Suspension Questions

[hunterjoe]

Dumb user thread.

Some questions about effects of suspension and tire changes. Newb here, usually just keep it stock. My 1500 has the Mopar 2" lift and larger tires (285/65/20) so I'm familiar with the effects there but the HD is a different beast.
I'm considering doing a level and 35s or 295/65/20. First off, if I just went with the larger tires with stock suspension what am I looking at for rubbing issues? Same question with a level? With the 1500 I went from P rated to LT so significantly heavier which I attribute to the majority of the MPG changes but they weren't significant. With the HD you already have LT tires so what type of changes would I expect to see?

Things I'm looking to get real world advice on are things such as mileage, capability (payload/towing), ride quality, anything else I'm missing. How do these things change by updating/upgrading the suspension. Thanks in advance.

 

[jetrinka]

Most people do not report any rubbing issues with 35's on a stock suspension truck - you may hear some reports of it very occasionally but I'd be willing to be its due to the carcass and overall make-up of the tire. Not all tires of the same numerical size are actually the same size. If you were to run into rubbing most people report it on the radius arm in the back and the swaybar up front. Lifting it may help with clearance between the tire and swaybar but likely not the radius arm.

Yes you already have LT tires so you likely won't notice any huge differences there. Other than some power loss due to changes in overall gearing from larger diameter tires and an overall heavier tire. I didn't notice any difference in mileage when I put 35's on my Power Wagon (but mileage has always been abysmal...)

Overall, as you stated it is going to be a much different driving experience than a half ton. The half ton having independent front suspension is always going to hold the road better than a solid front axle. There are always tradeoffs and typically bigger wheels/tires and lifting something is only going to make what you don't like about the truck worse. However they sure look nice and will perform better offroad.

 

[Poolmonkey]

Would never go bigger than stock on a truck I tow with....anything bigger than a small aluminum boat or tiny utility trailer, without swapping gears. But, there is no such thing as a flat or level road around here.

 

[hunterjoe]

Would never go bigger than stock on a truck I tow with....anything bigger than a small aluminum boat or tiny utility trailer, without swapping gears. But, there is no such thing as a flat or level road around here.

If I were towing heavy, I would agree. I’m going to 2500 for the payload, now towing numbers. But I totally get your point. Max I’ll likely tow would be 10k a couple times a year. Mostly just my 4,000 lb boat. Thinking just throwing on some 35x11.5s might be the ticket. Will see after I have the truck for a bit. Thanks for the reply!

 

[Brutal_HO]

Would never go bigger than stock on a truck I tow with....anything bigger than a small aluminum boat or tiny utility trailer, without swapping gears. But, there is no such thing as a flat or level road around here.

With 3.73 gears, going from 285/60R20 (stock) to 285/65R20 lowers the tow RPM at the same speed by ~50 or increase speed by 2MPH in top gear @ the same RPM. An effective gear ratio of 3.62

Going to 295/65R20 lowers it by 100, or speed +3MPH. An effective gear ratio of 3.56.

The effect on available power and MPG is negligible.

Prior to 2019, 4th gen Cummins trucks were geared 3.42 standard. Granted, they did run a smaller stock tire. A bit too low for heavy towing IMHO, but great for mileage runs empty.

The gas trucks probably suffer a worse fate.

 

[Rockcrawlindude]

35s are only ~5 or 6% bigger than stock.

I had No rubbing and No issues towing.