Hi, I was wondering what makes IFS inferior to a solid axle for offroad purposes? What limits the amount of flex out of ifs setups?

 

This picture is a great example. A SA, like the one in the rear, will keep the tires in contact with the ground. IFS, like the front, wont travel that far. More wheels on the ground means more traction.

 

Each side is independent of each other, thus when one side makes contact with the ground, the other can end up just hanging there instead of flexing like a solid axle would. That picture shows it perfectly how it happens. Also IFS parts are generally weaker then a straight axle and is unable to take the combination of larger tires, power, and a locker. I would never want to run IFS in a serious offroad vehicle because It just isn't able to hold up as well, also lift kits end up dropping the whole sub assembly and are a poor choice. The upside to IFS is that it has higher ground clearence then a soild axle would, and the on ride performance is much better.

 

IFS says what?

 

ifs is really limited because the cv drive shafts arent made to run at really bad angles so each wheel only has so much travel the only way to gain more travel/articulation with ifs is to go wider so the cv shaft is longer and can run at a better angle hence why all ifs 4wd prerunner guys are super wide in the front

 

It's just the travel and strength like every one else is saying...however....you can build an ifs up to do decently well. It just requires alot of money. It much more expensive to upgrade control arms and cv shaft etc...if you look at Total Chaos kits you'll see some nice travel, and some premium priced kits...I think hey are the leader in the bolt on ifs upgrade world, but are designed for go fast trucks..

 

Just wondering.. What are the thoughts on the military hummer? Since that has IFS all around.

 

Well the hummer is being replaced because it is a death trap. check out the asv1117 by textron.

 

yeah the hummer sucks ....but that turbo deisel will get up an go

 

the 6.2 diesel can't even get out of its own way. but it can carry some load. the ifs on the hmmwv does quite well actually. i've never gone rock climbing with a hmmwv, but it's wide enough to not flip under extreme angles. i drove one over 2 ft of snow with no problems.

 

I wouldnt say it sucks, its just not ideal for rock crawling!

How many straight axle rigs have won the baja 1000 or the dakar rally?

For off road racing it has serious advantages over straight axles.

XJTIM is correct it costs a fortune to beef one up, just look how expension a liftkif for a tacoma runs!

 

i guess for the heavyass up armoure 85 is fast lol

 

I've seen them on the trail...not a lot of travel at all...that said, they do have portal type cv shafts, gear reduction at the wheels which give them great crawling abilities and huge clearances underneath. for how wide they are and how the lockers work, it makes up for some of the lack of travel, but not all. It's scary seeing something with that much "girth" going through rock gardens though lol.

 

Yeah, saw a H1 hung up on a rock in Moab, broke axle shafts getting off, out of commission until new shaft got there.

As for why the IFS isn't as good as a solid axle on trails, it is because the IFS diff bolts to the frame so the shaft droop is between the bolted up diff and the hub and very short distance. As for not being able to run at high angles the CV axles do pretty good. Check out these axles: http://www.rcvperformance.com/store/catalog/index.php

The solid axles advantage comes from the way the axle is floating on the suspension and when a tire drops in a hole the whole axle from hub to hub is angled down into the hole. Longer distance = less of an angle.

 

IFS doesn't suck its like anything people like to bash things they've never wheeled or used a rig with it. its all in set up.

First up YJ on 31s soild axles front and rear no sway bar disconnects.

as you can see very little flex and the axle not drooping out.

next up long arm XJ around 8 inches of lift


and finally a 06 nissan frontier 3inch of lift no sway bar