Since the mental pic you now have in your head shows that the ends of the tie rod in front of the axle have to extend past the ball joint center line and well into the inside lip of most tolerably back spaced rims, what happens when you put the tie rod behind the axle?
What happens? Like to maintain the same Ackerman? If I'm not oversimplifying it, the tie rod would have to be
You can intersect the line in rear (edit: with a shorter tie rod). In front you can only get close, as the line runs through the wheel.
Nope, you can hit it perfectly in the front. That's why the steering arm is typically very close to the largest diameter of the rim relative to the knuckle. Look at a stock TJ sometime with factory rims.
Interesting. Ive never noticed there was enough offset of the steering rod end and the ball joint to actually be on the line. Ill look at my stock TJR tomorrow.
Slightly off topic but semi related, does the WJ swap screw up ackermann on the 94" wheelbase? Not wanting to do one again, just curious. Talking about running the tie rod on the intended lower arms, not trying to do that crap where they put it on the upper arm and use the RHD knuckle.
Not enough to matter. They did not change the knuckles for the 104" wheelbase TJ Unlimited and you can't tell.
Yeah wondered about that too. I knew they used the same knuckles and wasn't sure how much it really mattered or not. Good to know.
So what was the question behind the question there? I'm 95% sure you did not ask me that question to test my spatial visualization ability.
No, that was it. It has always just seemed very odd to me that the rear mount tie rod would work that way.
Meant to ask this the other day but forgot. So have you measured out what the TJ scrub radius actually is in stock form? Is it pretty much no scrub at all or a bit of positive scrub?
No idea since I don't build steering for a stock TJ set up since there are good options already out there.
I was actually going to look into this... But I couldn't find the steering axis of inclination spec, so I quit. I was curious about factory wheel and tire combo vs what I'm running and how it compared. As I read into scrub radius, it made me think it may be contributing to a bit of squirreliness I get under Max effort braking
Yeah I’m not sure either. I know that typically 3.75-4” BS on 35’s seems to be pretty highly recommended but I’m not sure if that keeps the scrub radius similar to stock or not. It might be close if you go in 0.5” BS increments per tire size I guess.
Ackermann is only a small part of it. Proper caster for the tire size and back spacing to put the extended kingpin axis line near the middle of the contact patch are also important.
I have not knowingly used them. You may have confused the OEM WJ ends with that style though. I don't and won't use them due to how they roll and how they promote bending the link under load because the force is not in line with the link.
