Accessibility Widget: On | Off

Are Upside-Down forks really flexy?

Create New Tag

1/13/2021 8:51 AM

hamncheez2003 wrote:

I still wish they had some RSU dual crowns and an inverted dual crown in there for us to see....

In the PB video?

|

1/14/2021 5:11 AM

@Primoz. I checked the FOX drawings, and they as well spec tolerance +-5mm for axle-to-crown distance, the same as RS on Lyrik from 2009. Wheel axle offset tolerances with +-2.5mm :-D. By any means do I consider such variances worth of premium price.
FOX 38 2021 spec

As for Ocho. Yes, it's shorter chasis when compared to FOX 38 (but only by the lower travel) but still, it has only one leg and handles the impact MUCH better than 38mm wide two stanchions, eventhough from lower height.

|

1/14/2021 5:19 AM

Ah, +/-5 mm tolerance on the ATC isn't something i'd give a lot of value to. The -2 mm tolerance on the hub width is... surprising, but I understand the +2 mm. I'm fairly certain (hopeful?) that their internal drawings have much more stringent tolerances than what is show nere, this is for the general public. Their actual tolerances wouldn't give them any leeway when dealing with warranties (this way they can say even faulty products according to internal spec are within public spec...). And this is probably meant for frame manufacturers, so you want to secure some space (maybe to account for any flex in the system) to prevent any frame impact.

I was hoping for some internal data, I'd really be interested in stanchion and bushing tolerances smile

|

1/14/2021 9:51 AM

Primoz wrote:

URL for the RS tolerances.

I never said it's not possible to make the inner surface of the outer tube appropriate to have a bushing slide on it. I said it's more expensive, as, opposed to castings, it requires finer control over the surface quality and hardness. And that it adds another component that requires this besides the stanchion. And it requires it on the inner tube surface, which logic dictates is harder to work on than the outer surface.

And I specifically said that even such a good idea (even a Lefty with keyed stanchions) isn't worth much if it's really hard to make it quickly, cheaply and with good reliability. We are bemoaning bike prices in the current state, would you be happy to pay 2000+ USD/EUR/etc. for a 150 mm singlecrown fork from the major manufacturers?

Regarding the Ocho vs. 38, the Ocho was on a 29er, the 38 was on a 27,5" bike. The same movement will appear larger on a 27,5" bike because of the difference in size of the reference geometry (wheel size). Plus the 38 has a longer travel, which, if you look at the last graph in my first post, plays a huge role as well. And the rider does appear to handle the huck a bit worse on the Nomad than on the Cannondale, insinuating a higher jump height on the Nomad compared to the Cannondale. Which would of course mean higher forces...

hamncheez2003 wrote:

I still wish they had some RSU dual crowns and an inverted dual crown in there for us to see....

Primoz wrote:

In the PB video?

Ya, the pinkbike video. It seems that RSU dual crown forks aren't necessarily any better than the latest crop of thick crowned 38s and Zebs

https://imgur.com/a/LwLDhkA

|

1/14/2021 11:06 AM

We'll get there. Don't know when, I'm thinking about how, but I can assure you, if I made this, I'll make dual crowns too!

|