front end understeer

duke boy · #1 (**permalink**) 12-01-2005, 12:18 PM

I put on the Hellwig and it made a big difference in keeping the truck from swaying from the rear, but now I notice that the truck understeers quite a bit. What can be done to correct this?

vfrkent · #2 (**permalink**) 12-01-2005, 12:50 PM

Are you sure its understeering more now? understeer refers to the front end wanting to push or the truck not wanting to turn, when you add roll resistance too the rear of the truck it will make it more prone to "oversteer" which is the back end wanting to come around on you.

If this is the case first I am assuming that your tires and the rest of the truck is in good running order, try running your front tires up in pressure relative to the back i.e. 36psi front 30psi in back.

Now remember this assumes your not carrying anything in the back, also if your tires are getting low on tread, the back end now with the sway bar on will make it want to oversteer easier.

If you can give more details about the truck and when your experiencing the event I can help you hone in on the problem.

I am running the Helwig bar on my truck and only notice more of a oversteer issue is when in mid corner I jump on the gas she want to come around.

Best regards, Kent

krodad · #3 (**permalink**) 12-01-2005, 01:08 PM

We got some snow and slick roads here last night, and all I've noticed on my truck with the hellwig is an ever so slight tendency to kick out a little if I get on the gas around a corner, but it also "recovers" easier from that than if it did not have the bar...I'm not sure why the recovery is easier, but I understand why the rear end can kick out just a little earlier. It is no big deal at all, just keep a light touch on the pedal around a slick corner. Never had it happen on simply wet or dry pavement.
I sure like the fact that for some reason, my stuff in the backseat stays where I put it now compared to driving without the sway bar. I did not believe that was really going to be the case, because the forces are still there...but the truck staying in a more level attitude tends to not "fling" my crap around.

duke boy · #4 (**permalink**) 12-01-2005, 01:38 PM

it is definitely an understeer issue. The only time I've had the truck oversteer is in the rain when I nailed the gas pulling out from a stop sign (I did it on purpose). Other than that, I've never lost the tail end, but in turns, the front tires squeel a little and the truck fights the turn and wants to go straight. The tires are almost new, so tread shouldn't be an issue. I think all my tires are at around 35 lbs or pressure.

vfrkent · #5 (**permalink**) 12-01-2005, 06:10 PM

One other thing to consider when you add the rear swaybar is, the roll stiffness has gone way up relative to the front, so now the front "feels"
like it is pushing more, the solution is to add the urathane front swaybar bushings it makes a dramatic difference in the front wanting to roll when turning.

You can get the bushings from a number of suppliers, I bought mine from Wheelers in Grantspass, they advertise here and are a great bunch of guy's.

The other thing to add at the same time is the steering rack bushings, there is a great amount of compression in them giving the effect that the Tundra has slow steering, by changing them it feels as if the steering ratio has been quickend, the truck is now a true pleasure to drive in the curves.

Best regards, Kent

duke boy · #6 (**permalink**) 12-02-2005, 07:48 AM

Quote:

Originally Posted by vfrkent

One other thing to consider when you add the rear swaybar is, the roll stiffness has gone way up relative to the front, so now the front "feels"
like it is pushing more, the solution is to add the urathane front swaybar bushings it makes a dramatic difference in the front wanting to roll when turning.

You can get the bushings from a number of suppliers, I bought mine from Wheelers in Grantspass, they advertise here and are a great bunch of guy's.

The other thing to add at the same time is the steering rack bushings, there is a great amount of compression in them giving the effect that the Tundra has slow steering, by changing them it feels as if the steering ratio has been quickend, the truck is now a true pleasure to drive in the curves.

Best regards, Kent

I imagine that the front swaybar bushings are pretty easy to change. How hard are the rack bushings to change?

vfrkent · #7 (**permalink**) 12-06-2005, 12:05 PM

The rack bushings only take about 1 hr to change its not bad but makes a noticable change.

Best regards, Kent

DJ · #8 (**permalink**) 12-06-2005, 06:06 PM

Check the alignment. If total toe is way off, it can result in understeer or oversteer, depending on the direction it's off, in which case a change in the roll stiffness can result in a change in the under- or oversteer.

duke boy · #9 (**permalink**) 12-07-2005, 08:00 AM

Quote:

Originally Posted by DJ

Check the alignment. If total toe is way off, it can result in understeer or oversteer, depending on the direction it's off, in which case a change in the roll stiffness can result in a change in the under- or oversteer.

Would that be covered under warranty?

DJ · #10 (**permalink**) 12-07-2005, 09:23 AM

Quote:

Originally Posted by duke boy

Would that be covered under warranty?

Typically not.

Vehicle manufacturers put wide tolerances on wheel alignment settings so they can more easily say "it's in spec", and they will do so even when the alignment is "in spec" but really bad. The problem they face is fraud. When a bad part is replaced under warranty, the bad part can be returned for inspection. A simply re-alignment has no bad parts to return.

rando · #11 (**permalink**) 12-16-2005, 06:45 PM

I put a Hellwig bar on the rear. The difference in cornering characteristics is very dramatic. My front end definitely does not understeer. I had a feeling that it would oversteeer if pushed to the limit, so I was looking for it.

Driving down Kingsbury Grade 3 days ago in the early morning twilight, there was a fog that had apparently been higher over night, then dropped to a lower elevation, so I was above the fog, but it had laid down a thin sheet of ice on the road. I've driven the road at least 1,000 times.

I went in to a left hander, above the notorious "ice corner" at about 40 MPH. Same as always with questionable traction, but no snow. About half way through the corner, the back end started coming around. I though I might completely spin and I was headed straight toward a string of cars coming up the hill. I countersteered and added a slight amount of throttle and managed to get the thing back pointed in the right direction and settled down. If it wasn't for 20 years of snow driving I don't think I could have saved it.

The Hellwig bar is designed for a truck with a big heavy camper. It's too aggressive for an unladen truck IMO. Sure is fun on dry pavement, below the traction limit though.

TetTundra · #12 (**permalink**) 12-17-2005, 01:15 AM

Quote:

Originally Posted by rando

I put a Hellwig bar on the rear. The difference in cornering characteristics is very dramatic. My front end definitely does not understeer. I had a feeling that it would oversteeer if pushed to the limit, so I was looking for it.

Driving down Kingsbury Grade 3 days ago in the early morning twilight, there was a fog that had apparently been higher over night, then dropped to a lower elevation, so I was above the fog, but it had laid down a thin sheet of ice on the road. I've driven the road at least 1,000 times.

I went in to a left hander, above the notorious "ice corner" at about 40 MPH. Same as always with questionable traction, but no snow. About half way through the corner, the back end started coming around. I though I might completely spin and I was headed straight toward a string of cars coming up the hill. I countersteered and added a slight amount of throttle and managed to get the thing back pointed in the right direction and settled down. If it wasn't for 20 years of snow driving I don't think I could have saved it.

The Hellwig bar is designed for a truck with a big heavy camper. It's too aggressive for an unladen truck IMO. Sure is fun on dry pavement, below the traction limit though.

That bar helped to keep your rear end contact patches on the road, with better weight distrubution above (less body roll). I've had mine on and off, and don't notice a huge difference. When on, I think it corrects the natural understeer in the truck. We're talking infintestimal differences here, tho.

KLS · #13 (**permalink**) 12-17-2005, 03:53 PM

I disagree with vfrkent, and agree with rando, except I don't know if the bar is too stiff as he suggests.

I added the front urethane bushings and noticed very little difference. I think the best solution is to find a shop that will align to DJ's spec.

Ken

rando · #14 (**permalink**) 12-20-2005, 11:52 AM

The rear sway bar gives the front end more even weight distribution, hence more traction and less tendency to understeer.

It does that by putting more load on the outside rear tire. To do that requires less weight on the inside tire and a net decrease in the amount of traction available at the rear. And the difference is not a small one. When you find yourself at the limit of available traction and note which end gives up first you'll know what I mean.

Not looking for an argument. Just posting a fair warning about what happens at the limit. I've seen it, and I know the bar caused it. I've slipped around enough on snowy/icy roads to notice the difference.

The Hellwig bar is 1 1/8" diameter. The front is 1". The front end is the heavy end in an unladen truck.

cupidstoy · #15 (**permalink**) 12-20-2005, 07:46 PM

can't resist posting this link. suspension is such an interesting topic and there is so much misinformation about it, i thought this might be a good read for anyone who wants to learn the effect of adding the hellwig.

http://www.automotivearticles.com/12...way_bars.shtml

rando, i originally thought you had posted a mis-statement about putting more load on the outside rear tire. then i would have had to apologize because i would have been wrong. that's exactly what happens.

the trick is to balance the traction of the rear of the vehicle to the front of the vehicle to control over/understeer. since our trucks are designed to oversteer with the front sway bar in place, adding a larger bar to the rear doesn't necessarily mean it's going to understeer. i think most folks on TS found the larger bar in back is actually about right for the way the truck is set up. of course there are lots of factors here like tire stickyness, road conditions, load in bed and upfront, etc... there's always going to be a situation where the available traction in the front or the back is going to flip the balance in favor of over or understeering. i recommend sizing the rear sway bar for the conditions you see most often. for most of us in the US, that's dry pavement. if you live where it rains alot or there is more snow and ice then dry weather, or you carry a load all the time, you might want to go with a different size bar or none at all. for example, the folks in the offroader forum know all too well that hellwig isn't always good when articulation is the name of the game. it's all about what you want to do with your truck and understanding how to make that happen in a safe way.

just thought this was interesting and i learned something myself...