Suspension and Components› Suspension Kits

SuspensionMAXX

Rear Block and U-Bolt Kit 1.5-Inch Lift

$189.99

SKU: SMX-156215

In Stock
In Stock
Ships by Sep 9
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The SuspensionMAXX SMX-156215 is a heavy-duty rear block and U-bolt kit designed to provide a 1.5-inch lift. This kit is specifically for 2020-2021 Chevrolet/GMC Silverado/Sierra 3500 DRW (Dually) 2WD/4x4 models equipped with 3-inch wide leaf springs and top-mounted overload springs. It features Super Heavy Duty U-bolts that are 3/4-inch diameter larger than stock.
Show original supplier description
The SuspensionMAXX SMX-156215 Heavy Duty Block and U-Bolt Rear Leaf Spring Leveling Kit is engineered to increase rear suspension height by 1.5 inches, making it ideal for achieving a level stance, fitting larger wheels and tires, or supporting heavy loads. Constructed with durable alloy metals, this kit includes solid steel blocks, heavy-duty Grade 8 U-bolts, tall nuts, and extra-thick washers. The U-bolts are 3/4-inch diameter, exceeding stock specifications for enhanced strength and longevity. This kit is specifically designed for 2020-2021 Chevrolet/GMC Silverado/Sierra 3500 DRW (Dually) trucks in both 2WD and 4x4 configurations. It is compatible with vehicles that have 3-inch wide leaf springs and top-mounted overload springs. Installation is estimated to take approximately 1.5 hours and is supported by SuspensionMAXX's Technical Support Program. SuspensionMAXX products are 100% American Made and come with the MAXX Structural Lifetime Warranty, backed by excellent customer service and technical support.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandSuspensionMAXX
Part NumberSMX-156215
CategorySuspension and Components

We’re here — turning wrenches, just like you.

Call us, follow along, or come say hi.

(760) 282-4645 Instagram Google

Buy with Confidence

Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

View Full Return Policy

Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy