Link Question

[chans]

I have some questions on a link setup I'm thinking about using on my CJ. Because of the exhaust and lower hanging aluminum oil pan I'm thinking of doing a front setup like the Clayton and RE kits.
http://claytonoffroad.com/product_info.php?products_id=285&osCsid=edb229e2cb1ce2fbe47251639b922e4f
I will probably get some TJ brackets and put them on my front axle with air shocks and a custom track bar. Is this setup decent on side hills with the Y at the end of the link or would it be better to try to run a 3 link and run the bottom links on the outside of the frame and the top link under the frame?
When looking at the Clayton kit it looks like the rear arms are already what I was planning on also since with the pass offset axle I'm running it would be hard to run a crossmember. So my last question is when I plug the rear link numbers into the calculator if I mount the bottom links on the bottom of the frame and the top links on the side it usually ends up with around 100 anti-squat. The only way to make it zero is the run perfectly flat upper and lower arms. Since I don't see many if none rigs with totally flat arms what is an acceptable anti-squat number? Thanks

 

[UNSTUCK]

That isn't a bad number for AS. That is neutral, which means you shouldn't get any bounce. If it will all fit, I say run it.

 

[reddman]

That isn't a bad number for AS. That is neutral, which means you shouldn't get any bounce. If it will all fit, I say run it.

100% AS is only "neutral" if you always have perfect traction and zero wheel travel. I would consider 0% to be more neutral (parallel links have 0% AS).

At exactly 100%, you are unloading your suspension by the exact amount of force as the weight transfer from acceleration loads it. In other words, the rear end won't squat or lift at all under acceleration as long as traction is maintained. Lose tracion and that goes out the window.

At 100% AS (or any number above 0% iirc) there is also a loss in torque available to the wheels, because some of the torque is transferred through the suspension, lifting the rear end, counteracting the weight transfer. Because some torque is being transferred through the suspension, if you lose traction, the unloading of the suspension will stop, and the rear will drop. Once it gets traction again it will partially unload again and that can create axle hop.

I'm not saying that 100% AS can't work ok in off road (it works awesome in drag racing), but I would certainly shoot for a lower # if your packaging allows it.

 

[RockMonkey]

(parallel links have 0% AS).

Only if the links are parallel to each other and parallel to the ground. That's almost never the case, even on rigs that are built to have very little anti-squat.

 

[chans]

So what anti-squat numbers do people usually find acceptable to eliminate any wheel hop? Would only 0 get rid of it all when a wheel slips? By lowering where the lower link connects to the frame it greatly lowers the AS but then it becomes a rock magnet the more it is dropped. So about the best I can get with the setup I'm thinking is around 86 on the AS if I can figure out how to raise the upper mount on the frame higher but most likely it will be in the 90s. Would that be better than a properly done SOA leaf setup with traction bar where wheel hop is concerned? Thanks for all the info. It is getting confussing trying to plan it out.

 

[reddman]

So what anti-squat numbers do people usually find acceptable to eliminate any wheel hop? Would only 0 get rid of it all when a wheel slips? By lowering where the lower link connects to the frame it greatly lowers the AS but then it becomes a rock magnet the more it is dropped. So about the best I can get with the setup I'm thinking is around 86 on the AS if I can figure out how to raise the upper mount on the frame higher but most likely it will be in the 90s. Would that be better than a properly done SOA leaf setup with traction bar where wheel hop is concerned? Thanks for all the info. It is getting confussing trying to plan it out.

Unfortunatley there is no magic number for it, it is a compromise. High AS will provide more "bite" at the moment of torque application, as long as you have traction. Low AS will "bite" less under forward driving torque, but it reacts more consistently in low traction situations.

IMO anything over 100% AS (for off-road use) needs to be reworked. But there are things that are at least as, if not more, important than AS, like packaging constraints, roll axis angle, roll center, wheel recesion, etc., so don't get too hung up on one piece of the puzzle (AS). Also keep in mind many of these numbers are calculated from numbers you guessed on, like COG height.

You would be very hard pressed to get AS numbers that good with a traction bar, plus their are other benefits to a linked suspension.

 

[chans]

Unfortunatley there is no magic number for it, it is a compromise. High AS will provide more "bite" at the moment of torque application, as long as you have traction. Low AS will "bite" less under forward driving torque, but it reacts more consistently in low traction situations.

IMO anything over 100% AS (for off-road use) needs to be reworked. But there are things that are at least as, if not more, important than AS, like packaging constraints, roll axis angle, roll center, wheel recesion, etc., so don't get too hung up on one piece of the puzzle (AS). Also keep in mind many of these numbers are calculated from numbers you guessed on, like COG height.

You would be very hard pressed to get AS numbers that good with a traction bar, plus their are other benefits to a linked suspension.

Thanks for all the info. It looked like the other numbers were going to be good like roll axis angle was at 0 and I was mainly unsure about the AS but I don't have any exact measurements yet for the kit. I guess the thing to do now is start buying all the parts when I can and jump into it in 6 months to a year.

 

[reddman]

Thanks for all the info. It looked like the other numbers were going to be good like roll axis angle was at 0 and I was mainly unsure about the AS but I don't have any exact measurements yet for the kit. I guess the thing to do now is start buying all the parts when I can and jump into it in 6 months to a year.

Nice, you should update this thread with your final numbers and your impression on how they work when you do it.