Video: 77designz Develops a Bike Frame
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
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.
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.
Here you can see the basic sketch that already features all geometry and kinematic details.
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.
The final 3D concept which is now going to be transformed into a prototype.
Learn more about 77designz
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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
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.
Nice bike! Pity I'm too a 6" 29, handy nomad still looks good too!
This one is good too for a primer
polebicycles.com/what-is-anti-squat-and-pedal-kickback
I quite like Andrextr's stuff too.
He was doing Kinematics explanations on VitalMTB lately, no more videos on YT though.
So what's the plan, next steps? Prototype, riding and then what? Investors, Kickstarter, licensing? This needs to make it to market!!!
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 ;-)
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
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
And thanks for the information with different pulley sizes. That makes sense.
Cheers
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
@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 ...
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!
www.pinkbike.com/photo/16002150
Looks like a great design for a trail bike doesn't it? haha
Check this facebook video: www.facebook.com/77designz/videos/1951684304905360
Forgot to add it to the article.
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
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.
"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
www.pinkbike.com/news/eurobike-2018-final-randoms.html
internal, external, in and out ternal?
Trunnion mounted shock?
how bt chain growth?
Boost, Super Boost, Boost to the Max?