Shortening wheelbase - what issues

[RatLabGuy]

Have a '93 Toy Xt Cab that will hopefully become a new race vehicle.
The wheelbase is crazy long, 122". Belly drag city!
I'm debating shortening it by 12" or even 19" to about the same as SWB trucks.
I see the following steps needed:
- bed will come off.
- I'm thinking I'll cut off the front/rear leaf spring hangars and move them forward. May change to late 80s springs which are a little shorter.
- replace driveshaft; it has the double-cardan style now, will prob re-use the CV at the output end
- have to shim axle for now angle
- make/mount new bumpstops
- move upper shock mounts forward
- ??

What other problems arise from this that have to be dealt with?

One thing I see is that moving the front spring hangar forward on the frame puts it farther "downward" along the curved part, maybe even to where it is horizontal to the ground (like happns w/ the 63" chevies).
On one hand this will natively add some lift (good), but also change the operating angle of the leaf spring, so that instead of being mostly up/down and slightly forward at full flex, it'll be angle more rearward.
I guess some longer shackles would help deal with that?

Anything else?

 

[1stgenxxx]

I have an 89 x cab and my wheel base is 118 on 40s...
If you push your front axle foreward much... Then you're gonna have to move the rear axle forward a pretty good bit. You'll be getting pretty close to the back of the cab.

 

[RatLabGuy]

I have an 89 x cab and my wheel base is 118 on 40s...
If you push your front axle foreward much... Then you're gonna have to move the rear axle forward a pretty good bit. You'll be getting pretty close to the back of the cab.

Still IFS and likely to remain that way for awhile.
The front isn't moving. Unlikely to see > 35" tires.

Yeah its going to look kind of goofy. I'm thinking he back end will end up being all tube anyway.
And top/back of the cab may get cut off, we'll see how zealous we get when the wather warms up and the sawzall comes out ;-)

 

[John B.]

My truck is an '89 X-cab with the wheel base shortened 11 inches. I'm running 38's and think that is probably the max without hitting the cab or sliders at full flex.

I'm running 4 inch lift Allpro springs with Allpro 1.5 inch extended shackles in the rear. My front axle has been moved forward 1.5 inches so my wheel base is apporx 112.5 inches.

Everything seems to work great. I did away with the 2 piece driveshaft and am using schedule 40 with U joints at both ends. Starts getting some vibration at 50 + MPH.

 

[RatLabGuy]

Wow John thanks for the pics. That is almost exactly what I've been thinking for looks - even the cage.
I like the tube fenders on front too.

 

[yoder519]

those are some wicked tube fenders. jsut realized i believe ive talked to you before at callentee back in the summer. prob dont member i was in a black 95 yota black wheels.

sorry to thread jack!


so your keeping it IFS, which means you just movin the rear axle forward? or did i misread somethin

 

[RatLabGuy]

so your keeping it IFS, which means you just movin the rear axle forward? or did i misread somethin

yep thats pretty much it.

Looks like technically w/ 19" forward the tires (33") might just barely clear the cab but it'd be really close and surely look odd.
I'll probably do a round 12".

 

[John B.]

Wow John thanks for the pics. That is almost exactly what I've been thinking for looks - even the cage.
I like the tube fenders on front too.

Thanks for the compliments! I meant add that I was also concerned about the front of the rear spring being mounted on the flat of the frame and creating a wierd angle but it really is not as drastic as you would think.

Good luck with the build!

those are some wicked tube fenders. jsut realized i believe ive talked to you before at callentee back in the summer. prob dont member i was in a black 95 yota black wheels.

Thanks for the compliments also and I do remember talking to you either over the 4th or the Toy Run.




When my house sells I plan on cutting off the cage and fenders, the frame @ the motor mounts and behind the cab, then four linking and tappered front and rear, full hydro steering. Then redoing the exo in smaller tube DOM. Currently, all of the tube is seamed schedule .40.

 

[RatLabGuy]

Thanks for the compliments! I meant add that I was also concerned about the front of the rear spring being mounted on the flat of the frame and creating a wierd angle but it really is not as drastic as you would think.
Good luck with the build!

Yeah I measured it today, that front hangar is already close to the inflection point on the frame, it looks like the vertical change would only be about 2" or so. not as bad as i'd worried.

Did you run into any other oddities? What did you do for a driveshaft, just get one custom made or mod the existing one that is behind the CSB?
I figured I'd want to keep the back half of it, so I'd have the CV to put against the output flange to help deal with the new angle, them shim the rear diff upwards.
Man that 2-piece shaft is long, 65"!

 

[John B.]

Did you run into any other oddities? What did you do for a driveshaft, just get one custom made or mod the existing one that is behind the CSB?
I figured I'd want to keep the back half of it, so I'd have the CV to put against the output flange to help deal with the new angle, them shim the rear diff upwards.
Man that 2-piece shaft is long, 65"!

I wanted to simplify the rear driveshaft so we took away the carrier bearing and made it a one piece. Shortening the wheelbase 11" combined with my dual case set-up made it a manageable length. The shaft I'm running on the truck has standard U-joints at both ends and my spare has the CV @ the T-case. I can switch them out and tell absolutely no difference. Both shafts are home made of schedule .40 on lathe to check for trueness. These actually feel better than the first one (fubared @ Mt. City) I had made @ Fleet Pride.

The trickiest thing to figure out is what to do with the gas tank. I did want to spend the money on a cell and worry about finding a fuel that would work so my tank is turned side-ways and raised up just behind the cab. The diamond tread box looking thing is actually covering up my factory tank. You will notice in the pics my filler tube is now on the opposite side from factory. Moving fuel lines and building brackets for the tank where by far the most time consuming but still easier than the cell route I think.