Go from 15" to 16" wheels on Trailer

**Old Man** · 10-08-2021, 09:49 AM

Hi All - Anybody go up from 15" wheels to 16" wheels?
I have a 2021 Reflection 260RD fifth wheel that rides a tad nose high with my F250 Diesel Super Duty. The rear stabilizer jacks sit little more than 4" off the ground when fully retracted and have scraped a few times going over speed bumps. If I move up to 16" wheels, my thinking is that I'll gain a little trailer height (1.5") that may help with both of those concerns. Has anybody done this? Any thoughts, considerations or comments are greatly appreciated. Thanks.

**huntindog** · 10-08-2021, 02:05 PM

Originally Posted by Old Man

Hi All - Anybody go up from 15" wheels to 16" wheels?
I have a 2021 Reflection 260RD fifth wheel that rides a tad nose high with my F250 Diesel Super Duty. The rear stabilizer jacks sit little more than 4" off the ground when fully retracted and have scraped a few times going over speed bumps. If I move up to 16" wheels, my thinking is that I'll gain a little trailer height (1.5") that may help with both of those concerns. Has anybody done this? Any thoughts, considerations or comments are greatly appreciated. Thanks.

I did it on a couple of TTs I owned. My main reason was it allowed me to run LT tires. I am not sure where you get the 1.5" from? The wheel size doesn't have much to do with height. The tire size does.

**Canyonlight** · 10-08-2021, 02:35 PM

Originally Posted by Old Man

Hi All - Anybody go up from 15" wheels to 16" wheels?
I have a 2021 Reflection 260RD fifth wheel that rides a tad nose high with my F250 Diesel Super Duty. The rear stabilizer jacks sit little more than 4" off the ground when fully retracted and have scraped a few times going over speed bumps. If I move up to 16" wheels, my thinking is that I'll gain a little trailer height (1.5") that may help with both of those concerns. Has anybody done this? Any thoughts, considerations or comments are greatly appreciated. Thanks.

Jeff we did this in the spring of 2018. We had the GDRV Customer Service Center perform work on our 303 including installing 6K axles, 16" tires and wheels. We gained 1/2" from the wheel and 1.25" in tire diameter for a total of 1.75".

We also gained a little height in the springs as the 5.2K axles/2600 lbs springs were at and exceeding limits for our 303 when loaded on the fridge side resulting in a light sag on the street side vs the curb side. The fridge side when loaded was about 800 lbs. heavier.

In addition early GDRV Reflection fivers did not have the 2" tubing between the frame and axle mounting. We had these 2" tubes added as well to ensure we had more clearance......w/o doing this, we would not had enough clearance between the top of the new setup and bottom of RV especially in situations where the spring was compressed due to road bumps, etc.

The attached picture taken before leaving the FCS Center after measuring front and rear RV to ground shows we were nearly level. RV was empty.

Click image for larger version.

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Dan

**BobLandry** · 10-08-2021, 03:58 PM

The 16" number is tire diameter. The difference in the sizes being 1" breaks down to 1/2"(radius), which is what you would realize in height change given the same tire aspect ratio.

**Second Chance** · 10-08-2021, 06:47 PM

You can compare tire diameters using this calculator (be sure and use 1/2 of the diameter as the height you would gain):

https://tiresize.com/calculator/

One thing to keep in mind is clearance from the top of the tire to the underside of the trailer or slide. Typical leaf spring trailer suspension systems have 2-1/2 to 3" of travel... you don't want the tire and the subflooring making contact on a bump or pothole.

Rob

**Old Man** · 10-09-2021, 08:33 AM

Originally Posted by huntindog

I did it on a couple of TTs I owned. My main reason was it allowed me to run LT tires. I am not sure where you get the 1.5" from? The wheel size doesn't have much to do with height. The tire size does.

First I called Grand Design customer service who said it was a modification and they couldn't comment. Then I went to Les Schwab Tires who said I had the clearances to do it. Existing 15" wheels with ST225/75R15 tires have a 28.31 inch diameter. New 16" wheels with ST235/80R16 tires would have a diameter of 30.79 inches. An increase in diameter of 1.48". LS didn't give info about keeping the 15" rims and getting bigger tires. I'll check that out. Thanks.

There is about 8-10 inches of clearance to the subfloor and my tires are currently 7" apart. The suggestion by LS would reduce this distance by about 3" leaving 4" gap between tires, which I understand is okay.

**Old Man** · 10-09-2021, 08:40 AM

Originally Posted by Canyonlight

Jeff we did this in the spring of 2018. We had the GDRV Customer Service Center perform work on our 303 including installing 6K axles, 16" tires and wheels. We gained 1/2" from the wheel and 1.25" in tire diameter for a total of 1.75".

We also gained a little height in the springs as the 5.2K axles/2600 lbs springs were at and exceeding limits for our 303 when loaded on the fridge side resulting in a light sag on the street side vs the curb side. The fridge side when loaded was about 800 lbs. heavier.

In addition early GDRV Reflection fivers did not have the 2" tubing between the frame and axle mounting. We had these 2" tubes added as well to ensure we had more clearance......w/o doing this, we would not had enough clearance between the top of the new setup and bottom of RV especially in situations where the spring was compressed due to road bumps, etc.

The attached picture taken before leaving the FCS Center after measuring front and rear RV to ground shows we were nearly level. RV was empty.

Dan

Dan, that looks really good. What I'd like to have in my set up. Thanks for the input and info. I'm still looking at options and hopefully it'll look as good as your setup. Nice.

**AZMike** · 10-09-2021, 09:33 AM

Originally Posted by BobLandry

The 16" number is tire diameter. The difference in the sizes being 1" breaks down to 1/2"(radius), which is what you would realize in height change given the same tire aspect ratio.

Not to split hairs, but I think you mean that the 16" number is wheel diameter.

**powerscol** · 10-10-2021, 09:43 AM

Originally Posted by Old Man

Hi All - Anybody go up from 15" wheels to 16" wheels?
I have a 2021 Reflection 260RD fifth wheel that rides a tad nose high with my F250 Diesel Super Duty. The rear stabilizer jacks sit little more than 4" off the ground when fully retracted and have scraped a few times going over speed bumps. If I move up to 16" wheels, my thinking is that I'll gain a little trailer height (1.5") that may help with both of those concerns. Has anybody done this? Any thoughts, considerations or comments are greatly appreciated. Thanks.

I did it on my Reflection 220RK Look for my post here and the other place - I included sources for wheels, etc. A couple of things you need to check. Clearance from top of tire to floor and everywhere else should be 3". If you don't have that consider Sumo springs to act as bumper stops. I have the HD set installed - another write up.

I just drove to Georgia and back from SW Colorado) with no issues (huge ride and handling improvement). Going out the trailer was fully loaded (including 1/2 rank water hauling my daughters stuff to her.

Hope this helps