My understanding is that an analysis of the yeti switch system revealed that it would function better if the pivot had a larger diameter....the larger the better. I suppose they could have put a 48 inch pivot in there and the tangent to the circle would essentially be a straight line, but that might be heavy and would rub you badly in the wrong place and complicate the installation of a dropper post. The existing stanchions are essentially a little bit a circle of infinite diameter.

 

My understanding is that the issue was with the original switch pivot following an arc described by the circular path that the eccentric switch mechanism created. With the SI, the pivot now follows a straight up/down path. I wasn't aware that the actual inflection point was an issue.

 

The issue is that Yeti didn't want to keep paying royalties to the Sotto Group.

 

Yeti seems to have thrown the original Switch suspension under the bus when they brought out the new Switch Infinity models.

Yeti said that the original Switch system had an inflection point in the linkage (i.e. linkage changed direction while rear axle was still moving smoothly up through the travel) and that it was a subtle issue. But the new SI system also has an inflection point, where the slider changes direction while the rear axle is moving up along its axle path.

Fundamentally, if it was an issue for Switch, then it is likely an issue for the Switch Infinity setup.

Now... I spent a year + on a SB66A (until the swing arm broke, as it did for many - Yeti was great with the warranty by the way), and i really thought it was a terrific bike. But to me it seems odd that Yeti brought up the "issue" with the Switch linkage, while introducing another linkage with the same fundamental configuration, at least with regard to the linkage having an inflection point during the rear axle travel.

Does anyone have insight on this?

While it's always fun to generalize, I don't think we threw anything under the bus. The original Switch design was awesome for a ton of reasons, but there were a few situations in which we found we could reach its limits - mostly hitting high speed, square-edged stutter bumps at or near the inflection point. The rear wheel would tend to hang up a bit in those situations. At the time though, it was the very best we could design, so we figured that narrow range of negatives was far outweighed by all the positives we achieved with that system.

However, engineers being engineers, our design guys began to wonder if we could retain all the great characteristics of Switch but solve the problem described above without adding weight or complexity. It took 3 years and a lot of late nights, but they eventually came up with Switch Infinity.

The issue is that Yeti didn't want to keep paying royalties to the Sotto Group.

Haha... Incorrect.

 

Haha... Incorrect.

It's fun to speculate ;p

 

P.S. All of this was covered in a lot more depth than I can offer when we launched the SB5 last summer
First Look: 2015 Yeti SB5c with Switch Infinity Technology - Features - Vital MTB
Great New Rides | Bicycling
Yeti SB5c - Review - Pinkbike

Happy reading,

JP

 

I heard from this guy - that knows stuff- that bike companies make changes every once in a while.

 

I heard from this guy - that knows stuff- that bike companies make improvements every once in a while.

Fixed it for ya. :thumbsup:

 

Switch, Switch Infinity, and the question of inflection point in the linkage ...

Accidental post. Fat fingers

Sent from my iPad using Tapatalk

 

OK, so this is way over simplified, but with rotational work there is an inertial term that is summed, thus leading to the "notchiness." I believe...

Rotation and Work-Energy Principle

But in translational work, only mass influences the amount of work needed to change the direction of the sliders in SI:

Work-Energy Theorem

So, by virtue of the fact that less energy is needed to "switch," SI is a more smooth feeling system at the inflection point.

Disclaimer: Only a humble MS in MechEng working is mostly sales these days, not a suspension or kinematics expert

 

Okay, I get that (also an engineer). They key to your comment is that 'SI is more smooth', which is engineer-speak for 'the issue is still there but not as bad'. The rotational component shouldn't be much of an addition compared to the translational mass (most of it is there). My thinking is that avoiding an inflection point that's in the middle of the axle path would be preferred (i.e. the linkage changed direction when the axle changes direction), regardless of whether it is translational or rotational, as this would eliminate any sort of mid-stroke inflection. The inflection point creates an event mid-stroke (i.e. the notch sensation), which isn't going away with SI, it's just reduced.

I'm again going to comment that the SB66 was awesome, and I'm sure the SI is even more super-duper. ...but there's a hair to split here.

 

Psssh... what a bunch of malarky. Everyone knows the Switch Infinity bikes feel smoother because of the Goldilocks wheels.

 

Well, I'll finally know Sunday at GBS...gonna ride me one up the Gulch.

 

Possibli, but there is more at work here. The original Switch is a far more complicated system, kinematically speaking. Without modeling and study of this, it is very hard to explain the "notch." However, my butt calculator could sense it was there when I rode my 66a. Again splitting hairs here, because the 66 was so good; better than anything else (except maybe the 95 ) that I had ever rode.

It is fair to say that Yeti could have continued with the Switch, and not developed Switch Infinity, and still enjoyed great market success. However, instead of taking a skeptical, jaded, and contrary view let's applaud them for pushing the technology and improving. Racing after all demands this attitude. And certainly the success the Yeti has enjoyed in the EWS confirms this to a great extent.

So, in short, go apply a butt calculator to a SB5c and then report back At least that's my plan...

 

Butt calculator applied; SB5c frame in desert turq boughten

 

Was the bump stop on the original switch design there to prevent the concentric pivot from rotating beyond the intended inflection point under high speed compressions? It didn't seem to engage when gently cycled with the shock removed but once the rubber was worn on my SB66 it made a racket over hard compressions, which seems to indicate the bump stop was there for this purpose. Perhaps this is one of the negatives John P. was referring to. If that concentric rotated past the intended inflection point I could definitely see how it would lead to a "notchy" feeling.