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Shock compression - PB bottom-out slow mo vids

slyfink

Turbo Monkey
Sep 16, 2008
7,716
3,422
Ottawa, Canada
I looked for a thread to put this in, but couldn't find a good place for it...

anyone see the bottom-out videos over on PB?

I find it interesting that on most full-sus bikes, the shock seems to bottom out in a two step process. It seems to compress initially by 80-90%, and then goes on to full compression. I wonder if that has something to do with the shock tunes, or whether it's simply that bike and body hit the ground first, and then ass comes down as heels drop for the final compression... I also wonder if that has any real-world impacts.
 

HardtailHack

used an iron once
Jan 20, 2009
3,546
1,253
Is the clutch dead on the Trance near the end? It looked to behave worse than the one on the hardtail.

What sort of crank was the one that snapped?
EDIT- Praxis it would seem-
1641510918904.png

 
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Kanye West

220# bag of hacktastic
Aug 31, 2006
3,606
348
Initial compression is from the sprung mass of the bike and the lower legs of the rider coming down with a lot of energy, then there's the settling of the upper leg and upper body mass joining the rest of the bike.

The human body moves at one frequency. The bike moves at another.
 

Bikael Molton

goofy for life
Jun 9, 2003
3,725
853
El Lay
Haaaaa that photo is gold!


Is the clutch dead on the Trance near the end? It looked to behave worse than the one on the hardtail.

What sort of crank was the one that snapped?
EDIT- Praxis it would seem-
View attachment 169999
 

ChrisRobin

Turbo Monkey
Jan 30, 2002
3,247
130
Vancouver
If you focus on the bar ends when buddy bottoms out, you can see them move around a lot relative to the stem. Goddam.
 

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,606
348
You'll notice the 35mm bars on the Spire didn't budge at all around the 2:15 mark....

If you want to see the bars flex in person, turn the front wheel 90 degrees and press up and down towards the top tube. Noticeable and measurable difference in that gap.
 

slimshady

¡Mira, una ardilla!
You'll notice the 35mm bars on the Spire didn't budge at all around the 2:15 mark....

If you want to see the bars flex in person, turn the front wheel 90 degrees and press up and down towards the top tube. Noticeable and measurable difference in that gap.
I told this story before, but 4 years ago I was beta testing a 35mm bar for a local brand. I went back and forth between it and my standard issue 31.8mm Race Face Atlas, which I had previously considered a stiff bar.

I drew a couple of quick conclusions after several 4 feet drops:

- I decided to stay with the 35mm bar and don't look back. The Atlas flapped like a drunken bat in comparison.
- The compliance I previously attributed to my fork came actually from the handlebar.
 

slyfink

Turbo Monkey
Sep 16, 2008
7,716
3,422
Ottawa, Canada
Speaking of flexy bars... (this is my own thread, I feel entitled to derail it!)... I opted to try and run a 35mm aluminum Chromag bar after witnessing my buddy crack a carbon bar on a flow trail last year... (granted it was a. either a knock-off or factory reject, and b. at least 15 years old. yes my buddy was a dumbass for even running it)

But the aluminum bar is waaaay too stiff. So I'm thinking of giving a OneUp bar a try. Anyone have experience with those?
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
10,074
6,863
The OneUp is supposed to be more compliant, not tried it myself but it's likely what I'd go for.

The alloy 35 Kona bars I had on a bike were like a scaffolding pole, the carbon e13 I got last year on a different bike are only slightly better.
 

slyfink

Turbo Monkey
Sep 16, 2008
7,716
3,422
Ottawa, Canada
The OneUp is supposed to be more compliant, not tried it myself but it's likely what I'd go for.

The alloy 35 Kona bars I had on a bike were like a scaffolding pole, the carbon e13 I got last year on a different bike are only slightly better.
yeah, that's why I'm thinking of getting them. Looking for a bit more comfort on the wrists, but hoping to not be taking my life into my hands with a carbon bar....
 

mykel

closer to Periwinkle
Apr 19, 2013
3,591
2,241
sw ontario canada
Interesting.
I love my Syntace vector carbon bar in 31.8, so I would be interested in how the 35mm version compares. Other than that the One-Up would be top of the list.
 

HardtailHack

used an iron once
Jan 20, 2009
3,546
1,253
I told this story before, but 4 years ago I was beta testing a 35mm bar for a local brand. I went back and forth between it and my standard issue 31.8mm Race Face Atlas, which I had previously considered a stiff bar.

I drew a couple of quick conclusions after several 4 feet drops:

- I decided to stay with the 35mm bar and don't look back. The Atlas flapped like a drunken bat in comparison.
- The compliance I previously attributed to my fork came actually from the handlebar.
My 35mm Tune carbon bar was pretty damn flexy but that was part of the reason I bought it.
More sweep and flex didn't help my hand or shoulder at all so I went to a straighter stiffer carbon bar and I prefer it a heap.
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
10,074
6,863
Interesting.
I love my Syntace vector carbon bar in 31.8, so I would be interested in how the 35mm version compares. Other than that the One-Up would be top of the list.
I had those on my trail bike for the last 4ish+ years, now moved over on to the fatty.