20" wheels...reducing tow capacity?

[jmb667]

Hey, all! New here, still looking at what we want out of a TT (I have another thread running asking about possibilities there). But another question dawned on me today as I was reading some other posts: are our 20" wheels going to be a problem?

We have 275/55R20 Toyo Open Country A/T II tires on our Tundra's stock Platinum wheels. These were put on in January to replace the Dunlop sport tires that were on it. But based on my reading, I'm wondering if this is going to give us a problem...and if 18" wheels and tires would be better (or just a new truck, for all the anxiety figuring this all out is causing me).

Thanks again for your help!

[jmb667]

Ok, so yeah, freaking myself out for no reason. Thanks for helping me get my heart rate back to normal. Again, I'm new to all this and tend to get a bit overwhelmed.

The trailers I've started looking at are much lighter; we have to "sacrifice" some features we wanted, but I'd rather go easy for our first and see how we like it before thinking about mods or a new truck.

[BenK]

Also note that wheels have a rating or spec

In the early days of over sized wheel dia's...they were mostly 'P' class tire
wheels taken from 'cars'

Today has more 'LT' class tire wheels, but the tire selection is mainly 'P'
class and the 'LT' class expensive compared to 16's

Rim width 'MUST' be within the tire's recommended rim width. If you go outside
of that, then know what you are doing. As it is re-engineering to a higher
degree. More so with low aspect ratio tires

[APT]

The tires have plenty of load capability. That's not your restriction.

[jmb667]

Ok, just checked my tires on the Toyo website. The new Open Country tires i have, despite being A/T are "P" rared, not LT. It would figure that all the Tundras now have "P" class tires except the 17" Rock Warrior version (which I traded in 2011 for my current Platinum). Max load on them is 2403 (I assume that's each?). The LT version in a smaller wheel size is MUCH higher.

So it really sounds like Toyota spec'd this version of the Tundra to do very light pulling and mostly be a large people-mover. They don't really expect you to do much pulling with the Platinum trimline.

I just don't relish the idea of dropping another couple thousand dollars on new tires and wheels before I can really consider the trailer... Or am I overreacting, and freaking out for no reason?

I appreciate all the help!

[APT]

Tundra Crewmax Platinum - check your payload on the Tire and Loading sticker on your driver's door. That's likely to be your limit well under the 9000+ tow rating.

[The_Texan]

Hankook DynaPro ATm LT LR-D or E is available in size 275/55R20. That is the one on my truck. I'm sure that there are other LT makes and models in the stock size, without changing sizes.

[jus2shy]

Well with your tire size, I'm assuming you have "P" style tires versus LT. My truck came with 275/55R20's stock as well and is an F-150. I recently bought new tires but I decided I want to get an "LT" style tire since I didn't like the squirminess of "P" style tires when hauling dirt. So I went up a few sizes to 275/65R20 since that's a stock super-duty sized tire and they're the cheapest LT tires I could use without having to buy a new set of smaller rims. I've also always liked 35" tires on my truck and only reduced my effective rear axle ratio from 3.73 to 3.55. When the OEM's spec'd the tire size, most tires in that size have the same load rating, so payload capacity wise you should be perfectly fine. The nice thing of the 275/55R20 P series tire is that they do ride softer when unloaded. I noticed that my truck rides a bit firmer having to run higher tire pressures to maintain payload capacity, but I actually prefer that on my rides.

[blt2ski]

tread type will not matter.

size of the rim may or may not matter...example. 235-85-16, 265-75-16, 235-80-17, 265-70-17, 225-70-19.5 among other sizes I know of, are ALL about 31.5-31.7" tall or diam. Any of these can be exchanged for the a different size, and generally speaking, not towing, power difference should be noticed!

Please note, I also said generally speaking.....if you go from an aluminum rimmed say 235-85-16 to a steel rimmed 225-70-19.5......the 19.5" setup will weigh probably 5-7 lbs per tire more than the 16" size, your but and the motor will have more drive train loss, so you will probably notice some lag in acceleration.

The simple answer as one can see, is "it depends" upon if the rim diam are different, to no difference, then back to a difference.

On the other hand, one can do the same for axel ratios, as to which is best for towing. one can have a 3.42 ratio with a 28" tire, a 3.73 with a 30" tire, or 4.10s with a 32" tire, have the same chassis, motor, trans etc, and ALL three rigs will have the same mph shift points etc. As the tire diam has made up for the axel ratio difference! So as some may or may not notice, the F350 with a 4.33 gear setup, is the same as an F450 with a 4.33 gear setup. But reality is, being as the 450 has more payload, it has a higher potential trailer potential. Same could be said for a GM 1500 with a 3.42 geared half ton with the 6.2 motor, and a 2500 with the same motor etc.

Marty

[Slownsy]

Don't think read the numbers on tiers and compare to yellow sticker.

[jmb667]

Thanks for the input! The tires are the same size as the OEMs that were on there, just a different type of tire (A/T vs sport). So I think I'm most likely good to go in that regard, it sounds like.

Thanks again!!

[The_Texan]

VintageRacer wrote:
20" wheels are the stock wheel and so will not impact load capacity or towing capacity at all. None, zero, ziltch. Aftermarket 20" aluminium wheels that didn't have an acceptable load rating might have, but stock is stock, so stock ratings apply. Tire size is a totally different subject from wheel size. Overall rolling diameter of the stock tire would have to be compared to the overall rolling diameter of what you put on. If you are within say 5%, probably no impact to towing capacity that you would really notice. A taller tire will reduce the overall gear ratio and reduce torque delivered to the road by the ratio of the tire diameters.

Brian

Brian gave you the CORRECT answer......Stock 20", like mine, No impact at all. After market "may" but you need to see what the load rating for that wheel is.

[CapriRacer]

From the tire's perspective, it doesn't matter if the vehicle is towing or just loaded up. The tire doesn't know the difference.

Replacing a tire with one that has less load carrying capacity is directionally unsafe. Better to replace with larger load carrying capacity.

So pay attention to load carrying capacity (Load Index)

[VintageRacer]

20" wheels are the stock wheel and so will not impact load capacity or towing capacity at all. None, zero, ziltch. Aftermarket 20" aluminium wheels that didn't have an acceptable load rating might have, but stock is stock, so stock ratings apply. Tire size is a totally different subject from wheel size. Overall rolling diameter of the stock tire would have to be compared to the overall rolling diameter of what you put on. If you are within say 5%, probably no impact to towing capacity that you would really notice. A taller tire will reduce the overall gear ratio and reduce torque delivered to the road by the ratio of the tire diameters.

Brian

[Turtle_n_Peeps]

What is the diameter difference between the two? I can get smaller diameter tires on a 20 than a 18 if I want and so can you. Then you can just plug in the two in a free online final ratio calculator.

To give you an example, there is not much difference between the two stock Ford wheels.