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Sorry for a minor derail, but you mentioned my favorite ski of all time (Head Monster 103 Team).
This might actually be a perfect (inverse) analog for USD forks. That ski wasn’t actually that stiff longitudinally, but the two layers of metal made it quite torsionally stiff. It held an edge through chop because you could bend the ski but it didn’t deflect. The key was you had to check your ego and ride the ‘correct’ size and not try to look cool with a 193 in the lift line.
Where it did suck was deep fresh snow because it was full camber with very little tip rise.
Bottom line, maybe we are at the point in product evolution where forks are ‘Horses for courses’ like skis. Gotta have a quiver.
I'll fly the pro USD flag, although I'm very biased...
I think you're slightly underestimating the nuance between an amazing fork and a crap fork. At this point you might have rode two forks of the same manufacturer and model but yet they feel vastly different. To me, that's down to fork manufacturing being on the knifes edge of production manufacturing tolerances. For example, 4-6lbs of extra seal drag is garbage, .25deg misalignment of tubes is total garbage, and if a 14" long stanchion deviates more than .0004" (human hair is ~.002") - steaming hot garbage. You might say those are all issues that can equally effect either a RSU and USD fork which is true. So my argument is that the difference in lubrication, bushings, and compliance in a USD fork may seem trivial looking at it from a macro perspective, but if they can add up to just a consistent 1% improvement, a rider can feel it.
Anyways here's a more tangible difference between RSU and USD to think about. These two forks have the same stanchion length, a2c, bushing overlap and travel. If you imagine the force of the wheel being applied at the axle, on the RSU fork the leverage on the bushings remains constant through travel since the distance between the axle and bushings doesn't change. On the USD fork the leverage on the bushings is decreasing deeper in travel as the bushings close the distance to the axle. This makes for a massive difference in friction in the second half of travel and that's even before you factor in the additional friction from the stanchion flex on RSU forks.
Very interested to see the continuing development of the USD forks, since in addition to the fore-aft stiffness, bushing and seal lubrication, there's also later room for sliding upper bushings like the recent EXT USD dual crown, which just isn't possible on a RSU design. I haven't tried one yet for myself but looking forward to it!
Just to clarify, sliding bushings could be used on a RSU fork even with cast magnesium lowers. Yes, some technical challenges, but possible.
Also for those not familiar with moto forks, the stanchions are almost completely filled with oil thus submerging the bushings in bath oil. The oil then fills the diametrical clearance between the running surface and bushing. Could be done in mtb forks, just need to consider the weight penalty.
Great thoughts, everyone. Lots to think about here. Excited to try one out.
One pro that I think a lot of us could agree on is that USD forks subjectively look much cooler too. So theres a plus.
Have you listened to the Vital podcast Darren did on the 9.1 a while ago? A lot of this does get discussed in there to hear it from the source.
MIght thoughts on these,
"compliance" this can mean a lot of things but in theory can be tuned in either form factor
Bushing performance - definitely some benefits in USD because the bushings are closer to the ground which shortens the lever bending force on them, which gets shorter as teh fork compresses, even without dynamic bushings.
Lubrication - just tipping the bike up doesn't 100% cure this issue in a RSU fork. You still compromise things like needing a thick oil which won't run off the bushings easily, while USD can use something thinner which has less viscous damping at high speed while maintaining low friction at low speed.
Creaking - RSU forks mostly creak because of the minimal overlap with the crown and tubes. This could be fixed but would increase stack height for a given amount of travel. USD has more real estate available when pressing those parts together since you can have a huge overlap.
on the harsh moto forks, it hard to know what would be causing that - since most/all MX forks are USD anyway. It could be the damper but its pretty well known the dynamic bushing design can bind under big hits, as the upper tube bends while the bushing is being forced past the lower crown. That's why is hasn't been adopted for most MTB USD forks too.
Until you see the mudguards to go with them 🤮
Not so bad…
https://www.pushindustries.com/collections/nine-one-replacement-parts/p…
I would be curious to know if that flaps back and forth, as it has some pretty long supports from the axle area upwards.
It could very well work, every problem is temporary
how much does this add to unsprung weight? wasn’t the dvo one similar and quite porky?
I don’t know how much the DVO one weighed but they claimed it was a fender and structural piece so there might have been extra material in there. I had one of those and it rode amazing
It's ~72g, and nothing like the DVO arch.
A ton of effort went into optimizing the guards, supports and fender to be stiff and lightweight.
After having gone back and forth a few times now between the Intend and PUSH forks, I feel the ability to tune the flex (torsional and fore/aft) is a big benefit of the inverted design. Historically this has been a weak point, with the single crown Shiver being slightly terrifying at times with the ability of the front wheel to wander aimlessly in rock gardens. This is no longer the case (at least with the Intend and PUSH forks), with the amount of flex being beneficial. Similar to what Reece is talking about in regards to the Dorado here:
It is for sure terrain dependent, but in the rough the inverted forks have a very calm feel at the handlebars and simply track where pointed. In contrast, a traditional chassis design like the RS ZEB has more feedback at the bars and requires a stronger grip. There is more a sense of fighting and battling against deflection and it's harder to stay on line in embedded rocks.
In regards to the Intend Edge and PUSH 9.1, the flex and chassis feel are quite different between the two. The PUSH fork has gone back to the factory for some requested inspection, once it returns there will be multiple back to back test sessions between them to really dig into the details.
Two things that have kept me from jumping on an Intend or Push.
- Sounds silly to some, but a big deal for others. Fenders. Buggers me why, with all the innovative capabilities available, why Intend hasn't bothered addressing this.
- Reviews. Push's transparency and attitude has been fantastic leading up to the release of the Nine One, but what's the deal with not having a review to accompany the product? I thought for sure Vital would have been given an opportunity to run this. I'm apprehensive because of this.
For me as it is now, Push is on the top of the list, but only just. Purely because of Darren's attitude and an almost 'open book policy' and soon to be available fender. But that could change in a heart beat. Intend has the most respectable/uncompromised reviews via AstonMTB, and it has a solid track record. If Intend could pull their heads out and figure an elegant fender solution I'd give them my money in a Flash.
The uppers-mounted Intend fender looks dorky as heck and has nowhere near the coverage of a good RDS fender for sure. The USD stanchions and seals are self-cleaning though, so you're really only protecting your face and torso from splashing. The fender helps with that a bit. I am more annoyed about the leg guards situation so I made my own. Poor looking but good enough.
Did you ride the Intend with different hubs? Did you feel any difference in flex? I swear to dog that a Vesper with torque caps feels flexier than a good ole Hadley, but it can all be just in my head as I built the Vesper wheel to be more flexy.
We love the silence of Onyx rear hubs, but at PUSH, we recommend not using the front hub. The only customers to complain about excess flex have been on Onyx hubs and switching hubs solved the issue every time.
We've looked into the issue and I've personally tested a hub, but we couldn't find anything that stood out and it rode completely normal. At this point it seems like it's a case-by-case issue, but we are going to continue to research the topic.
Low mount fenders are now readily available for our NINE One front fork.
As for reviews, it just comes down to availability. Since launching the fork, we have been overwhelmed with trying to satisfy demand and haven't had a single fork to spare for the media. We have been focused on scaling our production for the past year and have made significant progress. We look forward to getting the forks in the media's hands. That being said, there are a number of rider reviews online, including on the NINE ONE product page from customers who paid for the fork.
Thank you for that insight!
Vesper or the original style?
Right on, thanks for the insight.
Any chance 180mm of travel could become a thing?
As of next week i will join the intend owner party. Really excited but a bit worried about setup as there seens to be alot of stuff to keep an eye on, compared to my marzocchi coil wich is not really much to deal otver then a few dials for compression and rebound.
Is there any manuals from intend at all?
Congrats! They ship the forks with a spec sheet that also has instructions - assembly instructions, air spring setup and progression, compression/rebound, axle torque specs, cable routing.
Sorry to derail, but is that a picatinny rail on the down tube of that reeb?
Good eye, looks like it. I can’t imagine gun parts selling well with the bike crowd even if it was highly functional and had cross over value. Anyone make a water bottle that looks like a scope?
It's used as a quick connect system for our on-board data logging units. Video showing the setup:
https://www.intend-bc.com/fork-setup/?v=5f02f0889301
just setup the recommended air pressure, set the compression right in the middle (6 clicks) as well the rebound and go ride, change from there.
this one is for the "but i need stanchion guards" cry babys:
https://www.instagram.com/p/DKuvOI0sxyf/
😃
If I didn't have to deal with predatory exchange rates/fees, paypal fees, overseas shipping costs, customs fees, tariffs and other random fees du jour, and shitty shipping services w/ high risk of goods damage on top, I wouldn't worry about scratching the lowers much either. 🤷♂️ I am a fan but there's limit for what I want to waste the $$$ on.
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