bn30813

im beginning to feel like the oem 275 65 18 fortitude wont cut it, so I want to get some ko2 or toyo rt for their 10 ply construction. my tt is 35 ft and want to see if anyone made that leap going to from 275 65 18 to 275 70 18 or 285 65 18... did you have to adjust your hitch? camping world installed the hitch cause I don't have the tools or the ability to torque anything greater then 180+ so they set it up for me when I bought the trailer. If I get new tires, looking to increase size at the same time. thanks for yall input in advance!

smokeywren

No experience, but I can do the math.


Using BFG All-Terrain T/A KO2 as the example, the LT 275/65R18 is 32" diameter and 648 revs/mile.


The LT 275/70R18 is 33.2" diameter and 627 revs/mile.


That 1.2" diameter difference = 0.6" difference in tongue height of an almost-level trailer.

Will you need to adjust the tension on the spring bars? No. If you have the hitch dialed in so 50% to 60% of gross tongue weight remains on the rear axle when the springs bars are snapped up, then changing the height of the tongue by a half/inch is not going to change your weight distribution off the rear axle.

Will you need to adjust the angle of the hitch head? No. If you have the hitch dialed in so 20% to 25% of gross tongue weightis distributed to the front axle and to the trailer axles, then changing the height of the tongue by a half/inch is not going to change your weight distributed to the front and trailer axles.

Will you need to adjust the adjustable shank on the WD hitch to keep the floor of the trailer level when wet and loaded for the road? Probably not.

I doubt you can see the difference in a hair over one/half inch difference in tongue height. With a 4' carpenter's level on the floor of the trailer, the bubble would barely move when you change the tongue height by a bit over one/half inch.

Most adjustable shanks on WD hitches cannot be adjusted only a half inch. Most are adjusted a full inch at a time. So if the floor of your trailer was perfectly level with the 65 profile tires, then changing to 70 profile tires won't move the bubble enough to justify changing the adjustable shank by a full notch.

SKBORDERS

All things being equal, the taller sidewall will cause more tire roll. However, if you also increase the load rating, it could negate that effect.

bn30813

I appreciate your replies smokey and sk. This is my first TT and WDH. normally, at work, the only things I have pulled in the past never needed a WDH. Just needed reassurance that I would be ok (moral support, lol). I was 90% confident based on the numbers but 10% skeptical due to reviews and rants found in searches made by the hard core tow heads. But then again, you don't find all the good stuff people say about everything on the internet, but you sure will find a lot of bad. Thanks again guys!!!