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Old 05-20-2022, 09:27 PM   #1
Mtad
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225/75r15 > 205/75r15?

I have a 2018 Bullet 1650EX and would like to lower a little. I'm considering switching the tires to 205/75R15s. Has anyone done this before? I'm going to be pulling with a Sienna which sits a little low.
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Old 05-20-2022, 09:57 PM   #2
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Quote:
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I have a 2018 Bullet 1650EX and would like to lower a little. I'm considering switching the tires to 205/75R15s. Has anyone done this before? I'm going to be pulling with a Sienna which sits a little low.
That would lower your trailer 0.6 inches. Is that enough to make it worth buying the new tires? That also makes them .8 inches narrower lessening your foot print on the road in a hard breaking situations. You can play with the numbers here to see how I found the information. https://tiresize.com/comparison/
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Old 05-21-2022, 03:48 AM   #3
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Quote:
Originally Posted by Mtad View Post
I have a 2018 Bullet 1650EX and would like to lower a little. I'm considering switching the tires to 205/75R15s. Has anyone done this before? I'm going to be pulling with a Sienna which sits a little low.
The industry standard for replacement tires is to NEVER use smaller tires than what is recommended on the vehicle certification label. The important part is; replacement tires MUST provide a load capacity equal to or greater than what the OE tires provide/provided.
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Old 05-21-2022, 04:40 AM   #4
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Smaller tires? No, I think you need to consider a smaller trailer or a larger tow vehichle. Small people movers don't make good tow vehichles. You need to look at the real numbers that are relevant to towing a camper. Look at tow vehichle payload, the subtract the weight of everything and everybody you put in the car. The trailer, use 13% of the gvw (not the empty weight) for a tongue weight estimate.

A 19' single axle trailer behind a light car will swing like a pendulum in a grandfather clock. Small vehicles like the Sienna are best towing small pop-up trailers that offer much less wind resistance.
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Old 05-21-2022, 09:08 AM   #5
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As Marshall stated I'd do some serious calculations on your mini van as to where it's even up to the task. That's a front wheel drive unibody van designed to haul people inside, was NOT/NEVER designed to haul trailers. Read the owners manual for trailer towing specifically using a WDH (weight distributing hitch), normally NOT recommended on unibody vehicles, but will be required towing a rv.
But back to your original question, you should be using a WDH with sway control, if not you need to, that the head has several holes to raise or lower the ball height, I'd raise the ball height so the the rv is level when hitched up rather than altering the rv height.
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Old 05-21-2022, 10:12 AM   #6
sourdough
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Going to the smaller tire size is a bad idea. Pulling that trailer with a Sienna is a worse idea. The Sienna has a MAX TOW rating of 3500 lbs. The trailer has a gvw of 4700 lbs. The OE hitch appears to be a Class II hitch. The max tongue weight will probably be UP TO 350 lbs. GVWR of 4700lbs x .13 = 611 lbs.

Summary? The Sienna is not rated for that trailer. As for trailer tires;
The OE ST225/75R15 LRD tires support 2540 lbs. each. The proposed ST205/75R/15 LRD tires support 2150. As has been pointed out you are never supposed to downsize from the minimum tire size/load range as indicated on the placard on the trailer (225/75R 15D) and you can see why. Downsizing will net you a loss of almost 400lbs of support per tire. Not only extremely ill advised but very dangerous for you, your family and anyone else on the road. Answer? Larger, better tow vehicle or much smaller trailer; the Sienna is not, and was never designed to be, a tow vehicle.
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