37"s vs 40"s HELP!!!!!!!!!

[cjrenne777]

I have been trying to deciede lately what I want to do for my suspension on my 09 6.4. I am currently running an 8'' fabtech radius arm kit with basic fabtech shocks and an add a leaf. I am not overly happy with the ride and have been talking to Trevor Hall at PMF. The guys is awesome, probably one of the most knowledgeable Suspension people in the entire Industy. Needless to say, all my future suspension will be PMF as well as my future vehichles.

We are debating where to leave it at 8", 4 link it and run coilovers with his traction block system in the rear and stay on 37" tires

or

do a 12" 4 link kit with coilovers, traction block system and 3.5 in drop shackles for the leafs in the rear and be on 22s and 40s.


To anyone who would know, what will the step up from 37 to 40 be like?
will it be that drastic of a difference?
I do not really care about how fast it is anymore, after 2 trannys, I have proved my point.
Right now I can cruise at 65-70 mph and be at 1650-1700 rpm with my current 3:73 gear ratio.

Just let me know how drastic of a change it will be

[CDUBYA]

You will love it! I had a white 08 with an 8" similar to the one you have, maybe not a good quality. But then i just sold that one and now have a truck that trevor built, with the exact setup you are looking at, 12" with coilovers and his traction block with 3.5" shackle in the back. 40's and 22's. i drove it home from phoenix and it was awesome to drive, the ride was a hell of a lot better then my 8".

I may end up just lowering it to a 10" because the cops around here are crazy strict and this truck is huge and draws a lot of attention. but if i can i will leave it at 12 cause it looks so mean!

Anything i can do to help let me know. I hope this info helps.

CW

[cjrenne777]

Yeah I am pretty familiar with Brians truck man, how did it do for mileage on the way home? I am asking to see how bad 40s will hurt my mileage. also can I see some pics? Brian or Trevor never really uploaded any of it, just a few.

[will175]

I had 40s on my last 07 Harley...Its more of the added weight if anything. Its quite a bit more tire thats why. I plan to run 40s again. It would look a little off with the 12" on 37s, but that is just my opinion. Just curious how did you remove the flames? Did you repaint? I have the one with the small orange strip on the top. Want to take that crap off, oh and I apologize that a lil off topic.

[no_pistons7]

my buddie had 37s then went to 40's and his milage went down noticably and it was alot more sluggish he said, thats on a 05.

[cjrenne777]

Originally Posted by will175

I had 40s on my last 07 Harley...Its more of the added weight if anything. Its quite a bit more tire thats why. I plan to run 40s again. It would look a little off with the 12" on 37s, but that is just my opinion. Just curious how did you remove the flames? Did you repaint? I have the one with the small orange strip on the top. Want to take that crap off, oh and I apologize that a lil off topic.

I wouldnt run 37s on a 12" I am debating to go upto 12 on 40s or stay at 8 on 37s. Most likely will sacrafice my mileage a little and go for 40s. the flames were just graphics, they were not painted on mine. they were the blue flames right under the windows. I specifically ordered this truck without the painted flames haha

[will175]

Oh shoot my bad didnt read it clearly, Sorry senior moment. And I guess it will all depend if you go higher or not. :-) Go big or go home...hahaha.

[CDUBYA]

I got 15 MPG hand calc'd on the way home, not to bad i dont think.
From my 37's to these 40's i didnt notice much of a difference but my 37's were on 24'' rims. these are on 22's.
I guess you saw those other pics huh, let me know if you wanna see more. This truck is a lot higher in person than those pics show btw. In Utah this is a high truck so people look at you funny wherever you go.

[kennybtyson]

I have the 22's and 40's with a 12" rize lift. I think if your worried about the mileage a little gearing can go a long way. I made a 300 mile trip pulling a 24' enclosed trialer with stock gearing and had a 1/4 tank left. City mileage really sucks. You can notice power loss but again gearing. Be careful if you go to 40's because it's hard to go down. I think about every now and then. Then I go look at the truck then it's a no brainer. KEEP THE 40'S.