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Posted: Sep 2, 2021 at 14:31 Quote
Original design reminds me of a Zerode. 2nd design is looks cool

Posted: Sep 2, 2021 at 19:32 Quote
ktm87 wrote:
looks so dang good!

Seriously Steezy, Mate!

Posted: Sep 2, 2021 at 22:38 Quote
f*cking rad looking Salute

Posted: Sep 3, 2021 at 1:14 Quote
kaimbell90 wrote:
GregoryEpps wrote:
kaimbell90 wrote:

Thank you! I appreciate that, your bike looks incredibly beautiful and I am really excited to see how it comes out!

As for the covered caliper, the small carbon piece you see in the corner is actually a brake cooling duct. Who knows if we will even move enough air through it to make a difference but I have to give it a try because it looks so cool in my opinion. Aside from the cooling duct you get a lot of added stiffness under braking load having it located like that, and I think it looks clean.

Tooling will be out of tooling board for the prototype. There is some good stuff out there with really low CTE that, thanks to my old place of work I can make a carbon prototype cheaper than an aluminum mule. I would also rather test in carbon so I can see the real world flex and clearances on this tightly packaged suspension layout. It will be a combination of compression (shock tunnel and some spots on the rear triangle) and bladder inflation, two halves for the rear triangle that will be bonded together.

Unfortunately, no it is not DW-Link. Although part of me wishes I did and just pay for the royalties (DW Link is amazing), I went for a VPP style setup with a mid-high instant center instead. Here is some X-ray vision for you:
X-Ray Vision

Love the frame design! Given that this is a VPP (Virtual Pivot Point) and the position of the idler is fixed, the anti squat will actually change through the travel, beyond the effect of using different gears, as the ‘Instant Centre’ will move. Typically the centre point for VPP is somewhere in front of the two pivots and crank set, and as it doesn’t stay in one place it’s definitely worth generating a dynamic model to see how the anti-squat changes. You might be able to tune the chain feedback characteristics to your advantage.

Despite what I just said, let’s go back a step. I don’t want to dampen your enthusiasm, but the point of the idler is to negate pedal feedback for high-pivot frames - they would be impractical to ride otherwise - so it’s worth going to the trouble of adding the complexity of idlers as the high pivot bikes absorb square edge bumps better (ie you can ride faster). As you don’t have a high pivot, you don’t actually need an idler in this design. VPP allows you to choose the pedal feedback / anti-squat anyway, so no loss.

What next? If you want the advantages of a high pivot and idler, the top link could become a single pivot, move the idler closer or concentric to the top link, and the bottom link could still drive the shock if you add a small dog-bone link. Not impossible with what you have so far!

Can’t wait to see how this progresses :-)
Hey thanks for your response!

There is a limit with VPP as to how much you can tune the anti-squat and pedal kickback when you start to create a more rearward axle path via the linkage orientation. The idler is placed to where i get the anti-squat as close to 100% at sag as I can for the majority of the cassette (it does change drastically throughout the travel like you mentioned). All while keeping my pedal kickback below 5 degrees at 24t.

I did not have any luck trying to achieve those numbers with no idler while keeping the axle path I wanted. Is there something I am missing here? I did quite a bit of playing around with it before adding an idler to be honest so if there is another way of looking at it I am all ears. Thanks!

I kind of figured after my post that you would have calculated anti-squat relative to the idler position, so no, nothing missed technically - just me thinking out loud! You would get VPP and a slightly more rearward able path - so it could be a killer combination. Would be nice to see some graphs of the more rearward displacement if you have any yet?

Nice print BTW…

Posted: Sep 3, 2021 at 13:12 Quote
Thank you all for the positive feedback!

Here are some pics with what componentry I can fit to the frame so far:


Geometry numbers, axle path, and chainstay growth throughout travel is visible here:


Leverage Ratio and Wheel Forces:

Anti-Squat and Anti-Rise:

Pedal-Kickback:

So my big question for you guys is, if the anti-squat numbers are falling that far into the negatives deep in the travel, is it going to impact suspension performance by wanting to sit back in the travel? Or does it not matter being so far into the travel?

Posted: Sep 3, 2021 at 13:24 Quote
I liked the previous iteration more just from the looks and the general layout. The latest has a long top link, which might be more flexy as well.

Posted: Sep 3, 2021 at 13:43 Quote
Grumposaur wrote:
I liked the previous iteration more just from the looks and the general layout. The latest has a long top link, which might be more flexy as well.

That's fair. I am sure the very sculpted look of this one is not everybody's cup of tea. The issue with the last iteration was in the rear triangle, it was incredibly difficult to package and left me wishing for more meat in a few areas (if you know what I mean). Just kidding. But seriously, I had to be pretty skimpy to get proper clearances everywhere.

As far as linkage goes, the new one is not much to worry about, The lower link is still very short, and the top link can be tuned with shaping, materials, mounting interface, etc.

Posted: Sep 3, 2021 at 14:11 Quote
It just a matter of personal preference. Both designs look well sorted in the lines etc.

Which dropper do you use for the model? Insertion depth appears rather short, which might also kink any cables going there.

And because it is pinkbike: how about water bottle mount? (and tool/tube mount) Smile

Posted: Sep 3, 2021 at 14:25 Quote
Grumposaur wrote:
It just a matter of personal preference. Both designs look well sorted in the lines etc.

Which dropper do you use for the model? Insertion depth appears rather short, which might also kink any cables going there.

And because it is pinkbike: how about water bottle mount? (and tool/tube mount) Smile
The model is actually of a rockshox reverb (colored to look like a fox transfer because i was too lazy to model it), max insertion depth on the frame is 170mm, and the bottom has a cutout for actuator, routing, and all that jazz to go under the “L” shaped tube.

This is on a medium sized frame, the big boys will get extra length for a longer post.

As far as water bottle mount, i have an idea for making it possible to mount two, but I think I will get more PB cred if i can make it mount 4. All jokes aside, yes. Not sure if i should mount it inside the front triangle, or was also thinking on the top tube towards the seat tube junction, since the standover is so damn low it would be easy access and still be out of the way. There will be a multi tool and tube storage built into the frame, either in the “L” shaped tube or somewhere in the downtube.

Posted: Sep 18, 2021 at 12:11 Quote

So now I've ridden my pinion bike the hole summer and well it works great on gravity and tech trails and that's mostly what I ride. Way too sluggish for xc riding.
But I thought I'll post 2 films from riding it.
At this time I'm home with a broken wrist and thinking of building a new new frame this winter.
So here you go. First one mostly blind tracks



And this one it's rather techy riding on the big 29 er


Hope you enjoy it. I'm having a blast on it so far!

Posted: Sep 21, 2021 at 12:11 Quote
merc-blue wrote:
About to start a Cargo frame build,
Cad is mostly done, gonna try to keep it reasonably light with most of the front
I'm looking at building most of it from 1.25x.035 4130 steel. the 2 little side braces will be 1x.035 and the centre tube will be 1.25x.049.

Anyone built anything similar got tips on tube thickness? this will mostly haul 3x toddlers around mostly and have electric assist so weight isnt a massive issue. so tempted to bump it all into .049 wall

i would go for a significantly larger center tube. from my reading people tend to use 1.5" square, or 1.875" or 2" .049 round.

Posted: Sep 21, 2021 at 15:54 Quote
DanAlmberg wrote:

So now I've ridden my pinion bike the hole summer and well it works great on gravity and tech trails and that's mostly what I ride. Way too sluggish for xc riding.
But I thought I'll post 2 films from riding it.
At this time I'm home with a broken wrist and thinking of building a new new frame this winter.
So here you go. First one mostly blind tracks


awesome bike and riding!

Posted: Sep 27, 2021 at 12:46 Quote
@kaimbell90 - some thoughts on the -220% anti-rise as requested: yes, I think this will be a problem as it will compress the suspension e.g. it’s now ‘pro-rise’. With all that energy going into compression then it just isn’t going into forward motion, so it could be slow going. Of course if you’re at full compression you probably won’t be pedalling - but the danger is as the rate is dropping so fast that as you compress the travel through pedalling it could create some sort of positive feedback loop, but I don’t know though.

Theoretically at 100% (1/3 of your travel on the graph) you cancel the compression forces with your pedalling forces - higher than 100% will help further with the added forces from stamping on the pedals. Keeping anti-squat in this zone is one of the attractions of the high single pivot, as once you decide on the amount of anti-squat in your design it pretty much stays the same through the travel.

More on all that in this article - it’s great. It totally nerds out on the details - thoroughly recomended: https://m.pinkbike.com/news/definitions-what-is-anti-squat.html

Posted: Sep 28, 2021 at 7:17 Quote
curbwzrd wrote:
merc-blue wrote:
About to start a Cargo frame build,
Cad is mostly done, gonna try to keep it reasonably light with most of the front
I'm looking at building most of it from 1.25x.035 4130 steel. the 2 little side braces will be 1x.035 and the centre tube will be 1.25x.049.

Anyone built anything similar got tips on tube thickness? this will mostly haul 3x toddlers around mostly and have electric assist so weight isnt a massive issue. so tempted to bump it all into .049 wall

i would go for a significantly larger center tube. from my reading people tend to use 1.5" square, or 1.875" or 2" .049 round.
I own a Bakfiet-like cargo and the main frame is a big ass single tube, and it's enough for children. Quite flexy tho, if you load near the maximum weight in cargo (100kg) I don't know the thickness yet, so I can't help, I may take measurements when I'll do a new fork.

For this case, I'd remove the small horizontal tubes at the top, and raise the two lower on the side, It will provide the same structural strength but with two less tubes in weight. Also the central part under the stem seems waay overbuilt.

Posted: Sep 29, 2021 at 4:40 Quote
faul wrote:
curbwzrd wrote:
merc-blue wrote:
About to start a Cargo frame build,
Cad is mostly done, gonna try to keep it reasonably light with most of the front
I'm looking at building most of it from 1.25x.035 4130 steel. the 2 little side braces will be 1x.035 and the centre tube will be 1.25x.049.

Anyone built anything similar got tips on tube thickness? this will mostly haul 3x toddlers around mostly and have electric assist so weight isnt a massive issue. so tempted to bump it all into .049 wall

i would go for a significantly larger center tube. from my reading people tend to use 1.5" square, or 1.875" or 2" .049 round.
I own a Bakfiet-like cargo and the main frame is a big ass single tube, and it's enough for children. Quite flexy tho, if you load near the maximum weight in cargo (100kg) I don't know the thickness yet, so I can't help, I may take measurements when I'll do a new fork.

For this case, I'd remove the small horizontal tubes at the top, and raise the two lower on the side, It will provide the same structural strength but with two less tubes in weight. Also the central part under the stem seems waay overbuilt.

I have had a Few revisions will upload some CAD soon of the revisions.
In my work I occasionally need to design simple structures but we always have clear load cases to consider as set out by Australian Standards but something like this I'm finding difficult.

I have access to Autodesk Nastran so may put it in there with some dead loads and see how it is loaded. but that's really only static analysis.

Shimano have some pretty cool Cargo E-bike drive units which I'm trying to get my hands on which will be cool, the big decision is weather I try and setup the "auto" shifting that can be done with the Shimano hub and Di2 or stick to traditional shifting.


 
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