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Travel Trailer Wheel/tire Size

Sam_Whiskey
Explorer
Explorer
We just purchased an 87 Kit Companion Classic.

Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

The actual tires are ST225/75R15.

Is there an advantage/disadvantage to having a larger tire?

Thanks!
Sam.
11 REPLIES 11

Sam_Whiskey
Explorer
Explorer
Coolbreeze01 - Sounds like I will stick with the 15 inchers.

Thanks.
Sam.

Sam_Whiskey
Explorer
Explorer
Coolbreeze01 - Sounds like I will stick with the 15 inchers.

Thanks.
Sam.

Sam_Whiskey
Explorer
Explorer
Huntindog - I measured the clearances as you suggested and they are all well within what you mentioned.

Thanks!!!
Sam

coolbreeze01
Explorer
Explorer
Sam_Whiskey wrote:
We just purchased an 87 Kit Companion Classic.

Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

The actual tires are ST225/75R15.

Is there an advantage/disadvantage to having a larger tire?

Thanks!
Sam.


I have upgraded to 225 75R 15 E tires on two trailers. My theory is more is better.

I have had tires delaminate in over 60 years of towing, but they stayed aired up.
2008 Ram 3500 With a Really Strong Tractor Motor...........
LB, SRW, 4X4, 6-Speed Auto, 3.73, Prodigy P3, Blue Ox Sway Pro........
2014 Sandsport 26FBSL

Huntindog
Explorer
Explorer
Sam_Whiskey wrote:
We just purchased an 87 Kit Companion Classic.

Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

The actual tires are ST225/75R15.

Is there an advantage/disadvantage to having a larger tire?

Thanks!
Sam.
Yes, within reason.
You need a minimum of 1" between the tires on a dual axle, and 3" from the top of the tires to the wheelwell. When doing this measurement, it is best to be on level ground. Otherwise you may have to compensate for one axle being higher than the other... It's not hard though. Measure them both and divide by 2. If it is 3" or more you are good to go.

I have raised all of my TTs in order to be able to use bigger tires and for more ground clearance.
The only negative I have encountered is a MPG reduction of about 1 MPG, but I have raised mine a lot more than the 1/2" yours was raised. Your difference is negligible.

Enjoy your TT.:B
Huntindog
100% boondocking
2021 Grand Design Momentum 398M
2 bathrooms, no waiting
104 gal grey, 104 black,158 fresh
FullBodyPaint, 3,8Kaxles, DiscBrakes
17.5LRH commercial tires
1860watts solar,800 AH Battleborn batterys
2020 Silverado HighCountry CC DA 4X4 DRW

canoe_on_top
Explorer
Explorer
The extra inch is only a 1/2 inch in added height, (axle to ground). It won't make a difference in whether you tip over or not.

Sam_Whiskey
Explorer
Explorer
Mitch..I did respond to you yesterday but it appears the response did not get posted. Apologies.

Sam.

Sam_Whiskey
Explorer
Explorer
Good info all. The max load for each tire is 2640 pounds. Our intent is to keep the trailer light.

My other concern, if it should even be a concern, is that extra inch and wind.
I have seen many big rigs and TTs being blown over during high winds. Could that extra inch be the straw....

Thanks.
Sam.

Campfire_Time
Explorer
Explorer
Keep in mind that while the bigger tires can take more weight, the axle is still the limitation. In my experience going to bigger tires is half a dozen of one, 6 of another. The bigger tires are nice but are little more than a "feel good". However if your rims look crappy and you're thinking about replacing those too, then now is the time to go a size bigger.
Chuck D.
โ€œAdventure is just bad planning.โ€ - Roald Amundsen
2013 Jayco X20E Hybrid
2016 Chevy Silverado Crew Cab Z71 LTZ2
2008 GMC Sierra SLE1 Crew Cab Z71 (traded)

JIMNLIN
Explorer
Explorer
I like moving up to 15" from 14" on any of my smaller trailers.
.. better tire selections.
.. smoother ride over say rough RR tracks
.. lower wheel rpm = less wheel bearing heat.

Now if the ST225/75-15 is a 8 or 10 ply rated tire then its gonna' ride rough.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers

'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides

MitchF150
Explorer III
Explorer III
What's the load rating on the 15" tires?

If they are at least LR C tires, then they will have a higher load rating than the 14" tires.

As long as they fit within the wheel well space for full suspension travel, they should be fine.

Mitch
2013 F150 XLT 4x4 SuperCab Max Tow Egoboost 3.73 gears #7700 GVWR #1920 payload. 2019 Rockwood Mini Lite 2511S.