Bike Check: Insanityofgravity's Titanium, Ultra High Pivot Freeride Bike

Sep 5, 2021 at 14:26
by Ralf Hauser  

I met a company representative at Eurobike this year that couldn't tell me the most basic features of their new bike and had the technical understanding of a walnut. Sad, really, and not the first time I found myself in this kind of situation. Stefan Laile is definitely not one of those people. When he starts talking, your mind has to shift into overdrive just to follow his most basic thoughts on suspension and really, all things bike. And just like that, ideas turn into a real-world bike - the UHP-FR V2.

UHP stands for Ultra High Pivot, FR for Freeride because of the extra travel and V2, because a quick & dirty first concept already exists, but a second attempt at it saw quite a few things changed in the end.

The work on the concept bike started about a year ago and for a month now Stefan has been riding his titanium prototype, trying to get answers in the real world that no other bike out there was able to give him. It's only natural that many of the features are custom-tailored to his size and the way he thinks it should handle.

Stefan Laile and his first version, the V1, hiding in the background.

Stefan does not work in the bike industry professionally but he considers himself a tinkerer who runs a blog as a hobby without profit. He didn't go to university, rather attending a Realschule (a type of intermediate secondary school) and getting a degree as a metal cutting mechanic with an additional education as a technician and a specialty in engineering. With a perfect grade average, the now 32-year-old could have gone on to study more but decided against it due to various reasons at the time.

Today, he works as a Tool & Fixtures Designer at a small business in Friedrichshafen for a living. Having access to a large tool shop with turning lathe, milling machine and testing bench at home helps with his endeavors and he does kinematics construction in Linkage X3, CAD construction with Fusion 360, readouts of air shocks in IOG_calc (his own calculation software) and force-travel measurements of rear shocks.

In his blog - which unfortunately is only written in German (although you can use Google translator to turn it into English and get an idea) - he looks at various bike companies' kinematics, helps to tune shocks, questions design decisions (and offers suggestions) and even takes apart some answers by Pinkbike staff regarding suspension, that we might have to reevaluate.

Most noticeably, his bike uses a really high pivot design, which in itself isn't really new. However, compared to some large-scale manufacturers, who have to abide by derailleur manufacturers' maximum cage movement, he does have other options. For others, only 27 mm maximum of rear center lengthening during travel is possible but his number sits at 77 mm - this feature alone should answer the question of whether this project bike was something that could be turned into a mass-produced bike easily. So, we're looking at a massive rear wheel axle path movement, which has been achieved by placing the main pivot ahead of the bottom bracket and in quite a high spot. The bike's high anti-rise value sits between 170 to 180 percent within the SAG area.

Using a regular chainring as an idler pulley.
Four bottle mounts with three being used for bottles (one for tools). Pinkbike users rejoice!

A long steer tube checks the personal preference box.

The reason why he chose to go for a giant-size pulley is more out of practicality than anything else. It was easier to just buy a 28-tooth chainring with SRAM direct mount, rather than having to machine an expensive prototype, but the large-size pulley can also distribute loads well. The bike's anti-squat comes to about 190 percent, depending on the gear used. In his opinion, this is the best-calculated compromise to keep the rear end stable when you need to accelerate hard in some trail sections or transfers.

In another study, Stefan wants to test the effects of a floating disc brake system with his design. The mounts already sit on the side of his seat tube and it's just a matter of time when he gets to it.

Travel measures 183 mm vertically at the rear, combined with a 190 mm travel RockShox Zeb out front and the shock length measures 240 x 75 mm. After taking apart, looking at and tuning different manufacturer's shocks, he picked Intend's Hover for his own bike since it allows him to set up the negative chamber the way he thinks it should be done generally, which is a whole other topic of discussion in itself.

An effective seat angle of 80 degrees ended up feeling a tad too steep for him in the end. That's why he pushed back his saddle slightly and feels that 78.5 degrees could be the sweet spot, if ever there should be another concept bike.

Since Stefan is rather tall at 192 cm, he picked a reach of 510 mm. A standout design trait is the extra-long steer tube length (160 mm), ending in a stack height of 688 mm. He wanted to experiment with a higher front and feels more comfortable and secure with this setup. The titanium frame without shock weighs 4.1 kg and the total weight of the bike comes to about 17 kg.

Mounts for testing a floating brake system with the design in the future.

Manufactured in China, the titanium frame in combination with a pragmatically chosen parts spec (including a few lucky sale opportunities) came to a bit over €6,000 in cost. Considering the amount of money you could invest in a bike out there, that's not the worst way to spend your cash on a unique ride.

It'll be interesting to see what we will see from Stefan Laile in the future, or if his one-off is going to remain a one-off. He tells us that his head is full of other ideas that he'd like to turn into reality, suggests that this won't be the last time we'll get to cover some insanityofgravity.


  • 90 0
 lol @mikelevy immediately suffered a heart attack after seeing the size of that idler
  • 28 96
flag RedBurn (Sep 7, 2021 at 10:00) (Below Threshold)
 Just wanna Say that NO ONE UNDERSTANDS OR CARE ABOUT THOSE GRAPHICS People want pictures and videos of the suspension good evening.
  • 7 0 that a 28t chainring? lol!
  • 8 2
 @RedBurn: Speak for yourself! I'm all about those yummy graphs!
  • 14 2
 I'm more worried about that oval chainring doing the opposite of what it's meant to now that the idler changes the angle the chain hits it at by 90degrees.
  • 5 0
 A bigger pulley is more efficient than a small one, so Mike should be totally on board with this!
  • 1 0
 @maglor: Better hop on that Shimano Biopace-train then!
  • 1 0
 if a skelontonized richard mille was a bike
  • 54 2
 Without the squish video I will not inderstand lol
  • 17 2
 totally concur, huck to flat. I didn't come here to for graph theory
  • 6 1
 @Dem628: graph theory is something very very different.
  • 46 3
 Take note people, this is a highly pivotal point in bike history.
  • 15 2
 It shocks me that this could be our link to the future of bike design.
  • 1 5
flag HGAB (Sep 7, 2021 at 18:28) (Below Threshold)
 Lol nice pun
  • 6 2
 About time, the industry has been idle for too long.
  • 3 0
 Idlike to end this chain of comments on a high note. But I can't pro to type worth beans.
  • 17 0
 Looks like modern day Brooklyn Machine Works. Nicely done.
  • 14 0
 Now imagine it with matching tires, spokes, housing/hose, a wireless dropper, and no fenders. Frame only is a clean design--right down to der hanger
  • 3 0
 @ceecee ...and integrated bottle mounts of course
  • 15 0
 man it must be cool to have, like, skills.
  • 10 0
 I would have expected a lot more hate for this considering it doesn't look like a session. Cool to see the comments aren't all just "it's really fkn ugly" though. People should be encouraged to design bikes differently if they want.
  • 9 0
 Damn the supply chain problem is really bad when all you can get is XXXXL headtubes for your ti bike.
  • 2 0
 I wish I had that head tube!
  • 5 1
 Counterintuitively, the drag probably goes _down_ (relative to other high pivot idlers) because of that huge idler. The chain only has friction where it rotates at a link, or rubs against a tooth while engaging or disengaging the idler. All those engaged teeth don't move relative to the idler, and so incur no friction, and the larger diameter means _less_ overall rotation per link.

Of course, it gives all that up with the huge angulation on the lower guide. Ah well.
  • 4 0
 The chain tension on the lower half of the chain (chainring to derailleur jockey wheels) is only relative to the spring tension of the derrailleur, so very little normal force and therefore very low friction. The chain tension between the cassette and chainring when pedalling is significantly higher, orders of magnitude higher, resulting in significantly higher friction forces for a high pivot idler than a lower guide wheel.
  • 7 0
 his idler literally looks bigger than his chainring
  • 9 0
 the oval ring needs to be turn roughly 90 degrees- with the idler pulley (idler chainring?) its effectively a biopace chainring!
  • 7 0
 @hamncheez: I wonder how many more people will run oval rings on idler bikes and not realise that they are doing the exact opposite of what is intended Smile
  • 2 0
 @Primoz: no probs with a Rotor oval system, where you can rotate the chainring 360 degrees to position it right
  • 2 0
 @derbart: on a Rotor crank maybe. Not on a Sram or Shimano crank though Razz
(most direct mount chainrings are clocked by design)
  • 2 0
 @Primoz: True with the 2 big S companies. I ride a Rotor oval on a Druid. Finding the right ‚clock‘ for me took me two rides and works perfect. It‘s really not difficult, if one understand how it works..
  • 6 0
 Bike companies take note- see the short seat tube and huge standover? We want this
  • 5 0
 We’re looking at you GT
  • 8 1
 looks like my ex wife
  • 6 13
flag the666ers (Sep 7, 2021 at 9:30) (Below Threshold)
 is she Russian ? ... I like lose womens
  • 1 0
 This is only an insult to your bearded ex-wife.
  • 4 0
 Not just a badass bike cobbled together in titanium. Those are some great lines and super clean, even the pivot bolts are well designed. Impressive to say the least
  • 6 0
 Looks like a donut
  • 3 2
 How is pedal kick back ever negative? Surely that can't be possible with anti-squat never going below 100% (and above 200% most of the time)...

Also, why would the gear selection change the pedal kickback in the this case? The cassette and idler always move together regardless of the gear, and the idler to chainring link always has the same gear ratio.
  • 14 1
 a hardtail has no pedal kickback
  • 3 0
 @mior: makes the rear suspension work a dream having no kickback
  • 7 0
 wouldn't gear selection matter because of the different angles the change is pulling on the cassette depending on which gear it's in?
  • 3 1
 @gtill9000: The angle that the chain (through the idler) is pulling on the cassette doesn't change through the travel. The idler to cassette section of the chain is fixed: they move together. The only chain section that changes when the suspension moves is between the idler and the chainring, and that section always has the same gear ratio.
  • 2 0
 Pulls the chain during compression; positive. Pulls the chain during rebound; negative.

Antisquat isn't just related to pedal kickback.
  • 2 0
 Anti squat largely comes from the moment generated around the main pivot (or in this case, instant center/virtual pivot) from the rear tire contact patch when accelerating, which increases substantially when the pivot is higher. So high pivot bikes dont actually rely on the chain tension for anti squat the way traditional bikes typically do.
  • 3 1
 I'm guessing the calculation is not correct. The way it's mounted I don't see a way for the idler not to be mounted to the swingarm. If it is mounted to the swingarm, the idler-to-cassette branch of the chain shouldn't have an effect, only the idler to main chainring should (as that is the distance actually changing). I that case allt he gear will have the same antisquat value. And the same goes for pedal kickback, it can't be negative in that case and doesn't change between gears.

Just as you said.
  • 2 0
 @Primoz: you’re wrong. Anti squat is also influenced by the ratio of the size of the cassette to the side of the wheel, so it changes with each gear. And much of the pedal kick comes from the cassette rotating relative to the swing arm, which happens a lot with 77mm of rear travel
  • 2 1
 @kleinblake: antisquat is defined by two components, the geometric part (defined by the suspension geometry, which is negligible with classic designs and high with high pivot designs) and the chain part because it's pulling on the suspension system. Because of that the chain part is defined by the chain line. Since going through the gears changes the chainline, that's why antisquat is different in different gears. It doesn't have anything to do with the sprocket vs. wheel size ratio.

The important bit here is that the chain part only comes into effect if the chainline length changes through the travel because it can only then have an effect through pulling on the suspension.. With a swingarm mounted idler this does not happen, therefore the chainline in the cassette to idler branch doesn't have an effect. But it does in the idler to front chainring branch, as the idler is moving relative to the chainring.
  • 1 0
 @Primoz: when the idler is mounted on the swingarm, both chainlines are involved in the AS calculation.
  • 1 0
 @i-track: no, the idler to cassette chainline is not involved in the chain force part of anti-squat because the relationship between them doesn't change through the travel. The distance and angle of that chainline between top-out and bottom-out is exactly the same, so it will not effect the anti-squat produced by the chain forces. Only the chainring to idler relationship changes through travel, so that is the only piece of chainline that will impart forces on the suspension.

(The relationship of the bottom jockey wheel will change through the gears and the travel, so mech clutch forces will impart different forces depending on the gear chosen, but that's a) not anti-squat, and b) negligible compared to chain force anti-squat)
  • 1 0

Just so you know, I wrote the algorithms that Linkage software uses to calculate AS for any configuration with the idler not on the front triangle.
Both chainlines (cassette to idler, idler to chainring) are required in the calculations.

Consider a high single pivot configuration, with the idler mounted concentric with the main pivot. Do you consider the idler as being attached to the swingarm or to the front triangle? (It’s both!) If the idler is considered as being on the front triangle, then you’ll get one value for AS. And by your logic, if the idler is considered as being mounted in the swingarm (infinitely close to the pivot), then you’d get a very different AS value.
Your suggested method fails at this boundary condition.

Lots of people use these graphical methods, but not many truly understand how it is developed.
Here’s some guidance. Consider a single pivot layout with a conventional drivetrain. When you intersect the chainline and the swingarm line, you’re actually locating the instant centre of the wheel wrt the suspended mass.
Knowing that, you can now consider the mechanism of a swingarm mounted idler, and work out how to locate the IC of the wheel wrt suspended mass for that configuration.
You’ll find that both chainlines are involved.
You’ll also find that this method gives the same result as the ‘normal’ method at the boundary condition when the idler is mounted concentric to the pivot.

Hope that helps.
Hugh McLeay
  • 2 0
 @i-track: how? If the distance between the idler (mounted to the swingarm) and the cassette doesn't change, it can't have any energy input into the system. There is a force, but the path taken is zero, so no work is being done.

Also, im not talking about a concentric solution, I'm talking about an idler mounted to the swingarm elsewhere than the pivot. Like in the case of the bike we have here.
  • 2 0
It relates to the amount of chain that is wrapped/unwrapped from the casette and idler pulley as the suspension moves through its travel.

I realise this bike is a swingarm mounted idler, but the case of a concentric idler is a crucial boundary condition to assist with understanding the difference between the two configurations (idler mounted on front triangle vs idler mounted on swingarm).

With a concentric mounted idler, you can consider that the idler is mounted on the front triangle, therefore the 'conventional' graphical method is applicable (and correct). Despite there being no distancing between the idler and the cassette, this method still uses the chainline from the idler to cassette in the algorithm. If you change the sizes of the idler or cassette (or both) it affects the amount of wrap/unwrap of chain on these items as the suspension moves through its travel. This is reflected in the change in point where the chainline intersects the swingarm line, and therefore affects the anti-squat.
  • 1 1
 @i-track: so in the case of THIS bike, where the idler is mounted on the swingarm and is not concentric to the pivot, the cassette - idler branch has no effect. As the chain is not wrapped or unwrapped in that part or those sides of the cogs, only on the idler - BB branch.
  • 1 0
 @Primoz: In THIS bike, the amount of chain wrapped on the top of the idler and on the cassette (around to the bottom of the cassette, directly above the wheel contact patch) will both vary as the suspension moves through its travel.

Please don’t dismiss the concentric pivot example as being irrelevant for this case. If you can understand the role of the rear chainline in the case of a concentric pivot idler, then you’ll see that it’s still relevant in THIS example.

Hope that helps.
Cheers, Hugh.
  • 1 1
 @i-track: How will it vary?
  • 2 0
 @Primoz: The chain isn't pulling directly on the idler; it's pulling on the casette (where the significant resistance comes from) via the idler. The angle between the runs of chain between chainring to idler then idler to cassette defines the magnitude and direction of the load on the idler. And that angle will change depending on what gear is selected. Hence gear selection affecting AS.
  • 4 0
 I think we all could benefit from a huck-to-flat demo with this bike. Might even attract investor money.....if it survives.
  • 1 0
 Huge respect of being so proactive and daring to try something quite radical, with just the main goal just being to improve bikes, not even to turn it into a business opportunity (yet). So much thinking, time and personal money invested. The guy is clearly a visionary and such a passionate rider. While my knowledge about suspension kinematics isn't good enough to have a worthy opinion about his design, his attitude I have huge respect for. I hope you will make it far and I'm looking forward following your steps!
  • 1 0
 I want to see a return of high-pivot bikes with floating brake mounts. High pivots result in seriously poor suspension performance when braking. My old 7" bullit was great until you used the brakes. Under braking, it basically became a hardtail due to aggressive brake squat. I added a floating brake mount and the suspension became active under braking. The difference is staggering and well worth the minimal weight and additional pivots.
  • 4 0
 *In the voice of Homer Simpson* - "mmmm, titanium, aaarrgh"
  • 2 2
 And if it was a Yeti branded.... "Take my money!!"
  • 1 0
 Is this the _Lan guy? Whos been doing several high pivot titanium bikes?,51029/setup,40252,51029/setup,42840
  • 2 0
 Don't think so... _Lan's Vital profile says he's from Angola...
  • 1 0
 @Primoz: Good catch
  • 1 0
 So it is possible to get a custom everything frame in titanium from China for €6000? I did not know this. Looks like a labor of love for Stefan!
  • 3 0
 I read it as it was 6000 € for the whole bike, not just the frame.
  • 4 0
 grim donut that could
  • 1 0
 Im gonna need to see a video of this bike being sent. 190% anti squat creates insane pedal kickback. Not sure what the design parameter here is.
  • 1 0
 There's more to antisquat than pedal kickback...
  • 1 0
 @Tambo: its the same effect just in different directions
  • 2 0
 @emptybox: They're related, but you can have a lot of antisquat and low pedal moving the pivot point very high.
  • 2 0
 @emptybox: (and running a suitably positioned idler)
  • 5 2
 I still think they should get Alan Millyard to build the next Grim Donut
  • 3 0
 Interesting that they named it after Elon Musk's son....
  • 1 0
 What's the meaning to make a bike that weighs like a dh bike, but with less travel and twice the price? I bet no one would pedal that thing uphill anyway
  • 1 0
 That is a amazing looking frame, would really like to try one?
But not sure super high pivot point is way to go?
Especially in Titanium !
  • 1 2
 WTF....I had a seizure when I first looked at it. Mad Max inspired mechanics nightmare. I don't have enough fingers and toes to count all those pivots. Somehow hate it and want it at the same time.
  • 1 0
 They are 4 pivots. Typical of most designs employed these days (VPP, Horst,DW,ect)
What your probably looking at is where the chainstay and seatstay bolting to essentially thr swing arm. Which then utilizes a pull link to rotate the rocker link.
  • 1 0
 I'm with Mike Levy on this, the idler pulley thing has got out of hand now. The bike is nice though.
  • 1 0
 This guy Is 100% bad ass. Best bike I have seen in a while. Instead of going mainstream he when his own way. Respect.
  • 13 11
 Looks like a session
  • 2 0
 The Idler!
  • 1 0
 Directly from early '00 ... Freeride guys !!
  • 1 0
 Awesome, love stuff like this.
  • 1 0
 You got me on my knees, Laile.
  • 1 0
 Awesome to see a truly novel and well thought out design
  • 2 1
 A BTR Fab, and an sultry, older Brooklyn Machine Works walk into a bar...
  • 1 0
 I want a second oval for the idler.
  • 1 0
 me looking at the graphs ¯\_(ツ)_/¯
  • 1 0
 insane sick
  • 1 0
 The grim Ti-Nut
  • 1 0
 Nice head tube gusset...
  • 1 0
 Those welds though!
  • 1 1
 Nice bike, but pity about the amount of brake jack?
  • 3 5
 with a drag coeffieciency of a tank
  • 12 0
 Interesting combination of "coefficient" and "efficiency".
  • 1 2
 nvm found it

You must login to Pinkbike.
Don't have an account? Sign up

Join Pinkbike  Login
Copyright © 2000 - 2023. All rights reserved.
dv56 0.038220
Mobile Version of Website