A PINKBIKE ORIGINAL
THE GRIM DONUT
Part 1: we went to Taiwan & made a bike from the future...
Words by Mike LevyWhat happens when a joke becomes reality? It took tens of millions of years for the opposable thumb to show up, and only slightly less time for mountain bike geometry to get to the point where our bikes aren’t actively trying to kill us. This whole evolution thing is a long, slow process.
Just one ride on a machine from a decade ago is all it takes to realize that development hasn't been standing still—bikes these days are damn good. But it sure does seem unhurried sometimes.
Brands design bikes to sell them, shocking I know. From a business perspective there’s just not a lot of upside to taking huge risks in the geometry department. So for all their talk of "game-changing" and "revolutionary," it makes sense for many brands to design bikes to be on-trend next year rather than roll the dice on what
might be the future. Something risky may not win over customers, even if it's the future.
Yes, there are outliers, the people making wild things in their workshops, and occasionally the established brands can be adventurous, too. But, for the most part, the industry seems to be pushing the envelope forward by about, oh I don’t know, a single degree and a handful of millimeters every few years. At this rate, bikes will have their own opposable thumbs in another twenty million years...
But what if we skipped the evolution part and went straight to revolution? We've spent the last few years talking half-seriously about how we should just extrapolate where mountain bike development *might be* by pressing the fast-forward button. So what happens when a joke becomes reality and we do exactly that? We're going to find out.
Of course, bikes are really damn good these days, and steady evolution is probably in most riders' best interests... but in the name of “science” or something, it's time to take things a little too far by building a bike from the future. A very long and slack future, it turns out.
Geometry from 2030 The first step was to figure out what bikes would look like in ten years, and we didn't need one of those ''engineer'' types to figure that one out. Wheel size debates and chainstay lengths come and go, but if we see “longer and slacker” in one more press kit…
And unlike developing a new suspension design, geometry doesn't cost anything.
Go back a decade and lots of bikes had head angles hovering around 69-degrees, seat angles that felt about the same, and front-end lengths best suited to small children. Yeah, things were cramped and we flipped over the bars a lot.
So to get to our geometry from the future, we just took the numbers from 2010, punched them into our 2020 digital extrapolator, and boom, we had the numbers we'll be using in 2030. Hey everyone, you're welcome.
From custom carbon to catalog aluminum The best-laid plans often go awry, but that doesn't apply here given that our plans weren't laid all that well.
The dream of letting the factories fight over who was going to manufacture our wacky design was destined to be drowned in bubble tea. Tongue-in-cheek impossible suspension design aside, the startup costs for custom carbon fiber construction would have been far, far too high. Sure, we could have pulled a Tesla and pre-sold some bikes to pay for building them, but we’re too irresponsible to have that hanging over our heads.
Instead, the idler pulley, dual-link suspension layout (High Pivot Virtual™) and carbon construction were abandoned in favor of an already-designed catalog frame—but built with our 2030 geometry. This is where Genio, a relatively small but high-end Taiwanese factory, enters the story with their 160mm-travel GF7-1-160A frame.
You can call it the Grim Donut.
What have we done? With headtube angles pushing 63° these days, we had to go all the way to 57°. Along the same misguided lines, we've got some modern bikes with seattube angles around 78°, so we added 5° to get to an 83° seattube angle.
Hey, this geometry thing really isn’t all that hard after all.
Reach ended up be decided for us. We were constrained to 500mm because we didn't want to order a bunch of custom tubes or weld two toptubes together, but that seems like a big number so it's probably correct. And then we decided to call it a small-sized frame because, despite the long reach, the super-steep seat angle means the effective toptube length is actually a hair shorter than many small bikes on the market. But in a neat trick, it’s pretty damn big when you stand up! The seat tube is just 400mm tall, too.
If wheels have gotten larger over time, they're probably going to keep getting larger, right? No doubt, which is why we originally looked into making a 29"/32" wheel size combo (sorry). All we got were blank stares and dial tones when we tried to show tire companies the future, though, so our project had to roll on a 27.5"/29" mullet setup. The small rear wheel does allow for conservative 450mm chainstays (we wouldn’t want to get too crazy, right?). Other numbers include 155mm-long children’s cranks, and a 180mm fork mated to 160mm of rear-wheel-travel.
Genio took our geometry numbers, double and triple checked with us to make sure it was actually what we wanted for some reason, and then lit the torch. Eight long weeks later a box arrived at Pinkbike HQ with the very first Grim Donut prototype inside of it.
The build We assume that by 2030 all suspension will be attached directly to our brains via Bluetooth, but for now we went with a RockShox Lyrik and Super Deluxe Coil Ultimate. SRAM won the
Innovation of the Year and I'd put money on them being the first to try implementing that brain-implanted suspension microchip, so hopefully they'll offer an upgrade kit. We did try flipping the crown around to shorten the offset, but it ended up contacting the arch and we could feel the SRAM techs' disapproving eye-rolls from miles away.
It's obvious that drivetrains will keep having fewer and fewer gears when you look at the trends since the "glory days" of 27-speed bikes, so we went ahead and chose SRAM's 8-speed eMTB drivetrain. And shrinking crank lengths made it obvious that we had to run SRAM's 155mm kids' bike crankset. It actually looks super badass. TRP eMTB brakes with chonky rotors keep the e-bike theme going, along with e*thirteen's wheels and tires. We're also sticking with the OneUp dropper post because it'll probably still be running fine in ten years, and
someone is weirdly obsessed with those weird looking Tioga saddles...
And the rest is, errrr, history.
Stay tuned for part 2 - can you skip evolution? Has the Grim Donut gone too far or is it the right amount of stupid? We'll find out in the next episode.
Created by
Brian Park & Jason Lucas
Produced & Directed by
Jason Lucas
Starring
Mike Levy, Mike Kazimer,
Calvin Lin, & Yoann Barelli
Additional Footage by
Max Barron & Chris Ricci
Words by
Mike Levy & Brian Park
Photography by
Brian Park
Special Thanks to
Genio Bikes, Taipei Cycle Show, TAITRA
Astro, A-Mega, A Pro, Waki Designs for
the Grim Donut drawings, Duncan Riffle
at SRAM, Connor Bondlow at e*Thirteen
Sam Richards at OneUp, Cody Philips,
TRP Brakes, Chris Cocalis at Pivot, The
Aava Whistler Hotel, Nick Morgan at
Corsa Cycles, Karl & Radek Burkat
694 Comments
Wait. Maybe I don’t.
good in theory but don't some frame designs get too wide with 157 and result in heels rubbing on the seatstays? that's also down to each rider's physiology.
I demoed a Fugi LT and had a few encounters with my heel and the seatstay. Would need a second demo before calling it a deal breaker.
Oh, and for those that think it can’t handle any big air: you’re wrong. Clearly, Levy has already jumped the shark.
An overlay of their rear ends is available here - www.knollybikes.com/engineering
In any case...
“I'll tell you the problem with the scientific power that you're using here: it didn't require any discipline to attain it. You read what others had done and you took the next step. You didn't earn the knowledge for yourselves, so you don't take any responsibility for it. You stood on the shoulders of geniuses to accomplish something as fast as you could...”
Insane!!!
controlled brakes. All on some sort of paper mache frames that are biodegradable, lighter than carbon fiber and stronger than steel.
Don't let others underestimate you and give you the credit you deserve. This trolling keyboard warrior thing shouldn't take away recognition if the talent is there... Too small mediocre world for great minds.
I hope at least they paid you s good bill for the great drawing.
Although... One review I read recently of one of the Pole bikes mentioned the reach was too long for what they wanted so they sized down... but because the seat angle is so steep, sizing down meant the climbing position felt too cramp like they were hitting knees while seated on tighter corners.
I'm all for steep STA and slack HTA, but there's obviously a line and it's definitely a fine balance to getting it all right.
But now put all that on top of a long, long wheelbase... and it's going to feel weird... I don't know, it will be interesting to hear.
And yes, given the chance I'd still try it out. I'm sure there's something to be learned even if it's how far is too far.
I want to see a PinkBike experiment that tests the performance difference between climbing with a lighter bike (no water bottles) and water on the body versus the heavier bike (with water bottles) and less weight on the body. I think the lighter bike and carrying water on body wins with less watts and faster times climbing.
Also, the better shape you are in, the better you can handle the heat.
We are all children of the Great Donut. I wish to thank Pinkbike for this opportunity and the response at the Taipei show seems like I achieved the goal 10/10
How this vessel of plastic now owns the bike industry is mental.
www.pinkbike.com/photo/17994253
I hate you pinkbike
surely specialized will integrate a bladder into the frame; Tactical Water Access in Top Tube (T.W.A.T.T.)
www.specialized.com/us/en/shiv-fuelselage-hydration-system/p/155590
www.instagram.com/p/B7RXt9jH06J/?igshid=othpy7b7jhus
This is from Bike Radar in 2015:
A note on Chris Porter’s bike
Following years of experimentation and trial by stopwatch, Chris has arrived at a truly radical geometry configuration. With a head angle as slack as 59 degrees (although usually a slightly more conventional 61), and an offset of just 30mm, Chris has a monstrous trail figure. With numbers like these, you could almost call it ridiculous.
...that didn't stop Sick Bikes
Seriously, I think we are reaching the point at which we have proper MTB geo is being achieved with bikes like the Pole/Geometron/SJ Evo (yes I know I put Specialized with the other two). Large reach 480-500 mm, HA 62-64, SA 76-78.
Are you comparing front center to rear center or something? If yes, it's not how weight distribution works. at all.
Weight distribution between wheels is around 50/50, and it doesn't change much except if you're pedaling seated uphill, or braking. Even in super steep downhill, if you don't brake, you are close to 50/50.
Or, you are not a rider, but a passenger of an autopilot e-bike.
Geometry will dictate how easy it is to keep those 50/50, and how much there is in your hands/feet/ass. But at the wheels, nothing.
Oh, I forgot. There is riders who don't ride 50/50. You can see them each Friday on pinkbike's youtube channel.
Can we please stop talking about some ridiculous nerdy stuff that does not make anybody faster, at least on the level of people who bother commenting on Pinkbike? The sole point of my initial answer was that weight distribution is some esoteric factor only a company basing their marketing on geometry can find valuable. Read Nicolai, Pole and R.i.P. Sick. Saying Pole has good weight distribution is Nothing more but some fanboism of folks who desperately try to shine in a group chat, like a teenager hanging out with buddies and saying that weed is crap, you guys need to smoke real hash from Afghanistan.
"most of your weight..." Yeah and there is a tower in Italy that is mostly vertical, and it made it known all over the world. Please think with center of gravity, leverage, free body diagram... you won't see the 50/50 distribution easily but you'll at least understand physics behind. Putting an angle there don't make it really harder. Measuring it is the same.
What punctures rear tires and damage rear wheels isn't related to weight distribution. It's due to leverage, accelerations, and stiffness of your legs VS arms.
Beginner's weight distribution isn't far off. Except if they release the brake not moving, do a magnificent no foot superman to no teeth faceplant and end up on friday fails.
Sorry for "nerdy stuff". You summoned me with the "faul's ritual"
- going on a nerdy website
- showing false number coming from nowhere as a somewhat technical theory.
- being super confident about it.
Weight distribution is one of the important factor in the equations of self-stability for any bike. I don't see the issue basing your marketing on it. It's way more relevant than coil vs air or worse, "high speed adjustment knobs '
@Mondbiker And/or one without magnesium lowers. It's available. Wouldn' t even be heavy. But it is obv far easier to rant about "weight weenies"....
*Trigger warning- going to talk about weight
A Boxxer 29er is lighter than a Bartlett, and I'm guessing going to perform better.
Seriously tho, for a dual crown enduro fork to be widely accepted its going to have to weigh under 5 pounds. I don't think it would be hard to make. The top crown could have a dramatic rise to it (like the old Marzzochis) so each leg isn't that much longer than a single crown, and with the two crowns being significantly lighter and thinner, you can get a lot stiffer with little weight penalty.
@hamncheez Is that your metric? You expect to find the "future new hot thing in enduro" at bargain prices in the classifieds? That is not how that whole "product" thing works.
Here’s another idea, why don’t we get the shortest bike like a DJ and hit pumptracks, dirt jumps and learn toove on the bike? Oh you don’t have any of tgat? Why don’t you hit the shovel? Because more often than not, people who grab the shovel and a DJ or BMX tend to pass people with interests like geometry, Kinematics, data acquisition... i don’t know, just a thought
What shock manufacturer for mountain bikes is making sliding bushings? Are they used in moto?
The issue I see with them is weight and cost- two race-surfaces (is race the right term for the surface a bushing slides against?).
The one you posted is just a link to an image; whats the link to the product?
"Boss, there is something wrong, we get a lot of spam mails!"
"Just delete it, all Pinkbikers wanting some crazy geometry custom shit"
Being in product design, it’s great to push the limits in order to understand the boundaries. Also great to consider everything as a prototype. That old adage of Fail often, fail early may apply here, but I love it.
So a few thing come to mind here. #1 dynamic seat tube angles. Right ? Based on active variables such as terrain slope , input wattage, speed, etc. Could also marry that to head angle. A few bikes kinda do this , but the integration of all these things is something taj can visualize perhaps.
Funny though, aside from the ridiculous head angle ( what have mx bikes settled on for everyday riding ??? Hmmm) the rest of the bike isn’t that far fetched.
Look forward to video #2.
Somehow I feel like this will impact the outcome of these shenanigans.
At the very least, it explains the press fit bb.
I want to see 36" in 2030 - rolls better over obstacles.
And some new standards, BB and handlebar width etc.bracket/fillineverybikepart/bracket.
Or wait - some standards shown in slomo evolving the next years.
Then look at constant rise of Gravel, why not make even bigger wheels for gravel bikes?
It was consumer stupidity and bike industry shittiness that lead to the horrible 71/73 geometry that prevailed for nearly 20 years. Consumers didn’t get why a slacker geometry would work better on a mountain bike; it “looked wrong”because it looked like the bike their parents had. The industry churned out what those consumers wanted.
It wasn’t until some gnarly BC riders decided they needed bikes that rode better, rather than looked a certain way that MTB geometry went back to what it was in the 1970’s.
So to all of you who post about how a bike looks-it was your fault. I hope you’re happy signaling a prefabricated identity through your purchasing decisions. The bikes on the tailgate of your Taco look juuuuust right in front of the coffee shop, even if they could be better if they looked different.
And outside of DH racing noone really cared about downhill speed. The focus was on fun, stunts and tricks (just watch some Kranked films).
But that is a hard pill to swallow because BMX is cool, right?
geometrygeeks.bike/bike/pinkbike-grim-donut-2020
Sadly for most, the other trend is the increased use of motors, obviously the next "advancement" will be power steering through motorised headsets.
And yeah, i know there were tons of people pushing 11-36 cassettes on 36t front rings and shouting 'walk if you can't pedal or get in shape'. But that defeats the purpose of a bike. The best decision i've made in my biking career was to replace the Sram 11spd drivetrain with an Eagle setup 2 years ago. No more pushing gears too heavy up the climbs.
So yeah sure I may have been the odd one who has been just fine running 1x9 (though I live in The Netherlands) but the advent of 10sp definitely was enough for a lot of people to go 1x.
The failure of the Enduro in 2015 i think, when Specialized went 1x only with a 1x10 drivetrain on the cheapest model caused the local distributor to make a special model with GX 1x11 drivetrain just to make the bike make some sense.
That being said, the future trend Mr. Levy should be that we are not allowed to drink water at all - so the new frame you got is actually forward thinking with no allowances for bottles.
Saw a small company at IB a few years back that made a hub with air bladders inside attached to the wheel via 2 hollow spokes. One to raise tire pressure, One to lower it. Called Raven or something.
And that's the most obvious case, we have some old hiking trails going over pastures as well. You also have horse dung on trails from horse riding, etc.
wetransfer.com/downloads/e80e64999ad63ca2b87993b1f495898b20200114125532/161e3f
if you don't have linkage you can download it here
www.bikechecker.com
- it has 32.88% progression making it great for coils
- the anti-squat (at 30% sag) is in the 104% - 101% range in your climbing gears which is damm near perfect
- pedal kickback is stupid low at only 2.5 - 1.5 degrees in the high gears
Honestly this thing as far as I can tell is significantly better than a lot of high end bikes I'v seen on the market. I'm just hoping that head angle doesn't ruin it.
That 180mm fork gives about 150mm of vertical movement.
The benefit of a slack-er/ish headangle is the square bump performance then.
It all depends on what you ride. DJ bikes have stayed steep even to this day.
I just don't understand why you didn't knock on Trueloves door? I know there are even some people near you making frames out of their basement near you. Would have been way cheaper.
On a serious note, you could make it like they did on Buell bikes: newmotorcyclesstyle.files.wordpress.com/2010/04/newbuell1125cr282010291.jpg?w=300
The triple bottle cage idea is genius though, except the downtube would scrape the floor and either way two tons or snap.
The idler spocket is rising through the travel (more or less) with the idler to front ring part of the chain pulling the rear triangle back down.
Might be a good idea to do the huck to flat last? Maybe?
the bike might be heavy, but it can simulate any weight you want.
water bottles become irrelevant, you can hold two drinks at any time.
so practically the bike could ride itself. your just sitting on top or not.
Seriously, is there a place you can go to where they would make a mule from your design (kinematics and strength calculations included), but would give you the values of the tubes and the like? And that would do that for a decent chunk of cash (say similar to an off the shelf frame)?
Other than buying some equipment and learning how to weld i haven't found anyone being able to do that. And i'm willing to work within the confines of standard parts (pivot housings, yokes, etc.). And i'd be willing to go through the pain to source some of my own billet parts if needed (links and the like).
EDIT: oh, you meant for Pinkbike? Yeah, they might in that case
Should of gone with a nice even 50.
www.youtube.com/watch?v=KhLeyUPF-pA
TL; DR: In 2005ish, Cathros sponsor offered to make a bike with any geometry he wanted. Being like 6'7", he initially sketched up something similar to a Pole or Geometron, but in the end he chickened out and just went with their XL. Minaar had a similar experience on the Honda team, but he says that tracks, riding styles, and riders themselves weren't ready for ultra long geo yet, and probably would have been slower.
So fast forward 10 years from now this "joke" might actually be the norm.
The problem is that DH requires a whole different set of bike characteristics than enduro. DH is all about one run, and so its normal to expect that the guys will be on point for the entire duration of the run, managing the bike under them. For this, you don't actually want crazy long of wheelbases or slack head angles, because you are going to be picking the bike up quite a lot over stuff, and you want the ability to change weight distribution quickly to change the pitch of the bike.
The whole reason mullet setups came about is that running a 27.5 rear lets the bike have the same travel but shorter chainstays.
For enduro however, anyone can tell you that the days are demanding mentally as well as physically, and the longer the bikes are just safer and more confidence inspiring to ride at a faster pace, which means that when you are doing the final stages, you are less likely to crash.
The main reason why everyone hasn't followed Pole/Nicolai is because manufacturers want to release incremental updates to get people to upgrade every 2 years. More business for them, while they get time to plan even further in the future.
I've never done an Enduro race, so IDK
From what I understand about enduro, its less about speed through an individual corner and more about overall average speed. Some people are pedalers, others dh shredders, and they prefer the bike one way or another.
The thing about the "future" geometry is its theoretically the best of both worlds. You have long chainstays that equalize the weight better so you can turn the bike with enough weight on the front, while the overall long wheelbase and slack head angle means that on descents, the bike is stable.
We all know that a lot of the performance is due to the rider, but Pole sponsored rider Leigh Johnson is ranked 13th in EWS, which is pretty high, and he was relatively unknown. So its fair to say that the bike probably had something to do with it.
But why go all the way to Taiwan if a local builder like Daambuilt could have built your true dream, but in steel?
Who gave the guy who invented downcountry the keys to design a bike?!
Looking forward on how you liked the concept.
Yup, just like a horny teenager, we will do anything with a heart beat or ummm, as long as it's still warm.
Keep the bro-science coming!
media.npr.org/assets/img/2014/10/09/eas017ei_custom-70f39e8969935bcce80b2a04045ec7938a8577bc-s800-c85.jpg
I bet the wheel flop is true joy.
I’ll put money on there being a motor in that thing.
HTA ended up being 62°. So floppy & nearly impossible to quickly change directions.
Small jumps were really sketchy, but it felt better sending bigger ones.
However, unlike your DJ experiment, I think it would still benefit from the mullet configuration and the long AF wheelbase.
Moreover, PB scientists could put a scale under each wheel, and adjust CS lenght accordingly to the desired weight distribution.
Or maybe I'm all wrong, and it would turn to be just another trail abomination...
I would like to see the bending forks!
www.linkedin.com/in/vernon-felton-48a5508
this bike is as beautiful as the sun, in fact you cannot look at it
Oh well hopefully it pays better in archviz :p
this bike is as beautiful as the sun, in fact you cannot look at it
It’s not a motorcycle, it’s a Grim Donut.
Who’s Grim Donut is this?
It’s Mike’s.
Who’s Mike?
Mike’s dead, baby, Mike’s dead.
Very entertaining though Pinkbike!
Also this is awesome, I love every bit.
HPV
8008135
Parts Needed: bar ends, front derailleur
I don't see that changing in the current decade.
i.imgflip.com/396k03.png
What happened there?