Iron Horse Sunday Reborn - A Classic Downhill Bike Modified with Modern Geometry & Mullet Wheels

Back in 2004, Iron Horse debuted the iconic Sunday downhill bike that used Dave Weagle's DW-Link suspension design, which was a departure from the previous Horst-Link SGS model. Made popular during Sam Hill's era of dominance, Hill and the Sunday were an iconic duo with their flashes of magnificence on two wheels and metallic green paint. Much like the Intense M1 before the turn of the century, the Sunday became a common sight among privateers World Cup racers due to its proven capabilities.

Iron Horse dissolved as a high-end mountain bike company in 2009, but the Sunday made such an impact on the downhill race scene around the world that privateers and bike park regulars quickly bought up spare parts stock. Pivot Cycles' original Phoenix downhill frame was chirped by riders for taking some inspiration from the Sunday and trying to reincarnate original Iron Horse fans. One composite company, Zelvy, even made plans to manufacture a carbon front triangle to mate with the hardware and rear triangle of the existing Sundays, but the product changed form to become an entirely new frame, the Preston.

With all of the mystique surrounding downhill legend, Sam Hill, and the extinction of Iron Horse, it's no surprise that we still talk about those racing feats today or that riders wish for a Sunday with updated geometry.


Well, that's exactly the kind of project Austrian downhill racer and skilled machinist, Julian Neubauer, challenged himself to take on - an Iron Horse Sunday with modern angles and numbers. His goal was to arrive at a Sunday frame with his ideal geometry, but also meshed with a 29" front wheel and 27.5" rear. The process involved not only sourcing, chopping, and re-welding a frame more than a decade old, but also piecing together a suspension fork with equal complications. We got in touch with Julian to ask a few questions about what prompted him to try this, what challenges he ran into along the way, and what he plans to do with the revitalized bike.

Can you tell us a little about how you got into mountain bikes?

I started mountain biking around 2008, specifically downhill in 2009 after I was spectating at the World Cup final in Schladming. Little did I know I was going love it so much. Immediately after that race I got my first real mountain bike; a white Specialized Big Hit. A couple days after I got it I was riding in a bike park and had such a big crash. I wasn‘t allowed to ride for weeks after that, but things ramped up when I recovered. I was a pre-runner at the age of thirteen and raced my first Austrian National races in 2011.

What inspired you to buy an old frame, cut it up, and spend money on new tubing when there are plenty of great bikes out there these days?

I always loved the look of the Iron Horse Sunday. I love the look of straight tubes and sharp angles. And clearly because Sam Hill absolutely destroyed every track with those bikes. There is just something about railing an open turn, foot-out, flat-out. And since those bikes are not made anymore, I wanted to give an old bike a new life. Over the years of riding I noticed what characteristics I liked and I didn’t like.

Fast forward to 2020 and COVID... I was searching eBay when I stumbled upon an Iron Horse Sunday frame which had an "ok" price tag. I had some spare money and thought, why not? I realized you don’t have to have the newest parts and bikes to have fun. It’s about the feeling and passion. I started by buying this whole frame from someone in Germany. It had spare linkages, derailleur hangers and everything you need to build up a new Sunday. When I got it, I was super stoked and could not believe what I had.

During the pre-weld process I stumbled upon a single front triangle. It was quite cheap and I thought, before I cut the only frame I have into small pieces it would be smart to try some ideas first. This was our first try for me and also for my welder. And actually buying an old frame is like around €300-400 and the tubing wasn’t that expensive too so why not? I am really lucky to have friends that can weld aluminium and only want a pack of beer as payment haha. So I got a custom made frame for much less than a new frame from any bike company.

What parts did you need to modify for re-use from the original frame?

I took an old Iron Horse Sunday frame and cut out everything I needed. This included the head tube, seat tube, plus the CNC part connection to BB and the gusset from seat tube to top tube for the front triangle.

For the rear triangle I used the old dropouts and the bearing mounts. Then I ordered some tubes for the main frame and rear triangle to be able to accommodate a 27.5” rear wheel. This was the most difficult part for me. In Austria it is not common to use these alloys like 7020, 7005, 6061 or 6069. But I found a company in Germany who sold me a couple of tubes for both the front and rear triangle. I also changed the geometry of the front triangle while I was at it. It’s like a XL Sunday if you want.

Are you a welder or machinist by trade?

I completed a technical trade with all sorts of machining operations, but it’s not my profession. Maybe I should start thinking about becoming one! After that I studied sports equipment technology in Vienna. I think it’s quite fun to explore and tinker with geometry, materials, and so on. Some of my friends are welders and machinists, which I am super grateful for. They helped me create this piece of art into a reality.

Were there any issues with the triangles twisting in the jig?

I did not notice any distortion. We only spot welded the frame in the jig. The big welds were made with the frame not being in the jig. I think it’s similar to how frames are welded in factories. This was already the second prototype. The first one we kind of pushed it against the wall because we had no frame jig. The geo was really weird, but rode alright. The BB was too high and the head tube angle too steep. But we solved everything with the new frame.

Would have been easier to build something from scratch from steel or aluminum?

I would say no. The main reason for me to use a donor frame was because I wanted to create a “new/modern” Sunday. If I had to machine all of the parts myself then it would have been much more expensive. But there are some companies that already offer dropouts, tubes and what not if you want to build your own bike. However, those parts may not have been suitable for downhill use.

For the fork, you machined your own crowns and used Boxxer stanchions with 29" Lyrik lowers? What offset did that result in?

Yes. I stumbled upon a report about the “Rockshox Lyxxer”. There I read about the custom made Boxxer crowns. First, I thought I may be able to use the crowns from the new C1 Boxxer, but unfortunately, the spacing between the stanchions was too far apart. Then I started to measure all of the available RockShox stanchion spacings. They Lyrik spacing was in between the old and new Boxxer. I took all the necessary measurements and constructed them in Autodesk Inventor. A very good friend machined them for me out of 7075-T6 aluminium. The steerer tube is made from a different material, but I don’t remember exactly which one I ordered. I used the black stanchions from the B1-B2 Boxxer with 29 inch boost Lyrik/Yari lowers. I did not want anything crazy for the offset. I aimed for an offset of around 48 mm.

I take it you are a big Sam Hill fan then?

Big is an understatement hahaha. This dude is my biggest hero and I would love to have Sam Hill's and Brendan Fairclough's signature on this bike since they raced the silver green Monster Energy edition Sunday back in 2008.

Are you planning to ride this bike?

I am planning on doing everything I can with this bike. It is my absolute dream bike. I have a spare Kona Operator Carbon frame that I removed the paint from in my basement, but I am really excited to ride with this new Sunday until death sets us apart haha.

Where do you ride most of the time?

I try to ride many different downhill tracks, but I mostly ride in Schladming and Semmering. Semmering is around fifty minutes from where I currently live. Schladming one of my favorites, for obvious reasons. I would have done anything to race the Schladming 2007, 2008 or 2009 World Cups. That would have been my dream come true! Especially with my Sunday!

What races have you competed at in the past?

I mostly compete in Austrian National and European Cups. Occasionally, I try my luck at World Cups. My goal is to qualify for a World Cup with the Sunday I made.

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Julian would also like to add, "A big thank-you to my good friends, the welder and the machinist, who helped me create this wonderful machine. Also thanks to everyone involved in the process. This is a dream come true!“