tire size recommendation for a 7/9 drop.

[fluffyfreak]

Like the title says, gonna do a 7/9 drop on my 86, I know thats extreme, but I like low trucks and dont wanna bag this one (yet ) and would like to run 20s on it with a 35 series tires, will those be too tall?

[bbbc10]

ur gona have a lot of problems wth that much drop

[fluffyfreak]

What kinda problems?

[bbbc10]

control arms n crossmember hitting the ground...I jus totaled my frame last year do to control arms getting caught on something an I wrecked my truck an that's jus wth 5" drop in front

[Ziegelsteinfaust]

At that point people either remove or modify there inner fenders for clearance.

Also like the guy above had problems. Your going to have to section your cross member, and Z your frame to keep hang ups down.

[lolife99]

How do you expect to do the 7" front supension drop?

[Burmanater]

My 5 inch front drop smacks the control arms and the crossmember is only about 3 inches above the ground. 2 more inches of drop puts your crossmember somewhere less than and 1 1/2 inches and your control arms would be on the ground or pretty close. Unless the rims and tires you want to run supply the clearance I just don't see this working as a static drop without serious modification.

[tinydb84]

2-3 inch Z with spindles and springs. Flip kit with shackles and hangers. Probably need 30 inch tires and lots of clearancing... I'd like to see the outcome. Probably look cool but at that point just bag it.

[VTX-Black]

I'm there and am currently bringing mine back up

Suspension hits speed bumps.

Wheels hit inner fenders

Exhaust hits ground

Lost drive shaft from the front at highways speed because the PO didn't account for a change in length with the drop
http://67-72chevytrucks.com/vboard/s...d.php?t=627343

[bbbc10]

what do you mean lost drive shaft an what length changed?

[VTX-Black]

I haven't measured the geometry to know for sure, and others with more experience than me can give you better advice, but our driveshaft yoke wasn't deep enough into the transmission and pulled out enough to jam at an angle and destroy the U joints at speed.

I was following when it happened and I never want to see the front of a driveshaft hit the ground again. It took out the headers for example. Could have been much worse.

It could have been the 700R4 transmission swap, or the extreme drop, or a bad calculation by the builder, but either way, check it to be safe. In a bit isn't enough.

if the axle rotates back enough to worry about pinion angle, you may also have to worry about driveshaft length

[Ziegelsteinfaust]

Usually when you drop a vehicle in the rear around 5-7 inches you need to remove about 3/4-1 inch of drive shaft length.

The above post sounds like someone got a little bit in a rush, and over cut the drive shaft. Or found one just barely long enough to work most of the time.

[bbbc10]

hmmm never heard any one having problems like this before with a driveshaft...hope you get it all fixed

[VTX-Black]

Last week the truck destroyed my driveway when it puked to its tranny fluid after sitting for a few week. I couldn't find the leak but the tranny shop replaced the rear seal and this is when we realized that it had a vented yoke (the likely source of the leak when parked uphill), and a repaired driveshaft that was still dangerously too short

My springs arrive this week and once they are in place I have an appointment with the driveshaft shop to confirm that everything is good to go. He is also an expert on setting pinion angles so it should be all sorted very soon.