cerial
Member
- Joined
- May 9, 2023
- Member Number
- 6429
- Messages
- 8
I am building a mid engine rwd pile mainly for the street. But I would like to play in the sand dunes with it also. Leaf sprung solid rear and what will be a triangulated solid front. After a lot of playing around I have good numbers for the street at high speeds which will also be good in the sand at high speeds. High/top speeds being 60(sand) to 80mph(street) here.
So go build it already right? Well one little fact that is not often discussed and may throw a wrench into the works. My track widths are different. Which I don't think is a issue until I start to look at how it could POSSIBLY effect roll steer, anti roll, and overall under steer.
Skip to the bottom if you don't want/need background info on my pile of a build.
So here are some fun numbers. My pile has a 81" wheelbase with a center of gravity at 26" with a weight bias is 60-65"% rear. This is designed to be fairly universal as far as what can be bolted to the rear 9" tire width and selection wise.
It is being built as a fairly unlimited deal with dang near (cheap) stock parts that are easily swapped or replaced when they do break. 5.3 LM7, 2wd SM465, full width 78 F150 9". Things are going to be pushed and will break. This is setup to basically grab a spare out of the barn and swap it in a afternoon instead of being down for months waiting on custom junk. If you been there (and I imagine most of you have) you totally understand.
My current front axle and tire width won't change much. I am running a 24 3/8" tall tire that is 8 3/4" wide with the outside of the tires being 63" wide overall for a 54.25 track width.
For the rear I am currently running a 26 3/4" tall tire that is 9.5" wide with the outside of the tires being 73" wide overall for a track width of 63.5.
Now this is the minimal rear tire width I plan on running. Where things get fun is what I plan on bolting up after changing the 3rd out for the proper gearing for the application as I am only using 2 of the sm465's 4 forward ratios(3rd/4th straight throw). I plan on running UP TO a 18.5" wide 31" ish tall pro street or UP TO 13" wide 33" tall paddle. I have 16" between the frame and the 78/ 79 F150 stock 9" wms. I should be able to keep most of that tire close to the frame with rim offset moving that rear track inward with wider tires.
So the build a pocket knife of possibility. But I still need to make dang sure the thing can take a turn at "street speeds" so I don't end up on my roof the first time testing things out. I do plan on driving it "like a truck" most of the time. But the goal here is to set it up to lessen the chance of oversteer or roll potential keeping it enjoyable to drive from 60 to 80mph.
All my Triangulated front numbers are good currently. But they don't take into account the track width differences. I imagine having a track with an 80 to 85% difference front and rear is going to affect things. Or it may not and I am overthinking it. Just get to cutting the frame and building already. Unless I am not overthinking it and I need to redo all my numbers again.
So go build it already right? Well one little fact that is not often discussed and may throw a wrench into the works. My track widths are different. Which I don't think is a issue until I start to look at how it could POSSIBLY effect roll steer, anti roll, and overall under steer.
Skip to the bottom if you don't want/need background info on my pile of a build.
So here are some fun numbers. My pile has a 81" wheelbase with a center of gravity at 26" with a weight bias is 60-65"% rear. This is designed to be fairly universal as far as what can be bolted to the rear 9" tire width and selection wise.
It is being built as a fairly unlimited deal with dang near (cheap) stock parts that are easily swapped or replaced when they do break. 5.3 LM7, 2wd SM465, full width 78 F150 9". Things are going to be pushed and will break. This is setup to basically grab a spare out of the barn and swap it in a afternoon instead of being down for months waiting on custom junk. If you been there (and I imagine most of you have) you totally understand.
My current front axle and tire width won't change much. I am running a 24 3/8" tall tire that is 8 3/4" wide with the outside of the tires being 63" wide overall for a 54.25 track width.
For the rear I am currently running a 26 3/4" tall tire that is 9.5" wide with the outside of the tires being 73" wide overall for a track width of 63.5.
Now this is the minimal rear tire width I plan on running. Where things get fun is what I plan on bolting up after changing the 3rd out for the proper gearing for the application as I am only using 2 of the sm465's 4 forward ratios(3rd/4th straight throw). I plan on running UP TO a 18.5" wide 31" ish tall pro street or UP TO 13" wide 33" tall paddle. I have 16" between the frame and the 78/ 79 F150 stock 9" wms. I should be able to keep most of that tire close to the frame with rim offset moving that rear track inward with wider tires.
So the build a pocket knife of possibility. But I still need to make dang sure the thing can take a turn at "street speeds" so I don't end up on my roof the first time testing things out. I do plan on driving it "like a truck" most of the time. But the goal here is to set it up to lessen the chance of oversteer or roll potential keeping it enjoyable to drive from 60 to 80mph.
All my Triangulated front numbers are good currently. But they don't take into account the track width differences. I imagine having a track with an 80 to 85% difference front and rear is going to affect things. Or it may not and I am overthinking it. Just get to cutting the frame and building already. Unless I am not overthinking it and I need to redo all my numbers again.
