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Yet another physics (I guess) question

freeridekid

Monkey
Oct 18, 2003
789
0
U-District, WA
I've been riding my diamondback xts moto the whole time i've had it in the rear shock mount, which my dad recently told me was probably the shorter travel setting. i just switched it to the forward (or closer) position and i'm just making sure i'm right in thinking it's the longer travel position.

here's the bike: http://www.diamondback.com/items.asp?deptid=1&itemid=116&va=0

right now the shock looks just like it does in the pic
 

Booker

Monkey
Feb 5, 2003
233
0
Louisville, KY
freeridekid said:
i just switched it to the forward (or closer) position and i'm just making sure i'm right in thinking it's the longer travel position.
Just yesterday I had a monkey tell me the same thing regarding my Ironhorse SGS. I felt like a retard. Here i have been racing and riding all in my short travel position and the bike has felt awesome. I switched it over to the long travel mounting hole last night and did a quick spin around the yard. FACKIN' AMAZING!! It felt even better. I just wish i would have figured this out a few months ago.

For some reason i thought "closer mounting hole = shorter stroke"
What i didn't consider is the arc path the linkage makes. The hole toward the rear/top has to move further to get the same ammount of travel as the bottom/foward hole and the shock has a limited ammount of stroke. I ended up mapping it out in AutoCAD. It made my brain hurt.
 

Booker

Monkey
Feb 5, 2003
233
0
Louisville, KY
Kornphlake said:
You guys are lucky you just found a brand new bike for free :thumb:
Yeah. The coolest part is i loved the bike befor. :drool: It just ripped through anything. Last weekend i was at Snowshoe commenting on how fast the bike felt through rockgardens ect. I can hardly wait to get back out there with full travel.
 

RhinofromWA

Brevity R Us
Aug 16, 2001
4,622
0
Lynnwood, WA
LOL AutoCad. :D

I never have used it but it shouldn't take Autocad to figure out which one gives more travel...if you were looking for how much more travel etc but not to see which gives you more.

Tie a peice of string around say a pencil, and the other on a pen cap or something.

With the eraser end on the table and the rest off the table and hte string hanging down, lift the pencils sharpened end as much as you desire with the string near the sharpened end and also near the eraser.

What happens? When the string is close to the sharpened end it pulls more string than when it is tied near the eraser. Apply this to the bike. The linkages main pivot (on the DB main frame) is the eraser end The seat stay end is the same as the sharpened end of the pencil. Puting the shock in the rearward (sharpened) spot would require more shaft travel for the same wheel travel or net you less travel with the same shock. Mount it near the eraser end and you will get more travel (It requires less string for same distance of travel leaving extra for more travel)

Of course when moving them you change the leverage ratio and probably made you bike feal "softer" because you effectively lightened the damping rates and spring rate with the new ratio. :D

See simple.
 

Booker

Monkey
Feb 5, 2003
233
0
Louisville, KY
RhinofromWA said:
LOL AutoCad. :D....................

Tie a peice of string around say a pencil, and the other on a pen cap or something.
.............................. See simple.
Hahahaha. Basically I just drew the pencil and pen cap in AutoCAD and did the same test. I got confused and broke the pencil....... :think: :p
 

freeridekid

Monkey
Oct 18, 2003
789
0
U-District, WA
RhinofromWA said:
LOL AutoCad. :D


Of course when moving them you change the leverage ratio and probably made you bike feal "softer" because you effectively lightened the damping rates and spring rate with the new ratio. :D

See simple.
yeah, i stiffened it up a bit and then went out riding and i definitely felt a difference. it felt fine before but now it feels great. of course some of its just in my mind i'm sure. now i have an excuse for always getting near last at the WIMs (not really)