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joshmtb Added a reply to Kinematics

9/30/2025 2:55am
Brining this back from a while ago.... Is anti squat then the ratio of moments about the instantaneous center of the rear swing arm? I.e.sum of the moment from the wheel and chain tension divided by moment caused by accelerating the center of mass?

joshmtb Added a reply to MTB Tech Rumors and Innovation

9/29/2025 3:51am
Whilst the pivot might have a few more broken frames than others, there's no way that impact would cause that on an in tact frame. Either it was previously damaged or defective. No way it would a survive a sin le run at a world cup or hardline if it was that weak!

joshmtb Added a reply to MTB Tech Rumors and Innovation

9/26/2025 4:04pm
All ball bearings have an amount of slip. You can't rotate a sphere in a u shaped track without slip unless you have an infinitely small contact. I.e. have an infinitely stiff material. By making the balls and races really hard you minimise the contact patch and slip. The sliding friction is minimised by including a lubricant.

Jakub_G Liked a reply to forum topic MTB Tech Rumors and Innovation

9/25/2025 11:45pm
You mean like numerous specialized prototypes, intense prototypes, mondraker prototypes went into production right? That UCI rule only applies to road racing.
This forum topic has 30430 replies.

joshmtb Added a reply to MTB Tech Rumors and Innovation

9/24/2025 11:51am
You probably can, but you shouldn't. Any bearing even with the "gothic arch" style race design will experience microscopic amounts skidding. Running a bearing dry might feel good in an unloaded test but the moment the load is applied lubricants will help

NY_Star Liked a reply to forum topic 2026 Team Rumors

9/3/2025 3:32am
If you buy the YT team assets does it come with the WC points? Maybe BK needs to pony up!
This forum topic has 3191 replies.

AvgMTBEnjoyer Liked a reply to forum topic Frame Design

7/18/2025 3:01pm
I'll send them a letter back telling them I look forward to cooperating with them when I intend to take the bike to market, which is never. If they want to get between me and my hobby I'm more than happy just ignoring them 😂
This forum topic has 194 replies.

Evil96 Liked a reply to forum topic MTB Tech Rumors and Innovation

7/14/2025 10:38am
i still fail to see the issue, like every single biker had wheelsets they keep swapping around for fun like lego blocks
This forum topic has 30430 replies.

dolface Liked a reply to forum topic MTB Tech Rumors and Innovation

7/11/2025 3:06pm
Oblig:
This forum topic has 30430 replies.

joshmtb Added a reply to MTB Tech Rumors and Innovation

7/11/2025 1:39pm
I have no strong feelings about 32inch bikes or this bike except it has the most hideous attempt at bonding carbon to lugs I've ever seen! It looks like someone didn't even attempt to clean it up. I know it's a prototype but it's like 20mins work to get the right!

SlipperyWhenDry Liked a reply to forum topic Renthal Carbon Vs Aluminum

7/9/2025 8:00am
I've had the same question for a while and haven't been able to find an answer either! Would be curious to see if anyone has any input here.
This forum topic has 5 replies.

joshmtb Added a reply to Kinematics

7/1/2025 10:44am
For those looking for free ways to solve the maths.... I've used python + sympy for solving symbolic equations then using jupyter notebook as a handy way to visualise.

dolface Liked a reply to forum topic The flex stay discussion thread

6/27/2025 1:41pm
OK, I'm gonna lock this thread, feel free to start another one if you feel the need...
This forum topic has 150 replies.

joshmtb Added a reply to The flex stay discussion thread

6/27/2025 8:09am
The tyre nor your backside has the bandwidth to transmit/sense the vibrations of the amplitude and freqency caused by resonance in the chain stay. I'm like 95% sure at this stage you're confusing suspension design charecteristics for some fact about the flex stay. None of what the people with expertise in this forum are discussing is opinion or conjecture. An...

AgrAde Liked a reply to forum topic The flex stay discussion thread

6/27/2025 8:05am
Get a broom handle with no broom on it. Hold it vertically with your palm over the top of it, and thrust it downwards into a concrete floor as hard as you can. The broom handle hits the floor, and the high degree of compressive stiffness of the broom handle transmits the impact efficiently into your hand, and now it hurts. Your hand didn't get any closer to the ground than the length of the broom handle because it did not compress, or bend, it just transmitted the force along the length of the handle. Now with the bottom of...
This forum topic has 150 replies.

ex-ballz Liked a reply to forum topic The flex stay discussion thread

6/26/2025 12:25pm
This feels like a discussion with a Flat Earther.
This forum topic has 150 replies.

Primoz Liked a reply to forum topic The flex stay discussion thread

6/26/2025 1:28am
Some of us have years of education and experience from the field...
This forum topic has 150 replies.

CascadeComponents Liked a reply to forum topic The flex stay discussion thread

6/26/2025 1:28am
This has somehow morphed from talking about undamped spring force and rebound from a flex stay to transmission of vibrations. Very different things. Any frame will transmit vibrations to varying degrees. To figure that out you have to look at natural frequency and then also the frequency of impacts on whatever trail you're riding. I would guess that most flex stay frames have a higher natural frequency. Santa Cruz chose to design the Blur with a very thing seat stay. This is not something that is a requirement for the functionality of a flexure. In the huck to flat video...
This forum topic has 150 replies.

CascadeComponents Liked a reply to forum topic The flex stay discussion thread

6/22/2025 4:09am
This will be my last attempt at explaining why rebound damping at the shock will control the flex stay. If you take the blur rear triangle and attach the upper pivot to the lower pivot with a rigid member, you are forming a triangle and locking out the flex stay. If the shock were to be locked at any given position, it’s effectively doing the same thing. As such, for the flex stay to move the shock just move and therefore the damping at the shock is controlling rebound of the flex stay.
This forum topic has 150 replies.