phenian said:I bought a 2 year old Trek 1200 a couple of months ago and figured I would upgrade the forks to
carbon aero over the winter. Being a bit of an amateur at the moment, can anyone help explain the
key terms so I ensure I buy something that fits correctly.
Wheel size: forks are designed for a specific size. I guess you'll need 700c.
Threaded or threadless: steerer tube (top bit of forks that fits in frame) can be plain (for modern
ahead stems) or threaded for traditional headsets and stems. If threaded, length of threaded portion
is important. Most carbon forks are threadless.
Steerer diameter: The two common sizes for road bikes are 1" and 1 1/8". Frame (and existing forks)
will dictate required size.
Steerer length: Must be long enough, can be DIY-cut down.
Steerer material: Three choices (with carbon bladed threadless forks): Cromo steel (cheap, strong,
heavy), carbon (light, expensive, relatively delicate), aluminium (compromise). Maximum amount of
spacers below stem is limited (to not much) with carbon steerers.
Offset or rake - see: www.sheldonbrown.com/gloss_r.html and www.phred.org/~josh/bike/trail.html Most
are medium-ish - I think about 42 or 43mm for road bike forks. Unfortunately manufacturers and
dealers often don't bother telling you what it is.
Straight or curved blades or legs (curved are often incorrectly called "raked"😉: This won't make any
difference to steering or handling if offset is the same, and it usually is. It's debatable whether
one type is better (or any different in practice) than the other.
Braze-ons: some will have mudguard eyes or are designed to take cantilever brakes, etc.
~PB