Hello everyone, this is PiscesRacing.
If you’ve recently picked up the new Suzuki DRZ4SM, you’ve likely noticed that while it’s a blast to ride, the stock rear tire looks a bit lean. Today, we’re diving into the most popular upgrade for the DRZ4SM: jumping from the stock 140 width to a "Heavy-Duty" 160. Is it worth the switch? Let’s look at the data.
1. The Factory "Secret": Why a 4.5J Rim with a Narrow Tire?
During our teardown at PiscesRacing, we found that Suzuki was actually quite generous with the rim specs on the new DRZ4SM. The rear rim is a 4.5J width.
Technical Context: The classic DRZ400 usually came with a 4.25J rim and a 150 tire. The new DRZ4SM comes stock with a 140/70-17, but because the 4.5J rim is wider, it "stretches" the tire significantly. When we measured it with a digital caliper, the stock 140 tire actually expanded to 150mm once mounted. For comparison, other bikes using 4.5J rims usually run a 160 tire, which measures around 158-159mm.
Conclusion: The DRZ4SM chassis and rim are perfectly capable of handling a 160. The 140 was likely a conservative choice by the factory for weight savings or fuel efficiency.
2. The Upgrade: 160/60-17 + PiscesRacing Tubeless System
A common question from riders: "Will a 160 tire make the bike feel heavy?"
The answer is: not if you do it right. In the tire world, 160 is the threshold. Anything 160 and above is typically a "Heavy-Duty" tire construction—thicker sidewalls and more stability. To balance performance with that aggressive "Supermoto" look, our solution is twofold:
-
Tire Upgrade: Switch to a 160/60-17 spec.
-
System Upgrade: Eliminate the heavy, puncture-prone inner tube and switch directly to the PiscesRacing Tubeless System.
By going tubeless with PiscesRacing, you significantly reduce unsprung weight. This offset makes up for the slightly heavier 160 tire, giving you better road feedback and the safety of knowing a nail won't cause an instant blowout.
3. Real-World Testing: Will the TC System Error Out?
Some riders have expressed concern that changing the tire width might confuse the Traction Control (TC) system. We put our 160-equipped DRZ4SM through the ringer:
-
Cross-Mode Testing: We cycled through TC1, TC2, and Power Modes A/B/C.
-
Full-Throttle Acceleration: The sensors read perfectly. The anti-slip mechanism did not trigger prematurely despite the slight change in tire diameter.
-
The Feel: The 160 sidewall provides much more lateral support. In deep leans, the bike feels planted in a way the 140 simply can’t match.
4. Handling Details: Things to Watch For
While testing, the PiscesRacing team noted a few factory limitations on the DRZ4SM:
-
Brake Lever Clearance: The stock master cylinder lever has a relatively short stroke. If you use a two-finger braking technique, the lever can easily pinch your remaining fingers under heavy braking. We recommend adjusting the lever gap or upgrading to a Brembo RCS master cylinder.
-
Front Fork Support: With the extra grip from a 160 tire, the front end dive becomes more apparent during hard braking.
-
Nimbleness: Even with the wider tire, the bike retains its Supermoto DNA. It looks "heavy" at a standstill, but once you’re moving, the turn-in remains sharp.
5. Summary: Is It Worth It?
If you are a purist chasing the absolute fastest flick-ability, the 140 is fine. But if you want better cornering traction, a more aggressive stance, and a safer ride, the 160 Wide Tire + PiscesRacing Tubeless System is the ultimate upgrade for the DRZ4SM.
PiscesRacing now offers complete wheel upgrade solutions for this model. Still undecided on tire sizes or need more technical specs? Get in touch with us: