Errrrr..... no!
It's complex.....
Ackerman effect is where the wheels follow a 'correct' line through the corner. You already know that the inside lane of a running track is tighter and shorter than the outer lanes. If you tried to push a bike in the inner lane, you'd need to turn the handlebars more than if it was in the outside lane.
Replace the bike with a kart. The kart's left wheel would be in the inner lane, BUT the right wheel would be in lane 3. To have BOTH wheels remaining in their lane (i.e., pointing correctly around BOTH lanes) you'd need the LEFT wheel to be more sharply turned than the right wheel.
This 'difference' of angle between the inner and outer wheel is called the Ackerman effect and is where the inner wheel points in more sharply than the outer wheel BUT the wheels BOTH go 'dead-ahead' when you are pointing up the straight. The more Ackerman effect you build in, the more the difference of angle between both the two wheels when on full lock.
Now, there will be some Ackerman setting that will be PERFECT for you kart and driver..... no one ELSE can know what that PERFECT level of effect for you is without knowing your kart intimately.
There are two standard ways of increasing the Ackeman effect. You kart may NOT offer both methods. The first one is that, the more track rods are mounted towards the centreline of your stub axle, the GREATER the Ackerman effect (i.e., shorter track rod length.) The further OUT the track rod is mounted on the stub axle the LESS the Ackerman.
The second method is controlled by your steering column design and that's done with the 'spade' (the bit that sticks down from your steering column and to which you mount the other end of the track rods). Often, there is a single central hole to which you attach BOTH track rods at once. This gives you ZERO ability to change the Ackerman effect at the steering column. However, if you have a central hole AND two other holes which are each further AWAY from the central line of the kart than the central hole, the you CAN adjust the Ackerman effect here to. This time, the further OUT you mount each track rod (shorter track rod), the MORE the Ackerman effect.
Columns are complex things and they may even have 4 or 5 holes. The same rule still applies: further out (shorter track rod), greater Ackerman.
Now...... the complex piece. If you already have too much Ackerman effect, then shortening the trackrods will make matters WORSE! However, your kart COULD have the perfect Ackerman at this moment and thus changing it at ALL will make things worse. Finally, you might have too little Ackerman: now, shortening the track rods up to a certain amount WILL improve things..... but...... if you go PAST the 'perfect setting', you'll make matters WORSE again.
How can you tell...... that's the easiest bit (in principle!). You should set your kart up perfectly with the current degree of Ackerman effect and go and do 5 laps against a stop watch and then (let's guess) increase the Ackerman effect (shorten the track rods) and that DOES make you go faster..... then you'll know that you should use that Ackerman setting for THIS track on THIS day, with THIS weather. In that case, if you still have more holes to try giving even MORE Ackerman, you should try THAT setting too and compare it against the stop watch.
Obviously, if the FIRST change in Ackerman makes you SLOWER, then you should try doing the OPPOSITE to the last change you made and see if THAT improves your time. If it gets worse when you have tried BOTH shorter and longer track rods, the original setting WAS 'perfect' and you should return to it.
So...... now you can see how to change the mount of the Effect and how to find out if it makes things better or worse. You CANNOT tell this without trial and error (er..... testing!) and it's simply WRONG to think that there is one simple answer of: 'Do this and get THAT from the effect'. It's MUCH More complex than that!
Oh..... and finally.... you'll hear thousands of pit lane experts tell you that they 'ran Zero Ackerman by using holes X and Y'. This is B*LL*CKS!. All karts built since the early 1950s have had SOME Ackerman built into the design even if you use the LEAST Ackerman setting available to you..... you'll still have SOME Ackerman effect no matter WHAT you do!
Ian
|
|
Front stub holes by 'Started out fun' (15 Jan 2015 @ 23:53)
