3.0 vs. 3.5 secondary bypass?

[Psirus7]

Is there a significant improvement between running a 3.5 vs. 3.0 secondary bypass on a mid-travel kit? Looks like the price difference is significant for the 3.5/3x8” shocks with the extended rod-ends.

 

[letsgetthisdone]

What rear suspension is on the truck? If still leaf sprung, a 3.0/3.0 combo up front will be plenty. if you were link in the rear with big wheel travel, the extra damping of a 3.5 secondary could help the front "keep up" with the rear better.

 

[Psirus7]

3.5x18” w/ Bypass Rack in the back, sprung on Deaver +3s. Def nothing crazy like a linked rear.

 

[Nex]

 

[letsgetthisdone]

3.5x18” w/ Bypass Rack in the back, sprung on Deaver +3s. Def nothing crazy like a linked rear.

It's your money (extra ~$1200?), and the 3.5 front defintely won't hurt. But I don't wouldn't spend the extra cash on it with rear still being leaf sprung. You have probably 16-17" of wheel travel in the back. I'm guessing the mid travel kit is ~16-17" wheel travel. S0 the 3.0/3.0 in the front has way more shock than the single 3.5 rear. And I'm sure you have air bumps in back and will be adding them to the front with mid-travel kit.

 

[Peterb]

he should have over 18” rear travel with his 3.5s and the front mid travel probably applies more leverage to those front shocks mounted inboard so a 3.5 secondary probably makes sense

 

[Psirus7]

Yes, I have the SVC bump kit in the back. I was not planning on running a front bump kit (at least not initially).

 

[letsgetthisdone]

he should have over 18” rear travel with his 3.5s and the front mid travel probably applies more leverage to those front shocks mounted inboard so a 3.5 secondary probably makes sense

Leaf springs generally cycle less than the shock unless its a 64" leaf pack with the hangers relocated. Especially if you put an extended shackle on and don't relocate the rear hanger.

"Leverage" (what you mean is motion ratio) slows down the shaft speed. Doesn't mean the shock works harder. Just means the valving is different. The shock does have to generate more force, but it's also dealing with lower shaft speeds, so there's a trade off in heat generation.

The are of the stock 3.0 (really a 2.5" piston) and the 3.0 bypass is 12sq-in. The 3.5 in the back is an area of 9.62. So the 3.0/3.0 up front still has 25% more potential damping force than the 3.5 in the back. And then when you factor the stock 3.0 has valve on the port to reservoir to convert the shaft oil displacement to damping force, its more like about 30% more available damping up front.

It's OP's money, but I wouldn't spend the extra $1200.