Bump steer kit

[Pentalab]

At what point do any of you folks install a bump steer kit ? I'm lowered 1" on the front, and don't have one installed. I looked at the steeda install manual, for their version, and it appears to be a pita to do the alignment portion of it. Looks like you require a drive on lift + a pair of cum-alongs to load the front suspension.

I read some where, a while back, that if you exceed >1.5" drop on the front, that a bump steer kit is required.

I hit a gradual semi rolling bump the other day, on the right side doing 60 mph..and it ripped the steering wheel outa my left hand. Like an idiot, I had my left hand on the wheel at the 12 o'clock position, and the right hand on the shifter. It pulled violently to the left, then violently to the right, then straightened out, all in well under 1/3 sec. It was on an uphill slope.

 

[ddd4114]

I'm lowered ~1.25" in the front of my 2011, and I haven't noticed any significant bump-steer problems on either public roads or race tracks.

It sounds like your wheel snagged the side of the bump if it ripped the wheel out of your hand. Bump steer would not do that; it would change the car's direction for the same steering angle.

 

[dontlifttoshift]

At what point do any of you folks install a bump steer kit ?

Right after you measure how much bumpsteer you have and determine that it needs correction.

 

[claudermilk]

Like an idiot, I had my left hand on the wheel at the 12 o'clock position, and the right hand on the shifter. It pulled violently to the left, then violently to the right, then straightened out, all in well under 1/3 sec. It was on an uphill slope.

....and this is why you don't hang your wrist over the top of the wheel (not implying that you were THAT bad...right? ;p ). Hands at 9-ish and 3-ish, and only on the shifter to shift. That last is a habit I'm trying to change--my in-car track day video slapped me in the face on that regard.

I'm lowered about 1" in front and have not noticed any increase in bump steer. Even over typical bumps on the street and hopping curbs at the track. I have no plans to mess with the kits--they seem from postings around here to cause more problems than they solve in most cases.

 

[csamsh]

I had a bump steer kit when I was lowered around 2" in front. Then, I took it off for class legality purposes and lowered it more. I noticed no change in the handling of the car.

 

[Norm Peterson]

I don't think I've ever experienced violent bumpsteer like that. B/S is more where you have to keep sawing back and forth at the steering wheel to stay on line through a long curve that has a few heaves in it (as the suspension rises and falls in response).


Norm

 

[Speedfreak]

I was on stock shocks & eibach lowering springs for over 3 years & didn't experience any bumpsteer. Changed to Koni shocks & didn't experience anything either. Installed BMR A-arms & the bumpsteer was very prominent. After installing a Cortex bumpsteer kit, everything was back to normal.

 

[TheKurgan]

Every car I have seen a bump steer kit on loses a decent amount of negative camber...which imo has a negative effect on cornering.

 

[Norm Peterson]

Every car I have seen a bump steer kit on loses a decent amount of negative camber...

I'm afraid that I can't make the idea of a bumpsteer kit force you to run less-negative camber.

More likely what you've seen are cars that were lowered and the owner either actively wanted or got stuck with a stock-ish alignment to go with his bumpsteer correction kit.


Norm

 

[2013DIBGT]

Yup.. I got a Bumpsteer kit and have no issues achieving more Negative Camber then I would normally run. I'm at -1.5 now and still have about an inch more movement towards Negative if I wanted to before maxing it out.

I've just got done doing 302S Arms and Bumpsteer kit on my car. I think many would be very suprised how crapy their Bumpsteer curve looks if they took the time to measure it.

In any case, I would say that if you don't feel Bumpsteer happening then I would take the ignorance is bliss route because it is a PITA to setup. If on the other hand you do experience Bumpsteer then get ready to roll up your sleeves if your married to your current ride height. The other option is to raise the car closer to factory height and call it a day.

I went the extended balls route so I had no choice but to roll up my sleeves

 

[TheKurgan]

Ride height is what I was thinking doh. What I don't get is why some people say you need it while other cars do not. Most guys on the track do not want to give up their ride height. It seems to be a mystery why some need it and some don't. There has to be some logical reason other than seat of the pants feel. That seems to be where the difference is.

 

[Norm Peterson]

It's easy to link a lower CG to improved cornering, without understanding either the nitty-gritty of what's happening as you lower the car or how much performance is actually gained. Hint - although you gain a little grip on the outside tires by having less "weight" transfer onto them, your inside tires lose a little because now they're operating with a little more weight on them. You still get a net "gain", just don't expect a 5% reduction in CG height (about an inch) to give you a 5% improvement in cornering (think closer to 1%).

When you're getting close to being able to lift both inside tires, that's when CG height becomes critically important. Probably never going to happen with street tires, but perhaps could with race tires on a really grippy surface.


Norm

 

[dontlifttoshift]

I went the extended balls route so I had no choice but to roll up my sleeves

Bold for emphasis.

With a taller ball joint, you will need the bumpsteer kit. You changed the geometry, you need to correct it.

Did you measure bumpsteer without the taller ball joints?

 

[BMR Tech]

At what point do any of you folks install a bump steer kit ? I'm lowered 1" on the front, and don't have one installed. I looked at the steeda install manual, for their version, and it appears to be a pita to do the alignment portion of it. Looks like you require a drive on lift + a pair of cum-alongs to load the front suspension.

I read some where, a while back, that if you exceed >1.5" drop on the front, that a bump steer kit is required.

I hit a gradual semi rolling bump the other day, on the right side doing 60 mph..and it ripped the steering wheel outa my left hand. Like an idiot, I had my left hand on the wheel at the 12 o'clock position, and the right hand on the shifter. It pulled violently to the left, then violently to the right, then straightened out, all in well under 1/3 sec. It was on an uphill slope.

Do you have taller ball joints on the car, or OEM height?

 

[A John In NJ]

I always believed that I needed a bumpsteer kit as well since my wheel tends to swerve semi-drastically everything i hit a bump going over 35 mph.

Now i see i have bigger problems... fak!

 

[Speedfreak]

I was on stock shocks & eibach lowering springs for over 3 years & didn't experience any bumpsteer. Changed to Koni shocks & didn't experience anything either. Installed BMR A-arms & the bumpsteer was very prominent. After installing a Cortex bumpsteer kit, everything was back to normal.

I should have emphasized... I installed the BMR a-arms with the taller ball joints...

 

[TheKurgan]

I always believed that I needed a bumpsteer kit as well since my wheel tends to swerve semi-drastically everything i hit a bump going over 35 mph.

Now i see i have bigger problems... fak!

Nearly every S197 mustang does that. That is due to the live rear axle. That is what I'm trying to say in this thread is that every single person that has a S197 experiences this to some degree. The question is at what point is it intolerable ?

 

[tigercrazy718]

Bold for emphasis.

With a taller ball joint, you will need the bumpsteer kit. You changed the geometry, you need to correct it.

Did you measure bumpsteer without the taller ball joints?

So if you install Boss S front control arms, you should install a bump-steer kit too? Ugh, I might go back to buying the FRPP arms since I don't really want to spend more money or time to replace my blown ball joints.

 

[BMR Tech]

^ Yes, 100%!

If you install a taller ball joint, it WILL throw your bump out of whack.

You will need a bumpsteer kit, no doubt about it.

For those who don't have the proper tools (bumpsteer measuring kit) - you can get it very close by simply using a laser, marker, and 4 heavy dudes available to bottom out the suspension.







We made some geometry changes before our last track outing, and only had about 45 mins to get the bump under control....so I did this with the quickness.

It isn't "perfect" - but will get you damn close. It will DEFINITELY get you to where you don't even notice the bump.

 

[tigercrazy718]

^ Yes, 100%!

If you install a taller ball joint, it WILL throw your bump out of whack.

You will need a bumpsteer kit, no doubt about it.

For those who don't have the proper tools (bumpsteer measuring kit) - you can get it very close by simply using a laser, marker, and 4 heavy dudes available to bottom out the suspension.







We made some geometry changes before our last track outing, and only had about 45 mins to get the bump under control....so I did this with the quickness.

It isn't "perfect" - but will get you damn close. It will DEFINITELY get you to where you don't even notice the bump.

Ugh that sucks but I'm glad it was mentioned since I didn't know that was something I would have to do. My wife thanks you because that means I'm going to be buying cheaper parts now haha.