Steerer Tube Length Dilema

[adadaead]

I lookin to get a new fork for my bike. My head tube is 140mm (5.5in). The two forks i found on ebay say that one's steerer tube is 6 3/8in. The other is 6 7/8in. How long of a steerer tube should fit my 140mm head tube? Because i don't wanna buy a fork with a short steerer tube that doesn't fit. Thanks for any help.

[greyhair biker]

How long was the old one? You need one AT LEAST as long as the old one. Whatever you do, DONT get one shorter! Spacers are your friend! Assuming you are keeping the old stem and spacers (if any) you can always add spacers if you need. Take the head steer length + thickness of the headset cups top and bottom and add the length of the stem plus any spacers plus the steerer cap. You need a steertube at least this long...So, you got some measuring and adding to do.....and buy the longest one you can find to be safe.

[greyhair biker]

I hope you realize my explanation was oversimplified a bit on purpose. There are a few more factors that come into play here but I tried to give the most basic version I could. Anytime you start to play with your stem height, your spacers, etc., you change the geometry and feel of your ride...not alot but sometimes enough to feel the difference over the distance of even one good ride. Really, the overall lenght of your steer tube is the easy part...longer is better for the initial purchase. once you start to reassemble your kit you can play with the stem/handlebar height by adding/subtracting spacers to get the right feel before you decide just how much, if any, should be trimmed/cut off the tube lenght.
....Im a bit picky when it comes to this stuff...