step notch sizing questions

[nhtc33d]

I am ready to start the rear of my frame. I want to do a step notch with a little "growing room". I need to be able to lay frame with the rims/tires I have now(225/75/15). So how do you come up with the step notch size? Thanks for any help you can offer!

[lowrollin70gmc]

1. Level your pickup, mine had to be raised in the front to compensate for rake.

2. Measure between axle top and bottom of frame.

3. Measure frame under cab to ground.

4. Take (3)-(2) and that's your current notch size.

5a. If you want to have growing room, figure out your tire diameter (tape measure). The calculator shows yours at 28.287" now, so it should be near that.

5b. Find what size tire you want to run and calculate that diameter. Take this - (5a) and that's how much taller your new tire is than the old.

I don't see going with more than a 31" tire on the rear for a truck layin' frame, so just add 1.5" to your answer in #4 and you should have room to expand. A 31" tire is 4.5" of sidewall on a 22" rim, which is plenty.

[nhtc33d]

Originally Posted by lowrollin70gmc

1. Level your pickup, mine had to be raised in the front to compensate for rake.

2. Measure between axle top and bottom of frame.

3. Measure frame under cab to ground.

4. Take (3)-(2) and that's your current notch size.

5a. If you want to have growing room, figure out your tire diameter (tape measure). The calculator shows yours at 28.287" now, so it should be near that.

5b. Find what size tire you want to run and calculate that diameter. Take this - (5a) and that's how much taller your new tire is than the old.

I don't see going with more than a 31" tire on the rear for a truck layin' frame, so just add 1.5" to your answer in #4 and you should have room to expand. A 31" tire is 4.5" of sidewall on a 22" rim, which is plenty.

In your step #2 my measurement is zero(0)! I already removed my springs!!!

[nhtc33d]

Originally Posted by lowrollin70gmc

1. Level your pickup, mine had to be raised in the front to compensate for rake.

2. Measure between axle top and bottom of frame.

3. Measure frame under cab to ground.

4. Take (3)-(2) and that's your current notch size.

5a. If you want to have growing room, figure out your tire diameter (tape measure). The calculator shows yours at 28.287" now, so it should be near that.

5b. Find what size tire you want to run and calculate that diameter. Take this - (5a) and that's how much taller your new tire is than the old.

I don't see going with more than a 31" tire on the rear for a truck layin' frame, so just add 1.5" to your answer in #4 and you should have room to expand. A 31" tire is 4.5" of sidewall on a 22" rim, which is plenty.

In your step #2 my measurement is zero(0)! I already removed my springs!!!
I guess I got ahead of myself! So will i need to put the springs back in or can i take the measurement to the bottom of the frame under the cab and add the diameter of the axle tube would that give me the proper notch size?

[bedsled71]

just measure from the ground to the top of your axle. thats how much of a notch you need to lay the truck out

[bedsled71]

i could be wrong but i really dont think so

[gringoloco]

Quick/easy. Take the distance from the ground to the top of your axle. Subtract 6"(difference between under cab and under bed). This is how much notch you need. Add 1" for future growth...

[nhtc33d]

Originally Posted by gringoloco

Quick/easy. Take the distance from the ground to the top of your axle. Subtract 6"(difference between under cab and under bed). This is how much notch you need. Add 1" for future growth...

AHHHH.... Quick and easy.. two of my favorite words!! I will give this a try, Thanks

[gringoloco]

Forgot to mention: This assumes a 67-72 frame. Others I cannot speak for...

[tds]

Guess I need to get to work with the tape measure. I'm gonna try and notch for a 24 and would rather have it to big then too small.

[XXL]

Originally Posted by tds

I'm gonna try and notch for a 24

This doesn't really mean anything since your wheel will also have a tire on it. You need to be concerned with how tall your tire is.

[nhtc33d]

My frame is now sitting on the axle because i removed my springs. The measurement from the floor to the bottom of the frame under the cab is 8.5". So would mean my step notch needs to be at the minimum 8.5" to get the frame to lay? on another note, does anyone know What size is the KP notch is? I emailed them 2 weeks ago about some tech questions and never got a response. Thanks for the help!

[jlaird]

Originally Posted by nhtc33d

My frame is now sitting on the axle because i removed my springs. The measurement from the floor to the bottom of the frame under the cab is 8.5". So would mean my step notch needs to be at the minimum 8.5" to get the frame to lay? on another note, does anyone know What size is the KP notch is? I emailed them 2 weeks ago about some tech questions and never got a response. Thanks for the help!

before you go making a big notch, make sure you are prepared to tackle the front to make it lay. The rear is easy, the front is a little more involved.

[tds]

Originally Posted by XXL

This doesn't really mean anything since your wheel will also have a tire on it. You need to be concerned with how tall your tire is.

sorry i will clarify. i will not be running a 275/25/24 nor a 37/13.5R24. i will be trying to run a 305/35/24 which is 32.4" tall. i will be setting my notch to lay out on that and will see where it goes from there. i may have to go down to a 22 or a smaller 24" tire thou. also need to figure my bumpstop height

[nhtc33d]

Originally Posted by jlaird

before you go making a big notch, make sure you are prepared to tackle the front to make it lay. The rear is easy, the front is a little more involved.

I Z'd the front 4" and got 2.5" drop spindles. from what I have read I think this will be enough to lay the frame(Fingers crossed!!). I am really antsy in the pantsy to get started on the rear step notch!!
Heres a link to my build.
http://67-72chevytrucks.com/vboard/s...d.php?t=285353

[tds]

on a side note. i went a took some quick measurements. i could bag to a 32.5" tall tire in the rear, but i couldn't body drop it at all. so looks like i'm back to 22" tire in the rear so i wouldn't have to buy different rims when i body dropped.

[gringoloco]

Originally Posted by nhtc33d

My frame is now sitting on the axle because i removed my springs. The measurement from the floor to the bottom of the frame under the cab is 8.5". So would mean my step notch needs to be at the minimum 8.5" to get the frame to lay? on another note, does anyone know What size is the KP notch is? I emailed them 2 weeks ago about some tech questions and never got a response. Thanks for the help!

Yes. At minimum- 8.5" notch. Probably more like a 10" depending on tire size... The KP is standard eight, but they will stretch it to fit your needs up to ten.

Originally Posted by tds

sorry i will clarify. i will not be running a 275/25/24 nor a 37/13.5R24. i will be trying to run a 305/35/24 which is 32.4" tall. i will be setting my notch to lay out on that and will see where it goes from there. i may have to go down to a 22 or a smaller 24" tire thou. also need to figure my bumpstop height

My calculations have you at like a 12" notch w/ that tire = HUGE...

[nhtc33d]

[QUOTE=gringoloco;2655105]Yes. At minimum- 8.5" notch. Probably more like a 10" depending on tire size... The KP is standard eight, but they will stretch it to fit your needs up to ten.

Thanks again for the help! Looks like it's time for me to start cutting!

[tds]

Originally Posted by gringoloco

Yes. At minimum- 8.5" notch. Probably more like a 10" depending on tire size... The KP is standard eight, but they will stretch it to fit your needs up to ten.

My calculations have you at like a 12" notch w/ that tire = HUGE...

Yea I might just go with some 265/35/22s and just be done with it so I have some growing room. Any idea on that size notch. The tire should be just under 28 inches.

[gringoloco]

Originally Posted by tds

Yea I might just go with some 265/35/22s and just be done with it so I have some growing room. Any idea on that size notch. The tire should be just under 28 inches.

With a 28" tire:

14.0": radius of tire
+1.5": radius of axle tube
-6.0": height difference of frame
9.5": notch internal height

[tds]

so i should be able to get away with kp over sized 10". ill have to call them up about there price

[XXL]

Originally Posted by tds

sorry i will clarify. i will not be running a 275/25/24 nor a 37/13.5R24. i will be trying to run a 305/35/24 which is 32.4" tall. i will be setting my notch to lay out on that and will see where it goes from there. i may have to go down to a 22 or a smaller 24" tire thou. also need to figure my bumpstop height

That is a LOT of tire! Good luck with that. On the back, if you have a fleetside, you can get it to fit with a LOT of work (stepside... forget it!), but on the front, you're looking at cutting PAST the fender tops to get that much tire in there. You'll have to do the hood/fender integrated approach (like what IFC did on the "Matt's truck" or like camaro__thunder did).

[lukejames]

this notch will lay frame on a 22 with a nice tire it will also do a 24 with a balogna skin tire

[lukejames]

this is that same truck with 22's and notch much roo to spare lol

[tds]

Originally Posted by XXL

That is a LOT of tire! Good luck with that. On the back, if you have a fleetside, you can get it to fit with a LOT of work (stepside... forget it!), but on the front, you're looking at cutting PAST the fender tops to get that much tire in there. You'll have to do the hood/fender integrated approach (like what IFC did on the "Matt's truck" or like camaro__thunder did).

I'm still gonna do a 12 inch custom notch I think. As for the front I would only do 22s. I would really like a 22/24 combo. Also I have a fleetside. my truck is getting quoted for bags this weekend.