We need to pay attention to...
We need to pay attention to our racing shocks and evaluate them on a periodic basis. Here, a student at Patrick Henry Community College in Martinsville, Virginia, runs a shock on one of the school's dynamometers.
The shocks on your car need attention from time to time in order for them to work at their optimum level. Several times over the past few seasons, teams I have helped experienced shock failures. So it is in our best interest to check our shocks often and have them tested and/or rebuilt on a periodic schedule.
We talked to several of our shock experts on the topic of shock maintenance, and they offered some great advice. The shock companies are very involved with the racers and usually have their technicians in attendance at many major racing events. So they see and hear a lot about the pitfalls that can affect a racing shock's performance.
We developed a set of questions about shocks and presented them to our experts. Here is what they had to say.
1. Are there maintenance differences between twin-tube and monotube shocks?
Not really. "The two main things you worry about are seals and breakdown of the oil," says Jeff Sandt with Pro Shocks.
Nate Thiesse from QA1 Racing Shocks offers, "All of our racer revalveable/rebuildable shocks have a similar year-end maintenance schedule, regardless of twin-tube or monotube designs."
"Maintenance for both types of shocks are very similar. If possible, gas shocks should be checked for pressure on a regular basis," says Mark Bush, Afco's shock guru.
Curtis Henquinet of hlins Shocks says the only difference between each kind of shock is in the gas reservoir.
"Maintenance for both monotube and twin-tube shocks is basically the same. A regular maintenance schedule for freshen ups should be provided from the manufacturer," offers Scott Keyser, who designs and supports Integra shocks.
2. Can shock pressure cause premature wear and/or failure?
"The more pressure you run, naturally, will cause greater stress on seals and other components," says Sandt.
"Gas pressure settings in a monotube shock are very important to the performance of the shock valving and consistency," Keyser says. "If the proper amount of gas pressure is not run, the oil will foam and the shock will begin cavitating. Then the shock will fade easily and also lose its valving characteristics. Run with the manufacturer's recommended settings to eliminate any complications or premature failures."
"The gas pressure will not cause any premature wear or failure unless extreme pressures are used," Henquinet says.
"Radical valving, such as 11, 12, and 13 valves, that some racers utilize today create huge pressures resulting in forces that generate much higher shock temperatures. I usually recommend a much more frequent freshening of those shocks than I would a standard straight four-valve," says Thiesse.
"Excessive, extreme pressures could cause mechanical problems within the shocks in addition to having negative effects on handling. Users should follow the manufacturer's recommendations on pressure," according to Bush.
This cutaway shows the inner...
This cutaway shows the inner workings of a monotube shock. The chamber to the left contains pressurized gas and is separated from the shock oil by a piston. The shock piston holding the valves is shown in the main body of the shock at the end of the shock rod. Twin-tube shocks have a gas bag that compresses when the shaft moves into the shock body and displaces the shock fluid to control cavitation.
3. Are your shocks user rebuildable?
"Yes, Afco shocks are rebuildable provided the user understands the internal workings of the shocks and has access to a quality shock dyno," says Bush.
"QA1 shocks are revalveable and it's not uncommon for a racer at the track to be revalving a shock in the race trailer," says Thiesse.
"Yes," says Keyser, "Integra Shocks are completely user repairable, revalveable, and serviceable. Revalving kits, tools, and instruction manuals are available to the racer."
"Pro Shocks are not user rebuildable. We incorporate a different design to flow the oil, and we feel our shocks are best serviced by us," declares Sandt.
Henquinet says hlins shocks are completely owner rebuildable and revalvable.
4. Can a user send shocks to you for repair and/or to rebuild?
For those of you who plan to travel next year, Thiesse says that QA1 has a network of authorized service centers that range from California to New Hampshire and from Minnesota down to Texas, as well as international service centers in New Zealand and Australia.
Keyser with Integra says, "Customers can call us and send their shocks in to be rebuilt or repaired."
As we learned in Question 3, Pro Shocks does all the repair and retuning of their shocks.
Bush offers, "Afco shocks can be sent directly to our factory or to one of our authorized rebuild centers located throughout the USA and abroad."
"The racer can either send their shocks to us for repair or to one of our various dealers," says Henquinet of hlins Racing Shocks.
5. What maintenance schedule should the racer be on to help eliminate failures?
"The best maintenance is to check for bent parts, leaks, and basic shock function. All of this can be checked by the user. They only need to push the shock in and make sure it does not bind or leak. We also recommend changing the oil at least once a season," explains Henquinet.