suzuki, rm-z250, rm-z450
Jeff Allen

2018 Suzuki RM-Z250 vs. 2018 Suzuki RM-Z450

Sibling Rivalry: two motocross bikes

Welcome to the Sibling Rivalry series, where we take two bikes from the same manufacturer and pin them up against each other and see which machine test riders of varying age, height, weight, and abilities prefer. For our first brotherly battle, we have the 2018 Suzuki RM-Z250 and RM-Z450. The RM-Z250 is largely unchanged for 2018 with blue accents on the seat and radiator shrouds along with white number plates. The RM-Z450, on the other hand, received its first major overhaul in several years with a new frame and chassis, updated engine, and a Showa 49mm coil spring fork and Showa BFRC shock. Here’s what three test riders thought after riding the two bikes at Milestone MX Park:

RM-Z450, RM-Z250, suzuki
The RM-Z450 (left) is all-new while the RM-Z250 received only a few minor cosmetic changes for 2018.Jeff Allen

Steve Boniface
Age: 35, 5'7", 150 lb., Pro

The Suzukis were not my first choice in the shootouts we did back in September for the 450s and November for the 250Fs. However, the idea of riding the two bikes back to back on the same track and same day was appealing to me. Which bike would I like better on the rather small track of Milestone MX Park in SoCal? In addition to comparing the Suzukis that day, I thought it would be a great opportunity to show how close the bikes were performance-wise in relation to the Hondas, so we brought the CRF250R and CRF450R out as well. For the record, both of the Hondas ranked in the top two in my personal rankings in the shootout while the Suzukis were the bottom two.

The first bike I rode was the RM-Z450. After a few warm-up laps on the main track, I took three hot laps to get a good feel for the bike at race pace and to record the lap times in order to compare with the other bikes. Power-wise, the 450 is a big bike on the relatively tighter Milestone layout. However, the RM-Z450, as I first noticed during the shootout, is pretty agile and handles turns really well. I would say I was riding at about 95 percent of my ability just to stay smooth and be able to clock three consistent laps.

Suzuki RM-Z450 Lap Times

Lap 1 1:32.5
Lap 2 1:32.6
Lap 3 1:32.2
RM-Z250
"Both bikes corner very well, but the RM-Z250 is slightly better in this area as it's easier to set up for the corner and initiate it." —Andrew OldarJeff Allen

Shortly after, I jumped on the RM-Z250. The general feeling from the shootout was the bike was a little underpowered compared to the other bikes but that its handling and turning were really good. After some warm-up laps, I started my three lap-time sessions. The bike felt really light and agile, especially after riding the 450, and I was able to really attack the track and push to my limits. The RM-Z250's cornering was great, and even if it did feel like it was lacking power, I was able to carry good speed through the corners and maintain that momentum into the jumps and straightaways. My lap times were consistent and really not that far off the 450's for a bike with much less power.

Suzuki RM-Z250 Lap Times

Lap 1 1:33.1
Lap 2 1:33.4
Lap 3 1:33.2

All in all, I was faster on the 450 but had more fun riding the 250. The track you are riding, your riding ability, fitness, and goals while riding are some deciding factors when choosing between a 250 versus a 450. Now I would like to show you how close the bikes are to each other nowadays. Remember how I mentioned that both of the Hondas ranked in the top two of my personal rankings in our shootouts and the Suzukis were at the bottom two? The lap times were within a second of each other on both bikes when comparing 250 versus 250 and 450 versus 450. That’s not a lot between the Hondas, which won both shootouts, and the Suzuki RM-Z450 and RM-Z250 that placed fifth and sixth in their respective shootouts.

Suzuki RM-Z250 Lap Times Honda CRF250R Lap Times
Lap 1 1:33.1 1:33.4
Lap 2 1:33.4 1:32.1
Lap 3 1:33.2 1:31.2
Suzuki RM-Z450 Lap Times Honda CRF450R Lap Times
Lap 1 1:32.5 1:30.1
Lap 2 1:32.6 1:31.3
Lap 3 1:32.2 1:31.2
Steve Boniface
"The track you are riding, your riding ability, fitness, and goals are some deciding factors when choosing between a 250 versus a 450. —Steve BonifaceJeff Allen

Andrew Oldar
Age: 26, 5'10", 130 lb., Novice

Riding the 2018 Suzuki RM-Z250 and RM-Z250 back to back on the main track was pretty interesting, mostly because of the chassis differences. While both bikes have a fairly rigid chassis, the RM-Z250 felt quite a bit lighter because of the actual weight and engine size. However, the RM-Z450 chassis characteristics felt more well-rounded and better overall. Both bikes corner very well, but the RM-Z250 is slightly better in this area as it’s easier to set up for the corner and initiate it than the RM-Z450 is. The RM-Z450 feels a bit heavy when you first begin riding it, which would lead you to believe it might not corner the greatest, but it lays over in a rut very intuitively and predictably. The area where the RM-Z450 surpasses its younger sibling is straight-line stability. The RM-Z450 has a better balance between excellent cornering ability and straight-line stability. I felt a bit less confident on the RM-Z250 at speed because the chassis combined with the bike’s KYB PSF2 air fork can make the front end feel a bit twitchy at speed.

Evan Allen
"Due to its exceptional cornering ability and manageable motor package, the Suzuki is a blast to ride lap after lap." —Evan AllenJeff Allen

As far as suspension goes, I liked the RM-Z450’s setup quite a bit better, and that is mostly because of the fork. The Showa 49mm coil spring fork on the 450 is a big improvement over the Showa SFF TAC fork the previous-generation bike had, as it has a plusher and more comfortable feel. The same can be said for how it compares to the RM-Z250’s KYB PSF2 air fork. The PSF2 fork works okay on jump landings, but only when you perfectly down-side it. Otherwise, any type of slap-down landing results in a harsh feeling from the fork. It also delivers some negative feedback to the hands in braking bumps and small chop. On the other hand, the KYB shock on the RM-Z250 felt much plusher and more planted in comparison to the fork.

Engine-wise, the RM-Z250 had decent bottom-end and midrange power but signed off on the top-end and over-rev. As a result, I found myself shifting the RM-Z250 a lot. I also noticed the 250 builds rpm a bit slower than the RM-Z450 and has a little more engine braking. The RM-Z250 engine is fun to ride, but it requires a little more work to get it moving quickly. The RM-Z450 on the other hand had a much broader powerband. The engine is very user-friendly in the way it delivers power very in a very linear and smooth manner. The bike doesn’t sign off on the top-end like the RM-Z250 as well, which makes for much less shifting and a power delivery that is easier to ride.

Steve Boniface
"The RM-Z450 is pretty agile and handles turns really well." —Steve BonifaceJeff Allen

At the end of the day, if I had to choose between the two, I would opt for the RM-Z450 because it has an easier-to-ride engine, plusher fork, and a better overall chassis. I realize my lap times don’t directly reflect my choice, but I think I may have been able to lay down a faster third lap on the RM-Z450 had the tire not begun to go flat. All in all, both bikes were fun to ride and, as the lap times show, I was fairly consistent on both bikes.

Suzuki RM-Z250 Lap Times Suzuki RM-Z450 Lap Times
Lap 1 1:54.1 1:53.9
Lap 2 1:53.4 1:53.7
Lap 3 1:51.2 1:54.7

Evan Allen
Age: 20, 5'8", 120 lb., Novice

From the moment I threw a leg over the RM-Z250, it felt like home. However, after a few laps on the vet track, I quickly realized the suspension needed some adjustment. It’s likely because I am a lighter rider, but the suspension seemed far too stiff. That being said, the suspension on the other bikes in the 250F class don’t feel this harsh. After just a few laps, I quickly lost confidence in the front end as braking hard into tight corners was unsettling. Additionally, I struggled through fast sections with small chop and acceleration bumps due to the lack of front end stability. The stiff fork beat up my hands and had me feeling fatigued in short order. In contrast, when the fork fell further into the stroke after landing from a big jump, the suspension felt very plush and comfortable.

Evan Allen
"With similar suspension components, the two Suzuki machines could become equal counterparts for me." —Evan AllenJeff Allen

At the rear of the RM-Z250, I had similar problems with the shock. As I came out of a corner and tackled acceleration bumps, the rear end danced around like a desperate bridesmaid. Constantly bouncing from side to side, I would have to chop the throttle in fear of being catapulted off the track. When hammering through acceleration bumps, I would blip the throttle when coming out of a rut and the shock would rebound far too quickly and aggressively, thus kicking me out of the saddle as a result. The suspension characteristics were inconsistent and somewhat unpredictable. When the rear end would struggle in braking bumps, the fork seemed okay, that is until I let off the front brake and initiated my lean into the corner.

The rear end managed fairly well when barreling down the fast sections of the track, but at the same time in these instances, the front end would nearly rattle my hands numb. As I adjusted my riding to the suspension characteristics—after nearly learning the hard way—I was able to effortlessly lean the bike over and carry speed through the corners. The yellow machines have a reputation for their profound cornering ability and I sure found that to be true. Consistently, lap after lap, I was able to precisely hit my marks with minimal effort.

Andrew Oldar
"Engine-wise, the RM-Z250 had decent bottom-end and midrange power but signed off on the top-end and over-rev." —Andrew OldarJeff Allen

Without a doubt, the RM-Z250 has the least exciting motor out of the 250F bunch, but that’s not necessarily a bad thing. Due to its exceptional cornering ability and manageable motor package, the Suzuki is a blast to ride lap after lap. It makes it easy to maintain good technique because the bike doesn’t tend to wear you out, which makes for an overall package that truly relies on skill. As with a 125cc two-stroke, you must be exact with your shifting, corner speed, and clutch work. I personally own a 125 and the RM-Z250 is a good step up for me.

Evan Allen
"I was consistently faster on the RM-Z450 due to its plush suspension, predictable motor, and iconic Suzuki handling." —Evan AllenJeff Allen

After spending a fair amount of time on the RM-Z250, I turned my attention to big brother. Instantly after getting on the RM-Z450, I felt right at home. Although the bike has a beastly motor, it was extremely manageable and offered a linear power delivery throughout the entire powerband. I became very confident in the bike due to its predictable power output. The alpha of the family consistently put power to the ground, whether I was tracking through a flat corner or hammering a bowl turn, the RM-Z450 stayed planted when needed, but also had the ability to break loose and steer with the rear when desired.

The RM-Z450 features updated suspension components for 2018, which complemented its phenomenal handling characteristics everywhere on the track. To my amazement, the 450 outshined the 250 with its ability to stay planted in the rough acceleration bumps. Absorbing every bump with ease, the suspension kept both wheels on the ground allowing me to maintain my momentum easier while connecting one corner to another. Even though the 250 has exceptional handling, the 450 outperformed its junior due to its extremely plush suspension. This allowed for more consistent braking, cornering, and handling everywhere on the track. As the fork fell into the beginning of the stroke, it created immense amounts of front wheel traction which the lap times showed.

Steve Boniface
"The RM-Z250 felt really light and agile, especially after riding the 450, and I was able to really attack the track and push to my limits." —Steve BonifaceJeff Allen

I was consistently faster on the RM-Z450 due to its plush suspension, predictable motor, and iconic Suzuki handling. Although I generally prefer riding the smaller-displacement 250F machines, in this case, the RM-Z450 would be my go-to bike. Perhaps Suzuki has future plans to swap the KYB PSF2 air fork that is currently on the RM-Z250 to the Showa 49mm spring fork that its bigger brother has. With similar suspension components, the two Suzuki machines could become equal counterparts for me.

Suzuki RM-Z250 Lap Times Suzuki RM-Z450 Lap Times
Lap 1 1:17.1 1:16.1
Lap 2 1:16.4 1:15.9
Lap 3 1:17.4 1:14.7