I met Vladimir Yordanov on a chairlift two years ago in Morzine. I was testing brand new downhill bikes and he was riding a ratty old Mondraker Summum with a Manitou Travis fork and Marzocchi Rocco shock. We had a huge chat about bikes, geometry, and suspension tuning, and he was seriously into it. The reason that he rode that bike? Because everything was adjustable including the suspension which was fairly easy and cheap for a student to open up, tinker with, and play with the shim stacks.
Last night he messaged me a picture of this bike and asked if I want to take a look at it. Yes, preceded by the f-word was my response and we met this morning. It was one run old when we met, literally one run down from Morzine to Les Gets and it didn't even have a name when he arrived. He decided on 'Sequence' during our meeting. So I present you the Sequence downhill prototype.History
At 26 years old, Vlad moved to the UK in 2011, studied at Loughborough University to do product design and always wanted to make bikes. He said he never used the workshop for the assignments he was meant to do, but started carving foam models of frames and then rendering bikes with CAD. Previously, Vlad has designed some crazy looking aero road racer for Reap Bikes in the UK. He is also working on jet skis, trials bikes, and automotive parts for various companies.
Vladimir said he basically didn't sleep for the last seven days, laying up the rear triangle over last weekend that took three days. He spent this week getting the linkages machined, (which still have a rough finish due to time constraints). Then his car broke down before the drive over, so he booked a flight and boarded four hours later, arriving late on Saturday night.
The front triangle took a whole week a few months ago, built when he last took a week's 'holiday.' In total, it took around 100 hours to laminate the complete frame. He had his layup planned, but as soon as it started, Vlad says he realised a few things were different to what he expected and ended up with around 30% more material than he planned to use, part of this was a belt and braces approach that was called for on this first bike to make sure it survives the following week shredding in Les Gets and Morzine.
The method he used is different to the way most bikes are made, but he wouldn't let on to too many secrets, yet. Basically a way to get around using a giant CNC-machined mold like production bikes use. Six machined epoxy master molds in a positive form, opposed to the negative shape and alloy mold, a more labor intensive but works out cheaper in the end. Geometry and Suspension
Sequence Prototype Details:
Intended use: Downhill
Linkage: Dual link design
Wheel size: 27.5"
Head Angle: 62.5º
BB Drop: 0mm
Vlad thinks the geometry is pretty old school compared to modern standards, but I think it looks pretty spot-on for a medium sized bike. He had the linkage and geometry design locked in since 2012. There is 200mm of travel, with a few more in the longer 460mm chainstay length. He opted for the largest ZS56/56 headset to give some room for reach adjustment and +/-3º of the head angle using various cups.
Vlad describes the dual link suspension design as quite progressive in the beginning up to 100mm, the leverage ratio drops from 3.4 to 2.5. After 100mm upto 200mm, it backs off gently up to 2.6 to work with the air shock. The anti-squat values start high at 250% at zero travel, but in the sag zone it is closer to 120/130%. After 100mm of travel, it drops of below 100% to avoid pedal kickback under big hits. There is a maximum of 5º kickback, then falls to relatively nothing. The anti-rise is fairly neutral starting at 120% dropping to 90%.
The upper link is machined in two parts, then bonded and bolted together.
The frame currently uses all steel hardware, and the axles pass through 12mm molded holes in the carbon. The bearings are all pressed into the linkages and all the threads are in the axles. The 6000 series EnduroMax bearings are standard and all the same size, so finding replacements should be easy. Moving Forwards?
Vlad says he is not sure if he wants to start the brand, as he has so many other projects, but the molds are ready to use, and he says if 5-10 people really want one, he will start making them, so let him know what you think in the comments. There is still some optimization to do with the layup, and then stress testing and real-world testing, but for a first bike out of the mold it's impressive to behold, the finish looks better than many production bikes, only let down by the unfinished cable routing and quick release rear axle – but hey when you build something like this in your spare time you can't have it all when you want it. Vlad has no idea how much it would cost at the moment, but he says it would be incredibly difficult to sell it under £5000, absolute minimum. To make it in the UK, labor alone for one frame would cost £1000.
Vlad would like to thank Reap Bikes
, Easy Composites
for the frame build. And We Are One Composites
and Swinnerton Cycles
for helping with building the bike.