Crossfire System

[Rocket Jock]

This looks intriguing for reducing wear and improving the ride on rear duals. I ran across this a few days ago looking for replacement valve extensions that cracked in the cold from age. This thing may be old news to some, but has anyone tried this? I have often wondered what the difference in temps and pressures do to the duals, this seems to address all the issues, including slow leaks and blowouts.



https://truckpartsworld.net/product/...th-tpms-ports/


https://www.minderresearch.com/using...reminder-tpms/

[Isaac-1]

I installed one of these on my coach, which allowed me to run a MUCH cheaper 4 wheel automotive style TPMS system. Though one that supported the pressure range of my RV tires which operate at 80 psi

[powercat_ras]

I have used 85 PSI CrossFires for years on my RVs. They make the inner and outer tires wear evenly as they ensure both inner and outer tires equally split the load on the wheels on each side. It is also convenient for quickly visually checking that tire pressures are good when wheels and tires are cold. They also give you a direct access valve stem to add/remove air.

Between the CrossFire valve stem and each air line going to each tire, there is a one way air check valve that opens when air pressure is within 10 PSI of the CrossFire pressure. So on mine if a tire is at or above 75 PSI air can flow both ways to/from that tire. Below 75 PSI air can only flow into a tire, not back out.

Some things to consider:

My Vista has Ford F53 OEM Steel Rims and OEM Ford F53 Wheel Simulators. On this combination, there is no direct way to mount the CrossFires to this wheel configuration. I mounted the bracket holding the CrossFire to the center caps of the wheel simulators.

On this combination, the wheel simulator holes have sharp edges that will eventually cut into the steel braid covering of the air lines going to inner and outer valves. I solved this by placing some plastic wire loom sleeve around the air lines where they pass thru the wheel simulator holes.

[twinboat]

If the crossfire blocks the good tire from loosing air to the leaking tire, how can a single TPMS monitor both tires ?

Couldn't one tire be flat while the other is showing proper pressure ?

Do RV tires wear out or age out ? Even if you wear them out, how uneven would they be ?

[powercat_ras]

Originally Posted by twinboat

If the crossfire blocks the good tire from loosing air to the leaking tire, how can a single TPMS monitor both tires ?

Couldn't one tire be flat while the other is showing proper pressure ?

Do RV tires wear out or age out ? Even if you wear them out, how uneven would they be ?

> wear ???

Personally I found it difficult to keep inner and outer at exactly the same pressures so they would wear the same. Don't have to fight that anymore with the CrossFires.

> one tire flat other showing normal pressure?

CrossFire valve stem won't be showing proper pressure, it will be showing 10 PSI below the CrossFire pressure.

Worst case, one tire could be flat and the other at 75 PSI (10 PSI below the CrossFire pressure).

I set my TPMS to alarm at 5 PSI below the CrossFire Pressure. If one tire starts loosing air my TPMS alarms at 80 PSI. So you alerted that there's a problem on that dual tire pair, but you don't know which one.

If you are still losing air, the both tires will still be dropping pressure until the CrossFire closes the line to the low tire at 75 PSI. At that point you have one tire holding at 75 PSI and the problem tire at or below that. You also get a visual indication on the CrossFire "eye" instead of being yellow it will become red.

[Isaac-1]

Originally Posted by twinboat

If the crossfire blocks the good tire from loosing air to the leaking tire, how can a single TPMS monitor both tires ?

Couldn't one tire be flat while the other is showing proper pressure ?

Do RV tires wear out or age out ? Even if you wear them out, how uneven would they be ?

As mentioned above they will let air pressure drop to 10 psi below the crossfire rated pressure before fully closing, or alternatively they will slam shut in case of a blow out. I work from the attitude that I could detect a blow out without needing a TPMS, and have my alarm pressure set at a point above the 10 psi leak down range also.

[bobmac]

I have used 110# Crossfires on my Journey for 8 years and wouldn't be without them. They make topping up the tire simple and their visual pressure display can be checked for proper pressure every time I stop and do a circle check. I have had no issues with them although when the coach was pressure washed at a Blue Beacon, the operator cut braided tubing and the rubber tube near the tire valve and I had to replace the tubing. You will want to have steel valve stems on your tires if you intend to purchase a set. I find no need for a TPMS as our frequent stops to drain the dog provide an opportunity to circle check all tires amongst other things. Would recommend them to anyone!

[docj]

I had Crossfires on my MH for the first ~8 years we were full-timing during which we traveled ~50,000 miles. Although I used all the above arguments for having them I suffered repeated leaks and ended up replacing them several times.

When I replaced my drive tires last year I installed super long valve stems on the inside duals (not extensions) and I've been very happy with the result. Not sure why my experience was so different from those that have been posted, but I wanted to make people aware of a different point of view.

[Smitty77]

Going on year 7 or so. The trip before I had them installed, I took tire temperature readings when pulling off for fuel and or driving breaks. Inner dual was constantly higher then the outer dual, ranges of 5 to 7 degrees difference was not uncommon.

After having them installed, and doing the same temperature checks, the inner and outer were usually the same, or a few times a 1 - 2 degrees higher temp on the inside (This occurred usually when it was an extremely hot day, a few times traveling thru AZ it was 110+ when taking these readings. I speculate the inner dual was higher, due to the heat build up reflection from the roadway off of the chassis heating the inner tire. More air flow and on the outer tire.)

Also, on those extreme hotter days, it would not be uncommon for the axle facing the sun, to have higher temperature then the one on the shade side of the coach. And a few times, the outside dual (Sun side of the coach.) was the tire with the higher temperature. And due to the time that I was taking my first readings being in November, I did not have any times when he outside tire of the dual, was hotter then the inside...

I do monitor via TPMS, and I do like the sudden stopping of the air transfer due to a sudden loss of air in one of the tires. Reading low PSI still would transfer to the TPMS.

I believe they're a slick bit of equipment, and certainly does not harm or hurt tire safety in any ways. I believe the enhance tire safety.

Opinions vary!

Best to all,
Smitty

[BigLar368]

Originally Posted by Smitty77

Going on year 7 or so. The trip before I had them installed, I took tire temperature readings when pulling off for fuel and or driving breaks. Inner dual was constantly higher then the outer dual, ranges of 5 to 7 degrees difference was not uncommon.

After having them installed, and doing the same temperature checks, the inner and outer were usually the same, or a few times a 1 - 2 degrees higher temp on the inside (This occurred usually when it was an extremely hot day, a few times traveling thru AZ it was 110+ when taking these readings. I speculate the inner dual was higher, due to the heat build up reflection from the roadway off of the chassis heating the inner tire. More air flow and on the outer tire.)

Also, on those extreme hotter days, it would not be uncommon for the axle facing the sun, to have higher temperature then the one on the shade side of the coach. And a few times, the outside dual (Sun side of the coach.) was the tire with the higher temperature. And due to the time that I was taking my first readings being in November, I did not have any times when he outside tire of the dual, was hotter then the inside...

I do monitor via TPMS, and I do like the sudden stopping of the air transfer due to a sudden loss of air in one of the tires. Reading low PSI still would transfer to the TPMS.

I believe they're a slick bit of equipment, and certainly does not harm or hurt tire safety in any ways. I believe the enhance tire safety.

Opinions vary!

Best to all,
Smitty

We have had about the same success as Smitty over the last 4 years. Other than the stainless covering rubbing against the rims they have worked great. I have a TPMS system I used to use for my trailer but have never got around to hooking it up on the RV. I have never had to ad any air to any tire on a trip that we have made since owning the RV. Maybe we are just lucky.

[gmc70]

I installed the Cat's eye system which is the same thing as the crossfire. Very pleased with it. When filling with fuel all you have to do is look at window and know your pressure is right. I do not use a tpms. I like running the exact same pressure in both tires.