Thursday, July 7, 2011

Re-lubing, Re-conditioning the Downtube front suspension fork.

As I posted earlier, I found that my stock downtube 8H front fork did not have as much travel as my Full suspension downtube. I ended up buying an earlier downtube front fork from J. Monti. It did have more travel. The fork worked well, but I could detect a little grittiness coming from the fork as I bounced it up and down.

So, I undertook this project to recondition, or relube, the front fork so it could have freer up/down play. Tools needed:
*Socket extension bar (I think mine is 9” or 10”)
*5mm socket
*Cheap Automobile grease (I used Coastal hi-temp grease)
*Skintight nitrile or other surgical type gloves (to keep your hands clean)

It is a straightforward job. You undo the Vbrakes, remove the wheel. Remove the protective caps on the top of the suspension fork. Insert the socket extension until you feel yourself gripping the screw head. Then, just turn counterclockwise. The fork will separate from the bottom part when you fully loosen the screws. And, the bottom fork bars will slide down.

As you hold the bottom part of the fork, turn it over. The springs will come out. There are some rubber (?) inserts/bushings at the top and bottom of the springs (see pix).That’s pretty much it.

As I suspected, the springs were dry. Some dirt may have penetrated there contributing to that gritty feeling. I lightly cleaned the springs with a cloth. You can be anal and dip the springs in gasoline or some other solvent, but I didn’t do that. Then, I just liberally slogged the grease on the springs all over. I guess the springs looked like tree branches after freezing rain (only with grease not ice). Then, I dropped the springs in the bottom part of the fork, connected it to the top part, and rescrewed. Finally, attach the wheel and brakes.

Much better. I now have a front fork that “gives” much better than it used to. This is a job you can do if you want more play or, I guess, if you have too much play, you can remove some excess grease and dry up your front fork a little. I was afraid that there would be some sort of complicated spring mechanism that I would have trouble putting back together. It was nothing like that.

This guide doesn’t have to be limited to DT bikes, but other MTB-type bikes esp. with cheap suspension forks. You’d just need a longer extension (maybe) or a different size socket.