The word Luddite sometimes has a negative connotation but when you dive into it’s history the origins are pretty interesting, especially for those that appreciate handbuilt products like a custom bike. A Luddite is thought of as someone who hates new technology but when you look up synonyms you’ll find words such as adversary, antagonist, resister, opponent, working person. The Luddites were a group of early 19th-century textile workers that resisted the replacement of skilled laborers with machines and the resulting lower wages for those workers. Although not an issue at the time, Luddites would probably have risen against the moving of manufacturing to far away countries with cheaper labor forces and fewer environmental restrictions. But that’s the way of the world now and making things for a living wage has become increasingly difficult no matter where you live. In this age of complicated and highly engineered long travel dual-suspension frames with numerous pivots and linkages, the Softail is a throwback to simpler times when most mountain bikes were still made in the US out of metal and because of that I can’t think of a better name for my new bike.
I’ve dreamed about making a Softail for a long time but never thought I’d have the ability or opportunity. In the 90’s I swooned over the Moots YBB – a elegant pivotless titanium Softail that was maintenance free, quiet, and durable. I was fortunate enough to ride a YBB for a few years while racing on their grassroots racing team but sold that frame to fund another summer of racing with a different team. I regret selling that bike to this day! Some years after the YBB, Ibis came out with the SilkTi which was influenced by the YBB but designed to be a marked performance improvement. Like the YBB, the SilkTi was all titanium but used a machined chainstay flex-plate instead of round tubes to maximize flex in the vertical plane and minimize lateral flex with as thick a cross-section as possible. The other big difference in the SilkTi was the shock. Instead of the steel spring found in the YBB, the SilkTi had a two-stage “critically dampened elastomer” (CDE) that was engineered to offer more travel as well as more progressive and dampened travel. The resulting ride characteristics are quite different and I’d argue much improved.
The SilkTi suspension system is the brainchild of John Castellano. John is a legend in the early suspension world, having designed bikes for Ibis like the BowTi, SilkTi, and AL version of the SilkTi – the Ripley. He also designed and patented the Sweet Spot URT that was used by several companies including Schwinn and Klein at the dawn of full suspension, and heavily influenced designs by others such as Trek and Rocky Mountain. Since the Ibis days, he’s worked on his own bikes (the Fango) as well as with Steve Potts on various projects including this bike they displayed at the handmade show with an integrated flex stay rack!
At the 2016 NAHBS in Sacramento i attended a Ti framebuilding seminar given by Steve Potts and John was there. I asked if i could check out the chainstay plate he had brought with him and he told me all about it and the new version that fits 27.5×3 and 29×2.5″ tires that he had developed with Dave Levy of Ti Cycles. (The original Ibis Silk Ti was a 26″ wheeled bike that would have fit a max 2.4″ tire, the largest available at the time.) My interest was peaked again and once I had John’s business card I started crafting an email asking for help in building my own softail frame. Problem was, i hadn’t started building in Ti at this point so i didn’t send that email.
Fast-forward to two years later, I had built myself two Ti frames and started making test-dummies (I mean friends) Ti frames as well. I soft-launched Titanium to customers in 2019 and kept thinking about my next mountain frame, hoping i could make it a softail. I didn’t think i’d be able to use John’s design in a frame so i kept putting off contacting him.
Last year while laying on the couch after breaking my leg I was scheming to make a bike that I would tour on the Colorado Trail and elsewhere after recovering. A friend sent me a Trek IsoStrut from their Supercaliber to use on a frame but that seemed (and is) much more difficult to produce a frame around. Besides, a pivotless design is really what I wanted or need and I knew a softail would make an awesome bikepacking rig.
Castellano’s CDE shock offers around 1.75″ (44mm) of rear wheel travel to help with seated climbing and add a bit of control and cush on the downhills. In comparison, the Trek Supercaliber gets 65mm of travel with the Fox Isostrut and builders have gotten 80-100mm with the Castellano plate (or another version of a Ti plate) by adding a set of pivots and a swingarm (Blacksheep, Dean, and Ti Cycles). Castellano also developed a long travel CDE shock that gets around 80mm of travel but that shock would need to be located inside the front triangle and lessen available space for bottles and a framebag.
I finally sent John an email last summer (2022) and by the fall John and I had met for coffee, a bike ride, and a couple beers. He brought his singlespeed Szazbo mullet bike up to Auburn for a loop around the Foresthill Divide Loop. He’s a true tinkerer, engineer, and long time bike nerd. It was a ton of fun to get to know him a bit, hear his story and talk shop. I am extremely grateful for the many hours he helped me with the bike design, it was a huge learning experience. Just reading his patent was eye-opening. I highly recommend it since it outlines the history of similar suspension designs dating back to the late 1800’s! (A few pics below show what I mean.)
John received a patent for the Silk Ti in 2002. This includes a plate CS and suspension design using his CDE shock – a two stage elastomer damper that needs no service other than yearly grease (but he said that is probably unnecessary).
Compared to building a linkage rear suspension frame this was pretty straightforward, though there are several considerations since you’re welding a thick plate of Titanium to a relatively thin BB shell and dropouts. He sent me a few test pieces to practice on which helped a lot with dialing in the machine settings.
The next step was adapting my fixtures to make the seatstay subassembly. The shock collar is a 2″ diameter tube that holds the CDE shock above the rear tire and behind the seat tube. The collar is internally relieved so that the elastomer has room to expand as it compresses. A binder bolt and slot has to be added to hold the shock in place. The pictures below should illustrate all this.
John sent me the tooling he provides when someone makes a Silk Ti. Steve Potts made these tools and fixtures including a dummy shock, stub holder for mitering to the seat tube, and a fixture used to bore out the inner diameter of the shock collar after welding on the seatstays and binder bolt. Unfortunately, the box he shipped it in split open en route and the fixture used to bore out the shock collar fell out and was lost. I made a new version of it based on the photo i had of the one Steve made.
Bike Design: Being my everyday MTB and bikepacker i wanted the front triangle as large as possible, but having relatively short legs for my height i also needed to ensure there was some standover. With any frame using this system it means using as long a seat tube as possible. The CDE shock is less than half the length of the shortest air shock but it can’t be used on 29er frames with short seat tubes, at least with the shock in the rear triangle. Since the SilkTi was first developed, 26″ wheels have fallen out of favor and dropper posts have shortened seat tubes a lot to allow more travel, complicating this design even further. To fit 29×2.4 tires with my leg length and a 150mm dropper, this frame’s seat tube ended up at 525mm, though it could be a bit shorter. The brace helps to lower the standover and offer a handle when a framebag is filling up the front triangle. The CDE shock would fit behind the seat tube on more 27.5+ frame sizes than 29ers and would make a great “mullet” setup. Additionally, a gravel bike system would be ideal since seat tubes are typically longer and the amount and type of travel suits gravel well.
Geometry: I try new geometry each frame but this one was more of a settling in on what i prefer for a XC bikepacking rig. This is also my first non-short chainstay frame in many years – the plate is set at 442mm with a T47 BB shell and does not have adjustable dropouts. It’s possible to get a little shorter in the chainstay but not much. I went with a reach of 480mm, 655mm effective TT, 67 degree HTA with a sagged 140mm fork, an effective seat tube angle of 75, and a sagged BB drop of 60mm. With 29″ tires that’s a pretty common BB height but with 27.5+ it’s low and that’s how i like it. I always run 165mm cranks and the low BB makes the bike feel planted especially when fully loaded with gear.
There is some adjustment on the shock but no lock out of course. You can adjust the preload damper on the bottom with a Shimano BB spline tool or 3/4″ socket to fine tune small bump compliance. The preload adjuster can also be unscrewed all the way to change out the lower elastomer if one gains or looses weight such as when going on a loaded tour.
The Ride: My first ride was eye-opening and I had a huge smile the entire time. I took it out on a loop i’ve done since i was a kid on Mt. Tam. I had the bike with 29×2.4″ Schwalbe Wicked Will tires on 35mm wide rims and that’s about all it could fit between the chainstays with sufficient clearance. It’s a SMOOTH ride. It doesn’t have the bounciness I remember of the YBB where i’d be looking back at my rear tire thinking it was going flat. To be fair, today’s YBB’s are likely better, having added a small elastomer to dampen the steel spring. My overall impression is that the Silk Ti suspension is a very natural feeling, it just works…no tuning, no futzing, just riding. I’ve found that the first few rides are usually the most telling since your mind and body are used to the last bike you rode and that was a hardtail in my case. I didn’t feel any twisting of the rear and around corners, the Luddite tracked extremely well.
I have ridden a couple of “real” dual suspension bikes over the years but I’m just not drawn to them. I don’t ride that fast anymore and don’t want or need that much suspension. I’ve lasted this long so why start now? I saw all the growing pains of the first full suspension frames in real time. The creaking, loose pivots, poor performance, and it never seemed worth it or appealed to me as a cross-country rider. I could ride all the same trails on a hardtail and have no maintenance issues. I’d just go a bit slower and have to choose my line more carefully. On the other hand, the SilkTi softail is so simple, quiet, and maintenance free that I feel I have found my dually of choice. It’s subtle but very noticeable and adds a lot more compliance than what I’m used to with a hardtail.
My second ride was on 27.5×2.6″ Rocket Ron tires. This changed the bike feel to be more playful and quicker to maneuver – a ton of fun. The softail made the smaller diameter rear tire feel not as small and smoothed out some of the added sensitivity I normally don’t like about smaller diameter wheels. It’ll be fun to try a 27.5×2.8 rear and 29×2.6 front, but I’ll probably mostly ride it with 27.5×2.8’s. Isn’t dressing up bikes fun?!
Other details: Frame weight ended up at 5.25lbs with the shock. I used Syntace dropouts made by Paragon, a 140mm Paragon head tube, LOTS of bottle bosses for a bolt-on framebag and clamp on cable guides. Agave Finishworks did a stellar job with simple and clean anodized blue fade panels and headbadge. I’ve never had a bike this nice and I’ll be trying to protect the finish as long as possible with strategically placed Ridewrap.
Since building the bike I’ve had continued knee issues so haven’t been able to ride it much, but I look forward to many years of fun with my new dream bike. The next challenge will be making a rear puffy-stuff rack that won’t affect the suspension and handling too much.