Pinnit Cycles Shredmaster - The Armchair Engineer's Dream Is Now For Sale
If you can’t find the bike of your dreams, then why not build it yourself? That’s exactly what Andi and Peter did with their Pinnit Cycles Shredmaster creation. In case you missed it, James Smurthwaite covered the full details on the first version back in January, 2021. Since then, the two-man team has tested a second version and are producing a batch of ten frames for sale under the title Pinnit Cycles.
Frame Details
The highlights of the German-made aluminum frame include a high-pivot Horst-Link that provides 205mm of travel from a custom-tuned EXT coil shock and is complete with a 6-speed Pinion gearbox. It can even hold a water bottle and run either a 27.5” or 29” rear wheel.
Pinnit speaks openly about the hurdles of designing a frame and the level of their building standards. After riding the first prototype for two years, a crack developed at the head tube and down tube junction. From there Pinnit revised the design and sent a frame off to the EFBE test lab in Waltrop, Germany. Those changes made to the downtube survived 100,000 cycles and passed the Category 5 Gravity Tri-Test, but then the chainstay failed.
Based on the data and feedback from the EFBE, the Shredmaster is undergoing a third revision involving intricate machining to the chainstay yoke. These newly designed chainstays will be ready in 2-4 weeks, which they feel confident will surpass the testing.
Further advancements and fine details of the second generation frame include angular roll bearings with improved sealing capabilities and an anodized rocker link with keyed hardware from Radoxx.
Suspension Design
Even though the Shredmaster is a downhill bike, the anti-squat values for the full 29er start around 141% and drops to 110% at sag, which should provide a solid pedalling platform. Being a high-pivot design, Andi wanted to keep the braking forces somewhat neutral and preserve the geometry, so the anti-rise value is about 100% at sag.
A 31% progressive leverage ratio meets Pinnit’s requirements with a coil shock. That axle path moves a total of 23mm rearward due to the high pivot design and thanks to the idler placement, the chain growth is nearly zero, so pedal kickback isn’t an issue.
Geometry
In its first inception, the Shredmaster only existed in the XL size, but the team at Pinnit is now offering three frame sizes with reaches of 460, 480, and 500mm in length.
Two chainstay lengths are possible for either rear wheel diameter by way of two flip chips - one at the dropout to adjust the length, and another at the lower shock mount to compensate for the change in axle heights. In the full 29er mode, the two options are 440 or 450mm, and 6mm less for the 27.5" wheel.
Of course, the longer chainstays will change the leverage ratio slightly, but Andi has noted that. The longest rear center produces a 31.5% ratio, while the shortest bumps the progression up to 34%, as seen at the bottom of the geometry chart.
Availability
As for pricing, the aluminum, German-produced frame is not cheap, but it's not astronomical either. The base begins at €2,600, which doesn't include the gearbox. For that, there's the a choice of a Pinion or Effigear. Both of those include all of the necessary drivetrain components, like a tensioner, shifter, chainrings, and crank arms for an extra €950. The only shock option is EXT's Arma V3 that has been tuned in conjunction with SnurrTECH, Germany's EXT distributor, bringing the grand total up to €4,300.
Although Pinnit Cycles website is still under construction, the duo behind the brand ask anyone who is interested in pre-ordering a frame should reach out via their email address: info@pinnit-cycles.com or message Pinnit Cycles on Instagram.
This meme might be all that your marketing team needs, because there are only six pre-orders left at this time.
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At least it looks like it should just get pushed back.. but how many times can it realistically survive being smashed in a rock or log?
That said, if this is an armchair engineers bike then it makes total sense for us armchain engineers to comment on it.
THIS
www.youtube.com/watch?v=ZPQAtYaFNoM
Think about all the weight removed from the rear wheel and placed pretty much in the ideal spot on the center of the bike, paired with a 30t chainring and a tensioner that tucks UP... We are talking the best Downhill drivetrain possible.
Also, @pinnit-cycles : I think it is key to make it work with a belt (chain has more mass, makes noise and is more prone to derailment)
And to finish, Pinion now has an electronic shifter (with paddles, none of that Grip-shift nonsense) If the bike had that, it would be the standard for all DH bikes in 5 years time, I t just makes so much sense.
insertfacepalmemoji
but then, if people will buy into high pivot hype they'll believe anything.......
www.youtube.com/watch?v=ZPQAtYaFNoM
it has more ground clearance than a 36t ring, and the spring housing itself acts as a bashguard. Watch closely Time: 1m 11s
seems pretty silly to me.............
www.pinkbike.com/news/the-evolution-of-the-commencal-supreme.html
It was more horizontal and an obstacle would hit the rear wheel before it would hit the tensioner.
@naptime : I don't think this is a press release. This is an article. Press releases are written by the brand, this article is written by a PB editor (Matt Beer).
www.pinkbike.com/photo/24217859
The horizontal Roox is more of a chainguide than a tensioner, since it cant compensate too much lengthening by rotating, i dont think it would be enough. On the Commencal i doenst have to do it, because the derailleur does this job.
Other reasons could be:
A. Absence of good dedicated shifters (pinion runs on horrible grip shifters, but just now made an electronic version wich looks sooo good...)
B. Most gearboxes are not DH specific, they focus on 12 speed with huge range (600%) which a downhill bike does not need, thus making them heavy for no reason.
Also, there is one DH WC team that is experimenting with this: GAMUX. watch: www.youtube.com/watch?v=o1SGZcgxY3Q
@luckymixes : A: Effigear works with trigger shifters. Also, as unlike Pinion they don't have the sprocket concentric with the bottom bracket, it should actually work quite well with high pivot designs. Effigear has a few variations to choose from. And B: Pinion also has a 9speed variation. Agreed they could make a tighter range version for the DH market. Of course BeOne had their PeteSpeed system which was DH specific. Hayes owns the patent now, they're just not producing and selling the product. But it shouldn't take too much work. Actually now that we already have these idlers, is it still a bad idea to use a hub gear over there just like Nicolai used Pinion back in the days? Some complain Nexus and Alfine hubs have too much drag but I don't consider them too bad personally. Especially as DH bikes shouldn't really be too much about pedaling efficiency, as long as the freewheel is smooth enough.
As for shifters, it will eventually come to this, it is a matter of time:
www.youtube.com/watch?v=o8nVUP5yJ80
not only would make the entire drivetrain mainteinance-free (which is huge!) but also solves the problem of shifting under load
Your link Shows the Gates Version for belt drives
I am sure it will be the standard for DH in a couple of years.
High pivot with idler
Gearbox with belt
Electronic (AXS like) shifter
youtu.be/QgP_NT5dkYY
Plus, no maintenance! Pinion belt seems to be popular among "adventure bikes" so I think it is at leasy not terrible in the mud.
Gamux team rode it in Snowshoe last year, they surely know if it is yay or nay in the slop...
I'm not against something new or different. But my choices are largely influenced by
1. What does it cost to ride my bike per ride?
2. How likely is it to fail in a way that I can't fix it trailside?
DH is absurdly expensive, and expensive parts are breaking all the time, so being cost-effective was never the big selling point. A spare belt drive costs less than a good tyre, so it's not a dealbreaker.
That said, a gearbox is a very robust machine. The box and the belt should outlast several chains, cassettes and even a couple derailleurs. Not to mention that a lighter rear wheel with really good suspension should reduce the amount of flats and smashed rims.
And finally, DH bikes are washed like, every 10-20 runs? What I mean is, if it works for at least a week of bickepacking, it should be good enough for a race weekend, right?
Think about the gains:
- Chainless-like suspension kinematics. Best ever traction and braking.
- Shifting while coasting or in the air, with a crisp electronic shifter (Pinion Smart.Shift)
- No metal noises (watch some Zerode videos, they make the quietest bike sound ridiculous)
- Optimum weight distribution, the bike should be very stable and predictable in the air.
- No chain lube, no shifter cables. Just clean it and go.
look: www.pinkbike.com/photo/23826076
Not sure what you mean.
- Chainless-like suspension kinematics. Best ever traction and braking.
The suspension performance with either a belt or a chain (all else being equal) will be equal.
- Shifting while coasting or in the air, with a crisp electronic shifter (Pinion Smart.Shift)
Yes for those who consider that an advantage, that can indeed be an advantage of using a frame-mounted gearbox. Regardless of whether a chain or a belt is being used. Downside I can think of would be if this would increase drag when coasting with a dirty belt or chain.
- No metal noises (watch some Zerode videos, they make the quietest bike sound ridiculous)
Fair.
- Optimum weight distribution, the bike should be very stable and predictable in the air.
Weight distribution won't change much if you'd replace the chain by a belt, all things being equal.
- No chain lube, no shifter cables. Just clean it and go.
Fair about the chainlube. Obviously the shifter cables don't depend on the use of either a chain or a belt.
- Why singlespeed?
You can use a gearbox with a belt or a singlespeed chain like a KMC Z1. You don't need a chain like a HG chain that can be used with a derailleur system as there is no derailleur.
Between a singlespeed chain and a belt, I would prefer the belt, because it is less weight, and more importantly, less inertia, so less flapping around.
Chains go absolutely crazy when you watch them in slowmo, a belt would be much calmer, (even with the tensioner set up to a softer spring, which also helps suspension) Bonus, no noise.
All of this of course, provided that strength and durability is on par for DH, which now we are starting to see with experiments like this bike
Every bike review I have seen about gearbox bikes say it is very noticeable, and it makes sense to me. Fricition is less of a problem if you increase the sprung mass
also, I am talking about the whole concept of the bike, not just the belt.
The concept being, high pivot bike, gearbox, belt, and wireless electronic shifters. Does not exist yet, but I think they will
It is clear that I like the setup, and you and @vinay don't. It is OK by me, I am just playing armchair engineer here. No woorries mates
A belt's mass is half of a chain. If you say that there are no benefits, maybe you should ask yourself who is being an idiot here.
Maybe it breaks. Maybe it clogs with mud. Maybe it rides terrible for some other reason. All I am saying is that I would like to see a bike like that tested in world cup level DH.
And half of a 250g chain
Wow.
Such saving.
How much does the rear sprocket weigh in comparison with a single speed chain sprocket? I bet its 100g different.
And you never will/have for a damn good reason, no team is going to use on, because it makes zero sense. Considering the various things that have been tried, it would have been by now. Maybe you should go start your own team to watch them lose on belt drives.
It is the only possible reason for someone to loose his head over an internet discussion on this topic and start showing your lack of manners.
So, your argument is crying about a 83,95€ belt being too expensive and saying "if it worked, somebody would have done it by now." Congratulations.
There ARE people trying this stuff right now. GAMUX team started on Pinions with chain and grip shift, and switched to belts and paddle shifters in 2022. Season. Things have to be tested in order to say they work or not. Unno has a patent for a DH bike with a gearbox, maybe they will try belt, maybe not. All I know is that you should relax a bit and learn to respect others opinions
It is the only possible reason for someone to be this idiotic over and Internet discussion on this topic and deflect and change their argument so much.
So, your argument is '' just because pro teams haven't done in en masss (ala 29er) doesn't mean they aren't wrong'. Congratulations.
And yeah, when even 10% of the field are on belts I'll come back and concede defeat. You've been just as bad, if not worse for not respecting or considering other people's opinions, just bleating the same, wrong subject arguments again and again.
Tbf, it's only the belt I've ever been saying is a problem, I like the idea of a gearbox, if someone brought out an ebike (my solution to getting up hills lol) with a zerode g1 style frame mounted gear hub/high pivot suspension, I'd be all over that in a heartbeat, obviously there are companies working towards integrated gearbox/motor solutions but I'm not 100% convinced yet, the revolute one is a automatic cvt I believe, which sounds great for commuting, but not mtb where you sometimes want to be in a massively low gear preemptively.
still, if you would just have shortened the chain for the photo above, this shit comments show wouldn't have happened.
Sorry for being honest, but the whole concept looks great, and it is a pitty, that it is bashed for literally no reason / unimportant detail, that will be fixed anyway.
The other effigear gearbox (I guess you are referring to that one) is basicly welded into the frame, not mounted via screws.
That one easy allows a high pivot indeed, but limits you in everything else, so we went for the "pinion mounting" options
Exec: "These tensioners are really profitable. We need a way to move more units"
Pinnit engineer: "Say no more..."
Cool bike otherwise
In total there always must be, at least some, chain growth. (Unless for example you run a single Pivot point exactly though the BB, like in some slopestyle fullys, so there is zero change in length, that the chain has so deal with.)
That particular tensioner wasnt desgined for high pivot bikes, so the mountain plate is far from ideal for this frame. Our tensioner for this frame (similar like the one on the first frame we made) is not ready yet, so we used this tensioner...
That is the calculated chain growth (both upper and lower) out of linkage design:
www.pinkbike.com/photo/24219511
Excuse the quality of the pictures, that is the actual chain lengthening
(tested with our prototype tensioner and our new chainstay):
www.pinkbike.com/photo/24219512
-> there needs to be slack at the lower chain (that has to be managed by a tensioner), otherwise the chain would rip when you dive into the travel.
Also, Cedric Eveleigh would probably be happy to license his tensioner to them.
The tensioner on our first frame worked flawlessly, so we sticked with this design, since it is less prone to be ripped of, and indeed is less unsprung weight. The tensioner on the pics above was just the one that came with the Effigear and we used it to get one frame built until we have ours made.
,(it's 3am here an I went straight to comments so I coul easily be missing something.....?)
Bike looks cool and dig that you're getting after it with your design. Best of luck to you Andi.
Oh and thx
Do it wobble to da flow?
Do it snag on every rock?
Is it platinum, is it gold?
Could you throw it over ya shoulder?
If ya hot, it make ya cold
Do your chain hang low?
Random rider shows up on a Pinnit Shredmaster, swings mech over shoulder and tips their helmet " how you boys hangin'?"
[Reply]
Let's face it: bike drivetrains are a reminiscence from old road bikes. It just stuck and was perfectioned to the point that we no longer think about them.
It makes much more sense to have a closed gearbox, specially with a belt drive so we don't have a chain slapping everything and sounding like a trainwreck while we ride.
The last problems to be solved about gearboxes are:
- Shifters. Electronic ones make total sense. No more grip shift (Pinion), and no more finicky spring setups (Effigear)
- Weight and DH specific use cases. 5 or 6 gears with about 300% range should be more than enough for most situations.
I honestly believe that in five years time, we will be looking at the absurdity of today's derailleurs with a big laugh.
My point was not that the hanging pulley isn't awful, my point is that modern derailleurs are just a bit less awful than that, yet no one bats an eye.
If this is an outdated picture, why include it?
Awesome looking bike with the relocated tensioner.
The point is that this kind of empirical testing and analysis should be normal in this day and age. It's surprising because it shouldn't be surprising but is.
Learn how to use capitol letters… It’s not that hard.
Capitalizing the ‘c’ would refer the The Capitol of a country or state, or as a name of a team like the Washington Capitols.
Pinnit shredmaster
Erm.