Video: 77designz Develops a Bike Frame

Jun 11, 2018
by Giacomo Großehagenbrock  
The idea behind this video project is to document the entire development process from idea to prototype.

As you may not know, 77designz offers engineering services in addition to our components. We Stefan and Giacomo the owner of 77designz are particularly intrested in the kinematics optimization for long travel mountain bikes. We both found that there is something going wrong with the development of the axle path on long travel 29er bikes, so we started to analyze the market and figured that there actually is room for improvement.

For some years we had the idea to build a concept bike where we can try out all our ideas. Now the time has come and we have a concept that is extremely promising and we start. We will document the whole project from the first idea to the prototype via video series. We are sorry that it's in German but you can watch it with English subtitles and we will answer comments in english as well.

Watch now the first 6 episodes of We Develop a Bike Frame


EPISODE 1


In the first Episode, we introduce the project and our approach. The idea is to build a concept frame with an HPP but good Anti Rise.



EPISODE 2


The second episode of We Develop a Bike Frame is all about the Tech Specs.
29 "/ HPP / 160mm / IS2000 / Lots of Tire Clearance / Bottle Cage / Slack Steering Angle / Steep Seat Angle / Max Deep Groove Ball Bearing / AL 7020 T6 and so on.



EPISODE 3


In this episode we finally explain our kinematics concept from where the development process starts. With the 4bar High Pivot Idler Pulley Concept we can realize a true super bike.



EPISODE 4


In this video we explain in detail why we think that this kinematcs concept is great.

Kinematics

Here you can see the final kinematics we moved the Instant Center to the front to eliminate rear brake squatting.



EPISODE 5


This video is about the mockup process where we often switch between Solidworks and Linkage to check for clearance.

Basic Sketch

Here you can see the basic sketch that already features all geometry and kinematic details.

Mock Up

This screenshot is taken somewhere in the CAD process.



EPISODE 6


In this episode, we show you the most important steps on the way to the finished 3D model.

Final 3D Modell

The final 3D concept which is now going to be transformed into a prototype.

Learn more about 77designz


113 Comments

  • + 71
 Place a water bottle on a downtube and develop the frame and geometry around it. No compromises.
  • + 10
 Only compromise than, is the dirt in your mouth ;-(
  • - 35
flag fecalmaster (Jun 12, 2018 at 9:44) (Below Threshold)
 At least attempt a new concept of suspension. Adding a pulley to the same old ass design is far from innovative.
  • + 68
 @fecalmaster: obviosly you didnt get our aproach right. We are not trying to lauch a new bike company. We are researching about kinematics and we use that system that gives us the most freedom in design. Zero f*** given if that looks like trek or not.
  • - 2
 @chyu - no good frame designer would put a bottle that high in the front triangle if bottle location was priority #1. So no, the frame was not developed around the bottle placement
  • - 36
flag fecalmaster (Jun 12, 2018 at 17:36) (Below Threshold)
 @Giacomo77: Zero $$$ given for that design. Think innovative not retro, but that's your problem.
  • + 26
 Fecalmaster once again awes us with his superior intellect.
  • - 23
flag fecalmaster (Jun 12, 2018 at 20:01) (Below Threshold)
 @TightAF: The truth seems to butthurt the interior minds. Constructive criticism is only dealt with correctly by true professionals. Sorry about your butt.
  • + 4
 @bogey: Really, do you like reaching to your bottom bracket for water??? I find that super f****ing annoying even if sloping top tubes look great. When you need it (on uphills) it is easier to reach and gets used earlier in the ride thus lighter.
If you start your ride on a huge downhill with a full water bottle placed low and then build your frame around that principle.... You might be doing it wrong
  • + 8
 @fecalmaster: Tell us more about your superior exterior mind.
  • - 6
flag fecalmaster (Jun 13, 2018 at 9:06) (Below Threshold)
 @cdmbmw: For your pleasure anytime. I tend to stay away from bikes that have a terrible design based off of every other manufacturer on the market. Buying a "concept" bike that is a regurgitated version of the Kona I had 18 years ago seems like about 50 steps backwards. If someone has the time, money and resources,,, they should be creative and think outside the box. " Doing the same thing over and over and expecting different results is the definition of insanity" - Albert Anesthesia
  • - 1
 @blamacken: if you’re reaching to your bottom bracket to grab your bottle then something is wrong with your bottle cage. Is it mounted upside down!?
Mine sits just below to my rear shock which keeps the mass low which is good design. With one swoop if my hand I can easily reach the top of my bottle to grab it.
  • + 6
 @fecalmaster: since you had your kona 18 years back it probably was not an enduro. The chance to optimize enduro bike using a hpp just came with 1x drive trains. So yes we use an old fashioned but proven system to go new ways.
  • + 1
 @Giacomo77:
Nice bike! Pity I'm too a 6" 29, handy nomad still looks good too!
  • + 4
 @fecalmaster: your kona was a single pivot silly head
  • - 5
flag fecalmaster (Jun 13, 2018 at 14:32) (Below Threshold)
 @meathooker: Yes indeed
  • + 1
 @fussylou: glad you like it anyways ;-)
  • + 18
 Awesome! If you enjoy this kind of stuff, and want to see bike kinemtic explanations and comparisons on YouTube 'andrextr' channel name is one to watch
  • + 4
 Noticed Andrextr hasn’t posted in awhile. Anyone know why? Always Geeked out comparing new bikes with his videos
  • + 1
 @trocko911:
This one is good too for a primer
polebicycles.com/what-is-anti-squat-and-pedal-kickback
I quite like Andrextr's stuff too.
  • + 2
 @trocko911:
He was doing Kinematics explanations on VitalMTB lately, no more videos on YT though.
  • - 3
 Good luck hahahaha
  • + 13
 @trocko911: A baby child, and full time job, no much free time lately for videos eheheh Wink
  • + 14
 Kudos! 4 Bar high pivot with idler...I love that the design is born from a genuine understanding of the interplay between anti squat, anti rise, and shock progression. I love that these guys get the importance of anti rise optimization to maintain geometry and eliminate the seesaw effect.

So what's the plan, next steps? Prototype, riding and then what? Investors, Kickstarter, licensing? This needs to make it to market!!!
  • + 14
 Thanks buddy, I see you have a great understanding of our ideas.
Prototypes are in the making and after field testing we will decide how to move on with this project.

For now the end of this project is open ;-)
  • + 3
 @Giacomo77: agreed. love the combo of horst link, high pivot, and idler pulley. just so you know i'd buy one of these if you ever make it to production, even as an aluminum frame.
  • + 7
 77, FANTASTIC to see independent young people with great understanding of interplay and practicalities go at it systematic, step by step and without a fixed plan that forces you into a meaningless "launch date" or other non-product related stuff. First concept, then engineering, then testing, THEN business. I would totally buy this. In love with my NICOLAI G-16, building a YETI SB 100, lusting for a POLE Machine or the RAW Madonna. In the carbon realm, the new UNNOs, but only once they have different sizes. Keep it up guys and good luck from Norway.
  • + 4
 Thanks a lot for understanding and apreciating exactly what this is about ;-) You Rock!!
  • + 7
 Very nice, as a rider and bike mechanic, I can definitely appreciate the approach centered around functionality, performance, increased service life and ease of maintenance. Very interested to see how the project will evolve, keep it up guys!
  • + 1
 Hey, great Video! But this is only theory!
Commencal recently dropped their idler on their team-bikes immensely as you can see here(I know, it´s a single pivot!):
p.vitalmtb.com/photos/users/2/photos/122524/s1600_Leo18_AN3X4786.jpg?1528650738 (sorry, didn´t found a good one on pinkbike)
I would made a test-mule, where you can play with position of idler, because it is the key part!
Cheers
  • + 1
 I think the pivot is still high, but they lowered the idler pulley to create a little chain growth for peddling
  • + 5
 commencal kinematic is not comparable to this , their puley is on an arm but more importantly move with it , it's a key part of their design to stabilise antisquat without pedal kickback.

here , that pulley is fixed , and only act on antisquat and kickback value , antirise is modified by linkage pivot point.
BUT the place of the puley , with the arm move , cancel the kickback cause the chain growth is neutral to negative ( she be shorter and shorter when wheel move up)

so , if they (or you) want to act on antisquat , you only have to change the number of touth (more precisely the diameter of puley) too change it. no need to play massively on the pulley position , like do commencal.

best regard from france
  • + 1
 @Megazzz: I know that its not comparable kinematic-wise. But Commencal also thought that it had found the theoretically perfect place for their idler. So I was pretty surprised to see their current idler position massively down! Which seemed to work fine ;-)
And thanks for the information with different pulley sizes. That makes sense.
Cheers
  • + 0
 We noticed that already way earlier, when we anlyzed that bike ;-)
  • + 0
 We have known about the mistakes they made with their design since about a year. But that is not meaning that we are not eventually going to make mistakes too. It´s always easier to judge other designs.
  • + 2
 @mensch-mueller: the position that they used was perfect , if you don't take antisquat in account ... that position was done for contering any kick back effect ("interaction with suspenssion work" from their own words) , and perfectly done that job.

BUT , with a massive downside , it squat when you press the pedal ... so really don't pedaling well.
so , they move the pulley to find a compromise between good to high antisquat at sag (pedaling efficiency when sprinting) and a very little kickback.

"perfect" is always subjective Wink

@Giacomo77 it's a bike i analysed when i do my first own design , about 2 years ago ... that bike inspire me a lot !
it's not a mistake , more than a choice for design.
if you have (or will) ride Vallnord a day , you know that with their terrain and rock everywhere , it's make big sense ! they perfectly know that the bike will be less explosive at pedaling than others , but faster on rock garden , and vallnord IS a big rock garden.

if they have done a mistake , ihe's from their geometry that was very , very short and first V4 have a very particular balance to find between a rear that go away and a front that shorten a lot on impact. problem solve next year.
and , they broke a lot cause they have made a mistake on links ...
  • + 1
 @Megazzz: I couldn´t agree more thanks for your detailed statement. Every design is a compromise and there is no "general" perfect. It can only get perfectly close to what you want it to be.
  • + 2
 This video shows how ghost bikes were ahead of its time and how difficult is to biuld a bike that works both in track and in camera(because its just not enough to ride nice but should look also nice).
  • + 1
 i ve been thinking that since the beginning of the season, but none of the ghost riders seems to have liked the bike. the time ghost pulled out of the worldcup and could not suply frames for the rest of the season fischbach bought a demo and said that it was so much better -weird
  • + 3
 Yes ghost was having this concept before, but it´s just mm in pivot location that differ a good bike from a bad one even though it looks the same.
  • + 2
 @Giacomo77: also, the ghost TT was about the same length as the head tube....
  • + 1
 i was talking also about the chain with the extra socket.
  • + 0
 @blitz66: that´s true so many things changed since than.
  • + 5
 Pretty cool videos and project. I want to see that prototype! Smile
  • + 4
 You gonna see it and I would love you to analyze it ;-)
  • + 1
 @Giacomo77 Had the corsair marque with an idler pulley near the pivot in the high pivot swing arm, and a linkage activated shock. Fantastic downhill performance, poor climber due to little anti-squat..


Ideally one would be able to route the chain above the idler pulley for trail riding/downhill performance, and then route it directly without the pulley for climbing gravel roads. A shape-shifter-system for the pulley would be great!
  • + 2
 That was an very intresting bike especially as they made it work with 2x drive trains. We believe that we set the anti squat proper so there will be no need for adjustments but time will tell.
  • + 1
 As I understand it's all about anti-squat and rise here, but for me these are just two parameters in the equation of the perfect bike. If it was that simple, we only had perfect bikes around. At least under the premise that the other bike designers of the world are not just fools. So yes, nice concept and planning but I guess still a long way to go.
  • + 0
 Yes I agree we didn´t talk about geometry that much and they will definatly challanges come on the way especially if we want to bring it to production. So yes long way to go ;-) Where I disagree is that kinematics are that easy as many maunfacturers are making major mistakes here.
  • + 1
 My Lapierre Evo 2 of 2006 (130mm of travel) was suffering pedal kickback on the smallest ring of 22T, it was a pain in the climbs. I am not surprised full suspension bikes are "optimized" for a precise ring size, probably the default size they ship with fully assembled. Now this is a problem since most manufacturers do not advertise this optimization.
  • + 2
 Correct and sometimes product managers even change the ring size not beeing aware of that impact.
  • + 3
 how is your timetable guys? When do u think you get a rideable prototype to verify all your nerdy witchcraft that i dont understand?
  • + 3
 Prototype to proof the nerd talk is in production ;-)
  • + 3
 Looking forward to seeing it!!!@Giacomo77:
  • + 1
 @Giacomo77: If this ever gets to the sales floor/website, I'm getting one. Hopefully your time table is 1+ years out bc the wife will be pissed that I'm already trading up.
  • + 1
 @freestyIAM: Haha cheers for that, if this one gets into production it will take some time. Now it´s time to get them build and go testing. Yeah so stoke to do that ;-)
  • + 1
 @Giacomo77: I have to say i love the project and all your values look good the only thing i despise is internal cable routing! what chainring size did you design your antisquat around? and how would it do with a 28t in front with a 46-9t cassette at the rear? what are your thoughts on a gearbox design?
  • + 2
 The lines on this prototype frame look really clean. Nice to see this more and more (instead of frames that come out already looking bent or broken). Cheers!
  • + 4
 So we're basically accepting that GT has made the perfect trail bike?
  • + 3
 We are ready to test it. At least I am.
  • + 3
 www.pinkbike.com/photo/15597208
Looks like a great design for a trail bike doesn't it? haha
  • + 2
 i saw one of these new GT prototypes in a trail bike version at sea otter. i was drooling all over it cuz it was set up for slalom also. cant wait to see it in production, just like this frame above.
  • + 1
 So you talk a lot about antirise but you only show the antirise level by 0% sag. The shock linkage is very short so I assume the antirise gets worse when you approach 30% sag
  • + 2
 Sorry I accidentally skipped one video where you explain it
  • + 3
 @emptybox: good to here ;-) actually our anti rise is pretty stable through out the travel.
Check this facebook video: www.facebook.com/77designz/videos/1951684304905360
Forgot to add it to the article.
  • + 1
 @Giacomo77:
Thanks! That looks really good.
But how many different load cases did you take into account when designing the bike ? Did you calculate the limit of forces you could put on this bike? When does break ? I just want to know how much work went into this project
  • + 2
 @emptybox: to be honest we don´t do any FEM as it´s way to complex for welded frames. Plus there is barely usefull data available in order to feed the FEM. We work based on experience like mostly the whole industry.
  • + 1
 @Giacomo77: Well,this is a concerning statement. I would encourage you and your team to reconsider this assumption and be proactive in your approach.
  • + 1
 @Giacomo77: This sounds scary as fem can help predict problem areas of which I see a few unless you are familiar with weld affects and strength. Or are you just over building it? This too can cause issues.
  • + 1
 @allsk8sno: It´s not scary as we are in a super early stadium of development and far from bringing it to the market. To verify the kinematics concept and the geometry this is already way more than other companies do.
All that FEM does not help you with out data and in the end the right production process on hand to use the results. I´m telling you there are only a very few people who can actually analyse something like a welded aluminium frame and those guys are normally not working in the bike industry.
  • + 1
 @Giacomo77: @Giacomo77: I work in the motorcycle industry and we use FEA (ansys and Solidworks) on welded products with the results being very accurate to our real world tests on production parts and assemblies. Solidworks FEA is very basic and easy to use yet it gives accurate results on welded components. good luck with the rest of the 'experimenting' i will be following it keenly
  • + 3
 @doek: thanks for your insides I assume on motorbikes you can design a bit safer which makes things easier in general. But anyways this is something we are keen to learn more about in the future for now we accept some extra weight and experience to verify geometry and kinematics.
  • + 1
 @Giacomo77: You could do basic stressmodels that show you - especially for your linkage - where stresswise the painpoints are. Intention is a good guide and supported by basic numbers, I guess you can get more out of it? Ever thought on bionic design? Follow Force flows to improve rigidity? Nice project anyway! Keen to see more! Happy trails
  • + 1
 @Giacomo77: How did you settle on your anti rise values? I'd have thought you'd aim for something between 30%-50% as that where (I thought) the sweet spot is for balancing the paramaters of isolating suspension from braking forces yet enough interaction to get the bike to squat some to preserve geometry.

"Anti-Rise: Also known as “brake squat,” anti-rise occurs when the rear suspension compresses or “squats” into its travel while braking. This is more favorable than rise because it slackens and lowers the geometry and keeps the rider’s weight back which is more stable when going downhill, however too much anti-rise can result in a less active suspension and loss of traction. Anti Rise is how much the bike pushes back (like statement above) however on the back of the bike during braking you want the bike to squat slightly to counter the riders mass from shifting forward dramatically. 100% would feel like too much when talking about braking. (Chris’s thoughts on too much and too little, % range). Anti-Rise is common on low single pivot bikes." - canfield-balance-formula.com/glossary
  • + 1
 ERROR
  • + 1
 @mo3rki: we look at the linkage modell and check the forces under full compression to put them in consideration. I love bionic design but you need the maufacturing or it. At this point I believe we do reasonable if we would do this with carbon we should do it different. Glad you like the project. Cheers, G
  • + 1
 Nice work guys Smile I know it`s a lot of hours of work and years of knowledge. Check also my project:
www.pinkbike.com/photo/16002150
  • + 1
 Looks cool, good luck!!
  • + 2
 Really nice insight! Would love to see that bike hit production! Smile
  • + 0
 how is the cable routing gonna be?
internal, external, in and out ternal?
Trunnion mounted shock?
how bt chain growth?
Boost, Super Boost, Boost to the Max?
  • + 2
 External cable routing with no outer, custom mounting shocks only with dual elastomers each end for maximum small bump response, negative chain growth for that speed boost when your suspension extends, road 130 QR rear for that heel clearance.
  • + 1
 the bike will have internal cables as shown in E6 It will have actually a gear optimized upper chain growth. About 10mm at 50T Cog and close to non at 10T Cog It will have a 205x65 Trunnion Shock And 148 boost at the rear but we want to test with 49mm CL in front as our chain stay does not have to pass the chainring we have some freedom here to try tthings out.
  • + 1
 So when can I ride one?!?
  • + 2
 I like corsair
  • + 2
 Wunderbar.
  • + 1
 If anyone needs an Experienced SolidWorks guy please let me know.
  • + 1
 is the roller on the swingarm or not?
  • + 1
 On the chainstay above the main bb I think. It's shown in episode 6
  • + 1
 Yes it´s on the chainstay. It gave us the chance to fine tune the anti squat and makes manufacturing easier.
  • + 0
 if it is as "good" as their chainguides... pass
  • + 1
 If you have any issues with our chainguides drop us an email and we will fix it!
  • + 3
 Love their chain guides
  • + 1
 Great video!
  • - 1
 How to develope a bike frame?.....That is easy, you just copy everyone elses! Thats how its done these days is it not???
  • + 6
 I heard trek have a lovely bike to copy, think it's called a season or something like that Big Grin
  • + 0
 @Joebohobo: lol. Think you are right there, that name rings a bell!!
  • + 7
 We spend lot´s of time finding a unique concept, but in the end this 4 Bar design was the most promissing to get the results we where looking for. We would never do something unique just for the sake of it. This project is about researching about kinematics not about finding a unique design.
  • + 1
 Brilliant!
  • + 1
 Why not dual link?
  • + 2
 What do you mean by dual link?
  • + 1
 @Giacomo77: he probably means some sort of VPP (or related shortlink) system. I really like the polygon collosus design. Great axlepath, dropping antisquat in the late stages of travel hence not much kickback, good progression and no need for a idler. I always thought thats how i would do a 29 160mm bike. Can you explain the downside of that system ?
  • + 1
 @optimumnotmaximum: I like the work of poygon in general and I don´t have proper data to analyze their design so I´ll just refer to our first episode where we explain the general findings on standard 29er bikes.
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