Why Does Your Wheel And Tire Size Matter?

The correct wheel and tire combination make all the difference if clearing the fender well is your main objective. For those who have the 0-3 inch lift on their truck it is especially crucial due to the proximity of the tire to the fender well.

In this guide we’ll share our most preferred setup and why it works for us. Some people might claim that they can run a -44 mm offset wheel packages with 35 inch tires on a 2 inch leveling kit and have zero tire rub on the fender well. To be fair, in our experience this might be true of street trucks with limited suspension travel and never driven to their full potential.

Here at Thuren Fabrication our goal is always to provide durable components that can withstand the wear and tear you put your truck through all while maintaining a setup that will handle well and keep you happy for miles to come both on and off road.

The Myth: Lift Height Equals More Tire Clearance

The most common lift height for Dodge Trucks falls within the 0-3 inch range and the myth is that lift equates tire clearance. Regardless of your lift height, if you maintain proper suspension components geometry, aftermarket wheels with proper offset, your tire size and wheel size combo will clear the fender wells.

What matters the most is even a truck lifted from stock height to a 3 inch lift will still bottom out at the same rate and location. Our suspension systems and components are high performance and meant to be run hard and will handle great for everyday driving.

What Thuren Fabrication will not suggest

We are not going to suggest you baby our suspension in and out of driveways so your tires don’t rub on the fender wells. Through countless hours of research and development we have designed our suspension to have zero tire rub at full compression while driving at high rates of speed. We’ve done the work so you can rest easy and have confidence in your setup.

If you decide to lift your truck beyond the 3 inch threshold you will also need to lower/drop your bump stops 2 inches or more. Limiting travel for the drop brackets and additional components will allow you to install a larger tire size because the suspension will not be compressing as far of a distance. When designing our components, range of motion and mitigating wear, while creating longevity of your stock components as well as our products is our top priority.

Using Offset To Measure Your Wheels And The Advantage Of Using This Method

Regardless of how wide your wheel is, measuring the offset will give you the exact placement of the tire tread through its range of motion. A 6 inch wide wheel size with +18 mm offset and a 12 inch wide wheel with the same offset will both put the tire tread in the same exact place vertically through its range of motion.

For reference, offset is the position of the wheel mounting flange in relation to the axle and the distance to where the bead of the tire meets the rim. In layman's terms: offset is the distance of your center mounting points to the edge where the tire meets the wheel and its location within the outer ring.

Positive offset wheels move the center mounting surface outward while moving the outer ring toward the centerline of the vehicle. Negative offset will do the opposite in that the wheel's outer ring would be moved away from the vehicle centerline. I.E. +18 mm offset moves the outer ring inward as well as -18 mm offset moves the outer ring away from the centerline. The higher the positive offset number is, the more narrow the stance will be while a zero or negative offset will widen the stance of the truck.

The Issues With Backspace Measuring Wheel Sets

Backspacing measurements in regards to wheel size fitment can be a confusing way to determine if a wheel set is right for your truck.

To obtain wheel Backspacing:

• Set your wheel on a flat table outside (dress side) of the wheel up
• Measure from the table surface to the mount flange of the wheel

This measurement is known as backspacing and it is a mystery to a lot of people as to why wheel manufacturers ever introduced this method of measurement. The tire bead mounting surface is included in the measurement and can vary from manufacturer to manufacturer.

The gamble lies in the thickness of the bead mounting surface. Using the backside of the wheel as the only reference, an 8 inch wide wheel with 5 inches of backspacing versus a 10 inch wheel with the same 5 inch backspacing will locate the tire in two totally different positions through its vertical travel. Due diligence is required when using backspacing measurements for wheel fitment.

Trimming As A Means To An End

To fit larger than stock tire sizes under your rig, a fair amount of trimming the fender liner (plastic) might be necessary but not always. This is a completely normal requirement to fit substantially larger tires if you find your truck needing trimming. Additionally, it would be beneficial to trim the mudflap/plastic trim as well as the metal rocker seam behind the plastic trim. On average, it’s recommended to remove the bottom 4 inches of the backside of the fender liner for proper wheel/tire clearance.

To insure ease of use:

• It’s best to have the fender liner warm so cutting is easier.
• This can be achieved with warm weather, depending on where you live, or the use of a heat gun.
• Mark your cut line with a wax pencil or contrasting color sharpie.
• Check behind the fender liner for wires so you don’t cut them. If wires are present, secure them out of the way.
• Acquire a sharp utility knife.
• Wear leather gloves during the modification to protect your hands.
• As you begin the cut remember to take your time.

While cutting the plastic, the knife can move quickly and abruptly so be sure to take your time. During the trimming process pull the plastic away from the cutting area so the knife has a smooth and continuous movement.

Pro-Tip: look a few millimeters ahead of your knife point to stay on your cutting line. If you focus on the knife edge it’s easier to get off track.

If the sheet metal needs trimming as well, we recommend a long fine tooth blade mounted in a Sawzall to make quick work of the situation. Once finished, apply a bit of touch up paint and you’re ready to roll. If you’re onboard with the trimming procedure, the fitment information below is your next step towards smoothly fitting your truck with a larger tire size.

2003-2013 4-Link Trucks, With 0-3" Lift Fitment

The stock wheel offset for 2003-2012, and 2013 2500 trucks is right at +44mm. In our opinion, the best offset for aftermarket wheels is between +18 and +25 millimeters. This is the best measurement for avoiding rubbing on either the control arms or the fender wells.

Stock Control Arms Installed

With stock wheels and control arms installed, a 35 x 12.5 tire will still have an acceptable turning radius with a slight contact on the control arms at full steering stop left or right. If you’re running the same tire size on an +18mm to +25mm aftermarket wheel size, the rubbing issue at full steering stop will not exist.

Installing Thuren Fabrication High Clearance Control Arms

Installing our High Clearance Control Arms and 35 x 12.5 tire size on stock wheels will have zero rubbing issues from left or right steering stops. If a 37 inch tire size is more your flavor, on stock rims only a slight contact will occur at full steering stops.

If you buy a +18mm offset wheel size and a 37 inch tire size the above mentioned fender liner trimming procedure will be a requirement and possibly the sheet metal rocker seam as well. Our High Clearance Control Arms will be well out of the way for this setup and this is what we would consider an acceptable big tire solution.

Thuren Fabrication Alien Arms For A Zero Offset Advantage

Our in-house designed Alien Arms work best with a 0.0mm offset wheel size and 37 x 12.5 tire size. If you’re considering a wheel and tire package with +18mm offset and 37 x 12.5 inch tire, understand it will rub on the upper arms at full steering lock left or right.

Wheel And Tire Fitment For The 2013+ 3500, 2014+ 2500 Trucks Including Power Wagon: 0-3" Lift

At 57mm, the stock wheel setup for the 2013+ 3500 and 2014+ 2500 will require a +18 to +25 millimeter offset range in order to achieve proper fitment. The same goes for the Power Wagon which in stock form has a +42 to +57 millimeter wheel offset.

The +18mm to +25mm offset will give the best overall clearance for tire and wheel combinations once you install a 0 - 3 inch lift. The above-mentioned platforms clear stock tire setups better than the Pre-2013 models. Most trucks come from the dealer with 34 inch diameter tire sizes, therefore fitting 35 inch tires is not out of the question...mostly.

A 35 x 12.5 tire size wrapped around stock rims will fit but will also rub on the radius arms. The same goes for a 37 x 12.5 inch tire size on a stock setup; however, it’s guaranteed that the turning radius will suffer dramatically coupled with rubbing on the sway bar and radius arm.

Applying a +18mm offset to a set of aftermarket wheels and a 37 x 12.5 inch tire diameter fits nicely with zero contact on the radius arm or sway bar. If it rubs at all through the vertical range of motion it’ll be very slight.

The 2009-2018 Ram 1500 Wheel And Tire Setup

Most information you find on the internet will steer you towards a 0.0 to 25 millimeter offset for your wheels. In our opinion, we like to keep our wheels and tires tucked within the fender wells post trimming procedure (if necessary). The factory geometry is our goal even after lifting our trucks or going with bigger tire sizes. Achieving this with the OEM +18mm offset wheels is our method for many reasons.

What Wheels Fit And Why

With the exception of one set of tires that had a side lug that was slightly invasive, the 35 x 12.5 inch tire size fits nicely with the +18mm offset rims. Maintaining the +18mm offset retains superb handling and scrub radius while also requiring less trimming. The overall appearance of this setup tends to look more professional and on purpose vs the wheels sticking out past the fender well profile.

2003 - 2009 Rear Suspension And Fitting A 37 Inch Tire Size

It's a common worry amongst Dodge Ram owners that if they upgrade to a 37 inch tire size, it will constantly rub on the fender well edge. We’ve found that it's not an issue if you’re running stock leaf springs, as the suspension is limited by the OEM suspension travel and therefore will not reach the fender's edge even at full stroke.

If you decide to perform our Overload Spring Modification, we suggest driving easy because you will get more travel out of the stock leaf pack. Try not to bottom out the suspension because it will most likely rub on the forward portion of the fender well opening.

To reach your full suspension potential and not fear bottoming i.e. tire rub, while driving it’s definitely time to upgrade your leaf springs to our Long Travel Leaf setup so as to move the rear axle back a bit and have the spring rate that’ll allow you to drive your rig aggressively.

The 2010 - 2013 Dodge Ram Versus 3rd Gen Models: Rear Suspension

All leaf configurations for the 2010 - 2013 Dodge Ram will clear a 37 inch tire diameter because compared to the 3rd generation truck it has a slightly larger fender well opening. Even with our Overload Leaf Modification, rubbing on the fender well edge will not be an issue. Bottoming out should not be a concern for this generation of trucks so drive it like you wish.

The 2013+ 3500 and 2014+ 2500 models have received the same fender well opening treatment from the factory and will allow a 37 inch tire size without any issues.

The Wrap Up

With the proper amount of research you can have confidence in your purchasing of new wheels and tires. As with all setups it begins before install and we suggest putting in the work for your end game suspension settings.

Using our measurements to achieve proper wheel and tire fitment will have you rolling down the road worry free and less concerned about if your tires will rub and possibly have issues down the road. You’ll be able to drive as hard as you wish and enjoy the full potential of your rig.

If you have any questions on wheel and tire size fitment, please don’t hesitate to email (thuren.tech@gmail.com) us with your questions once you’ve read our tech data on our website.