Come back Ruby

posted on September 03, 2015 by Glen

First off, I wonder where the rest of these forks are? I’m sure there weren’t a lot of them, but still… I think this might have been the first thing I ever bought on eBay, A good fifteen + years ago. And it was outdated inventory from a bike shop then-I think I paid about $100 for this unused Rockshox Ruby SL . Unfortunately it had a 140mm or so threaded 1’ steerer, which didn’t seem like such a fatal flaw 15+ years ago. I was 35ish and still riding a 53cm road bike with low bars /short head tube, and I figured a frame built to use this fork would need an even shorter head tube to compensate for the added length. But that never got done and the box got shuttled around to different parts of the shop enough times that I lost track of it.

Come to mid-July, this year, and I am thinking about how much I would like having a short- travel, not-too-obnoxiously heavy suspension fork for our Midnight Century’s gravel washboards, (possibly spurred a bit by that insidious Cannondale slate video that people keep sharing links to?) and I remembered the Ruby fork- did it even still exist? An hour or so of searching found the dusty box behind the file cabinet next to the desk, everything intact, just like when I got it, factory spare parts and all. I had already come up with a work-around for the steerer issue in my head on the ride home that day. It was seeming like a 30min job at that point…Until I stuck my wonderful 32mm Stampede Pass tire in the fork. Or in the opening of the fork, as it barely touched the bottom of the dropout slot. Seems RS put all there R&D money into a semi-offroad fork that only supports the 23-25 c tire platform. And 25 was pretty tight, IMHO. I gave up on that project for the night .

Next day I couldn’t stop thinking how nice it would be to have that suspension option, and at that point figured there was nothing to lose with the Ruby fork, so I decided to go all in; whatever it takes to make it a part I can use, or send it to Richard Belson’s island of misfit toys.

The steerer was an easy fix. I first cut off the threaded portion, leaving around 4” of 1” steerer tube to work with. I then took a regular steel 1 1/8” steere with the butted section cut off , and brazed a crown race seat on, and turned it to size. The ruby crown race seat was bulge-formed, and I had to machine out the inside of the replacement steerer end to slide over that, a nice press fit. I then milled a pair of ½” x 1 ¼” slots on each side of the 1 1/8” steerer, put the whole shebang together and made it permanent with some rosette welds.

The tire clearance issue was not so straight forward. I started with a 1 ¾” hole saw, and removed as much of the brake bridge as I could without compromising the caliper mounting situation. This gave me some pretty good tire clearance on the sides, but it was still pretty tight on the top.

Like unsafe to ride close. Fortunately, the dropout slots are really quite long- something could still be done. I found the drawer full of tiny Campy dropout adjuster screws, dug up a drill and tap the right size, and got to work.

With these screws carefully adjusted and Loctited in place, I had the desired result…

Unfortunately, this led to another problem, that the tire could now crash into the crown at full travel…hadn’t anticipated that. A little research showed that there was once an “ adaptor kit for touring” which let you run 28c tires. It appeared to just be 2 3mm spacers and two lower leg bolts that were 3mm longer, so I figured I could make my own custom adaptor kit. 25 and 7 comes to 32, and I decided to throw in an extra mm for good measure, so some 8mm spacers were made and some metric bolts from the local ace hardware were customized to suit, Loctite and assembly came next, and damn…

That’s going to work. I did have to find a 17 degree stem and invert it to get my bars back down where they were. My weight was on the border line between the stock springs and the heavier (that came with the fork) and I decided to run the heavier ones, and it seems like the right choice. They don’t bob much when unlocked/standing up, and they smooth out the kind of stuff I want them to do. When the lockout is locked out, there is some flex in the system and I can hear the tire rub the brake shoes just a bit. Real world use I found I didn’t lock out very often. The older 105 caliper isn’t really strong enough to give much flex under braking, yet is still more than adequate for me.

I don’t know what the overall travel is, but it looks like I have about 5mm of sag and an active 20mm of travel getting used beyond that.

The month or so that I rode this fork made it clear that this needs to be re-evaluated: short travel, reasonably light road suspension fork. If I had a few more of these, I would keep it on the bike. As it is, it’s the one-and-only, so its going to be an “event fork.”

Cannondale, please consider making the lefty on the slate available aftermarket or oem…everybody else, get on it. And make it look nice.