just in case you want to change it in the future), mark the steerer, subtract a few mil, then remove from the bike and cut.

Even if you don't have a vice (which you should as they don't cost much) I'd take the forks off the bike and cut them on a nice flat surface like a table or chair.

As for cutting, use a good/new 24 tpi hacksaw blade, go slowly, and use an old stem or some tape wrapped around the steerer to ensure a 90 degree cut. Sand down with some wet and dry. Don't snort the fumes. Some people cut most of the way through then turn the steerer and cut from the other side but it's not necessary if you're careful.

maddog 2

beat me to it TD 8)

venster

I just paid £7.50 for my LBS to do it.

Very reasonable if you ask me considering the hash you could make of it.....

steve2021

Thank you very much everyone that's very helpful. The forks should be here tomorrow and I will take the plunge!

robbarker

http://www.parktool.com/repair/readcalv ... asp?id=196

John.T

I would leave the steerer long enough to have a stack of spacers both above and below the stem until you have definately got the height right then do a final cut. You can not put any steerer back so it is as well to get it right first. Also a good idea to leave a 5mm spacer above the stem as you said to give a little adjustment. It also looks OK with most stems.
Above all - MEASURE TWICE AND CUT ONCE. (maybe 3 times)