Front End Differences...

[coloradotbucket]

Ok, maybe this a dumb questions, but why do some of the T buckets, or T bucket kits have Suicide type front ends, and others don't ? Whats the difference in Handling and so forth ? I am planning on a building a Model A Tudor one of these years but I would like to have it have a Suicide type front, and I see this mostly on T Buckets, but usually not on other types of hot rods... whats the story ?

 

[tfeverfred]

If by "suicide" you mean a dropped axle, that's about all I do see. It can vary from car to car, but on most T Buckets, it seems that 4" is the norm. Now there are a few I've seen that were 6" drops and they were very suicidal looking!

 

[coloradotbucket]

Well Fred,

What I mean is that if you look at say, my front end, I have a spring mount on end of the Frame, but if you look at older T Buckets, some of them have more of a model A type look where the Front Wheels are set back more. Look at the one on the Ventures record cover and its way different than ours

 

[tfeverfred]

Okay. This is what I consider a "suicide" frontend.

I can't find a Ventures album cover pic, but I think I know what you're talking about. Maybe the reason that we don't see more of them is because they tend to make a lot of cars not really safe.

 

[coloradotbucket]

Yea, thats one for sure, with I beam axle. Do you think that setup is unsafe ? I have nothing to compare it too really.

 

[EX JUNK]

A suicide mount is where the axle is placed in front of the radiator and front cross member. This is usually done to allow the frame to be lower and thus lower the car. (You could "Z" the front of the frame and get the body lower though but then the radiator would be higher than the cowl which would not look good.) With the axle mounted in the "conventional" position the frame will hit the axle if you try to lower the car too much. Safety really has nothing to do with it. Good construction is what has everything to do with it. Beside that, a T Bucket tends to look "stubby" and comical with the axle mounted like a Model A. A car has to "profile" correctly to look good.

 

["The Bat" out of hell]

Okay. This is what I consider a "suicide" frontend.

I can't find a Ventures album cover pic, but I think I know what you're talking about. Maybe the reason that we don't see more of them is because they tend to make a lot of cars not really safe.

There's only a few things wrong with that frontend in the pic,and it's just not done yet. The one thing bad that I do see a lot of,is that guys turn the spindles/steering arm back word,putting the arms out front as seen in the photo,the ackermen of the arms has not been fixed* yet in photo and if left that way will steer for crap in turns and brakes if used in a turn will not stop the rod[tire will just slide ,rod goes strait with out making the turn=crash!
*fix is bend arms out as close to backing plate as they will go and still hook tierod up[longer tierod needed] or replace with arms that go out and a little around backing plate for really right ackermen.

 

[donsrods]

I have to disagree with the statement that it will handle like crap. I had no choice in my build but to put the arms out front.........no room behind for a tie rod. Car drives straight as an arrow and it corners just fine. I drive down offramps at speed, turn into parking lots, etc and it tracks great. Only thing I do get is some minor scuffing when parking at low speed, especially backing up. I can live with that.

I realize it would make the front end perfect to put the tie rod behind, but sometimes with a low, suicide front end you just can't do it that way. Of all the front end sins you can commit, poor ackerman is the least sinful.

Don

 

[RPM]

I have to disagree with the statement that it will handle like crap. I had no choice in my build but to put the arms out front.........no room behind for a tie rod. Car drives straight as an arrow and it corners just fine. I drive down offramps at speed, turn into parking lots, etc and it tracks great. Only thing I do get is some minor scuffing when parking at low speed, especially backing up. I can live with that.

I realize it would make the front end perfect to put the tie rod behind, but sometimes with a low, suicide front end you just can't do it that way. Of all the front end sins you can commit, poor ackerman is the least sinful.

Don

I agree Acerman don't know nuttin about T Buckets, they do just fine with the steering in front of the axle.

Did anybody besides me notice that the drag link in the above picture is on the right side of the car?

 

[coloradotbucket]

Yea, this one must be from England. My car handles well enough but has a HUGE turning radius.

 

[tfeverfred]

Great input. My question would be, how much of a drop is considered unsafe? I know that there are quite a few guys who love the "in the weeds" look, but in my opinion a 6" dropped axle is pushing it a little. I realise there are other issues which would effect the safety of the install.

Any thoughts?

 

[EX JUNK]

By making new steering arms you can retain proper Ackerman with the tie rod mounted in front of the axle. I know this for a fact because I accomplished it with my build. I have seen only a VERY few that have done it. Some guys have what I call a "neutral" arm. By that I mean, the mounting point of the tie rod is in line with the kingpin but drawing a line from the center of one through the center of the other the line goes straight, as in parallel with the frame. The line should intersect with the same line that is drawn from the corresponding on the opposite side and meet at the rear end housing.

With a "reverse" Ackerman the lines will project out at an angle and NEVER meet. In the "neutral" mount the lines will project as parallel and never meet also.

On the road handling will not really be affected with either type but low speed turns will require a little more effort and will experience some scrubbing of the front tires along with an increased turning radius. If these are things that you can live with, then I say by all means don't take the time to attain correct Ackerman.

I just feel that there are a whole lot smarter people out there than me who have devised these principles and I try to adhere to them as much as possible.

 

[blownt]

steering arms and tie rods in front or rear of the front axle and the ackerman angle has very little effect on a T bucket. If you were to build a good road race chassis with tight suspension and go around corners at 45+mph then yes you would go after the correct chassis setup and geometery. But just cruisin in a bucket you will not tell ANY difference at all if the steering arms are angled toward the center of the rear of the bucket or if they are angled toward the center of the car in front of you. I have seen just about all kinds of front end setups in a bucket and they all cruise just fine.

 

["The Bat" out of hell]

Not fixing to at lest some amount ackerman is just as dum as no front brakes at all. Yes I know there some that even think that's OK,very sad!
For those that seem to think your rod handles OK with backword ackerman,your kidding you self to the point of a crash to come. What I posted is the real facts,if you are turly that spaced out about how your rod works,I can not help ya.
I've designed & built more rods then many of ya,and many many more race cars.
A T--buckket has a lite front wheel load,and that makes bad engineering even more dangers because when the only one front tire that's working at all from that bad no ackermen, lets go of the road you totaly lost,the other tire was already not doing any thing helpfull.
Understand for those who are thinking it's OK,but that it is not.
Yes ,you can go in a strait line just fine,but in a turn,the inside tire starts to go much straiter then the out side tire that is trying to turn your rod,so there fighting each other instead of helping,giving the rod less then even one tire steering the rod. Try to keep in mind that this happens more the sharper the turn is=most likely the full skid happens at the time you needed to steer the most.
Go a head an keep fooling you self. Get in the crash and you can fine out the hard way.
Fixing the arms to at lest strait out from kingpin is much better then not doing anything,but still short of having it right.
Rods are fun,but don't need to be poorly engineered.

 

[Rick]

For us dummies can you guys draw some pics up so we can understand a tad better?

 

[LumenAl]

For us dummies can you guys draw some pics up so we can understand a tad better?

Here is a drawing with proper Ackerman... Note that from the kingpins to where the tie-rods attach to the spindles is in-line to the center of the rear axle...

Typical in cars that have the tie-rod up front, often your setup resembles something more like this... as you can see... not even close to being in-line.

Bottom line is this... when you turn the wheels on a car with proper Ackerman, the inner wheel has to turn sharper to be in tangent with the center point of the axis...

The car with the tie-rod out front without the Ackerman alignment would turn like this:

Now your front tires are not working together... they work against each other and depending on which tire has the most traction at any given moment wins... might be a little skidish...

A much more complete description and explanation is on the NTBA Tech Pages (NTBA Link Below) written by our own member GWB! (Note: Illustrations shown here where drawn by GWB as well). :rofl:

NTBA

 

[blownt]

OK Mr Bat, whatever ya say. We are all just stupid I guess. Only been drivin mine for 15 years and know nuttin. So be it.

 

[RPM]

OK Mr Bat, whatever ya say. We are all just stupid I guess. Only been drivin mine for 15 years and know nuttin. So be it.

I'll second that!!

 

[GAB]

I look at it like this...if your engine is a couple of degrees off on timing and maybe a jet size from optimum too, it will it still run. And in a bucket, it will be a rocket. Give it a good tuneup and can you tell a difference? You bet!

You tune up engines, why not suspensions also?

I wonder how much of this problem with death wobble might be attributed to an Ackermann problem? Just wondering?

 

["The Bat" out of hell]

Very nice write up on arkerman there LumenAl posted,lots of good info.
Some may not read it,just becuase it's so long,but they need to.


I start out always thinking anyone is smart,and only after some one dismiss facts and says bad engineering hads worked fine for them!,do I wounder about there brains maybe being cloged with there ego instead of thinking about things that can help them.. They been just lucky,not safe.
If my post poped some bubble,so be it,it may of helped some one too.
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