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Crossfire Dual Pressure Balancing & TST 507 System


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#1 Adonh

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Posted 07 May 2013 - 04:48 PM

I have an Airstream 39' 396 XL Diesel pusher on a Freightliner chassis with 275/70R 22.5 tires and rims with rear duals. I have been looking at the Crossfire dual pressure balancing device and a TPMS such as the TST 507 system and would like to get some feed back from the forum.

 

Thanks

 

Don


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#2 Tireman9

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Posted 09 May 2013 - 11:12 AM

I strongly support having a TPM system on all RVs including towed vehicles. If you get a puncture in your daily driver (car), there is a good chance you will feel it before it completely lets go but not in a big RV and especially not on a towed trailer of towed vehicle.

 

I, however am not sure of the benefits of having a hose connect both tires of a dual pair. If you use a good hand gauge the 1 psi difference is not meaningful and there is a possibility of a leak in one tire causing the 2nd tire to also loose air.


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#3 SSultany

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Posted 24 May 2013 - 02:30 AM

I agree with Tireman9 that any Big Rig should have a TPM . . .as it will save a lot of pre-trip tire pressure testing and give you the piece of mind that you WILL be informed . . .  in real time when any of your tires start to leak or get punctured. 

 

According to the experts, tires always lose pressure FIRST, before they get hot and blow out/explode. The TST gives you warning when any tire falls below the pressure limit that you set.  It gives you a margin of "time" to slow down, pull over while you tires are still on their rims.   ALL of the bad tales you hear about tires blowing with debris going into the bedroom/coach are due to the Driver not knowing that the tire has become overheated . .. due to loss of pressure. He finds out when it ruptures and . . .  if it comes OFF the front rim, you are in a world of hurt! 

 

Our 38' SAFARI has the TST 510RV Tire Monitor System with sensors on all  6 tires. The monitor can handle up to 18 separate tire sensors, in case you have a Toad - those tires can be monitored too. The newer TST 507RV system has user replaceable batteries for the individual tire sensors, which is probably what I would buy today.

I never leave home without it being turned ON. . . and no I am not a TST employee.


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#4 Xplorer

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Posted 24 May 2013 - 07:07 AM

I just installed 6 TST 507RV Tire Sensors on the Toad and 2 front tires of the MH.  I will install sensors on the rear tires next week when the weather clears.

 

After a little learning curve on setting the sensors to be read by the monitor, I tested the sensors on the Toad by using the monitor while driving a couple hundred miles around the area going different locations on the Interstate and city roads.

 

Once set, it works great.  Now while towing I don't have to be too concerned about the tires, if i pick up a nail etc.

 

I received the initial shipment from tst in 3 days at a temporary address.  I will receive the additional 4 sensors today 3 days after placing the second order.

 

The car has short rubber valve stems.  They are situated with enough clearance that they do not rub against the wheel covers while running down the interstate.  However, when I get a chance, I will probably change out the rubber stems for metal.

 

The MH has steel tire stems.  It was a little challenge getting them on the front wheels due to the location of the tire cover.  I needed about 1/4" to be able to install them without hitting the wheel covers.  I talked to a tech at a local trucking company, and he told me I could carefully bend the stem.  He indicated that is what they do all the time on the big trucks when installing them.  I used a rachet and socket as he suggested, and very carefully bent the stem the 1/4" needed for clearance.

 

The monitor picked up all 6 tires within seconds and as I monitored them during the day, the heat from the sun caused a change which was recorded on the monitor.

 

I am convinced and confident that the system works as advertised.  

 

One more toy, but an important one.  I did a lot of research on tpms systems over the last year.  I think they all may be comparable, but I went with the tst for the ability to change the batteries myself, and their reputation for customer service.

 

The sensors are lightweight and easy to install with the special wrench sent with the package.  They sent 2 wrenches, I keep one in the car and one  in the MH.

 

Good Luck with your choice.


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#5 billbaldwin

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Posted 24 May 2013 - 11:59 AM

I run Crossfire’s on everything with duals.  Good indicator for over under inflation.

One connection to fill both tires.  If one tire has a sudden loss of air the system blocks that tire away so you will not drain both tires.

With good tire maintenance practices, check pressure before a trip and each morning before you start, I see very little advantage to TPMS Systems.

The cost/benefit is out of line.  TPMS will not save you from a blowout, good tire management will.

The Crossfire will show if you’re over or under pressure at a glance.  Proper pressure at the start of the day is the key.  It’s not unusual for tire pressure to change by 5 to 7 psi under normal conditions and even more if altitude/temp changes during the day.

 

The toad might be the place for TPMS.  Again the key is to keep an eye on your tires, all of them.

I check my tires at every stop and the Crossfire make this easy.


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#6 Tireman9

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Posted 24 May 2013 - 02:21 PM

IMO running tires without TPMS would be like eliminating your engine temperature and oil pressure gauges.

 

If you think running without a TPMS is OK, I would challenge you to give yourself this test.

Get some tape or even a post-it and cover your water temp & oil pressure and Tach and any other gauge other than speedometer. Then set of you your days travels.  If you take a rest stop just check to see if you are leaking any fluids by looking under the coach. NO PEAKING under the taped over gauges.

 

See how long you are really willing to go without having this information available to you as the driver. If you peak even once then you are indicating you really know you need to know the operating pressure & temp of the engine, so what makes you think that checking the tires once in the AM and simply looking at your tires at each rest stop is good enough?

 

Yes, TPM is relatively new technology while engine gauges have been around longer than most of us. but why not use the benefit of TPM. The data says on average the RV owner will have at least one tire failure per set of tires. The cost of a single tire failure is more than the cost of TPMS and some TPMS can be transferred to your new vehicle or just replace the batteries.

 

I think they are a definite plus when it is time to sell your rig.


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Indy 2012, and Perry 2014

I am scheduled to present two seminars on RV Tires & Three on Genealogy at Redmond, OR  in August

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#7 billbaldwin

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Posted 25 May 2013 - 09:40 AM

Your right running without gauges would be foolish at best.  But this is not apples to apples.

You can't see your disk brake temp? 

I agree monitoring your tires is never a bad thing.  But you can not leave it to the gauges....

The cause of most blow outs is hitting something in the road or a degraded tire.

Modern tires can easily handle a range of pressure without damage.

I say if someone has $600 to spend get the TMPS.


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#8 thrushl

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Posted 31 May 2013 - 06:38 PM

I have an Airstream 39' 396 XL Diesel pusher on a Freightliner chassis with 275/70R 22.5 tires and rims with rear duals. I have been looking at the Crossfire dual pressure balancing device and a TPMS such as the TST 507 system and would like to get some feed back from the forum.

 

Thanks

 

Don

 

Your right running without gauges would be foolish at best.  But this is not apples to apples.

You can't see your disk brake temp? 

I agree monitoring your tires is never a bad thing.  But you can not leave it to the gauges....

The cause of most blow outs is hitting something in the road or a degraded tire.

Modern tires can easily handle a range of pressure without damage.

I say if someone has $600 to spend get the TMPS.

 

The crossfire is a very important asset with duals.  The inside tire always runs hotter than the outside tire. Hence the air expands and the tire gets larger carrying more of the weight of the coach.  Additionally, with the crown of the road the problem gets worse. 

 

The $150.00 for the crossfire is a cheap investment.  


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#9 Tireman9

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Posted 23 June 2013 - 02:35 PM

I wonder how many think about the fact that a tire running higher pressure can carry more load than one with lower pressure. If an inner dual runs hotter due to less cooling air it obviously can carry a bit more load.  OD growth differences are essentially meaningless on steel body radials.

Road crown is already managed with the Load tables that give lower load rating for tires in dual application.

 

I would rather have TPMS that would warn me as soon as a tire started to loose a few psi rather than have one tire sacrifice part of its load capacity to try and keep its mate inflated when there is a slow leak due to a puncture or valve leak.


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Retired Tire Design and Quality Engineer (40 years experience).
Retired Professional race car driver.
Retired Police Driving Instructor.
Member, FMCA Technical Advisory Committee
Delivered Tire Seminar for RV owners & two seminars on Genealogy at FMCA Bowling Green 2009, Madison 2011,

Indy 2012, and Perry 2014

I am scheduled to present two seminars on RV Tires & Three on Genealogy at Redmond, OR  in August

See my blog www.RVTireSafety.com and subscribe if you want notice of new posts.


#10 thrushl

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Posted 04 August 2013 - 10:59 AM

I wonder how many think about the fact that a tire running higher pressure can carry more load than one with lower pressure. If an inner dual runs hotter due to less cooling air it obviously can carry a bit more load.  OD growth differences are essentially meaningless on steel body radials.

Road crown is already managed with the Load tables that give lower load rating for tires in dual application.

 

I would rather have TPMS that would warn me as soon as a tire started to loose a few psi rather than have one tire sacrifice part of its load capacity to try and keep its mate inflated when there is a slow leak due to a puncture or valve leak.

 

 

Well Tireman9, I got to agree with you on that point.  In my case, I have the TPMS monitor on the crossfire.  It only uses one sensor for both tires per side.  I set the alert on the TPMS very tight so I should be able to catch a slow leak as you rightfully highlight.

 

I'm thinking that this approach will give me the best of both capabilities. 

 

You think I am missing something?


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Traveling the country with two cats and a wife!

 


#11 desertdeals69

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Posted 04 August 2013 - 12:09 PM

I prefer not the have flex hoses and I have seen too many failures in our RV business the last 30 or so years.


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#12 ahepburn51

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Posted 05 August 2013 - 12:06 AM

I run Crossfire’s on everything with duals.  Good indicator for over under inflation.

One connection to fill both tires.  If one tire has a sudden loss of air the system blocks that tire away so you will not drain both tires.

With good tire maintenance practices, check pressure before a trip and each morning before you start, I see very little advantage to TPMS Systems.

The cost/benefit is out of line.  TPMS will not save you from a blowout, good tire management will.

The Crossfire will show if you’re over or under pressure at a glance.  Proper pressure at the start of the day is the key.  It’s not unusual for tire pressure to change by 5 to 7 psi under normal conditions and even more if altitude/temp changes during the day.

 

The toad might be the place for TPMS.  Again the key is to keep an eye on your tires, all of them.

I check my tires at every stop and the Crossfire make this easy.

 

A lot can happen between stops. Case in point: two weeks ago we left the house for a weekend outing with our club. I checked the tire pressures at the house and everything looked good. My wife was following behind me in her car and we stopped at a Camping World about 20 miles down the freeway. A quick tour around the coach showed that everything looked good. Got back on the highway, with the wife right behind me, and drove another 5 miles to the campground. When we got there the wife said that about a mile back she saw the inner dual on the curb side wobbling. A quick inspection revealed a brand new zipper had appeared in the sidewall.

 

Now, it happened after we stopped, so no amount of checking would have caught it. If the wife had not been driving behind me and seen the tire wobbling, I could have driven on until the outer tire blew from overheating. A TPMS would have alerted me to the zipper failure when it happened and allowed me to take action. Bottom line: I'd rather have a TPMS monitoring my tires than a connection between the two tires that is SUPPOSED to properly isolate them - it still won't alert you to a failure on one tire.

 

Your right running without gauges would be foolish at best.  But this is not apples to apples.

You can't see your disk brake temp? 

I agree monitoring your tires is never a bad thing.  But you can not leave it to the gauges....

The cause of most blow outs is hitting something in the road or a degraded tire.

Modern tires can easily handle a range of pressure without damage.

I say if someone has $600 to spend get the TMPS.

 

Common blowouts are indeed caused while driving - and it's those occurences that are best served by a TPMS monitor. If the tire lets go and does no damage to the coach then you won't know about it until the second tire fails from overheating - then you've got more damage to repair. In our case, the roadway was clean and smooth. I saw no debris that would have punched a hole in my sidewall, felt nothing when the tire let go, heard nothing, saw nothing out of the mirror or rear-view camera. My wife saw no debris emerge from under the rig - her only indication that something was wrong was the tire wobbling on the rim. A TPMS will alert you at once to the first tire failing, allowing you to get off the road quickly.

 

I just ordered a TST system, with 6 flow-through sensors for the grand total of $299 with free shipping - maybe they were $600 last decade, but the prices are much more reasonable now. Go ahead and connect your dual tires together if it makes you feel better, but it's no substitute for a monitoring system.


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#13 desertdeals69

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Posted 05 August 2013 - 11:58 AM

I was told by a tire mfg that a zipper split on the sidewall is usually caused by under inflation.  I had that happen to me before I installed Tire Minder system.  Now I will know when I am loosing air.


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#14 Tireman9

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Posted 05 August 2013 - 12:38 PM

Well Tireman9, I got to agree with you on that point.  In my case, I have the TPMS monitor on the crossfire.  It only uses one sensor for both tires per side.  I set the alert on the TPMS very tight so I should be able to catch a slow leak as you rightfully highlight.

 

I'm thinking that this approach will give me the best of both capabilities. 

 

You think I am missing something?

 

If you have the air pressure monitors in all your tires I think you have done a reasonable job.  If you already have the "crossfire system" I guess this would mean you could save some $ and just get a 4 sensor TPMS.

I do understand the concerns some have on hoses.

This is my set-up 209qedy.jpg

 

Note how I have the ends of the hose BOLTED firmly down. I think that it is possible that many of the hose failures are due to inadiquate mounting of the hose so it can move which could fail the hose and/or valve.


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Retired Tire Design and Quality Engineer (40 years experience).
Retired Professional race car driver.
Retired Police Driving Instructor.
Member, FMCA Technical Advisory Committee
Delivered Tire Seminar for RV owners & two seminars on Genealogy at FMCA Bowling Green 2009, Madison 2011,

Indy 2012, and Perry 2014

I am scheduled to present two seminars on RV Tires & Three on Genealogy at Redmond, OR  in August

See my blog www.RVTireSafety.com and subscribe if you want notice of new posts.


#15 Tireman9

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Posted 05 August 2013 - 12:42 PM

I was told by a tire mfg that a zipper split on the sidewall is usually caused by under inflation.  I had that happen to me before I installed Tire Minder system.  Now I will know when I am loosing air.

For those that may not know what a "zipper" failure is, here is an example.

2vki82v.jpg

 

This is what happens with a steel body tire, while Nylon or Polyester body ply melts, steel fatigues.  Think of what happens when you bend a steel paperclip back and forth.


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Retired Tire Design and Quality Engineer (40 years experience).
Retired Professional race car driver.
Retired Police Driving Instructor.
Member, FMCA Technical Advisory Committee
Delivered Tire Seminar for RV owners & two seminars on Genealogy at FMCA Bowling Green 2009, Madison 2011,

Indy 2012, and Perry 2014

I am scheduled to present two seminars on RV Tires & Three on Genealogy at Redmond, OR  in August

See my blog www.RVTireSafety.com and subscribe if you want notice of new posts.


#16 desertdeals69

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Posted 05 August 2013 - 02:44 PM

Thats exactly what mine looked 

 

For those that may not know what a "zipper" failure is, here is an example.

2vki82v.jpg

 

This is what happens with a steel body tire, while Nylon or Polyester body ply melts, steel fatigues.  Think of what happens when you bend a steel paperclip back and forth.

Thats exactly what mine looked like.


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#17 ahepburn51

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Posted 06 August 2013 - 07:02 PM

Here's what ours looked like, from the outside:

 

zipper1_zps3c417ebc.jpg

 

...and from the inside:

 

zipper2_zps8d759f6f.jpg

 

Right now we're waiting to hear back from Michelin how much, if any, help they will give us on replacing the tire. It only had about 2000 miles on it when it blew.


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San Jose, Ca, USA

RV: 2007 Bounder 35E Workhorse

toad: 2008 smart car or 2006 Ural Tourist

FMCA Member #F431612


#18 phranc

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Posted 07 August 2013 - 08:36 AM

I have the Crossfire and a single TPMS mounted on the crossfire indicator .. Works for me . A visual check at the fuel stops and an alarm when moving .

 TPMS on toad also. If I need to add air to coach it sure makes it easy


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#19 billbaldwin

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Posted 07 August 2013 - 03:46 PM

You have made a believer out of me.

I'm adding TPMS to my MH and Toad as soon as I can get them.


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#20 Tireman9

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Posted 12 August 2013 - 12:51 PM

Here's what ours looked like, from the outside:

 

 

 

...and from the inside:

 

 

 

Right now we're waiting to hear back from Michelin how much, if any, help they will give us on replacing the tire. It only had about 2000 miles on it when it blew.

 

If you bought a Road Hazard warranty should be no problem. Otherwise I have to wonder why Michelin should be responsible for a tire that suffered an air loss due to puncture, cut or valve leak?

 

Simply Google    Radial tire zipper failure    and you will find numerous examples


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Retired Tire Design and Quality Engineer (40 years experience).
Retired Professional race car driver.
Retired Police Driving Instructor.
Member, FMCA Technical Advisory Committee
Delivered Tire Seminar for RV owners & two seminars on Genealogy at FMCA Bowling Green 2009, Madison 2011,

Indy 2012, and Perry 2014

I am scheduled to present two seminars on RV Tires & Three on Genealogy at Redmond, OR  in August

See my blog www.RVTireSafety.com and subscribe if you want notice of new posts.





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