Brand New Tech: The Sequence Downhill Bike - Crankworx Les Gets 2018

Jun 24, 2018 at 10:40
by Paul Aston  


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.


One man and his bike. Vladimir started this project in 2011 and finally rode it down the mountain this morning. That might seem like a long process, but between University, work placements and more than full-time employment, it's a fantastic achievement.


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.

bigquotesI had been on a placement at Vax vacuum cleaners just doing renderings which should have been 12 months, I just got bored of that and then met Martin from Reap Bikes, I showed him a foam triangle hand carving of this bike and he told me he would help me make a downhill bike if I designed him a road bike. I quit the Vax placement after six months and went to work for him.

Of course, I started with geometry and we found some things we didn't like, so we did the usual longer/lower/slacker, haha. Everyone was pushing me to buy a bike [because he didn't have one to ride], and then I made a drunk decision on a Friday night after six pints to commit one full week to make. I made a hardtail frame because I already had the parts to fit it, the foam core collapsed when curing it, and I was gutted. Paul from Easy Composites in Stoke provided all the materials to help me to commit to building this downhill bike and get the project moving.
Vladimir Yordanov




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.

bigquotesIf this survives a week in Morzine, which it should do with the amount of carbon I used, I am going to hang it on the wall with all of the mud from this week. Then laminate a new one and ride that!Vladimir Yordanov



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
Size: Medium
Travel: 200mm
Linkage: Dual link design
Wheel size: 27.5"
Reach: 440mm
Chainstay: 444-460mm
Wheelbase: 1250mm
Head Angle: 62.5º
BB Drop: 0mm
Headset: ZS56/56


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.




A ZS56 headtube at this length can offer up to three degrees of head angle adjustment either way.
The chainstay can be adjusted between 444mm and 460mm with the flip chips, there are two sets of holes to receive the IS brake mount.

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%.



Views: 28,537    Faves: 11    Comments: 9



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.





128 Comments

  • + 144
 Looks like...this is pretty damn impressive. What a beautiful bike Vlad, can't imagine how sweet it felt to take that beast for the first lap after all that hard work and dedication. Hope you can find a way to put it into production!
  • - 72
flag chyu (Jun 24, 2018 at 22:49) (Below Threshold)
 Looks like a fury.
  • + 39
 Thanks @mackdaddy55! Yeah it was actually hard to focus on the riding in the beginning, there was too much happening in my head. But after a couple of runs and jumping straight into the deep end, I fully stopped thinking about the frame mid run.

I don’t think we can ever talk about proper production with this bike. I am definitely making a short run of prototypes which would be available to buy. This will give me the option to do minor layup tweaks for every different rider, and also keep the quality to the standard I want.

Cheers
  • - 15
flag fecalmaster (Jun 25, 2018 at 0:33) (Below Threshold)
 That frame sounds like an a great old guy in line at Dairy Queen.
  • + 2
 @fecalmaster: hahaha just heard it.. I need to thank the vuvuzela guys from crankworx
  • + 62
 Sexiest bike of the year
  • - 4
flag jclnv (Jun 24, 2018 at 17:51) (Below Threshold)
 Really? More than the Unno's?
  • + 23
 @jclnv: Yes. I'd say so
  • + 0
 @jclnv: Pole Machine DH is the biggest competitor imo
  • + 47
 Lucky enough to be good friends with Vlad - the hours of work that have gone into this is incredible. Massive respect for producing such a stunning bike!
  • + 37
 Vlad should have named it impaler.
  • + 27
 That's inspiring Vladimir! I hope it rides as good as it looks!
  • + 18
 Thanks! I'm currently figuring out the riding part of it. Up to this point it all has been theoretical, and mould fabrication related. Having made the sturdy frame to play with, I'll focus on getting the shock and fork dialed up, and after that it will be the everlasting game of tuning in the right amount of flex into various areas of the frame.
  • + 13
 Vlad's by far the most knowledgeable person I know when it comes to bikes, suspension and frame design and without a doubt I can imagine the frame he's come up with over the past several years will be a seriously impressive performer. Although it may not be "groundbreaking" he's taken all the best bits from the best frames out there and put it into one.
  • + 12
 Could we not get some proper lighting so we can actually see what it looks like?
  • + 5
 Watch the video, shows it clearly and it's beautiful
  • + 3
 @mdelorme where is your camera-mounted flash?
  • + 1
 @natedh9: Rookie move on my part. I'm so sorry I let everyone down and didn't properly illuminate the bike with some pro level on camera flash. #Imclearlydoingitwrong Next time I'll just use my phone.
  • + 2
 @mdelorme: Hey, you're a better photographer than probably all of us, and the dark/contrasty shots look cool, but we just wanted a few with better exposure or less contrasty lighting so we can see the frame details
  • + 5
 I gotta say I'm impressed by those who take the endeavour of building a bike themselves, like this guy, or resistance bike, or anybody else doing this (BTR etc). I've done a CG bike and the amount of reflexion/work was already huge, so much respect to those doing the real bike that can be ridden.
"Started in 2011"
  • + 24
 I completely agree WIll. It is not easy at all. What makes it even harder is the little amount of information that is available out there.. It is one thing seeing a ready painted product, and a completely different one getting a proper view at the whole process. It is good in a way that some companies started to sneak some shots of their production process, but in the very very early stages of the development of this bike, when my knowledge about composites was limited, it was far from enough. At some point this year, maybe towards November- December, there will be 10-12 minute video showing the stages of the process I used to make this frame. I'll include information about materials, tools, techniques and approximate man hours, which has no value for the big companies, but would definitely help the people making things in their spare time. Cheers!
  • + 2
 @vydesign: That would be so awesome, I can't wait to get some insights on the process. Could you shed some light on the software tools you used in the initial design process? What apps did you use for design and simulations? I have a background in 3D modelling (for animation) and I've just picked up a copy of Fusion 360 because I'd like to make some accurate frame designs, and 3d print in small, just for fun. Congrats on the Sequence Proto, it really is beautiful bike!
  • + 2
 @cyclo-maniac: Second that.
  • + 2
 Any software with parametric modelling should be able to do the job. Some do it better than others but it is really a personal preference and figuring out your workflow. For what you mentioned @cyclo-maniac , fusion 360 would do a great job. To be honest you should be able to do a full frame, run some simulations on the linkages, flip moulds or masters and also do your toolpaths in fusion. There is no right or wrong way, and any tool is as good as your ability to use it.
Cheers
  • + 2
 @vydesign: Thanks so much for that info. I was afraid I'd spent all this time learning Fusion only to find out midway that there are far better tools for the job. Good luck in your future endeavours, its always very inspirational to see someone pull something off like this.
  • + 3
 @vydesign: You were able to keep recording the spent manhours each time you worked on this project? :-) I stopped it in my 1st project 7 years ago. Now, I simply estimate it as 2 hours per each calendar day since the beginning of my latest project. A sane person wouldn't spend 3 hours working instead of relaxing for the period of several years, it really takes really commited person to stand that.

Vladimir, after finalizing kinematics, when did you finalized frame shapes design? It is very timeless. Overall, the the frame is functionally simple, yet there is some stunning beauty incorporated. The admitted carbon top layer is beautiful.

What tool did you used for stress analysis?
  • + 3
 @cyclo-maniac: CAD modelling itself is pretty well tuned in every tool these days. Big problems come when you need to stress analyse the kinematics. I've been working with Inventor 2012 on old laptop and due to weak HW performance for stress analysis I tried to find some free cloud service. Luckily I found simscale.com where you're granted 3000 core hours for free, you can run multiple simulations parallely. I highly recommend it, it jump-moved me in latest project.

Inventor/Fusion allows you to do that as well, but you must have the assembly constraints properly set-up. Otherwise it'll lead to wrong results. I don't know how Solidworks handles this.
  • + 4
 Hey @fluider I usually spent another 6 hrs a day and maybe double that on weekends so I can get the project done. One of the problems I found was that starting and stopping takes a big chunk of your time - getting in the mood, pulling tools out, arranging your workbench, etc.. Simple things that aren’t actually pushing your project forward. So by spending a larger chunk of time every time you work on it you might get surprised how much quicker you will progress. But 2 hours is simply not enough.. I hope I didn’t discourage you!

Cheers, Vlad
  • + 2
 @vydesign: No worries, you definitely didn't discourage me. Some days I do nothing, some days I spend 2 hours in job by mental work on my private project and another 2 hours at home when children fall a sleep. I do a lot of work mentally without perpetual (re)modelling of design, and then do actuall CAD models. I can work like that because it is a design-it-and-get-it-made style of project. Simpler, but risky.
  • + 1
 @vydesign: That would be awesome, I would like to try your method!
  • + 7
 There was a time when welding up your own hard tail was very cool. This bike has that same artisan feel but with modern materials. Thanks for sharing your masterpiece.
  • + 8
 Looks like a.... oh no hang on a sec...
  • + 2
 Carbon Turner DHR
  • + 5
 A little bit more background on Vlad for those of us who haven't been on the same chairlift would be great!

@paulaston he moved to the UK, from where?

I know it's late but come on! I wanna know! Big Grin
  • + 36
 Hi Milko, I come from Bulgaria. I've spent most of my conscious years of my childhood messing on and with bikes. The town I grew up had loads of single track type of trails, which were 99% natural.
There was also the usual activities that everyone goes through, but I've always preferred to spend my time riding or modifying frames to change leverage ratios, geometry, stiffen up areas with a welded plate or two, which were usually ridden until their death..
And don't be too harsh on @paulaston ... I'm amazed how he managed to do this whole article in a such a short period of time!
Cheers
  • + 1
 @vydesign: Здрасти, I suspected as much! Thanks for providing a little bit more context.

Pretty cool, you've come a long way - from welding reinforcements to a carbon prototype of your own design, respect!
Looking forward to seeing what comes out of the project!

Ah, that was meant to be a tongue and cheek poke, sorry if it can even across as hostile @paulaston
  • + 1
 if it came across*
  • + 3
 Vlad that is truly a gorgeous bike and I do hope you bring it into production as I would upset my wife to get one. And if you do bring it out keep it raw carbon as it looks sick like that. And get all the testing done as I reckon you would shift many units.
  • + 2
 There's a reason cheaper carbon manufacturers don't leave their carbon frames raw...
  • + 3
 I must be brain blocked,

Help me understand how a suspensions leverage ratio increases through the travel?

"quite progressive in the beginning up to 100mm, the leverage ratio drops from 2.3 to 2.5. After 100mm upto 200mm, it backs off gently up to 2.6 to work with the air shock"

The quote above is stating the leverage ratio rises from 2.3 to 2.6 to 1 as you go through the travel meaning the leverage ratio is increasing which means the springrate and damping do less.

On the other hand a progressively valved shock means the higher the shaft speed the more damping force.

When i think of a progressive frame design I was led to believe the leverage ratio would digress to give the rider more support.

Where am I missing the boat?
  • + 4
 It is a typo @jewpowered. Well spotted.
It starts from 3.3 then drops down to 2.5 at 100mm of travel and after that gently goes up to 2.6 at 200mm
  • + 2
 having looked into playing with composites for car parts, this is a very impressive project.
so many home built or low volume bikes look awkward in some way but this genuinely looks like it could have come from one of the major player quite easily.

Also if this is meant to be a medium it is nice to see a 440mm reach, i still think many frames are too short in the reach, at 5'8" it seems crazy that i should need a large or extra large in some cases to feel comfortable on the bike.

Respect is definitely due for this build!
  • + 2
 Nice rig! I personally like the double-link, VPP, DW-Link design (full floater). Rode a Santa Cruz as well as an Intense (Uzzi is my current ride) and I always appreciate the chain tension and bump sensitivity when going uphill. My question is: What are the advantages on a pure DH bike, e.g. what made you choose this link design above others? Just out of curiosity...
  • + 1
 Good question, I'm curious too. Does it have anything to do with patens? Isn't the double-link patent free, while many of the other linkage systems are proprietary systems.
  • + 1
 @cyclo-maniac: vpp and fsr patents expired
  • + 3
 Watching that rear shock work reminds me of what I would like to do to this sexy machine. The commitment and skill involved here is truly impressive. When I win the lottery first call I make is to Vlad.
  • + 3
 Vlad, this is bespoke frame building...it looks great, and you can make a few each year, while working on other projects.
Take yourself out for a pint and toast to you're excellent skills & perserverance!
  • + 1
 I was fortunate to meet Paul who provided the materials for the bud today at his and Vlad's local trails (also my regualr spot). Having never met either of the lads before, I instantly got questioning about this unfamilier bike and was fortunate to get a short go on it and wow it was absolutely amazing. Very slack which I am sure would make it great on technical descents and overall one of the most beautiful bikes I have ever seen. In fact if I could afford a frame Id be popping over to Vlad's village (about ten minutes away from my house) to give him the money for one. An absolute credit to everyone involved and I hope I get the chance to ride it again! Big Grin
  • + 5
 MTB needs a new demo, Demo what we deserved!
  • + 4
 I would do anything to have my bike be raw Carbon with no paint. So sick.
  • + 3
 No comments about the HTA? This beautiful bike happens to be able to go down to 59.5* ... Dang...
  • + 1
 Haha 59.5 is a bit ridiculous...wouldn’t feel that great on flow trails. I think 62.5~63 is the sweet spot
  • + 3
 @housem8d: Riding 62deg at 180mm on my 27.5 and if feels spot on. Of course the 37 offset, reach and stem length are also key. I think we'll see further evolution towards moto geo for DH oriented bikes....
  • + 4
 @Soilsledding: The biggest issue with going any slacker with MTB forks is the amount of fore-aft bend and subsequent stiction. We need upside-down forks before we can really try slacker. Mondraker's have been raced sub 60º by Fabien Barel and Damien Spagnolo earlier this decade.
  • + 3
 @Soilsledding: I believe most modern motocross bikes are around 62 degrees, give or take a bit, and they play with a few offsets as well.
  • + 2
 @paulaston: very true!
  • + 1
 @paulaston: I don´t think that USD forks made it to broader use in DH public in near future. It would be a marketing masterpiece to sell heavier and flexier fork /which is not a bad thing, but convince non-technical public, brainwashed by big brands, will be difficult/.

On the other hand this head angle numbers are just a numbers. They will vary based on dynamic SAG /when bike is moving and dampers start controlling suspension/.
  • + 1
 @housem8d: Remember in 1990 when 71 head 73 seat was the sweet spot? Or when the Sweet Spot TM was literally a thing? The bad old days were something special.
  • + 1
 @alexsin: my 1st fully was an sx trail so I got lucky haha. Its not as hard to make a good hardtail Wink
  • + 1
 Seriously impressive piece of kit. Was lucky enough to meet Vlad and check this out in person last week. The guy is a genius and will all most certainly become a big name in the industry!
  • + 1
 very impressive and inspirational with what you did with a positive mold technology plan on giving a go my self within the next year its good to see what you can acheive with patients and hard work
  • + 3
 Got to be one of the coolest bike I’ve seen ????????
  • + 9
 Only you know the answer to that question
  • + 1
 Bike is lit!

Serious question here. Is Vlad talking £5000 complete bike or frame only?

How tall is Vlad? Will there be sizes other than medium? 29er? LOL
  • + 3
 Hi @gonecoastal, this is the rough price for a frame only.

And about the sizing, I’m 180cm tall, so 440 reach with a 50mm stem feels just right for me. There is always the option of extending the reach 8-10mm with cups so this can bring you to 450 reach.

After figuring out a layup that I’m happy with, another size for the front triangle can be made. All I need is 6-7people to commit and agree between each other on a preferred reach value, so I can recover the cost of making a 29er 480 or 490 reach front triangle mould. Rear triangle would stay the same.

Cheers
  • + 1
 @vydesign: Thanks replying back and adding your height in the response. Allows myself and others to get a gauge for the sizing.

The frame only pricing is too rich my blood. I wish you success in your frame building adventures.
  • + 2
 God luv 'im, and people like him. It's people like this dude who push our species forward
  • + 1
 Well done for getting this far. It's very hard to get any type of carbon frame made in the UK below £5000 for a privateer. I'm in the exact position. Good luck! Smile
  • + 2
 Drop dead gorgeous Drool looks like a mix between a Canyon Sender and VPP linkage with some Specialized Demo
  • + 2
 I think you'll be busier now replying to all the comments Big Grin Well done Vlado! Keep them custom! Браво!
  • + 3
 Smashing laps in Morzine man. She needs to be tortured properly
  • + 1
 @vydesign: Come and try it in Sopot...in the state it is now will be a torture Big Grin
  • + 2
 yep send one for testing in Sopot, Bulgaria ....if it survives.... Razz ill test it there.....all summer..
  • + 1
 So cool! I was following the project on easycomposite's social media and i'm stoked to see a write up here!
  • + 1
 I saw this in Swinnerton's in Stoke-on-Trent when it was being built up, really nice looking in the flesh
  • + 2
 Is that a carbon Turner DHR?
  • + 1
 looks like a lapierre dh 727 had a baby with specialized's one sided demo.
  • + 1
 Congratulations for the jewel that you managed to achieve . It's really beautiful . Great .
  • + 1
 I met this guy yesterday at my local and what a bike it is , if you get this contactact me over the mudguards lol
  • + 2
 Hope it comes to production, looks so sick
  • + 1
 Huuuge respect for this project! I hope it stays togeter in one piece(..and Vlad too,of course)
  • + 3
 True artist, respect!
  • + 3
 Yes...very nice shapes here
  • + 0
 Very similar looking rear teiangle compared to the unno dh bike
  • + 1
 I love seeing a dream come to life. I hope you get enough interest to build more of them.
  • + 1
 i want to work for you vlad. not just bikes. i want to do it all! bad@$$ work!
  • + 3
 Fuck that's sweet
  • + 3
 The pagani of dh bikes
  • + 2
 Very nice. Like the detailing where the swingarm meets the seattube
  • + 1
 That detail of the spiral pattern in the carbon weave on the top tube ... Craftmanship..
  • + 2
 you could fit a water bottle in that front triangle!
  • + 3
 Funny enough, you can fit a 750 bottle without a problem.
  • + 2
 You are a legend Vlad! That is one hell of a bike you've made bro!
  • + 2
 Quite the Sequence was required to develop this beauty.
  • + 4
 Not sure why you got downvoted, but that’s how I came up with the name ????
  • + 1
 @vydesign: haha cool! Great looking bike btw.
  • + 2
 I'm very impressed!
  • + 1
 Ive got IT! It looks like a Demo mixed with a YT!!!!
  • + 3
 Except for the parallel lower link that makes it unlike either.
  • + 2
 Sexy AF. Nice work Vlad.
  • + 1
 Beauty build Vlad! Stoked to see it turn out and make it to Les Gets!
  • + 1
 love this RAW design.. ;-)
  • + 2
 Very Nice frame)
  • + 2
 Make it!! Sikk work
  • + 1
 That is excellent work! Beautiful machine.
  • + 1
 Impressive result of a commited work! Impressive!
  • + 1
 That's inspiring as f*** !
  • + 1
 Goddamn dude great design
  • + 1
 Perfect size and geo for 5'9" me.
  • + 1
 This is a beautiful bike!
  • + 1
 You could fit a watermelon behind the brake hose and shift housing.
  • + 2
 That sequence is sexy
  • + 1
 Nice work Vlad, but something that nice deserves at least Ohlins!
  • + 4
 I spoke with the ohlins guys yesterday and I might do the second build with ohlins. The reason I went with fox was so if anybody wants to try the bike, it is a case of few clicks here and there + air pressure and they can actually test the frame, not the forks.

Cheers
  • + 2
 Clean I like
  • + 1
 How can you contact Vladimir???
  • + 1
 Carbon Turner DHR ; )
  • + 1
 Lahar like.
  • + 0
 What kind of warranty you got on that thing?
  • - 1
 get those shitty saint pedals off there pls
  • + 1
 ????
  • + 2
 Don’t worry. I have something in mind for the pedals Wink
The reason I put saints is because I ran them on my previous bike and I wanted to see if my feet are gonna stay easier on the pedals or they are gonna be all over the place. It is just a test!
  • - 2
 Looks like a demo?
  • + 0
 I said the same thing, but with both sides to it
  • + 0
 Kinda like a Pivot I reckon.
  • - 1
 No kinematics, no care
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