mburing

Hey guys, I have a 2010 F150 with a 2" leveling kit on it. I'm currently running 235/80r17 which is around a 32" tire. I was recently told by a rep from rough country that with their 2" leveling kit that I clear up to a 35x12.5. Furthermore I asked the guy if I could put this tire on my stock wheel which is 17x7.5 and he said that it would work fine. I would really like to go up to the 35x12.5 if it will work, but I'm skeptical to do it at this point.

Can anyone weigh in on this or even better, is there anyone that has is successfully running this size tire on a factory wheel and only 2" leveled in front?

Thanks

Mecpinstaller

To answer your question, Yes , a 35 12.5 tire will fit if you put the leveling kit on. Zero rubbing if its 4wd, minor rubbing that can be trimmed of its 2wd. However , there are a few things you need to strongly consider that nobody ever tells you until your invested. 1. When you put the 35 inch tires on your gonna lose acceleration , and what is gonna feel like a lost of power. 2 You are changing the tire gear ratio extremely so in order to run a 35 inch tire and not have a sluggish truck you will need to regear your axle if you have 3.55 or 3.7 stock gears. If you do not regear This will put alot of strain on your transmission and I've heard alot of people who had to rebuild the transmission after it ruined it, or replace it. If you have the 3.7 gears it may not be as bad but really 4.10 is desired. HOWEVER, people are running 35 inch tires on that truck all day everyday without regearing the axle and live very happy lIves so don't let it discourage you. You can always regear in like a year

Truckin

iTrader: (4)

I've seen guys put 35x12 on a 7.5rim and say it's fine...finding a tire shop to do it would be hard. Least in my area.

mburing

Thank you guys both for your feedback. I placed the order for the tires today and went ahead with 35 12.5. I should have them installed at some point this week and will let you know how everything goes. mecpinstaller, I'm glad you said something about regearing. I will have to do some homework on what factory gears are on my vehicle, because if it is sluggish after the new tires it is definitely something that I am going to look into changing out. Any idea on how to figure that out?

Sounds like you have a fair amount of experience in this area, is switching out the gears too terribly difficult to do on my own?

mercury24

Let assume you have 3.55 gears for the moment . Factory gearing will always be a mix of acceleration and mpg a compromise so to have better acceleration step up one gear ratio higher than what factory would be and it will feel like you added HP . Us this calculator to figure out the gear ratio you will need https://www.ringpinion.com/calculators/Calc_RPM.aspx . You will need to know what your stock gearing is and your stock tire height is and go from there .
So using this calculator and a 31" tall tire stock with an aod trans 3.55 gears at 60mph your rpm would be 1616 rpm's so the closest gear with a 35" tall tire would be a 4.10 gear that would give you 1653 rpm's that is very close to stock in terms of acceleration . So if you want better acceleration I would go with a set of 4.30 gear @ 60mph your rpm's would be 1734 118 rpm's more than stock and with 4.56 gears @ 60 mph your rpm's would be 1839 rpm's 223 rpm's more than stock . So you have 3 gears to select from ( assuming you have 3.55 gears now ) 4.10 to stay the same as stock or go with 4.30 or 4.56 gears .

mburing

Thanks for the feedback Mercury24, that is really helpful information. This at least gives me a better idea and some resources on making a more educated decision on regearing in the future based on the outcome I'm looking for.

I'm still questioning whether or not this is an undertaking that I can handle myself or if I should plan to take it to a shop to have it done? Is this a relatively simple modification to make, or am I asking for trouble to do it myself at the house?

tareed94

I've never seen someone do them themselves, but that doesn't mean it can't be done.

You're likely going to need to find a questionable shop to install that tire on that rim. It's outside of manufacturer's specs so most places won't touch it. Argued with a NTB manager about this after he said an 8.5" rim was too narrow to fit a 35x12.5 even though the site said it was approved.

mburing

Well that is encouraging

I was planning on taking it to NTB to have them put on, but sounds like that may be a hassle.

I guess I will start looking for alternatives proactively. Did the NTB you were dealing with end up putting them on? Just curious what the outcome of that stand off was?

tareed94

Nope. They flat out refused to put them on. They said it wasn't an approved rim width, and that they would rub. The manager was borderline screaming in my face in the showroom. I left and went to Firestone down the street and had no issues.

Main thing is know what you're talking about when you go in. Look up the tire you have on order on the manufacturer's website. They'll tell you the "approved rim width" range, and reputable shops generally follow that and won't install outside of that. You could take it to the offroad shops or somewhere like that. They will generally do those installs as they often are doing heavy modifications, or stretching a 12.5 to fit a 14 width rim.

Other issue you may have is uneven tread wear on the sides due to the load not being evenly distributed due to rim width.

mburing

Well if anybody at a tire shop is going to tell me that it is recommended to mount the tires on the wheels I have, it would be a waste of their time. I'm going to call up to a small mom and pop place near the house that I have used in the past for small jobs and hopefully they are fine with doing it. If not I can take it to the off road shop near the house, but last time i got pricing on anything from them it was pretty steep, so trying to avoid that.

Again, I appreciate the feedback. Wish me luck! I will try and post pics once it is all said and done.