Chain Maintenance

It is now the middle of summer so depending on what part of the country you race in, you could be finishing a series or just reaching the midpoint.  Either way, it is a good idea to keep up with your kart maintenance so your kart is in great shape so you can finish out the next races on top.

An experienced racer sent me some interesting information on how he handles chain maintenance so I thought I would share that with you.

Some racers will tell you that if you buy a good high quality racing go kart chain you never have to do any maintenance on the chain.  You definitely should buy a high quality racing go kart chain but it still requires care in order to get the maximum performance and life from it.

Be careful and do this at your own risk as I assume no responsibility for any injuries that could occur using this method. Make sure you read the instructions first and have all the tools and supplies available, as well as the necessary personal protective equipment.

Remove chain from kart using a pro style chain breaker. Do not use a master link for go kart racing. It will fail! Also, do not use one of those cheaper motorcycle chain breakers which seem to damage the chain almost every time you use one. Wipe off any excess dirt or debris with a cloth rag or shop towel. Pour about 10-12 ounces of type F transmission fluid into a 2 lb. metal coffee can. Fold chain up until it is slightly smaller than coffee can and place chain flat in the bottom of the can. 

In an open area, outside, away from people, structures, and anything that can burn, place can on a lit propane or Coleman type stove burner.  Make sure you heed the word outside or you may find yourself sleeping with your go kart. If you don't already have a stove like this you can find a propane single burner in the camping department of your local department store fairly inexpensively.

Turn flame on medium and allow transmission fluid to heat up and come barely to a boil. As soon as fluid starts to boil carefully remove coffee can using a large pair of channel lock pliers and place it on the ground or a heat-proof surface to cool. Be sure to watch carefully and remove the can immediately when it starts to boil.  If fluid stays on the flame very long it will start to pop and shoot drops of boiling fluid out of the can and onto you and everything else nearby.  

Allow fluid to cool about 5-10 minutes.  Remove the chain and hang on a nail over a coffee can or another drip pan to allow the fluid to drip off.  Allow the chain to cool for a few hours.

When you are ready to reinstall the chain, wipe it off with a clean, lint-free cloth and then put it back on your kart using a professional style chain breaker.

If you are go kart racing on asphalt I recommend doing this about every other race and using a chain lube after putting the chain back on your racing go kart. If you are dirt racing, you should do it every week and use chain wax instead of lube. I have found that chain wax will repel dirt but chain lube makes dirt stick to chain. Using this method you will find that your racing go kart chain will last a long time working exactly as it did when new.

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So there you go.  Let me know if you have used this technique before and how well it worked for you.  

More of the Back - Rear Track and Torsion Bars

Last time, we talked about axles and hubs and how making changes to these parts can make a big difference on how your kart handles.  This will allow you to optimize your kart for track conditions and improve your race times.

The changes to the axles and hubs that we described before assumed that there was no change to the rear track width.  Widening the rear track can have a big effect on grip. It increases the lever arm to the outside rear tire and also adds flex on the axle similar to how changing the stiffness of the axle works.  Increasing the rear track width will increase the flex and should be done on those days when it is hot and sticky and you have understeer.

Rear torsion bars are the last of the items that can be used to make large changes to the rear end of your kart.  Most karts have adjustable or removable rear torsion bars. They are used to add stiffness to the rear frame so they should be added when the kart is loose and the track is slippery.

After that, the tuning parts have a smaller impact on the kart rear end, but they still should not be disregarded. The rear seat struts and the seat are part of the chassis system and add stiffness to the chassis.  Seats tend to be expensive and difficult to replace, so this is not the best place to look when tuning the kart chassis, but if you have to replace your seat, realize you may need to start again through the tuning process.  The lower bumper bar can also have some influence on your kart. Most racing rules do not permit removing it, but adjustments may be possible there.

It is a long list of items, and in the end, don't forget you can also consult your chassis manufacturer as they can help you understand how to make the system work together. 

In the Back - Axles and Hubs

This is the first of a two part series about adjusting the rear end of your kart.  When a kart is properly set up and optimized to race day conditions, steering effort will be reduced.  The driver will be able to maintain maximum speed as the kart floats around the corners because it is neither too loose nor too tight.  The driver will also fatigue less because he or she is not fighting against the kart.

The rear end of the kart has the majority of the weight along with most of the moving parts so when tuning your kart for performance, that is a great place to start.

When approaching a corner, you turn the steering wheel, the rear inner wheel lifts and grip is transferred to the outside rear wheel.  The stiffness of the rear end is a big factor in how much grip is transferred to the outside tire and how fast that is done. 

The rear end of a kart may seem simple, but the axles, bearings, hubs, torsion bars, seat struts, rear bumper, and even the seat will impact stiffness. The stiffness of the axle will make the biggest impact so it is one of the most important things to get right before changing other things. When conditions are cold or the track is slippery, use a stiffer axle to transfer the weight to the outside tire more quickly. When the track is hot and sticky, use a softer axle to flex more.  This will be a recurring theme throughout the process.  More flexibility is needed when you have more grip.

Next up is the rear hubs which manage the weight transfer to the tire through the axle. The hubs work like a stiffener on the axle with longer hubs overlapping more axle and therefore making the whole system stiffer. Use long hubs on cold slippery days when the kart feels loose and you have oversteer.

Next time, we will move on to the rear track and torsion bars.

The Test

No, you do not need a #2 pencil and there will not be a grade assigned at the end.  We are talking about testing to improve your kart performance and ultimately your race times.  So, how do you test?

First separate out testing and lapping.  Testing is determining how changes on the chassis or the engine setup affect performance. Lapping is the process of making lap after lap around the track to improve the driver's line and consistency.  As we have said before, the biggest change from race to race is the driver so do not underestimate the benefit of lapping.

For a day of lapping, you will want to have the kart set up at a pretty much baseline configuration for both chassis and engine and have your fuel can ready.  The idea is to pound over a hundred consistent laps until the driver can hit his or her marks every time.  The point is to learn to drive the kart near its limit of control, and do it every single time.

For testing, you also want to start with the baseline configuration.  Get the baseline setup that your chassis manufacturer recommends, put everything back to that, make sure your engine package is solid and consistent, and you are ready to start.  Next make a list of the parts and changes you want to test.  The goal is for the driver to learn what the system does when a change is made - determine how it affects the turn in, apex grip, exit handling, etc. so that he or she can maximize the kart's performance.

Start with changes on the big things (seat position, axle, ride height) and then move to the small fine tuning adjustments.  Be cautious however,  and understand that the track changes throughout the day and from day to day. While speed and lap time is the ultimate measure of success in the race, it is more important to note what exactly was changed and how the kart felt.  Although there is no measurement unit for how tight or loose the kart feels, try to quantify it on say a scale of 1-5 or 1-10. That way, as you change each thing and note its effects, you will be prepared to tune for the conditions.

Some suggestions of possible things to test:

How does seat position effect handling: recommended, forward, backwards, raised?

How does a softer and harder axle effect handling?

Third bearing hooked up or loose?

Second set of seat struts?

Rear ride height: neutral, high, or low?

Front ride height: neutral, high, or low?

Different front bars?

Addition of rear and/or side torsion bars?

Increase/decrease front and rear track width?

Increase/decrease Caster?

Increase/decrease Camber?

Toe in/out 2mm from stock?

+/-3 psi of tire pressure: front/back?

Different wheels: aluminum vs. magnesium?

Karting Brakes

The following is an excerpt from an article by V. Hill which you can read in its entirety at www.KartPartsDepot.com in the Depot Depository.

From the very beginning, karters seemed to focus more of their attention on the go portion rather than on the stopping portion of kart racing. Brakes have seemed to take a back seat to the power plants and chassis in the search for speed.

With the advent of the very large penetration of European karts, mainly Italian made karts, the number of brake choices for the karter is even larger. Every brand of kart seems to have their own take on brakes and the parts are not interchangeable from one brand to another. For the karter, this means that he or she may need to keep more parts in their own selection to support if they have more than one brand of kart they use in their racing arsenal.

The science of brake design and developing brake technology is more about the materials used in the manufacturing of the brake rather than any new or fundamental changes in the mechanics of the brakes. The basic design parameters are pretty much set for the karter.

The disc is one component you can tune to tailor the brake system to suit your individual needs. Karters have made discs out of everything from Detroit wonder metal, Cast Iron, Steel plate, Aluminum and even exotic metals like Titanium and Beryllium. But the material of choice seems to always gravitate back to Cast Iron. Nothing seems to be able to beat this material for it ability to under go many heat cycles without distorting. It is relatively inexpensive and it has great wear capabilities. Carbon-Carbon was even tried for a short time. It offered great performance and it was incredibly light - often the disc would weigh less than the nuts and bolts used to hold the disc to the hub. But it was very expensive; really expensive, a single disc could cost $200.00 to $500.00 dollars depending on the application. The Carbon-Carbon disc also required special Carbon-Carbon brake pads so the cost was really astronomic.  But no matter how much things change, they still seem to be the same. Cast Iron is the material of choice and that holds true in 90% of the racing series around the world, not just karts.

More about Kart Dynamics

First let's define caster and camber. 

According to Wikipedia, "the caster angle or castor angle is the angular displacement from the vertical axis of the suspension of a steered wheel in a car, motorcycle, bicycle or other vehicle, measured in the longitudinal direction.  
Camber angle is the angle made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of the wheels used for steering and the vertical axis of the vehicle when viewed from the front or rear. If the top of the wheel is farther out than the bottom (that is, away from the axle), it is called positive camber; if the bottom of the wheel is farther out than the top, it is called negative camber."

Clear as mud, right?

Let's start with camber, also known as toe-in and toe-out. Toe in, or negative camber is when the wheels are mounted so that the front of the tire is angled slightly inward toward the center of the kart. castor is the angle, from vertical, of how the wheel is supported. See the photos below from intraxracing.

Now that we have that basic understanding of terminology, I am going to point you to a detailed article by driver coach Chris Livengood at

http://www.kartpartsdepot.com/EXIT_OVERSTEER_KARTING_p/029.htm

He walks you through what to look for and the adjustments that you need to make to your kart to maximize your cornering capabilities.