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Old 03-21-2007, 01:42 PM   #1
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2006+ Big Hit with 8.5" i2i shock

It seems the new Big Hit is getting more and more popular on this forum so I thought I would share a tip. Your Big Hit comes with an 8.75" i2i length shock (either a Vanilla R if your cheap or a DHX 4.0 if you get the Big Hit III), with 2.75" of stroke getting about 8.2" of travel. This is great, and for most people this setup works perfectly. With an average 8" travel fork you can achieve 66-67 degree head angles with around a 14" BB. These are pretty competitive numbers and can be great, especially in tight and slower trails. However, for the rest of us who will gladly sacrifice a little slow speed handling for increased tracking, traction, and better weight distribution at speed...there is an answer.

By swapping to an 8.5" i2i shock with 2.5" of stroke, you are only sacrificing a half inch of travel yet you are lowering your bottom bracket to 13.25" and slackening the head angle to 64 degrees. This smaller shock also enables you to drop your fork even farther in the crowds while still achieving sub 66 degree head angles. Your new lower bottom bracket will corner with much more confidence and allow you to potentially carry significantly more speed. A lower front end will increase your stability and better your weight distribution on the bike. The slack head angle will especially help stability during high speeds and rough sections, as the trajectory of the compression of the fork is now even more parallel with the ground and with the direction that the hits are presented.

A lot of people don't realize that swapping i2i lengths can be done on many different bikes to achieve geometry results normally out of spec. For instance, I would never be able to lower the crowns on my Boxxer as much with an 8.75" shock in the rear because I would then have too steep of a head angle. But if I raise my Boxxer in the crowns to achieve the head angle that I desire...then my front end is too high and more flexible and not as direct...hence the switch to the shorter stroke shock. You can always use the other mounting hole in the swinglink which will give you stock angles.

Just thought I would share. I originally rode an 8.5" with my Big Hit, then tried the 8.75" for the last 6 months, and now I am back to the 8.5" and I sure am happy I swapped back. While I had adapted my riding style to fit the steeper angles...I feel 10x more at home with the slacker angles I have now. You can really drift into a corner with significantly more confidence. Just watch those pedals through the rough sections.


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Old 03-21-2007, 04:09 PM   #2
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Do shocks naturally compress a tiny bit at resting position? Because otherwise the 8.5 i2i shock I put on my Stinky might be a 7.875 instead (I didn't measure it before installing it because I am a trusting soul, but when I take the tape to it now, it keeps coming up around 8"). And if it is a slightly smaller shock, is this necessarily a bad thing, or is it completely functional (per your BH) and just a slightly geometry-altering adjustment?
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Old 03-21-2007, 04:53 PM   #3
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Quote:
Originally Posted by secret william
Do shocks naturally compress a tiny bit at resting position? Because otherwise the 8.5 i2i shock I put on my Stinky might be a 7.875 instead (I didn't measure it before installing it because I am a trusting soul, but when I take the tape to it now, it keeps coming up around 8"). And if it is a slightly smaller shock, is this necessarily a bad thing, or is it completely functional (per your BH) and just a slightly geometry-altering adjustment?
I would never go beyond a 1/4 inch longer or shorter i2i from the stock. At that point you need a different bike. An 8.5" i2i shock is exactly 8.5" from the center of one eyelet to the center of the other eyelet. Anything smaller...is not an 8.5" shock. 8.5" shock should have 2.5" of stroke. A 7.875" shock will have 2.25" of stroke.

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Old 03-23-2007, 07:27 PM   #4
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by shortening the shock to 8.5 i2i, you actually forfiet .8". its because a quarter inch of shock stroke doesn't translate to a quarter inch of wheel travel. if that where true, then if you had a 2.5" stroke shock, youd have 2.5" of travel on your bike. thats obviously not true.

to find the new travel, you have to set up a porportion:

8.2 inches of travel/2.75 inches of stroke = X (the new travel) / 2.5 inches of stroke.

cross multiply, and get 20.5 = 2.75X, divide both sides by 2.75, and get 7.45 inches of wheel travel.

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Old 03-23-2007, 07:42 PM   #5
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Quote:
Originally Posted by bootsie
by shortening the shock to 8.5 i2i, you actually forfiet .8". its because a quarter inch of shock stroke doesn't translate to a quarter inch of wheel travel. if that where true, then if you had a 2.5" stroke shock, youd have 2.5" of travel on your bike. thats obviously not true.

to find the new travel, you have to set up a porportion:

8.2 inches of travel/2.75 inches of stroke = X (the new travel) / 2.5 inches of stroke.

cross multiply, and get 20.5 = 2.75X, divide both sides by 2.75, and get 7.45 inches of wheel travel.
no one ever said a quarter inch lost in stroke equals a quarter inch lost in travel. I think everyone is aware that stroke does not equal travel. 8.25" of travel to 2.75" of travel is a 3:1 ratio, so a 2.5" shock in the same eyelet holes will approx get 7.5" of travel. 0.75" difference in travel between the 2 shocks. I simplify and say it is about a half inch because it barely feels like you have lost any travel and because when you sit there and measure it on the frame to see the difference, it tends to give you a little more then on paper. You dont really get a full 8.25 in my opinion and you get a little more then 7.5 with the new shock. Do it without the spring on the bike and make the measurements.

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