Two New Prototype Yeti’s: 303R-DH / 303R-SS
Tuesday, April 22nd, 2008Yeti brought out a few prototypes at Sea Otter this year that needless to say turned a few heads.
Yeti 303R-SS, one of three prototypes spotted at Sea Otter
Details are still obviously being determined and both bikes are in different prototype phases. They are quite interesting however in the implementation of the rail system Yeti uses on the 303 but built off of a more conventional single pivot setup. The slopestyle is said to get around 5.4″ of travel and has an 1.125 upper / 1.5″ lower headset cup. The DH sled should be more affordable than the current 303 and with less heft.
303 R DH
A less expensive DH bike that uses a single pivot coupled with our 303 technology. By utilizing a horizontal linear rail we are able to create a rate similar to the 303 DH. The single pivot design has a different wheel path than the 303 DH but we were able to simplify the design and lighten up the frame significantly.
- Travel: 8.5”
- Projected Weight: 10 lbs
- Head Angle: 64.5 – 65.5
- Chainstay: 17.25”
- Projected price: $2499
Yeti 303R-DH (click to enlarge)
Yeti 303R-DH rail setup
303R-SS
Designed for aggressive trail riding, slopestyle, and gravity bent all-mountain. The rate on this bike has been designed to be stiffer so it holds the rider up in g-outs, berms, and really flowing terrain. The stiffer overall rate also makes it more difficult to bottom-out.
- Travel: 5.4”
- Projected Weight: 7.5 lbs (Fox DHX air)
- Head Angle: 68 degrees (32 Float / 140) 66.3 degrees (36 Float / 160)
- Chainstay: 16.5”
- BB: 13”
Yeti 303R-SS (click to enlarge)
Yeti 303R-SS rail setup
You can see more on the Yeti site under their photo section where they divulge some more info regarding leverage ratios, a lot more pictures, and other interesting tidbits.
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April 22nd, 2008 at 11:44 am
loving the Yeti 303 R SS
April 22nd, 2008 at 2:24 pm
I just made a mess in my pants…I promised myself I wasn’t going to spend all my summer earnings on a new bike but I don’t think i can resist now.
April 22nd, 2008 at 3:10 pm
FTMFW!!!
Those are seriously the sweetest rides that I’ve seen from Yeti. They are so good looking! Keep it up Yeti!!
April 22nd, 2008 at 4:46 pm
I dunno, those designs have a lot of extra moving parts which in my mind represent cost, points of failure and maintenance.
I would need some pretty convicing evidence that the rail design alters the single pivot wheelpath and spring curve enough to warrant it.
Wasn’t it Santa Cruz who recently came out and said that wheelpath should not be the primary concern in suspension design? (this was in relation to the new Blur)
Factor that out, and all you have left is a progressive suspension curve which I question the importance of given the features of shocks like the DHX which are designed to offer progressive damping.
You guys are right though. It sure looks pretty!
April 22nd, 2008 at 8:03 pm
Good news: Afordable new models.
Bad news:Thats the end of, made in the USA.
April 23rd, 2008 at 4:53 am
Yikes, more pretty looking but poorly designed bikes from Yeti. Wheelpath is nothing but single pivot. Rail is gimmick which in these cases makes the suspension LESS progressive and MORE linear. Not what I would want for a DH bike or a SS bike for that matter. Lucky for Yeti the shock tuning is so good these days they can probable tune out Yeti’s linearity a bit. Not my cup of tea I’m afraid.
April 23rd, 2008 at 6:40 pm
Actually, the ideal leverage ratio curve for a coil spring shock is linear. The more linear, the more tunable the shock is. You can have a linear shock rate curve (straight line) that has a slope (positive or negative). The slope dictates the progressiveness…the greater the slope, the more progressive. So in reality, the linear leverage ratio is ideal.
April 24th, 2008 at 4:53 am
Yeah, linear is ideal…if you hate small bump sensitivity and want to blow through your travel on big hits…
April 24th, 2008 at 10:40 am
As a previous owner of a Yeti, I can say all the extra links, bearings, and mechanical complexity add up to a pain to maintain, as MattPatt suggested. Yeti over complicates mechanical design, and actually seems to be increasing complexity from year to year. Special tools are required for each model. It seems like a very self gratifiing design principle at Yeti (ie look at this cool complex thing I just made).
April 24th, 2008 at 10:46 am
Can you please explain to me what the ideal curve should be? Thanks.
April 24th, 2008 at 12:08 pm
Ideal Curve according to Aaron: In a word, progressive. High leverage ratio at the beginning of travel for good small bump sensitivity. Progressing to low leverage ratio by the end stroke to avoid bottoming out. This, when combined with hi/lo compression damping to reduce pedal-induced bob at the beginning of the stroke, is ideal in my opinion.
The Yeti on the other hand, has nearly the same leverage ratio at the beginning of the travel as it does at the end. Just doesn’t make sense to me…
April 24th, 2008 at 12:58 pm
Just because the leverage ratio curve is linear, does not mean it is not progressive. Linear describes the shape of the curve (how “straight” it is), it does not describe its orientation (slope).
Consider a plot with LR on the Y axis and rear wheel travel on the X axis. Draw a straight line that has a negative slope (high LR in the beginning and low LR in the end). You then achieve a curve that is linear AND progressive. This way you get great small bump sensitivity, bottom out resistance, and ideal shock tuning ability.
April 25th, 2008 at 3:57 am
Taco, I understand your point. There is often no distinction made between slope of the curve and the shape of the curve. So when I refer to “progressive” and “linear” I am referring to their commonly held, and simplified, definitions. ANYWAY…
So, I invite you to do your own math. Plot the LR vs travel on the Yeti SS. You’ll find it’s a not a curve at all. It’s virtually a flat line. Far from ideal! The DH bike does at least have some progression…
April 25th, 2008 at 4:17 am
PS - When I say “flat line”, I mean horizontal flat line… So slope = 0 and shape is almost linear.
April 25th, 2008 at 10:28 am
Aaron, I would invite you to do the correct math…There is indeed a slope to the SS curve…for confirmation go the the Yeti site where they have pics of their protos:
http://www.yeticycles.com/#/photo/
…check out the 7th photo where it clearly states “Slope 20%, Linear” for the SS leverage ratio.
April 28th, 2008 at 5:02 am
Oh my, I’ve done some kinematic sketches, and things are worse than I thought. I think the SS is actually regressive in rate.
First off, a slope of 20% means nothing except to the Yeti guys. Assuming that this is the slope of the LR vs. wheel travel curve as mentioned previously by Taco, then this tells us nothing because LR is unitless. Besides, the slope should be negative for a progressive rate! Unless it’s regressive…
Which in fact, I think it is, and I will try to explain without diagrams. You see in side picture of the bike that the chainstay is perfectly in line with the shock slide. As the suspension moves through it’s travel, the chainstay will no longer be in line with the shock slide. As the angle between the chainstay and shock side increases, the wheel travel will be able to move proportionally more than shock slide. This means the leverage ratio has increased. If we assume the starting rate is 2.4:1, the end rate will be higher…say 2.6:1 (guess). A regressive design! And the opposite of ideal in my opinion…sorry Taco!
April 28th, 2008 at 12:23 pm
Wow…where to begin.
What do units have to do with a percentage slope?…nothing. The percentage slope can be determined regardless of the units of the Y axis (Yes, even if there are no units). In this case, the percentage slope would be considered to be ([LR_Initial-LR_Final]/[LR_Initial}*100%). If the slope is negative (Progressive) than the percentage slope is Positive!
Next, it is actually the Seatstay that is parallel to the slider, not the Chainstay. This leads me to your next mistake. Yes, the Seatstay is in-line with the slider when the shock is fully extended. Then, as the shock compresses, the angle between the Seatstay and the slider does indeed increase.
However you are missing a couple key parts of the system…The chainstay(and its corresponding main pivot), and the slider angle. When considering the entire system, it behaves the opposite way that you describe. As the suspension moves through its travel, the slider(and shock) actually moves more for the same amount of axle travel. (CAD helps for this)
I think Yeti would know better than to design a regressive bike…especially when Justin Leov took 3rd in DH on the SS at Sea Otter.
April 28th, 2008 at 5:07 pm
Taco…got me on the seatstay/chainstay…my mistake. And I’ve never seen that formula for “slope” of the leverage ratio, thanks for informing me. I can’t really debate this any further without CAD, so I guess I’ll have to leave it. I do hope I’m wrong and that what you say it true. I’d quite happily be proven wrong…
April 28th, 2008 at 6:04 pm
Aaron, thanks for the debate, it is always fun talking bikes/engineering. No hard feelings…I can get carried away with the stuff. I completely agree, it is hard to visualize suspension without CAD (especially leverage ratios). Cheers.