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AWD space saver spare tire?


ghostone

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Hi all, Does anyone know if the "space saver spare tire" that comes with the AWD vehicle is the same diameter as the (4) 19" wheels and tires that are on the vehicle.

I was wondering as I had heard that it isn't and with AWD this is a no no, hope someone can shed some light on this.

2009 SXT AWD Stone White

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The idea of the spare is to get you to the nearest service station so you can get the old tire repaired and reinstalled. Driving around with mismatched tires on an AWD DJ is an invitation for disaster with the drive train.

Note that if your tires have any significant wear and one of them fails and needs to be replaced, you are well advised to change the other 3 at the same time.

So it doesn't matter whether it is the same diameter or not, because even the difference between a new and partly used tire is enough to mess up the vehicle.

Also - make sure you rotate your tires regularly - all the more important with AWD.

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Thank you for the information bramfrank, here is a thought I have on this...

I wonder why...that when the computers for the AWD system do notice a mismatch for whatever reason it does not lock out the final drive clutch that is electronically controlled and illuminate the I/panel warning light till you correct the problem thus causing no damage to the system, this unit does not use a viscous coupling.

The AWD as used on the Journey is a Borg Warner model: ITM 3e

2009 SXT AWD Stone White

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Fair question, I suppose, but there'd need to be some intelligence in the system to differentiate between a persistent difference and one that originates with a wheel slip I suppose.

Perhaps a note to the manufacturer making the suggestion would actually get some attention . . . . no. . . . Really!!!

Edited by bramfrank
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  • Official Dodge Support
Hi all, Does anyone know if the "space saver spare tire" that comes with the AWD vehicle is the same diameter as the (4) 19" wheels and tires that are on the vehicle.

I was wondering as I had heard that it isn't and with AWD this is a no no, hope someone can shed some light on this.

2009 SXT AWD Stone White

ghost,

I was able to look in to this and have been advised by our technical assistance group that when the limited use spare tire is installed the wheel speed sensor registers that wheel is spinning faster and turns the AWD is system off - this is programmed in the ABS/AWD controller software.

Hope that helps.

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Thank you DennyB, that is what I wanted to hear, to recap my understanding of it then, using the limited use spare wheel would trigger the AWD/ABS controller to disengage the electrical coupling at the rear differential assembly and that would shut down AWD system, staying disengaged until the problem of wheel size is corrected...excellent, thank you again.

2009 SXT AWD Stone White

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Fair question, I suppose, but there'd need to be some intelligence in the system to differentiate between a persistent difference and one that originates with a wheel slip I suppose.

Perhaps a note to the manufacturer making the suggestion would actually get some attention . . . . no. . . . Really!!!

Hi again bramfrank, after what DennyB from Dodge Cares has said today...we do have an intelligent AWD system, so all the AWD Journey owners can sleep peacefully now.

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The idea of the spare is to get you to the nearest service station so you can get the old tire repaired and reinstalled. Driving around with mismatched tires on an AWD DJ is an invitation for disaster with the drive train.

Note that if your tires have any significant wear and one of them fails and needs to be replaced, you are well advised to change the other 3 at the same time.

So it doesn't matter whether it is the same diameter or not, because even the difference between a new and partly used tire is enough to mess up the vehicle.

Also - make sure you rotate your tires regularly - all the more important with AWD.

based on what i have read so far I have a question :

Lets say 2 years into having new tires you get a flat that cannot repair in one wheel. When replacing that 1 tire you might have to replace ALL based on the fact that wheel wear can mess with the AWD as that tire would have more tread on it ??

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Hi biohazard, from what I have read by AWD tire specialists on the web, they say in the situation you have mentioned you do have to replace all the tires if the remaining 3 tires have less than 50% tread life left on them, that equates to...50% tread life = 5/32" of an inch this has to be measured with a proper tire depth gage, a new tire has 10/32" of an inch tread depth, if anyone has other information on this please inform us.

2009 SXT AWD Stone White

Edited by ghostone
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  • 6 months later...
  • 4 months later...

From my real world experience with my 2010 R/T AWD . . . got a flat on the highway, pulled over right away when safe, changed the tire - put the temp spare on . . . started to drive and the car pulled to right (was right front that was flat) and AWD light came on. Was going slow, and then finally the pulling stopped, although the AWD light was on. I only had to go a little way into town to get the tire repaired. Once back on the car, and driving for about 1/2 a block, all warning lights out and drove normal again.

My question is, why can't there be correct size spare and not have the issue of AWD turning off and making you think that there is something wrong with the car ?????

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From my real world experience with my 2010 R/T AWD . . . got a flat on the highway, pulled over right away when safe, changed the tire - put the temp spare on . . . started to drive and the car pulled to right (was right front that was flat) and AWD light came on. Was going slow, and then finally the pulling stopped, although the AWD light was on. I only had to go a little way into town to get the tire repaired. Once back on the car, and driving for about 1/2 a block, all warning lights out and drove normal again.

My question is, why can't there be correct size spare and not have the issue of AWD turning off and making you think that there is something wrong with the car ?????

Weight and cost savings.

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  • Official Dodge Support

From my real world experience with my 2010 R/T AWD . . . got a flat on the highway, pulled over right away when safe, changed the tire - put the temp spare on . . . started to drive and the car pulled to right (was right front that was flat) and AWD light came on. Was going slow, and then finally the pulling stopped, although the AWD light was on. I only had to go a little way into town to get the tire repaired. Once back on the car, and driving for about 1/2 a block, all warning lights out and drove normal again.

My question is, why can't there be correct size spare and not have the issue of AWD turning off and making you think that there is something wrong with the car ?????

A12Rag,

@jkeaton is right, your vehicle ultimately costs less because your spare isn't configured to be a nice shinny rim with same tread as the others, saves space and weight too.

Using the spare would be considered a temporary necessity, likely the engineers didn't spend much time modifying the vehicle's functionality to compensate for this.

I know what you're saying though, it would be ideal if that didn't happen.

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Since the tire is an "emergency" temporary fix to a flat, the manufacturers can save a boat load of money by providing a "one size fits all" 16" space saver spare. The alternative, as in the "old days" was for the manufacturer to produce, store and supply steel wheels, spare tires and leave space for the various sizes of wheels in the design of the cars, during any given year in the design of the car. With the advent of the "one size fits all" space saver, the same spare on your DJ will fit the other MOPAR models also and thus MOPAR only needs one size for all of their models. Even in the "good old days", very few full sized spares came with styled wheels; they came with your basic weighs-a-ton stamped steel wheel. The space saver, saves space, saves weight (important for MPG) and manufacturing overhead. I'm just waiting for the run-flats to be perfected...then you won't even have a spare saving even more weight and cost. You'll get a flat and then have to drive the run-flat to the nearest tire shop to get it replaced...not too many years in the future. Further "down the road" will be the no-flat tire; it will never go flat or be under-inflated. They are working on that one, too. The trick will be, will we be able to afford the tech?

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  • 1 year later...

I have 19" wheels on my 2009 R/T. This morning I woke up to a flat tire on the drivers side. I replaced it with the spare tire so I could drive it to the repair shop. During the entire time the DJ was on, the low pressure and awd! indicators were on and stayed on. In the middle of the trip, the low pressure light blinked for a short time and then reverted to solid on.

I am assured that the spare doesn't have a pressure sensor in the stem and that is the reason for the low pressure indicator.

When the awd! light is on what does that mean? Did the spare tire cause the computer to activate the all-wheel-drive system?

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I have 19" wheels on my 2009 R/T. This morning I woke up to a flat tire on the drivers side. I replaced it with the spare tire so I could drive it to the repair shop. During the entire time the DJ was on, the low pressure and awd! indicators were on and stayed on. In the middle of the trip, the low pressure light blinked for a short time and then reverted to solid on.

I am assured that the spare doesn't have a pressure sensor in the stem and that is the reason for the low pressure indicator.

When the awd! light is on what does that mean? Did the spare tire cause the computer to activate the all-wheel-drive system?

Quite the opposite. The light is telling you that the vehicle disabled AWD and that you were driving in FWD only. As stated in this thread, it is done to protect the AWD system and avoid damage... In short, it is supposed to do that.

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In theory... If you have a flat on a front tire, you should take a rear tire and move it to the front and then put the spare on the rear. What you wind up with is two of the same size tires on the front and the mismatch on the rear. The system disables the AWD, leaving you in FWD and the FWD runs without strain on its system because the two tire on the front are the same size. I had a 2000 Neon and that was actually in the Owner's Manual. FWD system is then matched, steering geometry remains stable and suspension is balanced and braking (the bulk of stopping a vehicle is done by the front brakes) remains stable. That's what I've been taught...the mismatch, being in the rear has less impact on vehicle stability and safety.

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Spare tires are slowly becoming a thing of the past. I've owned two "loaded" vehicles (Intrepid ES and 300M Special, which I still have) that had/have full size matching spare tires. All of my others had space savers. More and more cars are coming out today with *no* spare tire, substituting an emergency inflator kit instead. The current Malibu does this.

The reason we have space savers on all Journeys is weight, cost, and space. If Dodge used full-sized spare tires, they'd have to drastically modify the car to fit them. Either eat up or eliminate load floor storage, eat up cargo space (as Jeep did in the XJ Cherokee), or mount it on the lift gate a la Wrangler, older Rav4/CR-V, etc. Given that cargo volume is essential for this type of vehicle, that was out of the question. Same goes for losing load floor storage, as the JC and RT platforms are known for their clever storage systems. Mounting it on the lift gate is absurd these days for anything other than a Wrangler... even Toyota has commercials advertising the fact that it was eliminated from the Rav4 in response to consumer demand.

When Dodge first came out with stow-n-go on the RS minivans, the space saver spare was actually moved to the middle of the van. An access panel in the floor between the front captains chairs let the user lower the tire to the ground using the jack wrench. I first discovered that as a salvage yard and was floor at the moronic solution that was an obvious last-minute design to allow the rear seats to fold flat into the floor. I imagine every single owner of that type of van simply used roadside assistance instead of bothering with having to lay on the ground to reach for the tire... especially since it ALWAYS rains when you get a flat...

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