Steering Column

[KingStromba]

From an engineering point of view, if you look at the column that is false.

1. If the weld breaks the steering will just become loose like it was before the weld. As people drive around with worn, unwelded columns all the time (ive seen loads), i really dont see this as a major concern.

2. Of course a garage will tell you to replace the column (£200+ veruses £30). They are in business, plus they may feel liability for welding a part they could replace.

3. Competition cars have welded columns. I would suggest this is not to save a few hundred quid, but that it conveys some performance advantage.

4. In a frontal impact the column would not collapse at the joint in question anyway IMO. It is more likely that the column would collapse over the rack. The lower universal joint is the likely place that the column would 'break' in an impact and the joins are weaker. If their was a probability of a colum through the chest from a welded column do you think the FIA would allow the welding of columns on competition cars? Surely these cars are more likely to suffer a frontal impact and therefore more likely to use the safest option for the driver.


Im not saying that i recommend everyone welds their columns. Far from it, if you can afford to replace the column, then go for it, more power to you.

But lets not make supposition and rummour about things we have no experience of. Ive driven both.

There is NO vibration
NO real difference in steering feels (slight at most)

Stating that their are safety issues, well i would say a welded column is SAFER than a loose column, yet people are prepared to drive around for months with soggy steering.

[big hp]

From an engineering point of view, if you look at the column that is false.

1. If the weld breaks the steering will just become loose like it was before the weld. As people drive around with worn, unwelded columns all the time (ive seen loads), i really dont see this as a major concern.

True, but probably worse due to the heat build up around the rubber componants. No not a major concern.

2. Of course a garage will tell you to replace the column (£200+ veruses £30). They are in business, plus they may feel liability for welding a part they could replace.

Probably don't feel comfortable doing it. Plus my mate had a company do his who generated too much heat in the column and melted the seals in the PAS rack, which ment they had a £500 repair bill for column and rack.

3. Competition cars have welded columns. I would suggest this is not to save a few hundred quid, but that it conveys some performance advantage.

My mates work/him build 1000bhp 911 and race them all over including Le-Mans. There columns are not welded and they both suggested I didn't weld mine. Solid columns on some cars yes but never welded.

4. In a frontal impact the column would not collapse at the joint in question anyway IMO. It is more likely that the column would collapse over the rack. The lower universal joint is the likely place that the column would 'break' in an impact and the joins are weaker. If their was a probability of a colum through the chest from a welded column do you think the FIA would allow the welding of columns on competition cars? Surely these cars are more likely to suffer a frontal impact and therefore more likely to use the safest option for the driver.

Agreed the column would probably collapse over the rack. It's just a risk I don't want to take.

Im not saying that i recommend everyone welds their columns. Far from it, if you can afford to replace the column, then go for it, more power to you.

Exactly, its down to individual choice. I'd prefer to change mine.

But lets not make supposition and rummour about things we have no experience of. Ive driven both.

I too have driven both. admittedly there wasn't much differance but to me it just felt it wasn't quite right.. But that could be down to a number of things.

There is NO vibration
NO real difference in steering feels (slight at most)

Stating that their are safety issues, well i would say a welded column is SAFER than a loose column, yet people are prepared to drive around for months with soggy steering.

Very true. Welding is a good compromise.

[2 live]

well..the column is kinda telescopic...the uj at the bottom is not where it collapses in the event of an accident...if u look bout 1/2 way up the cloumn ul see where the inner splined part of the column goes into the top part......welded or not the steering column will react the same way in the unfortunate event of an accident....and collapse inside itself.......which is also quite easy to knock back out n reuse too... apparently

[Swervin_Mervin]

Sp why's it called the anti-dive joint? It must do something.

[2 live]

its the joint thats connected to the part of the column that collapses.i.e the bottom half that slides up into the hollow top 1/2......

probly hence the name....it will do something...but it will do something for the car for sale to joe public........it will take out a little of the vibration on the rubber ...n thats about it, maybe even make it a little quieter...

[KingStromba]

From an engineering point of view, if you look at the column that is false.

1. If the weld breaks the steering will just become loose like it was before the weld. As people drive around with worn, unwelded columns all the time (ive seen loads), i really dont see this as a major concern.

True, but probably worse due to the heat build up around the rubber componants. No not a major concern.

2. Of course a garage will tell you to replace the column (£200+ veruses £30). They are in business, plus they may feel liability for welding a part they could replace.

Probably don't feel comfortable doing it. Plus my mate had a company do his who generated too much heat in the column and melted the seals in the PAS rack, which ment they had a £500 repair bill for column and rack.

The weld is no where near the rack. The column is welded next to the pedals.

3. Competition cars have welded columns. I would suggest this is not to save a few hundred quid, but that it conveys some performance advantage.

My mates work/him build 1000bhp 911 and race them all over including Le-Mans. There columns are not welded and they both suggested I didn't weld mine. Solid columns on some cars yes but never welded.

I meant Clio phase 1 competition cars. Ask Crono on CS for details about this. Also something to do with the manual steering.

4. In a frontal impact the column would not collapse at the joint in question anyway IMO. It is more likely that the column would collapse over the rack. The lower universal joint is the likely place that the column would 'break' in an impact and the joins are weaker. If their was a probability of a colum through the chest from a welded column do you think the FIA would allow the welding of columns on competition cars? Surely these cars are more likely to suffer a frontal impact and therefore more likely to use the safest option for the driver.

Agreed the column would probably collapse over the rack. It's just a risk I don't want to take.

Im not saying that i recommend everyone welds their columns. Far from it, if you can afford to replace the column, then go for it, more power to you.

Exactly, its down to individual choice. I'd prefer to change mine.

But lets not make supposition and rummour about things we have no experience of. Ive driven both.

I too have driven both. admittedly there wasn't much differance but to me it just felt it wasn't quite right.. But that could be down to a number of things.

There is NO vibration
NO real difference in steering feels (slight at most)

Stating that their are safety issues, well i would say a welded column is SAFER than a loose column, yet people are prepared to drive around for months with soggy steering.

Very true. Welding is a good compromise.

[Swervin_Mervin]

Taken from Circle Track:

"Anti-dive is a suspension parameter that affects the amount of suspension deflection when the brakes are applied. When a car is decelerating due to braking there is a load transfer off the rear wheels and onto the front wheels proportional to the center of gravity height, the deceleration rate and inversely proportional to the wheelbase. If there is no anti-dive present, the vehicle suspension will deflect purely as a function of the wheel rate. This means only the spring rate is controlling this motion. As anti-dive is added, a portion of the load transfer is resisted by the suspension arms. The spring and the suspension arms are sharing the load in some proportion. If a point is reached called “100-percent anti-dive,” all of the load transfer is resisted by the suspension arms and none is carried through the springs. When this happens there is no suspension deflection due to braking and no visible brake dive. There is still load transfer onto the wheels, but the chassis does not pitch nose down.

The method to achieve anti-dive is controlled by the upper and lower control-arm pivot points on the chassis. The exact determination is quite involved and is easily established with a good three-dimensional geometry computer program. In all suspensions there is a factor called the “side view swing arm.” This is a theoretical point of intersection of the arm planes projected into the fore-aft vertical plane through the wheel center. If this point is behind the wheel and above the ground, it will produce anti-dive. It will also provide anti-dive if it is below ground and ahead of the wheel. The other possible locations for this instant center are ahead and above ground as well as behind and below the ground. With these locations we have pro-dive. This means as the brakes are applied the suspension travels more than it would without any anti- features. The magnitude of the anti-feature, either pro or anti, is a function of how far the instant center is away from the ground. If it is on the ground, there is zero-percent anti-feature.

On passenger cars, anti-dive is added to make the pitch motions under braking more tolerable for the occupants because of the typical soft spring rates. The anti-dive is made the same for both sides of the car because most people brake in a straight line, and there is no directional preference on the street or in road racing for that matter. In circle-track racing it is common for racers to take any parameter to and beyond its limit.

In the evolution of the circle-track chassis, they have come to a solution that provides pro-dive on the left-front and anti-dive on the right-front suspension. The reasons for this are varied. For one thing, as the brakes are applied the car will deflect more on the left front than on the right. This will give a feeling of the front leading into the corner and not rolling out right away. This combination also provides for more of the load transfer to the front to be carried by the right-front wheel than the left front. The total transfer is the same; just the distribution is affected by the anti-feature in the geometry. More load transfer to the right front on corner entry is like adding wedge with the brakes on and is a stabilizing effect.

Anti-dive has an effect when there is a torque trying to rotate the spindle relative to the chassis. The typical case for this is under braking, but there is another case that can alter the loads and deflections of the wheels. This is the drag component of cornering load. When the wheels are turned and the tires are cornering hard there is a longitudinal load relative to the chassis centerline trying to rotate the spindle. To visualize this, think of the wheel turned 90 degrees!

Just like anti-dive in the front suspension, there can be anti-lift in the rear suspension that reduces rebound travel under braking. There is also anti-squat in the rear suspension under acceleration for rear-wheel-drive cars."


So there! I think I vaguely understand what's going on there.

[KingStromba]

Whats that go to do with a steering column?

[big hp]

I thought that when I read it.

[Swervin_Mervin]

Me too.