Sunday, May 1, 2011

Valve Stems & Extenders


Maintaining proper tire pressure is essential to a good ride, longevity of the tires and most importantly, your safety. As delivered from the factory, your Lazy Daze does not provide a convenient method for checking the pressure in the rear tires; the stock tire valves are hard to access with a pressure gauge. Most experienced LD'ers will recommend the addition of either valve extenders or longer, curved solid stems; either one will make life a lot easier....and safer.
Extenders, such as the common braid-covered type, are simply hoses that are added onto existing valve stems. Although many LD'ers have used these with no problems, they are somewhat failure-prone.
- The braided flexible stem can rub against the sides of the openings in the tires and wheel covers and develop a leak. For that reason, it is recommended to put a slit piece of clear plastic tubing around the edge of the wheel cover hole to reduce the risk of the extension being cut.
- Extenders should never be used with rubber valve stems. Many of the failures with extenders are not with the extenders themselves, but with the rubber valve stem. Being rubber, the stems are affected by the weight of the extenders and are flexed as the wheels roll down the highway at different speeds. Eventually the rubber fails, leading to a possibly catastrophic loss of tire pressure. If you use extenders, you must replace the rubber stems with metal ones. A few years ago, LD's started being delivered with metal stems. The outer end of the extender can and should be firmly held in place with clamps or pop-rivets on their brackets.
- There are 2 types of extenders: the better ones have an inflation pin that runs the length of the extender and keeps all tire pressure confined to the tire and short valve stem.
- Advantages: 1) Less Expensive. 2) No pressure within the extended portion, so a fracture will not cause loss of pressure in the tire. 3) All wheels are the same so regular tire rotation is no problem, you just move the extenders to the proper location.
- Dicor and Camco are two manufacturers of extenders.
-- Dicor part numbers:
--- Outer rear dual wheels: use Dicor's Air-Gard 125 degree stem extenders. In a Coast RV supply catalog it is part #92-9280
--- Inner rear dual wheels: use Dicor Air-Gard LS-534N-1F stem extenders. Coast Catalog part #92-8080. (Part #92-8079 for E-350)

--- Front wheels use Dicor's Air-Gard 45 degree extensions. Catalog #92-9221.
Formed valve stems, such as those from Borg or Chuck "Tireman" Carvitto, are long, rigid metal tubes that replace the existing short valve stems. Long stems like these are generally a more reliable solution than extenders.
- A lot of folks swear by the Tireman's custom-formed brass stems ($130-$140), which can obtained from Chuck at The Tireman.
- The Borgs stems are available in either brass or chrome-plated brass and were $110/$120 for a set of four. They're available from Borg Equipment & Supply in Tujunga, CA (800-300-2674)
- Advantages: 1) Very easy to check pressure and add air if necessary.
- Disadvantages: 1) Expensive. 2) Identifies each wheel position as inside duel, outside dual or front making tire rotation very difficult and impossible to follow recommended rotation sequences without dismounting tires from rims. 3) Air in the stem is under pressure so a fracture of the stem (while unlikely) will cause loss of pressure in tire.
Caution: For either type, be sure to carefully follow the proper installation procedures. At the minimum, you might end up with a slow leak; at the worst, a sudden failure and total loss of pressure. For example......
An LD'er bought new tires in January and moved to Borg metal stems. In March, he had a leak in the 2 of the 4 rear wheels at the valve stem. He took them to a tire shop which claimed they were installed incorrectly and 'fixed' them by removing a washer. The original installation was correct as detailed in the manual, but the 'fixed' version is holding up so far. He reports that he would buy the metal stems again, but would be more careful about who installs them. He suspects the original installation just wasn't tight enough.

If one buys a kit (from whichever source), here are three suggestions (in addition to choosing a competent shop; not always easy!):

- Familiarize yourself completely with the kit contents (are all the "pieces" there?) and understand the installation procedures *before* heading for the shop.

- Second, ask the service writer for the "tech" with experience installing long valves, and, if at all possible, monitor the installation!

- Third, check the installation carefully before paying the bill and leaving the shop:

1. Get a flashlight and be prepared to get down and look at the installation on the inner dual.

2. Remove the wheel covers (or better, ask the installer to leave these off until the job could be checked) and make sure that the rubber support grommets were used and that the valves are installed straight and not "tweaked".

3. Replace the wheel covers and make sure that the valves aren't rubbing on the side of the holes; this is a problem with the 8-hole configuration KII wheel covers used through 2006. You can have the wheel cover holes on both wheels enlarged using a plasma cutter to accommodate the inner dual valve. (The 4-hole wheel covers - 2006 > present - apparently have their own problems, but I can't speak to those.)

4. If you had air-through Alligator caps on the original valves, did the shop remove these and replace them on the long valves or just stick a cheap valve cap on the new valves?

5. Check the pressures on all 6 tires, and adjust to your rig's "specs". The tires should be cold, so one should get an accurate reading. It's likely that the shop has inflated all the tires to the "on the sidewall" max of 80 pounds.



Moral of the story - a poor install can ruin even the best of products.

Whichever type of stem you use, you can simplify the pressure-checking chore considerably with the use of inflate-through-cap stem caps. With these you do not have remove the cover to check the pressure or add air. An added benefit is that they extend the length of the stem a bit so the wheel cover doesn't interfere with the air chuck. One well-regarded brand is the Alligator V2b air-through valve cap; these are made in Germany, and are of very high quality. Myers Tire Supply (registration required) is one source, but the caps are sold only by the box:
http://www.myerstiresupply.com/shop/shopexd.asp?id=263&info=V2B-Inflate-Thru-Valve-Cap

Expedition Exchange sells the caps individually, but the price per cap is considerably higher than Myers:

http://www.expeditionexchange.com/air/

Contributors: Steve K, Joan Taylor, GaleLynn, Andy Baird, Rich Gort
Revised 3 May 2011
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