RV Tire Age, Batteries and Chassis Wear: The Hidden Costs That Sink Auction Bargains
RV tire age, not tread depth, decides whether the tires on an auction motorhome are safe, and a set of six or more large tires is often the biggest single bill you face after the hammer. Add dead batteries, trailer brakes and bearings nobody serviced, fluids that sat for years and a generator that will not start, and a bargain can carry thousands in deferred maintenance. This guide shows how to read each of these from a listing and fold them into your max bid.
Why RV tire age matters more than tread
Most RVs sit far more than they roll. A motorhome that covers three thousand miles a year wears out its tires by age long before it wears them out by tread. Rubber oxidizes and stiffens with time, sunlight and ozone whether or not the tire moves. The result is sidewall cracking, belt separation and eventually a blowout, which on a motorhome often takes the wheel well and plumbing with it.
Tire manufacturers generally advise annual inspection once tires pass about five years and replacement by around ten regardless of appearance. Many RV shops and experienced owners use a tighter working rule of six to seven years for tires carrying a heavy coach or trailer. Plenty of auction lots wear tires older than either, often with deep tread and shiny sidewalls, because the owner never drove enough to wear them.
Reading the DOT date code
Every tire sold in the US carries a DOT serial number on the sidewall. The last four digits are the manufacture date: two digits for the week, two for the year. A code ending in 2319 was built in the twenty-third week of 2019.
The full code is often stamped on only one sidewall, and the inner tire of a dual pair is hard to read without crawling under the coach. At an online auction, ask for a photo of the date code on each tire; many houses will provide it. Check that dates match across the set. Two new fronts and four aged rears is a common pattern that puts the whole rear set on your bill.
What a set of tires costs, in general terms
Prices vary with brand, size and region, so treat these as orders of magnitude.
- Travel trailers and fifth wheels run special trailer (ST) tires in common sizes. A set of four is usually the least painful line on this list.
- Class C and Class B motorhomes use light-truck tires on van chassis, typically six on a Class C with duals. Costs land in the same range as a heavy pickup.
- Class A motorhomes run 19.5-inch or 22.5-inch commercial truck tires. Each is several hundred dollars before mounting, and there are six of them, or eight on a coach with a tag axle. A full set on a large diesel pusher commonly runs well into the thousands, and it is one reason so many older Class As sell cheaply with ten-year-old tires on them.
Add mounting and balancing. If you cannot read the codes from the listing, assume the tires need replacing.
House and chassis batteries
A motorhome has two battery systems: a chassis battery that starts the engine and a house bank of deep-cycle batteries. Towables have only the house bank. Repossessed and surplus units often sit for months with small parasitic loads draining them, and a flooded lead-acid battery left flat for a season is usually finished.
Look for bulging cases, heavy terminal corrosion, a date sticker more than a few years old, and a listing that says the unit does not start or that slides would not operate. "Does not start" is frequently just a dead chassis battery. It can also be a real engine problem, so price it as one unless you can verify.
A chassis battery costs about what it would on a truck. A house bank ranges from a couple hundred dollars for a pair of basic batteries to well over a thousand for a larger bank, and far more for lithium.
Brakes and bearings on towables
Travel trailers and fifth wheels use electric drum brakes actuated by magnets, with wheel bearings that should be cleaned and repacked on a schedule most owners ignore. A trailer that sat outdoors for a couple of years often has rusted drums, seized adjusters, cracked wiring at the axle and a breakaway switch that no longer works.
At preview, look for grease slung around the inside of the wheel, rust on the drum face and frayed wiring, and test the breakaway cable if the battery is alive. Budget a brake and bearing service per axle at minimum, a full brake assembly replacement if the drums are scored, and remember that a triple-axle fifth wheel triples every one of those lines.
Chassis fluids and rubber on motorhomes that sat
A motorhome chassis that has sat for two or three years needs more than an oil change. Engine oil, coolant, transmission fluid and differential oil all degrade with time, and brake fluid absorbs moisture that corrodes calipers and lines. Gasoline older than a year varnishes carburetors and injectors and can take out a fuel pump; diesel grows algae and clogs filters.
A complete fluid service on a gas Class A runs a few hundred to low four figures at a shop; on a diesel pusher it is more, and that is before any faults the service turns up. Very low mileage on an older coach is a warning here, not a selling point.
Generator, propane and other dated systems
Generators that sit are the most predictable failure on this list. A gas generator left with fuel in it for a year usually needs the carburetor cleaned or replaced before it will run. Check the hour meter in photos, ask whether it was run at preview, and budget a service at minimum.
Propane systems age on a calendar. Removable DOT cylinders on trailers typically require recertification twelve years after manufacture and periodically after that, and many filling stations refuse an out-of-date cylinder. Permanently mounted ASME tanks on motorhomes do not expire the same way, but regulators age. Have the whole system leak-tested before the first fill; requirements vary by jurisdiction.
Appliances add their own lines: an absorption refrigerator that has not run in years may have a failed cooling unit and water heaters rust through when left full. Our inspection guide covers how to check each at preview.
Adding it all to your max bid
None of these items is a reason not to buy. They are reasons not to pay clean-and-serviced money for a unit that is neither. Build the bid from the top down.
- Start with the comp value for the unit in fair condition.
- Subtract buyer premium, sales tax, documentation fee and transport. Our fee guide walks through each, and the site's all-in estimate does the arithmetic, including a general reconditioning allowance.
- Replace that general allowance with your own list: tires if the codes are old or unreadable, batteries if the unit sat or does not start, brakes and bearings per axle on a towable, a fluid service on a motorhome, generator and propane service, and any appliance you could not confirm working.
- Subtract a margin for the risk you are carrying. What remains is your maximum bid.
Two habits make this work. Assume the worst for anything you cannot verify from photos or preview, and write the list down before the auction opens so a rising bid cannot talk you out of it. The bidders who get hurt on older motorhomes are rarely the ones who paid too much at the hammer. They are the ones who discovered the tire and fluid bill afterward.
Questions
How old is too old for RV tires?
Manufacturers generally advise annual inspection after about five years and replacement by around ten regardless of tread. Many RV shops and owners use a six-to-seven-year working rule for tires carrying a heavy coach or trailer, and plenty of auction lots exceed it.
How do I find the age of an RV tire?
Read the DOT serial number on the sidewall. The last four digits give the week and year of manufacture, so 2319 means the twenty-third week of 2019. The full code may appear on only one side of the tire.
Does 'does not start' at an auction mean the engine is bad?
Often it just means a dead chassis battery after months of sitting, but it can also mean a real engine or fuel problem. Unless you can verify, price the lot as though the more expensive explanation is true.
Do RV propane tanks expire?
Removable DOT cylinders on trailers typically need recertification twelve years after manufacture and periodically thereafter, and many fill stations refuse expired ones. Mounted ASME tanks on motorhomes do not expire the same way, but regulators age and the system should be leak-tested.