Miscellaneous Blog Posts

May starts awefully and ends awesomely (so I hope)

I went dirt jumping at the beginning of the Golden Week.

The weather was nice and it was warm, one of the first t-shirt days for me this year.

But I tried something unnecessarily tech and ended up with a sore leg. I started to manual before the jump and take off with just the back wheel, then a forward pitch moment in the air landed me overly nosedived. It happens, I know, so I jumped over the handlebar onto the ground as usual. But the spot I landed was already the launch of the next jump, so I just landed flat, no way to roll around and let go of the impact. My already sore right ankle and knee called it the day, and the pain was just as bad as when I snapped the PCL, sending me straight to the couch to stay in for a few days.

It was bad enough to force me to miss the two-year anniversary of Boogaloo, my bike friend’s bar. But after a few days of doing nothing much but icing and also going to Hoheikyo Spa, it finally felt better to my relief. I had just got the fork replaced, so injuries at this point are especially not welcome.

I had got this fork, used but nice;

Overhauled it, took off unneeded guts;

Cut and ground it;

I also got super low head bolts at the tips. This way, rail grinds cannot break the bolts. The fork is good and alive till the ends wear out.

The damping adjustment on the right leg will require taking off this bolt, but hey, you won’t touch it often once you set it up. No problem. There is way less sealing capability than the original bolts, but it’s not that bad, I filed down the end surface flat enough to prevent major leakage.

Let’s take a look at the connection between the frame and the fork. The current setup is the only loose ball integrated system in the world that I created by brazing on the lower cup, to which I’d like to add a final touch. The frame is put upside down in the pic, so the big cup on top is the lower cup, and the other is the upper, a Chris King cup with sketchy DIY paint on it.

This is a rather traditional tuning method sometimes called “unsealed bearing packing.” You take off the balls from the retainer pictured in the bottom right corner, and put in more balls than there originally were. It is said to offer more durability due to the load distributed onto more balls. In this case, I had to solve the rubbing of the retainer and the fork steerer tube. The cause could be the misalignment of cup and head tube, too much flex of the steerer, or bad design of the retainer. But I guess all of those are happening, so no further investigation, just solution. By the way, this loose ball integrated system really doesn’t offer any special merits, so it won’t be available on production frames.

Now two weeks later.



Umm, I’m open to fork sponsorship offers. I’m confident about fracture testing skills.

One thought on ‘May starts awefully and ends awesomely (so I hope)