Instructables

Replace a mountain bike front fork for older MTBs

Do you have an older full-suspension mountain bike whose front suspension fork is a little tired? Replacement parts for it may be non-existent, and labor costs to do the work may be more than the cost of a new bike, but there is no need to clutter up a landfill with a perfectly good bike just for a better ride. Replace the entire front fork for something more modern and still not break the bank! Besides - this is the ghetto, and we make do with what we have. This is a good thing to do for a Freecycle bike, too.

Another neat thing about replacing your front fork:  you can you can spend a little extra to try out different styles and heights of handlebars to make the bike work better for you. The bike, as set up by the bike shop, may not be adjusted for you and your riding style. You can experiment with different riding positions and handlebar styles to tailor the bike for yourself.

NOTE: big props to Utah Mountain Biking and other MTB forums for information and resources.
http://www.utahmountainbiking.com/fix/
 
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Step 1: Parts and tools

I paid a visit to my local bike shop (here in the ghetto) to see what it would take to make my old bike's fork better. The bike shop guy said that I had an older 1-inch (25.4mm) threadless headset (as opposed to a threaded headset), which would make replacement very difficult since new MTB headsets are all 1 and 1/8 inch (28.6mm). I did some research and found a manufacturer that still makes MTB forks that fit a 1-inch threadless headset: RST.

I know that RST makes forks that many MTB riders consider as "entry-level" (being generous), but let's face it - my bike is 15 years old, and the technology in a new RST fork, compared to what I have, is like voodoo. Besides, RST has been around for so long and sold so much product, that they have probably managed to get a good product or two out the door by now.

The deal with the RST forks is that they can be purchased without a steerer tube, and you just order the steerer tube that fits your bike. To find out where to purchase these forks and their steerer tubes, just Google on "RST no steerer" and choose from those retailers. There are usually three RST products you will find with no steerer: The Capa, the Neon, and the Gila. The Capa is advertised as a Sport/Kids product, the Neon is advertised as more of a city/trekking (dirt road) fork, and the Gila is advertised as more Sport Cross Country Trail fork. I decided to get the Gila (although the Neon may have been a better choice, for reasons I will get into later).

I am keeping the cantilever brakes, since upgrading them will require changing the brake levers, which will require getting new shifters (since the brake and shifter levers are integrated), and so on until half the bike is replaced. My goal in this project is to keep as much original equipment as possible to keep costs down - this is the ghetto.

The parts you will need to get will depend on your headset size. You should remove the top cap from the stem and measure the diameter - ordering everything and then finding out it's the wrong size will ruin your day and take two weeks of re-ordering and delivering to correct.

You will first need to order the fork, steerer tube, and starfangled nut for the steerer.  If there's a choice, get the longer steerer tube (265 mm) to give you some freedom for adjustment. As for the star nut, you can get the nut by itself, or get a 'headset kit' that consists of the star nut, bolt, and stem top cap (these are usually listed in the "headset parts" area of the website, even though we're replacing the fork, not a headset). I got a headset kit and a spare star nut just in case I had a problem installing the star nut, but I didn't end up needing it.

So, start by getting these parts:

RST Gila T9 26" Fork, No Steerer
RST Steerer 265mm 1" 25.4mm (or 1-1/8 in 28.6mm) threadless
Star-nut, Bolt and Nylon Cap (Headset Kit) for 1" (or 1-1/8" ) steel steerer tube

In addition to the fork parts, you will need these:

Tektro Front Brake Cable Housing Stop
Replacement brake and derailleur cables
a metric M6-1.00 bolt, the longest length available at the store
a metric M6-1.00 35mm hex-head bolt (or M6-100 20mm allen-key screw if you use a Neon fork instead of a Gila)

If you are going to experiment with ride position and different handlebar styles, you should also get:

Two or three Headset Spacer Kits to fit your steerer tube
A long, adjustable-angle 1-1/8-inch threadless stem with a 1-inch handlebar clamp
RST 1-inch to 1-1/8-inch steerer shim to fit the new stem to your steerer tube (if needed)
Handlebars with a 1-inch center to fit the stem
New grips (probably need those anyway)

==========================================

Tools needed:

metric allen key set
metric wrenches
hammer
jeweler's screwdriver, flat-bladed
scrap of 2x4
15/64 drill bit
grease
hacksaw (or jigsaw with metal-cutting blade)
half-round metal file
masking tape
Advar9 months ago
No wonder I couldn't find any spacers!
For real though, great project, I 95.5% perfer on hand McGyverism to "buy it new". Disk brakes are fab, but pad repacement makes my wallet cry, so I went (back to) Old School. Nice 'ible :)
jwolters2 years ago
ANSWER bars?
I thought this was the ghetto?
exabopper (author)  jwolters2 years ago
Yo, I can pimp my ride if I want! Stop oppressing me! ;)
I love cantilever "center-pull" brakes like in the picture, simple and they work. I absolutely hate V-brakes. They never work correctly and one side always rubs against the rim.
mrlunna133 years ago
Hello,
I have been trying to find a goose neck like that, to mount on my seat post. What brand is it? are they outrageously expensive (most mountain bike parts are for me)? Any and all help will be appreciated.
Thanks,
Jesse
exabopper (author)  mrlunna133 years ago
This particular unit is a "Zoom" stem, and I think it's like 90 or 110mm long. I got all of my stufff online, and I think that you can get it from walmart.com if you want to. Really, you should go to Amazon.com or bikeman.com and just search for "adjustable stem threadless" and you will find tons of these, usually around $25 to $30 (or more, of course, but that's about what I paid).

Be sure to measure your seat post - most stems are made for 1 1/8 inch fork steerer tubes and 1 inch handlebars. You can get a 1 inch to 1 1/8 inch spacer for the stem if your seat tube is smaller.
bedbugg24 years ago
Interesting, I've never seen a fork with a split steerer clamp.
exabopper (author)  bedbugg24 years ago
I hadn't seen one either, and that's the main thing I wanted to share with the readers - that, and the Tektro cable stop so that the cantilever brakes could still be used.
Yeah, you can get quite a lot of converters and things for bikes nowadays, like things that can make a bike without a disc mount have disc brakes, and something that you can use to split two cables into one so you can run both brakes off one lever!
exabopper (author)  bedbugg24 years ago
One new thing I found that relates to this fork project is a through-bolt that is used to instead of the star nut to hold the  stem top cap.  However, it costs about 10 times as much as a star nut, even with the long driver-bolt that I recommend using to install it.
Another thing you can get doesn't require a star bolt is this http://www.merlincycles.co.uk/?fn=product&productId=547&categoryId=66 when you tighten it, it expands and it can be removed when changing the fork...you just have to remove the old star bolt first, and they don't like being removed! i know that from experience lol.
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