Isuzu SUV Forum banner

bird dog whels

5K views 3 replies 2 participants last post by  paulevans76 
#1 ·
interco has some "birddog wheels" that hold a bead at low psi...

they are a 9" wheel.

now, in a search here, i read a post by an admin in 2008 stated that both the 7" and 7.5" neutral. he went on to state the backspace of the 7.5" was 3.75 inches.

im not sure if that info is prima facie here, but that would be incorrect. theres something wrong with the statement. either the BS is greater or theres a negative offset to isuzu wheels.
RIM WIDTH is inside bead to inside bead.
BACKSPACE is is the physical back of the rim, to the mounting surface.
OFFSET is the wheel center line to the mounting surface.

backspace measuerment has an accepted nominal .5 inch per side when calculating using the rim width center line. sooooo.. a neutral 7.5W wheel ought to have a backspace there'a'bouts of 4.25 inches (3.75+.5). the 7" wheel ought to be within a pinch of 4". if you want exact you need to field measure.

now... heading to the question im brewing up..

the patient is a gen one RS.

the birdgog wheels come in a backspace of 3.5" and 4.5". the goal is a 33x12.5x15.

assuming the rims truly are neutral, clearly the 3.5 inch backspace will stick out too damn far even with fender flairs, and likely wear out hub bearings too quickly.
the 4.5 inch backspace sets the rim .25"'s more inboard than the 7.5w snowflakes, which doesnt seem like a whole lot, but i dont know where the threshold for interference is. it seems any possibility of running these rims would be with the greater backspace product.

so, assuming theres no negative offset to isuzu rims, i guess im looking for input from 7.5" snowflake owners (or comparable aftermarket) with the wider 33"s as to whether or not im within interference limits utilizing a 2-3" spring lift and a 1" body lift. maybe 2" and 2" is better.

on the other hand, if there is negative offset on the stock rims im currently unaware of, i guess that limits me to the 3.5" backspace, which i doubt i'd like.

its a rather specific question, that i may not get a direct answer to, so any opinions are welcome.
 
See less See more
#2 ·
I think you are overstating the wear effects of an extra inch of backspacing. Pretty sure thousands of people have run the standard 15x8 3.75" BS steel wheels on their junk without toasting wheel bearings or balljoints or what have you. A little extra either way won't hurt much.

As for fitting and hitting with a 12.5" wide tire, more backspacing might reduce your scrub radius, but you will likely run into an issue of rubbing the frame or sway bar. Less backspacing and you might need to tap on the firewall a bit with the BFH, or clearance the fenders in a few spots...maybe.

If I were going to run 33's on a first gen I'd go with about 2" suspension lift (just enough to make a balljoint flip in the front necessary) and 1.5" body lift at the most. Enough to raise the gas tank a little but doesn't look as bad as a bigger body lift. I'd personally try to get all the parts to swap in the wide track suspension bits from a 2nd gen, so you'd get more travel out of the front, as well as swap to the wider rear 12 bolt, but that's just me. I was never one to shy away from the tires sticking out past the fenders, since wider = more stable. In my opinion, you should try to go at least 1" wider on each side for every inch you lift it, to maintain the "triangle of stability" as I think of it.

Anyway, those are my opinions, cost nothing and worth as much ;)
 
#4 ·
zimm said:
i dont see me doing that much effort for the wide track, but is there a thread for the conversion?
I haven't actually seen one for someone who did a 1st gen, but I think there are a few dudes who have done it and a few that are attempting it. I think I read geoffinbc might be trying it? I there was an Aussie guy on facebook who I think did it with a 1st gen rodeo/pickup.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top