# Increasing Wheel And Tire Size To 16"



## AK or Bust (Nov 22, 2010)

I'm about due to purchase a new set of tires for our 2006 Outback Sydney edition 28FRLS fifth wheel. It currently has Duro H78-15 ST225/75 D15 tires which I'm guessing might be the tires it came with new. The outback is not level by about an inch or so when I'm hitched up so I was thinking that upgrading the wheels and tires from 15" to 16" might be a good idea and resolve this out of level condition.

Is this something that I could safely do? What are the pros and cons of upgrading to a bigger tire ?

Any tips or to hear from someone with a similar rig that has done done this will be* greatly appreciated. Thanks, *


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## duggy (Mar 17, 2010)

I'm not speaking from experience, but the two things I'm thinking of are tire clearance in the wheelwells, and slightly raising the center of gravity of the trailer. If the tires end up one inch larger in diameter, that will only change those numbers by 1/2", so I wouldn't think either issue would be very significant.


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## AK or Bust (Nov 22, 2010)

duggy said:


> I'm not speaking from experience, but the two things I'm thinking of are tire clearance in the wheelwells, and slightly raising the center of gravity of the trailer. If the tires end up one inch larger in diameter, that will only change those numbers by 1/2", so I wouldn't think either issue would be very significant.


I didn't think about it only making a half inch difference overall. Since I haven't heard anything else pro or con, I guess I'll just stick with the 15" tires and rims. Thanks for the feedback.


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## wolfwood (Sep 19, 2005)

Jim, if the degree of off-level is a problem, you could flip the axles and get some added height ... we gained several inches on the toyhauler when we got new axles (and the dealer did the flip unexpectedly). Of course, you may also then need to add a step-up to your outside stairs. We also went up a size in tires because the new axles had a different lug pattern. We went from 14 to 15 .... don't know if there's a pattern difference between 15 and 16, too.


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## OBcanOB (Aug 23, 2007)

I changed the rims and tires on our 07 28FRLS to 16" so I could put on 10 ply. I had to have a small block put on the axle to make sure it didn't hit the undercarriage. I've pulled it about 10,000 miles without any problems. To me, it was well worth the time and money.


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## AK or Bust (Nov 22, 2010)

wolfwood said:


> Jim, if the degree of off-level is a problem, you could flip the axles and get some added height ... we gained several inches on the toyhauler when we got new axles (and the dealer did the flip unexpectedly). Of course, you may also then need to add a step-up to your outside stairs. We also went up a size in tires because the new axles had a different lug pattern. We went from 14 to 15 .... don't know if there's a pattern difference between 15 and 16, too.


Thanks for the info Judi, The axles are already flipped and all the modifications other than changing out springs and tires have been done. I'll keep that in mind about the lug pattern if I upgrade.


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## AK or Bust (Nov 22, 2010)

OBcanOB said:


> I changed the rims and tires on our 07 28FRLS to 16" so I could put on 10 ply. I had to have a small block put on the axle to make sure it didn't hit the undercarriage. I've pulled it about 10,000 miles without any problems. To me, it was well worth the time and money.
> View attachment 1500


I'm glad to hear someone with a similar outback has successfully upgraded to 16". I'll keep that in mind about the small block on the axles if do upgrade the tires. Thanks for the reply.


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## jdpm (Apr 12, 2007)

Jim, 
John and I own a 2007 Sydney 31frks fiver and upgraded our wheels/tires to 16" a few years ago. You will have no problem and you will love it. Like you said, the actual height difference is not that much but woth it just the same. 
Also, we switched the tires from the poorly rated ST trailer tires to LT tires. May I suggest to you that if you go the LT tire choice that you also upgrade your suspension equalizer to either the Dexter E-Z Flex or the Trail Air with the wet-bolt kit. 
One of the differences in ST tire and and LT tire is the stiffer sidewall of the LT. The ST tires have a more ball shapped sidwall which is a built in shock absorber. The LT tire is much stiffer so you loose some a lot of the shock absorbing traits of the ST but gain a lot of peace of mind. The suspension upgrade will take care of that. Plus when you install the suspension kit, you will most likely be shocked at the deterioration of the nylon bushings in the suspension. The wet bolt kit includes brass bushings with greaseable fittings.
If you do all this it's a great time to check all the brakes and propertly grease the bearings. Two of our brakes were coated with grease due to the use of the grease zerks - probably at pre-deliery. We couldn't believe the braking difference once we had none grease coated brakes!
You will find some pix of the tire upgrade as well as the suspension upgrade posted in our gallery on this site. Just like our profile and then gallery. Good Luck, Phillip


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## AK or Bust (Nov 22, 2010)

jdpm said:


> Jim,
> John and I own a 2007 Sydney 31frks fiver and upgraded our wheels/tires to 16" a few years ago. You will have no problem and you will love it. Like you said, the actual height difference is not that much but woth it just the same.
> Also, we switched the tires from the poorly rated ST trailer tires to LT tires. May I suggest to you that if you go the LT tire choice that you also upgrade your suspension equalizer to either the Dexter E-Z Flex or the Trail Air with the wet-bolt kit.
> One of the differences in ST tire and and LT tire is the stiffer sidewall of the LT. The ST tires have a more ball shapped sidwall which is a built in shock absorber. The LT tire is much stiffer so you loose some a lot of the shock absorbing traits of the ST but gain a lot of peace of mind. The suspension upgrade will take care of that. Plus when you install the suspension kit, you will most likely be shocked at the deterioration of the nylon bushings in the suspension. The wet bolt kit includes brass bushings with greaseable fittings.
> ...


Thanks for the info Phillip. Having the brakes and bearings looked at was one of the first things I did when we got our Outback.	Thank you for the explanation of the difference between the ST and LT tires. I already upgraded the equalizer so I guess I can add LT tires as another possible option in the tire decision. I appreciated the post.


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## AK or Bust (Nov 22, 2010)

duggy said:


> If the tires end up one inch larger in diameter, that will only change those numbers by 1/2", so I wouldn't think either issue would be very significant.


I found an interesting chart on the MAXXIS website regarding their tires and the overall diameter. Going from a 15" to a 16" MAXXIS will gain at least an inch or more in height.

The 205/75R15 has a 27.1" overall diameter
The 225/75R15 has a 28.3" overall diameter 
The 235/80R16 has a 30.8" overall diameter


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## jdpm (Apr 12, 2007)

Oh, one think I forgot to mention to you is what the clearance on the rotating bar that turns when the slide is operated. It is very close to the inside of the tire sidewall as it is. I have read other posts where this was an issue requiring the bar to be altered. 
In our case, we went to a 215 series tires which is slightly more narrow. At least in the LT tire that we purchased, the 215 series tire had the same exact weight capacity as the 225 yet was lightly taller. The slightly more narrow width took care of the clearance to the bar. Just thought I'd throw that out there.
If you decided to go with the LT tire, I highly recommend the BFGoodrich Commercial T/A. I have read many, many positie comments on thee tires and hav been very happy with them. We purchsed ours at Costco. Phillip


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## vdub (Jun 19, 2004)

Before going to that trouble, check your pickup to see if it can be lowered. Not sure about the GMC's, but Dodge's have two 3/8 inch pads under the axle. You can use those pads to raise and lower the rear end. I dropped mine by the full 3/4 inch and it makes everything pretty level as you can see in the picture below.


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## AK or Bust (Nov 22, 2010)

vdub said:


> Before going to that trouble, check your pickup to see if it can be lowered. Not sure about the GMC's, but Dodge's have two 3/8 inch pads under the axle. You can use those pads to raise and lower the rear end. I dropped mine by the full 3/4 inch and it makes everything pretty level as you can see in the picture below.


Thanks so much for that excellent tip VDUB. I contacted the senior tech at our GMC dealership and he researched it and then told me that they have a shackle kit I can get that will lower the truck 1"-1.5 inches which is perfect. So I ordered a set of 15" maxxis tires and will get the GMC shackle kit. It's a simple solution and economical.

I really appreciate all the input I received from everyone. *THIS IS WHY I LOVE THE OUTBACKERS FORUM and hope that it continues for many years !!!*


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## vdub (Jun 19, 2004)

Excellent! Good luck!


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