Friday, October 31, 2014

This




Thursday, October 30, 2014

Downhill Domination

On Downhill Domination if you go back and beat all the levels with the prototype bike, then with the Llama, then with the sheep, you win this final super secret bike:




As an aside, T-Bag is still the greatest video game character of all time:

Always choose T-Bag. Duh. Ride the pony.

Standover clearance

There's a nightmare bike thread going on Vital right now, and one of the bikes featured is the old Trek Y-bike that Sharples and Ronning were on circa '98ish. The featured bike is not a Trek, but a Gary Fisher by name, but same difference right?



The weird thing is, in the article, the supposedly scary nightmare part of the bike is the top tube. Spomer just keeps going on and on, "there's no getting around that potential for pain with that top tube!"

I know I'm tall, and a pro rider, and thus my preferences and habits don't represent those of the mean gravity rider, but does anyone out there regularly place their balls between and below their stem and seat when they ride? Think of the body position you'd have to be in to even get your balls there, I would have to consciously work to get in that position while riding, and I would need to be cruising around in a parking lot to make that move happen.

I've prepared this helpful graphic to illustrate where my ass and(or) balls normally go on my downhill bike, and most of my bikes:



Am I way off base here, and there's a mass of people who regularly crouch in the forward position with their center of gravity 3-6 inches away from their hands when they ride? Spomer, do you normally ride like that?

Sharples works for Felt, so I can actually touch base with him and see if he regularly rested the old marble bag on the top tube of his Trek. Me personally, I'm willing to bet the insane head angle, comically short top tube, mediocre suspension performance, and most of all the IRC Liferisk® tires he got paid to ride were a much greater "nightmare" for him than the inert piece of metal that he never interacts with, resting in a place far away from his person.


BREAKING NEW!!! from a LEGENDary friend

A local LEGEND I know actually said this with a straight face:


"Loam is good training for cyclocross, yes? Haven't touched the cross bike since April, can't recall doing an interval set since last winter, don't even know where my bike is, but hopefully flogging mtb's up big terrain and tons of hard grovelling up/down granite in the Sierra Nevada has done something good..... And 2 days rest after a hard month of PT and getting after it from injury is enough rest, eh? ‪#‎unusualtrainingtactics‬ ‪#‎cx2015‬ see ya'll in Bend!"


Reading his Facebook page is one of my favorite things.

Whatever you're doing right now, this will make you feel better



Happy humans are easier for robots to exterminate, so watch up.

Bernard Kerr



Three thoughts on the Pivot video:
  1. I'm always paying attention to new downhill bikes, and this is one of them. Boring as the video is, Pivot did some interesting things with this bike and it's cool to hear head man Cocalis drone on about the process. Obviously it's a DW bike, so that's cool. It has a 107mm press fit BB, a standard I haven't even heard of yet. It seems like the 157mm axle is catching on in downhill world, but the bike still has a standard 1.5" headtube top and bottom. It's an interesting grab bag of standards used on this bike. It has an insanely long top tube and an almost 51" wheelbase on the XL, making it even longer than the GT's. At 62.5 degrees in the middle setting it has one of the slackest head angles in production today. 440mm chainstays aren't "super compact" as Cocalis claims, but it's interesting to see where average chainstay length will land over the next few years with 27.5 DH bikes. To top it all off, it's dropper post compatible. Is the dropper post a good thing on a downhill bike? I don't know, but it sure is interesting. Why not, I guess? Does it ride well, will it break in half, is a 482mm reach length too long? I don't know the answers to those questions, but hey, there's a lot of noteworthy stuff regardless.
  2. That video is really boring. Not "Grubby in the Kootenays" boring, but still really boring.
  3. Bernard Kerr is the real deal. Most of those shots were practice, but plain and simple the guy looks comfy at speed. He's put up some serious results this year, and I wouldn't be surprised if he's on the way to being a consistent top ten kind of guy. Eliot is deadly fast, and I don't want to take anything away from Eliot's speed, but Bernard is phenomenally talented and clearly the class act at Team Pivot. Whatever they're paying him is not enough.


Bonus screen capture, at 4:05 in the video. Eliot Jackson with his knee pad around his ankle at Fort Bill:






Bonus Bonus screen capture at 3:59 in the video. Eliot riding down on a detonated rim, also at Fort Bill:


It's a hilarious clip for Pivot to use in a promotional video, because including clips of your team cosponsor's equipment clearly broken makes those December and January "hey [insert brand here], can we get another pile of rims and money for our race team" emails a lot harder to write. Please, make my day and reveal your limitless ignorance by blurting out "See! that [insert brand here] rim sucks. He broke it."

Chevrolet's VP of Occupational Hypnotherapy


It's nice to see that, after dying, the occupational hypnotherapist from Office Space made a smooth transition into another field, the VP of Marketing for Chevy:



"It combines class winning, and leading umm, you know, technology and stuff... [gasp, heavy breathing, then a slight moan]..."

Keep fighting off that heart attack, man. Keep fighting the good fight.

Monday, October 27, 2014

Bar height?

Something I've been looking at for a while, and could never quite figure it out:

Gwin always had his fork slammed on his Treks, with a bunch of stanchion sticking out the top of the crown, but since day one on Specialized he's been running the crowns really high, with very little stanchion sticking out the top of the crown.


Low front end on the Trek:






High front end on the Specialized:









And you can see this in his body position when he rides. When you watch the video, his handlebars just look higher on the Specialized:





The other lesson learned is that having no music as in the Lawlor/Specialized videos is a better choice than whatever that horrible teen bop semi punk emo obscenity was in the Trek video:





So why does he run his bars higher on the Demo? First off, I don't know. These are all guesses and who knows what the real reason is. But that's never stopped TEAM ROBOT before, so here are some uninformed guesses:

He's a brainless gorilla and has no idea what his bike feels like 


This one actually seems plausible, because a lot of World Cup guys act like brainless gorillas whose only thought is to crush. The story goes like this: when he got on the Demo that's just where his bars ended up, it felt alright on day one, so he just kept his bars there.

I find this explanation to be unsatisfactory. First off, these guys test stuff all the time, and if this new setup was just by chance, and was in fact inferior to the old lower bar setup, it would have been revealed in the countless tests he's performed for the multiple iterations of Demo 8's he's developed and raced for Specialized. Someone would have mentioned something. Also, even if he is a brainless gorilla, "it feels good" is probably still determined by real, tangible numbers and qualities of the bike, ie low bars felt better on the Session, higher bars felt better on the Demo. If there's a tangible reason that relates to geometry numbers, I'd like to know that reason. So we keep exploring for a better explanation.



The Demo has a lower BB height

Assuming these guys don't have custom frames, the Session BB sits right around 14" stock, and the Demo BB is right around 13.5" (338-353mm for the Demo in it's various adjustable heights, and 356-360mm for the Session). All told that's a range of almost an inch (22mm) between the lowest possible Demo configuration and the highest possible Session setting. If you don't like that and you don't want your bottom bracket to be super low, you can run your fork high in the crowns to raise your BB height off the ground.


Head tube angles are right around 64 degrees for both bikes, though just a hair slacker on the Session, so you could achieve almost exactly the same BB height and head angle on the Specialized by running the fork super high. Raising the fork an inch rakes out your head angle just under a degree, and raises your BB about 1 cm.

This explanation still doesn't answer my questions, though, because it ignores all the other geometry numbers. His BB and HA might be the same on both bikes after adjusting fork height, but his bars are still higher on the Specialized, resulting in a higher stack height from pedals to handlebar, and a wildly different feeling bike. Anyone who was psycho enough to measure and then emulate BB height while going from one bike to the next probably wouldn't slip the little detail that his stack height is an inch or two higher than it used to be.

I'm that psycho, and I wouldn't miss that detail.



Chainstay Length


This one goes out to all the haters. The argument goes something like this: the chainstays on the Demo were too short, his bike was unstable, so he raised the bars because he was scared. Initially that sort of makes sense, sort of, except it doesn't make sense at all. Short, unstable chainstays would cause a "looping out" kind of feeling when you shifted weight rearward, making you scared or hesitant to shift weight rearward. So to combat this sensation, he would raise his bars to shift his weight rearward?

Probably not. Also, his bars are still high on new bikes with longer chainstays, so yeah that's probably not it.




Suspension setup
This is going to take some explaining, but bear with me for a second. Or don't, I don't really care.

In my experience, really stiff forks pair nicely with relatively low front ends, and really high bars only work with softer forks. As a guy who ran really high bars on all his bikes for multiple seasons, this was actually a big lesson for me over the past season. I've lowered my bars a touch and stiffened up my forks on all my bikes as of late.

More on that personal bike/lessons learned theme soon.


Allow me to unpack this bar height/spring rate idea for you: It's all about shifting weight. If you have stiff forks, you need to shift weight onto your bars in order to apply enough force to make the fork move. Low bars accomplish this because shift your weight forward. Reverse engineering from that principle, if you have a soft fork, tall bars allow you to shift weight off your front end onto your rear suspension. Running a stiff fork and tall bars, though, is the worst of both worlds on anything but the steepest or harshest of tracks, because you have no weight on the front tire unless you're smashing a mega hole and you can't turn on the rest of the smooth sections.

The suspension theory makes sense because A) Gwin is famous for running his fork mega stiff, and B) the Demo has a much more linear leverage rate than the Session.


What's the intersection between a linear rear spring rate, a super stiff fork, and tall bars?

Start with the rear suspension leverage rate: if you have two 8" travel bikes set up with 450 pound springs, and one bike has a more linear leverage rate, the linear bike will feel harsher on small bumps and will blow through it's travel more quickly on big bumps, a "worst of both worlds" kind of situation. With a linear leverage rate you have to choose between harsh small bumps, divey suspension in big bumps, or some compromise between the two. Knowing how Gwin rides (out of his mind fast), and knowing his suspension preference (I don't care about small bumps, just give me the stiffest suspension possible so I can ride through big holes at mach 10), my wild guess is that he's been running a really stiff spring in the Demo, probably a stiffer spring rate than the equivalent spring on the Session, and the small bump performance of his rear suspension is probably less than stellar as a result. Of course the Fox guys can work their devil magic to make the shock have better small bump performance, but relatively speaking it would be worse.


Now throw a super stiff fork into the equation: you can only ride a jackhammer fork if your rear suspension is doing exactly what you want. Said differently, you can only handle one disaster at a time. If your fork is insanely stiff, and it's kind of skatey and unpredictable on small bumps, you need to shift your weight forward to deal with it and you need you rear end to be dialed, predictable, and low stress. If your rear end is extremely stiff, skatey, and sort of unpredictable on small bumps, you need to shift your weight rearward to control that near-disaster. You can't have a near-disaster on the front and the rear of your bike simultaneously and expect to ride it out.

My bet is that Gwin got on the Demo, had to bump up spring rates in the back so he could run the bike through big holes, and to compensate he had to make his fork softer. As a result, he raised his bars. That's my guess, but who knows? The only thing for sure is that, if you read all that, I look like a complete psycho right now.


The linear leverage rate thing isn't my bag, but Specialized has made it clear that they like it on the Demo and it's not going anywhere. The new S-Works Demo carries over a very similar, almost identical, leverage rate from the existing Demo's, so Specialized has committed to their linear spring rate for the forseeable future and that's what Gwin will be working with as long as he's on the Big Red S.

The real question is this: is that a bad thing? Is the difference between the Session and the Demo bad? The big overarching assumption surrounding any comparison of the Aaron Gwin Demo vs. the Aaron Gwin Session is that the Demo isn't working for him and the Session was, thus something was wrong and something needs to be fixed on the Demo.

I'm not sure that assumption is correct. Every internet armchair engineer looked at Gwins results on Trek vs. his results on Specialized and assumed the bike made Gwin slower, and suddenly in 2013 and '14 the broad internet concensus is that the Demo is "more of a park bike" (whatever that means), but most of those people wouldn't know their ass from a hole in the ground, led alone the subtleties of a winning bike setup. It's true that the Demo is different, and I for one don't agree with all of the design decisions, but they are just that: decisions representing the combined preferences and informed opinions of people seeking an acceptable compromise to multiple design challenges. There is no perfect downhill bike, and each downhill bike on the market takes a different angle on meeting the various and conflicting demands on such a bike.


I don't think it's a matter of Gwin putting a bandaid fix on a bad design, as much as Gwin adapting his setup to a different bike. Even in 2011 and 2012 when he was winning every race in sight, I don't pretend to believe that he was on a perfect bike. People assume that the Session was a perfect bike (look at the results, bro!), but I'm positive there were significant compromises made in the design and setup of Gwin's 2011 and 2012 Sessions, but the man is a single-minded freak of nature winning machine and he did what it took every day to make that poor Trek Session his bitch. I have no doubt he is doing the same thing right now with the Specialized people.

I think there are a lot of terrible, unrideable bike designs out there, and TEAM ROBOT is first to call those unrideable bikes out, but from what I've seen and heard I don't tend to think the Demo is one of them. While the Demo wouldn't be my first pick of downhill bikes due to the leverage rate, A) that's my personal preference speaking, and B) if I was winning or losing on a Demo 8, I hope I'd be smart enough to recognize that it's not the bike winning or losing those races.





Preach it