Are You Holding on to Trucks for Too Long and Spending Too Much?

We have all done it – held on to a tractor for too long, thinking that “I might as well keep it since it’s been paid for”.  And most of us have had that exact same truck breakdown as far away from home as possible, and need something like a new transmission or engine because we held on to it for too long.  The reason is simple – we can easily see what the interest and depreciation hit on the income statement will be.  It’s the unknown of how much the maintenance will be that is the problem.  It seems like we never learn and always discount what the repairs will cost.

Some old timers will swear that the 1972 Brockway or 1975 Ford Louisville that they have by the back fence would be less expensive to operate than these “new fangled, computerized things”.  They may have been, at one time, but I challenge you to get your local Mack dealer to find parts for that Brockway and get them to you by the next day.  Even better, let’s try and find a driver who is willing to run coast to coast in a vehicle that has even fewer creature comforts than the most basic rental truck.  While it might sound cool to do once, I would be surprised if you could convince the driver to do it twice.  Last year I had the opportunity take an early 1980’s Freightliner for a drive.  I had forgotten just how different a mechanical throttle linkage responds compared to today’s trucks.  And then there was the noise – you really don’t appreciate today’s sound insulation until you drive something that barely has any.  Looking for the fridge or microwave – sorry, it’s not there.  Looking to stand up in the bunk – you had better be short.

You might be asking why this is relevant.   Compare a 2018 model to a similar 2012 model, and you can see how they have gotten better. Things like automated transmissions, idling reduction technologies that still allow for a full hotel load on the electrical and HVAC systems either were not available, or were still in their infancy and subsequently unreliable.  I had one driver threaten to quit on me once because his bunk heater would only run for about 5 or 6 hours a night and he was tired of waking up in upstate New York with ice in his hair.  It was incidents like these that gave a lot of us a hesitation on getting newer vehicles.

So, what don’t we want to hold on to our vehicles longer?  As I have hinted, driver satisfaction tends to go up when they get a newer vehicle with more creature comforts than their old one.  However, there is little that dissatisfies a driver more than constantly sitting at the side of the road waiting for either a service vehicle or a tow truck because he broke down “yet again”.  Whatever you pay for a layover is less than what they could have made rolling down the road.  Throw in the additional costs of having an outside repair shop and you are probably looking at a large invoice.

So that’s what a breakdown will cost you, but what about the work that gets done in your own shops?  Fleet Advantage recently put out a report that estimates that a tractor requires approximately 2.5 hours a month to maintain while a three-year-old one requires 4.5 hours a month.  A simple guide that many people use is to assume that a technician costs you a dollar a minute.  So, in dollar terms, the newer truck cost you $150 per month while the older one costs you $270 per month (and that will only go up as the vehicle ages).  To put it another way, you will need almost double the number of mechanics for an average fleet age of three years compared to an average age of only one year.  Keep in mind that this only includes the mechanics on the floor, it doesn’t address the additional administration costs of having more bodies in the shop.  It also does not look at the increased inventory and parts costs that are needed to keep an older vehicle running.  For trucks that are only a year old, you are mostly stocking preventative maintenance items like filters, bulbs and fluids.  You will still be stocking those items with an older vehicle, but you will also need to stock brake shoes, drums, various exhaust system sensors and other higher priced items.  The inventory carrying costs are something that many people do not account for when looking at what it costs to keep an older truck.

The Fleet Advantage report suggests that by reducing your vehicle lifecycle from 5 years to 3 years, the expected average maintenance savings would be $17,150.  Reduce it to 3 years from 7 years and those savings go up to $42,830 per unit (to download a copy of the report click here).  Your numbers may be slightly different, but the trend will be the same – the annual maintenance costs will go up each additional year that you own that vehicle.

One other place where you could come out ahead concerns the current value of your used truck on today’s market, compared to what you typically use for a residual value.  In a strong used truck market like we have seen recently, you may see a significant gain (remember to check your financing contracts to ensure that there are no fees or penalties that you are not accounting for).  Yes, the capital cost of a new tractor is higher than the one you are replacing but the residual value should also be higher down the road.

Finally, look at what your preventative maintenance program covers and consider if it is catching everything that it should be within your shop.  Look at how often you have on the road repairs and what they are.  Is there a pattern, specifically are the same components failing at a similar mileage?  If you are seeing a pattern, add it as a pm program and catch them in your shop before they fail.  If not, then try to determine the average mileage to failure and use that as a guide.  Yes, your in-shop costs will rise but there should be a corresponding reduction in breakdowns that cost more than just the repair bill.

Regardless of what method you decide to utilize to reduce your costs, make sure that you are making sell/keep decisions on a total cost of ownership basis, not just on one or two factors.  Looking at all costs as a system instead of isolation will result in determining the optimal time to replace a vehicle with objective data, not just a “gut feel”.  You may just find that you are spending more in additional maintenance than you would in buying a newer vehicle.

Optimizing Shop Layout for Peak Performance

Shop layout is something that if you brought 10 companies together and asked for their ideal layout you would get 10 different answers.  This is because no two trucking companies are the exact same with the same fleet size, makeup or territory.  What will work for a regional carrier that has every vehicle back most nights will not be optimal for a cross-county truckload carrier that has trucks leaving every day of the week.  That said, every shop will have some similar guiding principles – safety, an ergonomic working condition, improved productivity and energy savings.  However, there will be a large degree of variation on how fleets accomplish these objectives.

To start there are two basic configurations for tractor-trailer fleet – a drive-through shop and a pull-in structure.  Both have their strong points depending on your geographic locale. A drive-though bay tends to be safer through the elimination of the need to back a vehicle either into or out of the work bay.  A drive-though layout also increases ventilation as both bay doors can be opened to allow for a cross-breeze and disburse any heat.  However, in a colder climate a pull-in structure allows for doors to be installed at only one end making heat retention much easier in the winter.  For a pull-in layout, additional forms of mechanical ventilation will be needed to keep temperatures comfortable in the summer months.

The number of bays is also important.  One issue some fleets run into is having the same number of technicians as there are bays.  The National Association of Fleet Administrators recommends a ratio of 1.5 to 2 bays per technician.  This is to remove the need to pull a vehicle out of a bay while a technician is waiting for parts to arrive.  Any unnecessary shunting is a waste of time and an avoidable cost. This also keeps your techs working on vehicles and staying productive by doing the skilled labor you are paying them to for.

The size of the bays is another critical factor.  Obviously, it needs to be long enough to accommodate whatever equipment you will be working on.  What may not be so obvious is the width of each bay.  It needs to be able to accommodate the maneuvering of trucks, technician work areas and storage for parts and tools.  Finally, keep the height of the shop as high as possible.  Workers will need the space to work on top of trailers so things like overhead cranes and fall arrest systems need to have sufficient overhead space for a technician to safely work.  If you build it high enough that the space can be converted into warehouse space, then you have made your building more valuable if you outgrow it and need to repurpose it.

The overall design of your shop should be directed at maximizing technician productivity.  One expert recommends building workbenches between each bay and equipping them with common tools such as grinders and vices, instead of only providing them in centralized locations.  This will reduce the amount of time spent looking for an available workspace or tool.  Additionally, look at having your bays designed for cleanliness.  Have the floor painted and provide cleaning items such as shovels, mops and brooms at each bay and make the technician responsible for keeping them clean.  A clean floor reduces slips and falls, making the facility safer for everyone.  Keeping the floor clean will also reduce any losses caused by vehicles running over tools or parts that have been left sitting on the bay floor.

While we are looking at safety, ensure that there is adequate lighting within the bays.  Begin by allowing for as much natural lighting as possible through either skylights or windows.  Next pick a lighting technology that provides a relatively white light.  High pressure sodium lighting gives off a yellow hue, which can make faded wiring look like the same colour.  There are a lot of modern LED lights that provide a white light and are significantly more energy efficient than incandescent bulbs.  They may cost a little more up front, but they tend to have a lower life-cycle cost.  Painting the walls white will also help to reflect the light and make your shop have a brighter interior.

Another common theme when building or reconfiguring a shop is to plan for the future.  Avoiding the use of load bearing walls will make a future expansion easier to manage.  Also remember to leave enough physical land space to allow for future building.  Putting your wall ten feet from your property line is not going to help you add usable shop floor space in the years ahead.  Having enough space in your electrical panel for future growth is also important.  While you are considering it, ensure that your utility room is large enough to handle things like a larger air compressor, a larger air dryer or just more circuits.  While it will cost more to put that capacity in up front it is generally more expensive to retrofit later.

The last thing to look at is the IT infrastructure that you provide your technicians with.  Are you providing computers for them to put in their work orders in a centralized location or are they closer to the bays?  To properly outfit a computer and a suitable cart or stand you are likely looking at around $2000 per machine.  That might seem like a lot to spend on a computer that is being used to enter in work orders, clocking onto job lines, entering comments and billing out parts.  However, let’s use an internal cost of $1 per minute for your technicians’ time and they spend 10 minutes a day just walking back and forth to a centralized computer that $2000 has a 200-day payback based on lost productivity – less than 1 year of working days! There is starting to be a trend towards outfitting the technicians with a ruggedized tablet that allows access to your shop management software as well as having some of the OEM diagnostic software available.  This will allow the technician to enter jobs, notes and parts in real time as well as pulling ECM data at each service to allow for predictive and proactive maintenance.  Your ROI will not only be based on the avoidance of unproductive time spent walking to a computer but also in the reduced inventory shrink caused by missing to bill all parts out to a job.

Not everyone will be able to do all these ideas – either because of budget or space restrictions.  However, it will be a good exercise to compare your shop with these suggestions and do a payback and ROI for each of them.  It’s possible that some of these items could free up enough time to either reduce headcount or having the ability to redeploy employees to a different shift – perhaps offering an evening or weekend shift to take advantage of when equipment is sitting idle.  You may just find out that a reasonable investment now could result in an improved bottom line going forward.

Stop Reacting to Breakdowns and Start Avoiding Them

Most of our shops handle preventative maintenance programs reasonably well in terms of oil changes, brake linings, and possibly even things like diesel particulate filters and automatic transmission services.  But what about other items that fail at a relatively similar rate such as DOC (diesel oxidation catalyst) inlet or outlet valves and NOx sensors.  These items are an integral part of the emissions control systems and are common causes of on the road repairs.  There are some reasonably inexpensive ways to move from being reactive to proactive.

Step 1 – Collect Your Data

The first way is by simply examining your repair records for patterns.  For example, have you recently seen a string of a certain component failing?  Have you had several on the road breakdowns all with a certain make of truck or engine?  At a minimum you should be keeping a spreadsheet tracking each breakdown, what components failed and at what mileage.  Even better is to have a report set up in your maintenance tracking program that will pull this information for you as well as things like truck make and model as well as engine make and model.  In fact, if your maintenance program does not have such a report you should consider either getting them to create one or hire a programmer to do it yourself.  Ideally, you should be able to tabulate the reasons for the breakdowns and what failed.  Include both on the road repairs and any work you did inhouse.

An additional step you will want to track is how much each breakdown costs you – did you need to put a driver up in a motel, did you need to rent a replacement tractor, was a tow required, or did you just have to pay that driver to sit while the repair took place.  Also include a per day rate for just having the equipment not being utilized – it may not be an out of pocket cost, but your company still incurred it.

Finally, you may have new equipment that you have not previously bought, or you may not have enough data on to make an informed decision on.  In this case networking with other fleets to determine failure rates and approximate mileages will have to suffice.  Other sources of information would be your dealership, a local maintenance association, attending a TCA convention or event or meetings of your state trucking association.

Step 2 – Evaluate Your Findings

Now that you are armed with this data, what do we do with it?  The first thing you are going to do is to start with your 4 or 5 most common failure points.    By focusing on a few common items, you can keep things manageable.  Next do a root cause analysis as to why those components failed.  For example, if you have a specific sensor that regularly fails do you tend to see a specific reason for that failure – say a damaged wiring harness or is it general wear and tear.  In this example, if it is a damaged wiring harness then ensure that your PDI service for that engine includes something like installing additional wire loom around that harness.  If a simple modification is not apparent, then look for trends as to when the component fails – either by time or by mileage.

Step 3 – Develop an Action Plan

Using our sensor example again, let us assume that there is no discernable reason why it fails, but you can see that the failures mostly come in a range between 200,000 and 225,000 miles.  This failure generally affects 50% of your tractors.  Please note that your costs may vary, and these are purely for illustration purposes:

Repair Costs:

Sensor                                  $200

Labor (1hr @ $100/hr)   $100

Total                                      $300 per vehicle


Breakdown Costs:

Tow                                       $400

Motel                                    $80

Meals                                    $20

Layover Pay                        $100

Staff Time (1.5hr)             $75

Lost Utilization                  $200

Total                                      $875


Normally when this sensor fails it is covered under warranty.  While I normally would not recommend forgoing warranty dollars, in this case it may be more cost effective to replace the sensors proactively. In this example each replacement would cost $300 and only half of the tractors incurs a failure, so you are spending $600 in replacements for every failure.   Regarding the lost utilization cost, the vehicle was down and not creating revenue for 24 hours at a cost of $200 per day (this will vary based on the purchase price, the term of the loan, etc.).  Overall each breakdown is costing you $875 between out of pocket and implicit costs.  At $600 to cover the replacements needed to avoid a single breakdown you have an immediate payback to give up the warranty dollars and do a proactive replacement.

Once an action has been determined to be economical, create a proactive program that will be applied to coordinate with a preventative maintenance point. Ensure that your technicians are aware of the required repairs and provide any necessary training.

Step 4 – Follow up, Evaluate the Program and Look for any Improvements

They say that the proof is in the pudding and in this case the proof is measured in a reduction in breakdowns caused by the component you are proactively replacing.  This is a step many of us neglect.  However  However, without it you can’t properly determine if the program delivered.  If you reduce the failure rate to 10% then you can call the program a success.  However, if the failure rate barely changes then you need to go back and look for something that the first analysis missed.  Regardless of the results you should redo your root cause analysis to determine if there are any further steps that pass the cost-benefit test.  Continue to look to other sources to see if the manufacturer has made any changes that require a change in the trigger point for the program – a new design may not fail until 300,000 miles meaning that an extended interval will result in fewer replacements per year and lowering your costs.

Finally continue to review your breakdowns and repairs to update your top five to ensure that you are keeping up with any changes in technology and stay ahead of the curve.

A Blood Test for Your Trucks

Your engine’s oil is the equivalent of your blood.  When your doctor wants to know what is going on inside you he doesn’t head you straight to the surgery.  She likely starts with taking a couple of tubes of blood and sends it off to a lab for tests based on what she has observed.  Showing early signs of diabetes – there’s a test for that.  Concerned about cholesterol and potentially blocked arteries?  Again, there is a relatively simple test that will show if further investigation is required.

The same thing is available for your truck’s engines.  Antifreeze in the oil is a major cause of serious repairs and engine failures.  There are many ways that antifreeze can get into the oil – failing seals, pin holes in liners or in the oil cooler among others.  By the time the oil is visibly discolored the situation has probably gone beyond the point of a simple and relatively economical repair.  A second major cause is fuel getting into the oil and diluting it or washing it off surfaces.  A bad injector or a damaged duel pump can cause fuel to leak into the oil pan and reduce the oil’s effectiveness.  Just as leaving an increased level of cholesterol could shorten your lifespan, ignoring any contaminants in the oil could result in a much shorter life for your truck’s engine.

When to start?

So when should you start an oil analysis program?  In short, right from the first oil change.  This gives you a baseline to compare future test results against.  By doing testing right from the start and then at every drain you will see when problems start – not just dealing with them when the truck is at the side of the road and waiting for a wrecker.  Beyond avoiding an on the road breakdown, there are a few other reasons you will want to do oil analysis on every drain.

Why to use oil testing?

The first reason is to determine if you are on the proper drain interval.  Many of us use the same mileage interval for all engines.  Without doing testing you may be losing an opportunity for an extending the distance between oil changes.  Alternatively, you may find that a specific run of engines requires a shorter interval to maintain peak performance.  Different manufacturers use slightly different metal alloys for their blocks, heads, etc., resulting in slightly different wear patterns.  In addition, different filter manufacturers may have a stronger solution for certain engines as opposed to others.  Brand A may be better for a Cummins while Brand B is superior on a Volvo and a Detroit may be best off with an OEM filter.  A similar discussion can be had with brands and types of oil.  Again, one engine may perform best with brand A’s conventional oil while another wants brand B’s semi-synthetic to get its best performance.  Your parts procurement department my just be focusing on price or single sourcing – both worthy goals – but without having some data that an oil analysis can uncover you may be increasing your total cost of ownership of certain equipment.  By paying a few dollars more for a filter or by dealing with an additional vendor or two you could find that you are able to extend you drain interval from 25,000 miles to 27,500 miles – an additional 10%.  If the truck is kept for around 600,000 miles, this means 2.5 fewer oil changes over it’s lifespan – a savings of between $500 and $1000 per truck over the time you own it.  This is only the lowest hanging fruit.

A more valuable return is in the detection of any contaminants in the oil – fuel, anti freeze, metal, etc.  Here you need to work with your lab to determine what is the correct level for an alert to be shown.  For example, many experts believe that even a trace amount of anti-freeze in the oil is too much and should trigger further investigation.  In terms of fuel dilution, the trend may be more important than just it’s mere presence.  The level of cleanliness of the oil and its trend should act as a trigger, especially if it is getting worse.  This could point to a change in operating conditions that may warrant a shorter drain interval or it cold point to a bad batch of filters.  The amount of metal in the oil is an item that both the quantity and the trend are important. Seeing an increasing amount should trigger an investigation into where it is coming from and what steps can be taken to prevent an over the road failure.  At the same time, comparing the amount to other engines of the same make/model and similar mileage could point towards a component that wears out more rapidly than with other engines.  Having that knowledge can allow you to create an additional maintenance point for those engines to either replace that part before they fail or at a minimum create an inspection program to monitor that item.

The reports you get back from the lab need to be reviewed, not just filed away in a cabinet.  At a minimum your maintenance manager needs to be looking at them for any alerts that the testing company.  Ideally, they are looking at the results against the last report to identify any items that are trending the wrong way.  Any of these items should result in a vetting program being triggered as they may or may not signify that a condition exists.  What should be put in motion is a further series of diagnostics that could include during a further, more intensive oil test as well as doing a more general computer diagnostic of the engine to look for any indications of a condition.  While we are discussing it, connecting your vehicles to a diagnostic computer at each preventative maintenance service is also a best practice as the data download will add to your predictive analysis toolkit!

An ROI on avoiding breakdowns is much more subjective, but here are a few costs that come with a breakdown:

  • An unhappy and unproductive driver. You are going to have to pay for layovers, motel rooms and meals at a minimum each time a major failure happens on the road.
  • You will likely be paying more for an outside shop to do the repairs. At a minimum you have likely required the services of a tow truck to bring your vehicle into a repair facility – a cost that could have been avoided
  • The per day cost of just owning that vehicle (payments, depreciation, licenses and permits, etc.) for the days that it is sitting there not generating any revenue.
  • Unless you can use a repair facility that you either already have an account with or that you can use a nation account, you are going to need to pay for the repair once it has been completed instead of having a 30-day (or greater) payment term. On a large repair the implicit financing costs could be significant, in addition to the costs of issuing a T or Com Check or using up credit card limit space.
  • Potentially the cost of a replacement vehicle if the repair can not be made in a timely manner due to shop capacity, availability of parts, etc. This again is a preventable expense.
  • The cost of a service failure to your customer, either in the load waiting for the vehicle to get repaired before delivering the load or the use of out of route miles to send another driver in to recover the load.

Best practices

Here are a few best practices that the Noria Corporation recommend for oil testing:

  1. More frequent testing and inspection. In short, do it every oil change.  Infrequent testing makes it much more difficult to catch faults and root causes before they become failures.
  2. More comprehensive examinations. Cutting back oil testing (both in terms of quantity and quality) can be a false economy.  It’s only by using a wide enough net that you can capture enough data to guide your techs towards areas that need attention.  This applies to all areas of condition monitoring.  The exact amount of monitoring may be different from company to company but spend the time to determine what works for you based on some of the failures that you have encountered in the past.
  3. Pin-drop sensitive alarms and limits. Keeping in mind that with regular testing an alarm should be considered just a trigger for further monitoring, having more alarms because of tighter limits is a good thing.  This puts your staff in the habit of looking for warning signs during an inspection instead of just reacting.
  4. Be wary of too few reportable conditions. Noria finds that on average 30% or oil reports should have some sort of reportable condition and not less than 10% (unless you are looking at very new vehicles).  Alerts do not mean your maintenance team are failing.  On the contrary they are a way to encourage continuous improvement.  Finally, they allow your shop to focus its efforts on items that provide the most uptime for the lowest cost.

Oil analysis is both a form of insurance as well as another diagnostic tool that you can use to predict failures before they happen and correct them during scheduled downtime instead of a on the road emergency.  Just as you would not send a mechanic to do all repairs with a hammer, think of this as an additional source of information that will guide your shop to use its resources more wisely, reduce overall ownership costs and be more efficient.

Tire Maintenance 101

We all know the importance of tire safety but were you aware of just how much they can have an effect on both your CSA ratings and your fuel usage? Unfortunately tires are a place where a driver could shave some time off their daily inspection – most of us have either just kicked or thumped on a tire to see if the pressure is “good enough”. Unfortunately “good enough” could be costing you.

To start, not having your tires at the proper pressure can cause premature wear, a reduced contact patch and increased rolling resistance. Additionally there are 12 possible tire violations possible during an inspection and all of them can result in the vehicle being declared out of service.

The Basics

Where’s a few basics – tire pressure can’t fall below 50% of the sidewall maximum pressure (note OHSA requires tires to be able to maintain a minimum of 80% and any that are running at less than this must be taken off the vehicle and re-inflated in a cage). There can’t be any audible air leaks. No belt material can be showing, not even from a sidewall cut. Tread and or sidewalls must not be separated. Steer tires must have a tread depth of no less than 4/32” and drive tires no less than 2/32”.

If you are looking for a driver gift that will have a great ROI, outfit all of your drivers with air pressure gauges and tire depth tools. Train your drivers on the proper way to use them and get them to document these on their inspection sheets. Make sure that the gauges are made for truck tires, both in terms of pressure and that they are long enough to be used on the inner tires. Why are these a good idea? Studies by Michelin have found that under inflating your tires by as little as 10% (which will not be noticed with that kick or thump) can reduce tire by between 9 and 16% over its lifecycle. On a $400 tire that means additional costs of between $36 and $64. Multiply that by 10 tires for each tractor and there is some serious money to be gained back by investing in approximately $20 of equipment!

Watch those pressures!

A lot of our shops use a generic rule of thumb for tire pressure – most will go with 100 psi. However, this may or may not be the optimal pressure for your tires and/or application. Work with your tire supplier to determine what will be the best pressure. Some tires wear better at 110psi while others operate better at 95 psi. That is where having a trusted tire vendor who knows your fleet and operations is important.

There are a few other things to keep in mind when your drivers are checking tire pressures. First, never check pressures after the tire has been run and is warm. This situation will result in a higher reading than if you check the pressure when the tire is cold. Two – try to maintain pressures for a loaded situation. This will make sure that you set your pressure at a “worst case” scenario and ensure that your tires have the ability to handle the loads you haul.

Mismatches are not good

Some other best practices include matching tread depths and tread patterns. We all have had to throw a mismatch on in an emergency, but doing so on a regular basis can cost you more than you think. Just a difference of 5/16 of an inch in circumference (which will be barely noticeable in tread depth) can result in the smaller tire being dragged up to 13 feet in a mile, or over 200 miles for every 100,000 miles of use. That could be the difference between a drive tire being a good enough casing to recap or not. Just having a slightly different tread pattern could result in that difference.

Some tire maintenance items that you may be missing

Rotate your tires. Bridgestone engineers have found that the first two rotations are the most important as the tires are still setting up their wear patterns. When the tread depths are at their deepest the blocks are more susceptible to wear. This is because once they get shorter they tend to stiffen up and get some resistance. They have also found that there is no magic number when it comes to when to rotate tires. Each individual company will have a different operating area and use pattern that will affect what works best for them. The best idea is to set an initial threshold and then study the wear patterns and extend or reduce the intervals as necessary.

Do a three axle alignment. If your drive axles are misaligned then the truck will want to go straight but the rear end will dog track and wear out the front tires more quickly. Additionally, don’t just use a standard alignment setup. If you tend to do tight turning radii then you may want to set your scrub to a higher level. Again, work with your tire rep to determine what the ideal toe-in/toe-out are for your application, even if they take you one of the extremes of the tolerances.

The last thing is wash the tires on a regular basis. Your tires are constantly picking up chemicals, mud and debris as they roll down the road. Leaving these items on the tires can speed up the deterioration of the rubber which can result in things like tread separation or just increase the air leakage through the sidewalls (a relatively normal amount is about 1 psi per month and 1 psi for every 10 degree drop in temperature). A wash will remove those items and prolong your tire life.