Bike Check: The BREWser, a 184mm Travel, Crazy-Slack Experimental Gearbox Bike

Feb 24, 2021 at 12:17
by Alicia Leggett  


What happens when a mountain bike takes inspiration from a trophy truck?

The BREWser: an experimental belt-drive, gearbox, 190mm front and 184mm rear travel bike with a 62.5-degree head tube angle.

Adam “Prosauce” Prosise, the mind behind the BREWser, is a machinist at REEB Cycles who describes his riding style as “smashing into things.” He grew up dirt jumping and racing BMX in Iowa with his two older brothers, and he says Rule Number 1 was ‘keep up.’ Now, he’s a regular on the Big Mountain Enduro circuit and consistently places in the top third of the pro field on bikes he built himself.

BREWser

The BREWser is a collaboration between Adam and a handful of willing friends: Chris Sulfrian, who taught Adam framebuilding; Tyler Brady, who helped with suspension kinematics; Steve "The Space Cowboy," who helped with engineering and aesthetics; and Pinion Gearboxes and Gates Carbon Drive, who helped figure out the whole belt-drive gearbox situation.

Details:
4130 Chromoly/7005 Aluminum Frame Construction
Pinion P1.12 gearbox, 600% range
Gates Carbon Drive belt system
RockShox ZEB 190mm 29” fork
Super Deluxe shock variation
Industry Nine Grade Hydra wheels. 29” F/R
Industry Nine stem 32mm
RaceFace Atlas Bars 35mm x 820mm
TRP DH-R EVO brakes. 223mm F, 203 R
Vittoria Mazza Enduro 2.6” tires F/R
OneUp 210mm dropper
Fizik Saddle
Oury Grips
HT Components pedals
Geometry:
Size: XXL
Seat tube: 450mm
Effective top tube: 680mm
Reach: 515mm
Stack: 660mm
Effective seat tube angle: 76 Degrees
Head tube angle: 62.5 degrees
Chainstays: 445mm
Head tube: 125mm
Axle to crown: 606mm
Offset: 44mm
Wheelbase: 1341mm
BB Drop: 23mm
Weight: "Doesn't matter where we're going." (It hasn't been weighed.)

The BREWser was built to be low-maintenance and indestructible, so the belt-drive and gearbox options were no-brainers for Adam, who fell in love with gearboxes a few years ago when he tried one at a bike park. REEB already builds belt-drive and gearbox hardtails, so Adam had friends in the right places, and the fact that the gearbox only needs an oil change every 10,000 kilometers fit right in with his vision for the bike.

BREWser
BREWser

Settling on the BREWser’s geometry was a bit more of a process. Adam has dialed in his preferred geometry numbers on several race bikes over the last few years, and has found that for him, longer and slacker is the answer. As he pushed the geometry a bit farther on each of his versions of REEB’s full suspension bike, he rode faster and faster until he and his coworkers had to redesign the rocker link to take more abuse. In designing the BREWser, Adam took the geometry numbers from his favorite bike, including his preferred 62.5-degree head tube angle, added a bit of chainstay length, and created a long-travel monster.

BREWser
BREWser

As for the material, the aluminum and steel combination was inspired by a trophy truck Adam saw at the Baja 1000 that had a raw Chromoly 4130 chassis with machined aluminum swingarms. Since Adam was already on a path of reducing unsprung weight by eliminating the derailleur and cassette, it made sense to keep the swingarms light and made of aluminum. The steel front triangle made for high strength and relatively easy fabrication.

bigquotesThis isn't just a bike. It's a trophy truck. Suspension is meant to keep your tires on the ground and in traction. One way to improve that is to decrease the unsprung weight. Since I was already losing the weight of the derailleur and cassette, the aluminum swingarm helped keep that weight down.Adam Prosise

The most difficult part of the design was making sure there was enough belt clearance on the chainstay and that there was enough travel in the belt tensioner for a full 180mm of travel. Luckily, Adam said, Pinion had a full CAD package of information about those components, so with some extensive modeling and a bit of luck, it worked out.

The result is a bike to rival the Grim Donut.

BREWser
BREWser
The BREWser is about as custom as it gets.

BREWser
BREWser
I have a soft spot for raw metal bikes. This one has a gorgeous industrial look.

BREWser
BREWser
This bike has just the right amount of flair.

When it all came together, Adam was blown away by how dialed it felt, he said. He takes pride in everything he makes, but he's glad he didn't waste everyone's time, given that he leaned on a variety of people for help with the project. He wants to thank everybody who believed in the BREWser, and also those who didn't.

bigquotesHave you ever been on a downhill bike and wish it could be efficient uphill? Have you ever been on an enduro bike that you wish had a little more downhill prowess? Well this does both. It doesn't feel any slower uphill, and on the downhill, it’s straight comical how fast this thing can go.Adam Prosise


The BREWser in its current form likely won’t ever be for sale, Adam says, because those numbers are not for everyone and aren't the most marketable. Still, it is being used to develop a similar but less out-there REEB frame that we’ll likely see in 2022.

In the meantime, look for Adam on the BREWser at Big Mountain Enduro races, the TransBC (pending access to Canada), and any rowdy trails near you.

BREWser



249 Comments

  • 222 0
 “Weight doesn’t matter where we’re going” AMEN!
  • 55 20
 All the more reason to throw a Boxxer on that baby and get rid of that fishing rod! I realize the Zeb is supposed to be stiffer than a Lyric, but there's no way it can be better than a dual crown for a bike like this.
  • 26 0
 Where we're going we don't need scales.
  • 23 2
 @justinc5716: keep that barspin option ;D
  • 25 9
 @justinc5716: imgur.com/a/LwLDhkA

After riding the Zeb, I'm not convinced the boxxer is any stiffer. Plus that review pb dropped this week wasn't exactly flattering....
  • 6 35
flag hamncheez (Feb 24, 2021 at 14:44) (Below Threshold)
 "It's a trophy truck. Suspension is meant to keep your tires on the ground " if you watch trophy trucks in slomo, they tend to spend more time in the air than on the ground....
  • 15 3
 Wight does matter (especially for anything to be pedalled uphill). But there are other things that are more important in the equation. Suspension/geometry efficiency, tyre rolling resistance, drivetrain efficiency, pedalling comfort/position. And last but not least how: FAT YOU ARE.
...I bet he weighed it and my guess is around 20kg.
  • 26 0
 @IluvRIDING: My guess they tried to weight it and the scale broke.
  • 2 0
 I kept mind-editing to "Doesn't matter, where we're going."
  • 4 0
 I want one please!!!!!!!!!!
  • 3 0
 XXL rider on an XXL bike.... Higher torsional forces to deal with, of course it's gonna be a tank
  • 12 0
 Ruthless dentist destroyer!
  • 4 3
 Speaking of (unsprung) weight, what does a 40t CDX sprocket made of stainless steel weigh? As much as a lightweight cassette?
  • 7 0
 While I don't care about weight (as I ridie a 41lb trail bike) I am very interested in knowing what real bikes weigh.

I find it a bit annoying when reviewers slam bikes (like the Norco Shore) because they are 37lb which to me isn't stupidly heavy considering how capable the bike is.
  • 1 2
 @hamncheez: Not sure you can blame the fork for that. See how the cockpit maintains alignment with the fork, posing frame flex as the culprit.
  • 5 0
 He may be lying a touch. Look at the wheelset - at least this dude knows where weight really matters
  • 2 0
 @dave-f: Wolftooth 32T stainless is 88 grams so I am not seeing a 40T reaching anywhere close to the 350 grams that the lightest 10-50 (ish) cassette weighs.
  • 5 11
flag mhoshal (Feb 25, 2021 at 8:53) (Below Threshold)
 @andrewbikeguide: not everyone runs that massive 50 tooth garbage. Some of us actually wanna use our leg muscles.
  • 6 0
 @hamncheez: I believe this is what he is referring to by "trophy truck" suspension keeping the tires on the ground.

www.youtube.com/watch?v=8DWpgP-KqiQ&feature=emb_logo
  • 6 0
 @hamncheez: I remember being blown away by that episode and the huck to flat tests! That level of deflection would be deadly on a sportbike and damn near un-rideable on a dirtbike. Bicycles have a long way to go. I really want to see some static test rig data showing fore-aft, torsional, and lateral stiffness values for all the major forks. No more of this claimed "17% stiffer" nonsense...give us actual numbers in lbf/in (N/mm)!
  • 2 0
 @justinc5716: them german bike magazines (I think it was bike) did that in the past. Not sure they still do but for sure they had a proper teststamd for that
  • 14 0
 45 lbs with a full water bottle and multi-tool. So call it 43 lbs. There are people out there building carbon Megatowers with carbon wheels at 39-40 lbs. Tires are 1447 grams a piece lined with Cush Core front and rear with DH rims. This is a near bullet proof setup. I dont really get flats anymore, and if I do I always continue riding at full pace. Stop thinking weight matters. Just ride your bike.
  • 4 0
 @prosauce: Half the benefit of a bike is to one-up your peer group. If my bike isn't lighter, what good is it to me? How else can I ascend the dominance hierarchy? Ride faster? Thats not happening, and I can't afford a Tesla.
  • 2 1
 @hamncheez: Drop your ego
  • 4 1
 @hamncheez: Try riding at the same level but with a crappier bike.
  • 4 0
 @prosauce: Just cracking jokes. Most of the time I have to ride at 5am before work, so I'm mostly solo.

I'm poking fun at the new culture rising here in Utah- the economy is on fire and there are peeps in the late 30s and 40s coming up in managerial and executive positions, and they don't want to golf. Mountain biking (and road biking even more) is the new golf here, and every one show up at the ride bringing their ultra competitive business mentality to the trailhead. you have to stand around and admire everyones bike setup (and car that it came in) to try and impress everyone else before the ride starts. Since you work 50+ hours a week, not everyone can find time for fitness so they have to compete in other ways (of course some do, and I get dropped by 50+ year olds on the road rides all the time).
  • 1 0
 @prosauce: Its a joke, good Lord! Relax lighten up.
  • 1 0
 @hamncheez: ha fun poke. But if you turnd up any were people know mtb this bike is a sure one up. Then down it would decimate
  • 1 0
 @fartymarty: I'm sure my bike is in that range, maybe even heavier. I've changed just about every part on my capra to what what I wanted. For the most part at least. Some things that I changed made it lighter, others made it heavier. But overall, For me at least, it is a better bike to ride.
  • 1 0
 @justinc5716: it’s still an enduro bike though. Definitely could be a dh bike if he wanted it to be.
  • 93 1
 What, no video?
  • 41 2
 Right?! Where’s the consistency
  • 30 0
 lmao. Brutal.
  • 6 2
 What, no shout for Cotic?
  • 3 1
 I was sure I was going to come down to the comments section and see all those people complaining about video heaping thanks praise on @brianpark for running this photo check. Imagine my surprise that no such post has occurred.
  • 2 1
 There are videos of Prosauce riding this rig. You just need to search them out...
  • 65 0
 Some people call Steve The Space Cowboy, yeah. Some call him The Gangster of Love.
  • 15 0
 I thought it was Morise?
  • 19 0
 *whistles*
  • 11 1
 @wowbagger: But he speaks of the pompatus of love
  • 11 0
 Some people call him mooorrice
  • 4 0
 Some say he has the speed of the cheeba
  • 3 0
 @sewer-rat:

That's more my speed of Space Cowboy. Jamiroquai over Steve Miller Band any day.
  • 2 0
 everything is good, and green, say I'm red again
  • 51 0
 That thing is a piece of art. Would love to give it a go.
  • 8 35
flag DoubleCrownAddict (Feb 24, 2021 at 14:40) (Below Threshold)
 The gearbox is so hidden it just barely looks like an e bike!
  • 3 0
 Super badass bike
  • 50 1
 @DoubleCrownAddict That's just like, your pinion man.
  • 39 0
 Anyone notice that the Rockshox shock is using a green DVO spring clip?

DVO metric coil shocks can have the stroke changed just by swapping out the spring clip. I've just got a DVO jade x coil and done it.

Interesting that it can be used on the Rockshox. This might be useful info for anyone with looking to change stroke on their Rockshox easily!
  • 5 0
 Big time.
  • 6 0
 Very interesting thanks for pointing that out.
  • 4 1
 Dont look to far into it. This shock was for testing and it was missing a lower spring retainer. It doesnt fit until you ride Fuzzy Bunny on Teton pass, then it "settles" in.
  • 1 0
 @prosauce:
Were you involved with producing or testing this bike?
How do you know?

Looks like it fits fine...
  • 1 0
 @prosauce:
Haha just realised its actually your bike.
Did you use it to change the stroke at all or just what you had at hand?
  • 1 0
 @whatisthecolour: Things are definitely not stock. The spring retainer was just what I had on hand, but it has been modified.
  • 43 8
 Shut up and take My money and my girlfriend!
  • 143 5
 Take my ex. She’ll have my money.
  • 5 0
 @jason3559: let me keep the dog please
  • 9 1
 @jason3559: My ex took my bikes and my Porsche, then added a personalized license plate that says "Was his". I'm the one laughing cuz I now live in the mountain biking mecca that is BC instead of the flatlands.
  • 7 0
 @dirtforbreakfast: can’t tell if joke
  • 24 1
 More gearbox bikes please! At first I thought this was an e-bike, which led to another thought: if dc motor/gearbox companies can agree on a few standards it could become a great going forward point like the threadless steerer was for front end design. A Universal bike gearbox/motor mount (UBGMM) standard could be pretty cool...
  • 5 0
 I was thinking about this the other day. A frame with interchangeable dropouts and a gearbox mount that could take an e-bike motor would be cool for those wishing to swap between the two.
  • 4 0
 It will be the next thing for sure, for these types of bikes at least. Cant see the derailleur system being developed much more than it already is.
  • 2 0
 I think Shimano showed a patent application for just this - gearbox that uses e-bike motor mounting points. One or two years ago I believe.
  • 19 0
 If Prosauce's riding style is "smashing into things" I don't know what a floaty riding style is. He always looks like he's floating above everything to me...
  • 14 0
 Adam is your favorite pro enduro racer's favorite enduro racer.

Xups in race runs? Yeah that guy.
  • 5 0
 Adam is also a real bike nerd too. We go to talking at Sedona Bike Fest and I was really surprised how I could throw really wild "what if's" at him and he had already thought of them.

If I wasn't on a Guerrilla Gravity, I'd totally own a Reeb.
  • 4 0
 @PHeller: I went for a reeb. Sweet bike and has that super small company feel
  • 4 0
 @PHeller: Yeah Adam and the whole Reeb crew are really sharp and their quality of workmanship is second to none. Also, if I weren't on a Reeb I'd be on a GG haha I might have to pick up a frameset in the future.

If anyone has the time and is curious to what level of nerdom the folks at Reeb put into their bikes, check out this vid from Jeff Lenosky youtu.be/_dNw6KO4Qd0

They go into detail about design and fabrication, setup, fixturing, tolerances, etc...aerospace manufacturing level of thought. They also go into why some mass produced frames may experience issues with wear or breakage. Pretty interesting stuff.
  • 3 0
 @szed3: That was a fun night drinking with the dudes!
  • 1 0
 @jeff-lenosky: it sure looked like it! haha
  • 1 0
 Sometimes floating turns into smashing into knee high rocks.
  • 16 0
 Talented man. That is gorgeous. Congrats.
  • 15 0
 You had me at rasta spokes...
  • 4 0
 Rude boy shufflin!
  • 1 0
 They match the heat flares of the steel welds... very nice touch.
  • 11 2
 I love this bike and the idea behind it. I'm 6'3", 260 (strong and fat), hate bike maintenance, and tend to destroy drivetrain and suspension components. I'd be willing to pay the higher upfront cost for something like this if there's a chance it would survive more than a couple seasons. It looks like an incredibly creative, well engineered project!
  • 12 0
 As this isn't in production you should check out Nicolai...
  • 1 0
 I’m 6”4 and a bit lighter than you at 230lbs but totally get where you’re coming from. So far, my current Intense Carbine build has been awesome and held up really well but I’d be interested in a Nicolai Geometron as my next bike (whenever that may be!) as suggested by @slimboyjim for all the reasons you’ve listed above
  • 2 0
 @arna86: I'm 6"4 and i'm happily riding an XXL G16. I drank the kool aid, i'm not ashamed to admit it, but after ten years of small frames and dubious geometry i've really found a compromise. My only gripe is that a lighter version (like the Saturn) might be better suited to the terrain i'm riding, but having bought it second hand i really can't complain.
  • 1 0
 @AlexRR: the G16 has my eye too. I like the look of the G15 but I’m not too sure why anyone looking it wouldn’t just go for the G16 instead (or the G13 if they wanted less travel). I didn’t realise the full build prices were as reasonable as they are compared to the competition either. They offer a really unique spec sheet of decent quality parts. My eye is wandering again....
  • 2 0
 @arna86: considering that you're from the UK i strongly suggest you to drop a mail to the Geometron guys, because their G1 is basically a "g16 2.0", and at the same retail price of the other models has some really meaningful improvements.
Also, take a look on the second hand market and don't be afraid, because these frames are basically indestructible
  • 1 0
 @arna86: I've just bought a G1. I'd highly recommend a test ride as the way the bike is set up massively affects how it rides, and it can be set up in a number of ways to suit your style. Get in touch with Mojo and they'll sort you out. Their G1 I think is slightly different from the Nicolai from memory too - I think it has a steeper seat tube?
  • 1 0
 @slimboyjim:

Get a G1, wild good fun. Do everything on it from shuttling to all day rides.
I'm 6'2 and have an XL. Crazy big but super stable though and starting to be able to corner it like I did a small bike. The ability to switch geometry and wheel sizes is amazing. Mullet is real for gravity tracks. I swap between 29 and Mullet alot.

EXT shock blows everything else out the water. Current build weight 39lbs. Robust.
  • 1 0
 @originalstraygoat: I've just bought one! Ha ha! Still waiting to take it out in anger though because of lockdown, but I agree that the shock is just crazy sensitive. Coupled with bikes being difficult to come by this year it didn't take long to make the decision!
  • 1 0
 6’6” 210lbs here... no issues with suspension for me but I too destroy drivetrains and find it so frustrating how expensive they are for the life I get out of them. Have been saving my money for a Reeb with a pinion for a while now... such a cool company.
  • 11 0
 Oh my Lord, oh my Lord - i need you by my side.
  • 8 0
 Looks perfect. Geo/travel is not for me but something a bit more moderate would be right up my (and probably a lot of others) alley.
  • 7 0
 K, so we've seen multiple long travel gear box bikes using standard linkage designs the last two years, other than weight which can be cut down through materials and design.... CAN WE JUST DO THIS ALREADY?
  • 1 0
 We are doing it! One of them is called the Katipo and it is awesome!
  • 1 0
 @Ders316: I know of the Katipo, its a beauty, but its one of few. Gear boxes make sense, they're durable, they have crazy range and they're safe some near by stumps at high speed. With more R&D that came from selling in large volume weight would drop. but here we are with un-sprung weight twigs that, if everything lines up just perfectly, might work.

Unless its SX, then it just exists for whatever reason.
  • 2 0
 @TheBrosCloset: I agree! I have been loving my Katipo for the last year and a half! I was talking to the guys at Pinion NA as well as Cycle Monkey in the Bay Area, and they were saying it is hard for Pinion to have the financial motivation to develop quickly for MTB. Most of Pinion sales are commuters. For them to put more money into MTB R&D, there needs to be a bigger MTB market, but for there to be a bigger MTB market, there needs to be more R&D... a chicken or the egg conundrum.

Either way, for bikes that arent super light xc/downcountry machines, I've been convinced gearboxes are the way to go
  • 6 1
 I've been saying to anyone who would lend an ear that there's no reason a downhill/enduro hybrid won't work.

I personally ride a 200/210mm dual crown, high pivot, dropper and dual bottle cage equipped downduro bike. Climbs well and descends like any other downhill bike.
  • 11 2
 Grim donut done right
  • 7 0
 neat machine, digging the kickstand.
  • 1 0
 that's genius
  • 6 0
 What a beast of a bike!
Thanks for showing us something different AND exciting.

Boner +++
  • 2 0
 I have been dreaming about this machine for years, as i owned a belt drive Buell for years, and it was amazing. So many miles through all of the conditions commuting, no maint ever. Fantastic build! I live in Golden, i would love to see this machine in person!
  • 3 1
 Truly amazing bike, great job!

One question on bikes with geometry like this, how do you keep weight on the front wheel? I recently sized down from a 480mm reach to 460mm reach on a bike with 433mm chainstay and 64.5degree HA because I wasn't happy with the front end grip, I had before this gone for a 50mm steam over a 32mm. Both the stem and the smaller frame both helped a great deal on increasing my front end grip.

How does a 515reach, 62.5degree HA and a 32mm stem work then? Sure the longer 445mm chainstays help but still the differance in front and rear centers must be huge? Adam is obviously a more skilled and faster rider than I am and this is a custom frame for him (by him!).
  • 1 0
 The key is being 6'4" and 180 lbs. I have no problem with front end grip.
  • 1 0
 At 220 lbs, "grip" lmao - least of my problems.
  • 2 0
 I've never loved a bike as much as I love this bike. Granted, I probably don't need 184mm of travel and would be better off on a 154mm frame, but I'm eager to see what REEB brings to the market with this. It might be my next bike.
  • 2 0
 I have real questions about the gates drive arrangement. I guess if you are mostly going down hill but as a bigger rider they just don't work. To keep enough tension on them and prevent them from slipping you had to put a lot of tension against parts of the drive train that just don't need it. Especially in high watt situations. Maybe if you are just spinning up and not having to power out climbs but this seems like a real flaw here. Also you can totally beat that belt drive weight with a single speed chain setup. Makes no sense. Otherwise pretty cool setup.
  • 1 0
 Have you only ridden Gates drivetrains on single speed applications?

First, most frames aren't stiff enough to keep alignment under max torque scenarios. REEB frames are some of the few that actually pass Gates stringent testing. When I raced cross, I hopped on one of the Raleigh cross bikes that was the factory Gates team bike. In the first lap, I skipped the belt multiple times. This was in a cross race. Nothing crazy steep, just putting power down out of turns. Since working for REEB, I have never skipped a belt on our single speed frames.

Second, I have put this through some of the steepest, hardest climbing we have in the front range of Colorado. Typically I run a 36t ring with a 50t in the back. The gearbox offers lower ratio than I typically run, and while standing in the lowest gear, I have never skipped the belt. Its not a problem.
  • 5 0
 Thats the sickest bike i've ever seen.
  • 6 1
 It doesn’t “rival the grim donut”- it slaughters it.
  • 3 1
 HTA is >5 degrees steeper than the GD. It’s rad, but it’s no doughnut.
  • 5 0
 This is nice and all, but you can't show this bike without the Bajastang?
  • 2 0
 Stay tuned... We have plans.
  • 3 0
 Awesome project! Adam is a super cool dude and I'm glad to be riding the V2 Sqweeb from REEB. Handmade is the USA in Colorado baby!
  • 3 0
 Rad bike. This article made me look at Reeb’s website for the first time. If I saw a bike like this on there, I could maybe be one of their new customers.
  • 3 0
 That is a beautiful bike. Please more gear box bikes! Did you hear that bike industry? More gearbox bikes please!!! I love it guys. Great job! Would love to ride that bike!
  • 2 0
 The industry will not sell you durable bikes. But REEB will.
  • 3 0
 One day, the behemoth manufacturers like Specialized, Trek etc will fall... and blokes in sheds will once again inherit the Earth.
  • 4 0
 So this bike is incredible. Very, very well done
  • 5 3
 If it's a rival for the Grim Donut - I want to see @yoannbarelli put it through it's paces - should sound a fair bit quieter than a shopping cart Wink
  • 6 0
 No man, this is a true bike, no fancy / no dumbness; not as the Grim Donut.
  • 2 0
 This is the kind of stuff that really turns me on. If anybody know of good tools for rear sus design for dialing in a set of kinematics to your liking let me know please.
  • 3 0
 "Linkage Design" is a good place to start...It's available here: www.bikechecker.com
  • 1 0
 @EvanTurpen: Yep. That's what I used on this bike. I have worked on creating my own spreadsheets for this, but it's hard to account for as much as you get in the Linkage package. Easy to use little program that will get you started. You can always double check with side calcs. and CAD modeling.
  • 1 0
 I love the wrench used as a kickstand in the first image!

This bike is a work of art- plus it’s nice seeing experiments in design that will get tons of real world use and abuse.
  • 2 0
 Normally I dont care for belt drive....but this is the coolest bike I have seen in quite some time. I would take it, belt and all. Seriously one bad ass bike.
  • 3 0
 If the Grim Donut was your dad's attempt at doing the moonwalk, this thing is Lemmy shaking his head out of pity for you
  • 1 0
 Wonderful mental image.
  • 2 0
 For a bike that’s designed with function over form in mind, this BREWster is the least awkward looking XXL bike I’ve ever seen!
  • 2 0
 Love the low maintainence aspect gear box that needs an oil change every so often and a belt drive that can go virtually forever. This is the future of MTB
  • 1 0
 Love the industrial look on it. It looks like it can't be reasoned with, it can't be bargained with. It doesn't feel pity of remorse or fear and it absolutely will not stop. Ever.
  • 1 0
 hey everyone, If you're following this thread and are interested in hearing more about it, we're doing a live stream tonight on my Youtube Channel at 9pm EST. It will also be posted in my timeline in case you miss it!
  • 3 0
 Not my style of bike, but by far the nicest one-off ever.
  • 2 0
 how far have we come when a 62.5 degree HTA looks "normal" in the side shot
  • 1 0
 The geometry is close to the Geometron G1. The weight probably isn't too far off, either. I love mine, but it isn't the best climbing bike I have been on.
  • 1 0
 The BREWser would be like a runaway freight train for your average sized MTBer but it must be incredibly fast for a rider the size of Adam!
  • 1 0
 "Suspension is meant to keep your tires on the ground and in traction."

Sure is! Need to tell some of the authors\editors around here.
  • 3 0
 THIS is the direction we should be going in.
  • 2 0
 What the grim donut was originally supposed to be before levy went to Taiwan...
  • 2 0
 Grim Donut officially died today, this thing is nutty! And that CSU is gonna creak like your grandmother having sex.
  • 1 0
 This isnt a FOX product...
  • 2 0
 Looks the biz! That must be heavy gauge alu. No seatstay bridge needed and 2-piece linkage joined with one bolt.
  • 1 0
 There's more than the eye can see.
  • 2 2
 'crazy slack' seems an exaggeration here....there are off the peg bikes with more radical geo than this, mine included. Looks great tho, bike is sick it's the headline i have issues with lol
  • 1 0
 I thought BREW Bikes had come back when I read that title! Sick looking rig you made there Reeb, do what everyone else is suggesting and put it into production!
  • 1 0
 Brilliant fabrication and build...

Do you need to dismantle the swingarm though, if you want to take the rear wheel off (i.e. take the belt off)?
  • 1 0
 Its one bolt to split the seat stay. Belt shouldn't need to be removed once installed. Wheel comes out like any other bike. No need to touch the belt.
  • 1 0
 @prosauce: It's two bolts to split the seat stay.

Fair point about the wheel removal, but you need to faff with the belt tensioner at some point I imagine, hopefully enough belt length to get on/off the rear cog.
  • 2 0
 @Sreyno: No, it's one bolt. I promise, I designed it. Smile
  • 1 0
 @prosauce: Ahh yes sorry... seat stay not chain stay!
  • 2 0
 Adam is a rad dude and an absolute shredder. I love seeing project bikes like this.
  • 1 0
 Beautiful bike as a gearbox MTB user I really like it's ability to reduce the chain and all maintenance that goes into cogs, derailleur and the like
  • 1 0
 Prob the coolest bike I've seen in a long ass time here on PB. Will Adam consider making this into a production model? I'd spring for a 27.5 version. Sooo badass.
  • 1 0
 Someday. This is a test bed, so you'll definitely see some variation of this in the future.
  • 2 0
 When one is built like a Sasquatch and rides the biggest bike made. Does the weight really matter to the rest of us?
  • 1 0
 once pinion makes a gear box with engagement under 6* degrees, it's gonna be a game changer. The current 15*degree engagement is so frustrating.
  • 1 0
 From somebody that has always ridden high engagement hubs, its not nearly as noticeable as you would expect.
  • 1 0
 that s the best looking and sounding bike for me i really want to see more bikes in this category 180mm downhill bike that can go uphill pretty good
  • 2 0
 FINALLY - someone makes a bike for riders of my size (1,96m). I'll keep my eyes peeled for this one
  • 3 0
 I wanna try
  • 2 0
 Uh.... me want one. Looks amazing.
  • 3 0
 I’d buy that frame.
  • 2 0
 Beautiful, looking forward to what Reeb has in store for us mere-mortals
  • 1 0
 How durable are those belt drives vs chain drives? It seems like they'd either suck or blow chains out of the water
  • 1 0
 We have a belt drive commuter with a Nuvinci hub. Three years of salt water ferry rides and stored outside have not fazed the belt at all.
  • 1 0
 Aaron just said: ``ride beltless``. Believe him ;-)
  • 5 1
 My wife chose one for her daily commuter, about 28 miles each way. It has a CDN belt which will probably have a service life about 2x longer than an average chain, CDX belts (sturdier and more expensive) should last longer. Belts can be damaged if mishandled (twisted during storage, levered onto a sprocket, ingest a stone or stick, etc.) and are sensitive to misalignment of more than 1-2mm front to back sprocket. Gates specifies how stiff the frame has to be to prevent misalignment under load. They need to be tensioned correctly within a certain range. Gates doesn't recommend them for mountain applications, probably due to the greater torque combined with abrasives. Hers tends to squeak if it's damp, which can be remedied by applying a special lubricant.

In short, from a practical standpoint it's a niche application that's several times more expensive (check out prices for sprockets and belts) to run than a standard chain. You do have to keep the system clean (and apply lubricant if it squeaks)

The biggest issue is that the primary market is commuters who can't be bothered to look after a chain, and figure there will be no maintenance. You can guess what happens when they get their first flat tire and have to properly align and tension a belt without mishandling it. And how often they clean it. Not to mention their expression when they find out what it will cost to replace it.
  • 1 0
 I have been dreaming of doing something like this but not enough to do anything.
  • 1 0
 Definitely doesn’t look like a session !
Good work sir , that’s a very nice looking bicycle you’ve made .
  • 2 0
 I love the raw steel and welds!! such a cool bike!
  • 5 3
 I wish someone would make better gearboxes.
  • 3 0
 Nicolai is making one which will be released later this year.
  • 2 0
 @alexsin: they already make a gearbox bike. New model ?
  • 1 0
 @alexsin: Mo info please?
  • 1 0
 Top 3s on a bike you built yourself.....if I had a hat, it would be doffed in your direction sir.
  • 2 0
 Can I swing by Lyons to gawk in person?
  • 2 0
 i saw that too. Nice new bridge over the St Vrain!
  • 3 0
 100%

If you're tall enough, take it out for a ride even!
  • 2 0
 Straight to production please!!!
  • 2 1
 Internal gearboxes and belts are going to change the game, or so I hope. Maintenance should be for trails, not bikes.
  • 1 0
 I once shared your enthusiasm, but then the gearbox manufacturers put zero development into their products and expected us to blindly accept their shortcomings :/
  • 1 0
 This vs grim donut in the one, and make a comparison vid, the race documentation, and an edit. We would all watch that.
  • 3 1
 This is what a bike should look. F' overpriced carbon
  • 1 1
 Yes, yes, yes! @ the bike industry - more of this and fewer carbon wonder bikes please.

Ps. when is the wireless electronic braking arriving?
  • 1 0
 Now that is REEB design I might drop $ for... waiting for a similar release in 22
  • 2 0
 Sh** just got real
  • 2 1
 Stunning! Start producing soon please.
  • 1 0
 yes please do, I want one, but with a chain
my size: reach 460mm and seat tube length max 420mm
costs? delivery?
  • 2 1
 Hey at least he was able to get a BME entry
  • 1 0
 Ill be racing Revolution Enduro this year. Tired of packed races and lifts. Lets get back to real backcountry racing.
  • 1 0
 @prosauce: I tried to get into it, but I was snowboarding for the day so I missed it
  • 1 0
 @sfrucian: Yeah, turns out everybody wants to race now so they can post it on instagram.
  • 1 0
 @prosauce: lol for sure. seems like they weren't actually opening registration evidently.
  • 1 0
 I need that rasta wheelset
  • 1 0
 Wondering how tall is he?
  • 1 0
 Adam is 6'4"
  • 1 0
 DAMN!!!! That thing looks like a weapon!
  • 2 1
 Makes the Donut look like a Session.
  • 1 0
 Hide the women and children.
  • 1 0
 Nice! definitely right content PB
  • 1 0
 Gorgeous custom bike!!!! This Grim Donut Group test is getting loaded
  • 1 0
 Want. This. Bike. Awesome project!
  • 1 0
 That bike is Rad! We want more options like this......
  • 1 0
 Apart from the Gearbox the Geometron G1 is the bike to beat .
  • 1 2
 @pinkbike has anyone taken a moden geo steel frame and built it up with NOS/reconditioned components from say pre 2000s? Boxxer pro, Magura rim brakes eg etc etc etc?
  • 1 0
 Definitely a looker Droolemoji
  • 1 0
 DAMN!!!! That's a bad ass bike , well done!!
  • 1 0
 Look like a... sunday? even the stickerjob.
  • 1 0
 That. Is. Fucking. Awesome.
  • 1 1
 Looks lovely,but if I were to build an indestructible bike,I wouldn't use the belt drive..
  • 1 0
 This thing needs some 32 inch tires
  • 1 0
 This is probably my favourite home brew bike so far. Outstanding work.
  • 1 0
 Will we ever see a gearboxed high-pivot bike with no gripshift?
  • 1 0
 This over the Grim Doughnut everyday of the week..
  • 1 0
 Follows Grim Donut coverage, says "i can do better than that"
  • 1 0
 Yeah, that bike is Sick AF!
  • 1 0
 Another custom crusher by a rad dude! Awesome job Adam!!
  • 1 0
 Looks like my old turner flux. But monster.
  • 1 0
 look for me riding this bike in the next Mad Max movie.
  • 1 0
 I'll take one XXL for big mountain riding and one XL for Park.
  • 1 0
 I want a 130mm version of this. With an 700 lb spring.
  • 1 0
 Adam says bike weighs 43 pounds.
  • 1 0
 That thing is so cool
  • 1 1
 The Grim Donut's older brother.
  • 1 0
 Now we’re taking!
  • 1 0
 I like!
  • 5 6
 To look at this beautifully engineered metal bike and people actually buy plastic????
  • 1 0
 Yes!!
  • 1 0
 YES
  • 1 0
 Grim CRONUT!!
  • 1 0
 yeah boy!!!!
  • 1 1
 Looks like a bike Mad Max would ride, love it!
  • 1 0
 That is bad a$$ tup
  • 1 0
 That looks AWESOME!!!
  • 1 0
 Take my credit card!
  • 1 2
 Gosh darnit, just buy a DH rig already!)) This Grim Donut competition is getting quite freaky.
  • 1 0
 Downhill bikes are slow unless you live next to a chairlift. Terrain is not steep enough in Colorado for DH bikes to be worth it. Check race times at all the bike parks around here. People are winning on trail bikes.
  • 1 1
 Looks alot like the new Nicolai gpi pinion frame, only more travel
  • 1 0
 ME WANT!!!!
  • 1 0
 Its size xl not XXL
  • 1 0
 I would buy this
  • 1 0
 Fricken badass!
  • 1 0
 Awesome work Adam!
  • 1 0
 Mental!!! Keep pushing.
  • 1 1
 no minions
  • 1 1
 Dual ASSGUYS on that thing
  • 1 2
 Vittorias dawg.
  • 1 0
 Those Mazza's are badass, check 'em out
  • 2 5
 You couldnt ride this thing, you would have it hanging on the wall in your livingroom instead.
  • 8 1
 Bikes: Tools, not jewels.

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