Santa Cruz Bicycles Bronson 4 MX - Full Suspension Carbon Mountain Bike
Santa Cruz Bicycles Bronson 4 MX - Full Suspension Carbon Mountain Bike

If in doubt, take a Bronson out

You know what’s hard about choosing what model of Santa Cruz suits you? It’s having to narrow down what kind of riding you want to do. But what if you don’t want to be pinned down by labels? What if you want to just be a mountain biker in the broadest sense of the word? What if you want to choose how you ride rather than what to ride? If this sounds familiar, then try a Bronson.

Our demo crew have a saying, ‘If in doubt, take a Bronson out’. The 150mm-travel bike can go deep on any landing and the VPP™ suspension design makes sure that there’s no wasted energy when heading back up for another go.

If you value style at speed or want to have fun feeling fast, then mixed wheels (29” up front, 27.5” out back) show that the spectrum is a loop not opposite points on a scale. The larger front wheel provides more traction and stability that’ll make you feel more confident squaring off the turns and diving for the inside lines. But a 27.5-inch tire in the rear means this bike still loves getting up on the back wheel and into the air.

From flat out on the trail to fully flat over a table, each generation of Bronson rider redefines expectations of what a mountain biker is.

  • Thrasher in need of a micro-machine? Check out the 5010
  • Big fan of the Bronson but want pedal-assist? Check out the Heckler eMTB
  • Love the Bronson and want to see what Juliana has to offer? Check out the Roubion
  • Proud owner of a Bronson? Find all the Rider Support info you need to keep enjoying it

Key Features:

Available in: Carbon C and Carbon CC
Wheel Size: MX
Front Travel: 160mm
Rear Travel: 150mm

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Santa Cruz Dealer Logo: Mike's Bikes
Santa Cruz Dealer Logo: Evo
Santa Cruz Dealer Logo: Competitive Cyclist


Reach 405430455475500
Stack 594617626635649
Head Tube Angle 64.7°64.7°64.7°64.7°64.7°
Seat Tube Length 370380405430460
Front Center 722757786811842
BB Height 344344344344344
BB Drop 1029/1029/1029/1029/10
Wheelbase 11491188122112491284
Rear Center 427431435438442
Head Tube Length 110100110120135
Top Tube Length 536570599623653
Seat Tube Angle 77.6°77.2°77.1°76.9°76.7°
Standover Height 701709731729728



Frame Sizing

If you're on the cusp between the recommended height range of two sizes, the absolute best thing is to try to ride them both. At a minimum, check the stack/reach measurements on your current bike and compare it to the new model you are looking at to get an idea of a fit you are already comfortable with. If riding the bike is not an option, consider the following.

Personal Preference

A larger size frame will be more stable, and will give you more room to move without upsetting the weight-balance of the bike. The larger size will put the front wheel further in front of you, which gives the feeling of security and conversely, it will require more significant body movements when you WANT to shift the weight-bias of the bike. Think hard about your riding style and how active/intuitive you want it to be vs stable and speedy. You'll need to work a bit harder to muscle the larger bike around.

Body Dimension

Not all bodies at a given height are the same. If you have longer legs and a shorter torso than the average person your height, that may push you towards the smaller of the recommended sizes. If you're all torso and arms, most likely you'll want to size up.



142 - 155cm
142 - 155cm


155 - 165cm
155 - 165cm


165 - 175cm
165 - 175cm


175 - 185cm
175 - 185cm


185 - 196cm
185 - 196cm


Veronique Sandler riding the new Bronson MX
Riding the Bronson in the forest
Digging at the dirt jumps with the new Bronson
Jumping the Bronson mixed wheel mountain bike
Veronique Sandler on mountain bike trails on the Bronson
Veronique Sandler riding the new Bronson MX
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Design Details

Upper link and shock with 150mm of travel

Design Details

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150mm VPP™ travel

The 150mm-travel bike has enough travel to go deep on any landing and the VPP™ suspension design makes sure that there’s no wasted energy when heading back up for another go.

Mix of both worlds

The mixed wheel configuration of a 29-inch wheel up front provides traction and stability, while the 27.5" rear wheel allows for quick back wheel steering and lifting.

Geo to match

The Bronson's chainstay length is matched to frame size so every rider, no matter their height, gets the same balanced geometry and bike fit.

Coil or air

The Bronson frame fits all sizes and types of rear shocks.

Made to last many lifetimes

The legendary Santa Cruz fit, finish and quality construction put this into a league of its own. The frame, bearings and optional Reserve wheels come with a lifetime warranty and any service is easy to do with our Rider Support pledge.

Tough Carbon Frame

Why scrap a frame when a simple bearing service can make one last a lifetime? That's our stance on sustainability at least, and it's why our carbon fiber doesn’t just mean lighter, it means tough as hell, lifetime warranty and crash replacement support.

Bronson CC mixed wheel mountain bike in Paydirt Gold

Maintenance Information

Reserve Wheels

How to find your serial number

Something not right? Use our warranty claim form to file a claim. We'll do everything we can to get you back to riding as fast as possible.

File a claim for a Santa Cruz product

If you have any other questions or would like to follow up on a warranty claim, contact our Warranty Department.

Bronson Tech Support

Suspension SystemVPP
Front DerailleurNo compatibility
Headset/HeadtubeIntegrated (IS41/52)
Seat Post31.6mm
Seat Clamp36.4mm
Eye to Eye length230mm
Fork Compatibility160mm
BB Shell73mm Threaded
Max Tire Size2.6"
Max Chainring Size36t
Water Bottle Mounts1
Shock Mounting Bushing Front30x8 (standard bushing)
Shock Mounting Bushing Rear30x8 (roller bearing)
Brake Mount180 PM
Fork Offset37mm (XS) | 44mm (S-XL)
Fork Offset (Rockshox Lyrik)42mm (S-XL)

Download the shock setup PDF for this bike and get even more detailed sag, high/low rebound, and high/low compression recommendations for shocks below and get recommendations for the fork in each build.

Fox Float Performance

Rider WeightAir PressureShock Sag
100lbs (45.5kg)105 psi16.5-19 mm
120lbs (54.4kg)125 psi16.5-19 mm
140lbs (63.5kg)145 psi16.5-19 mm
160lbs (72.6kg)165 psi16.5-19 mm
180lbs (81.8kg)185 psi16.5-19 mm
200lbs (90.7kg)205 psi16.5-19 mm
220lbs (99.8kg)225 psi16.5-19 mm
240lbs (108.8kg)245 psi16.5-19 mm
260lbs (117.9kg)265 psi16.5-19 mm

RockShox Super Deluxe Ultimate

Rider WeightAir PressureShock Sag
100lbs (45.5kg)85 psi16.5-19 mm
120lbs (54.4kg)105 psi16.5-19 mm
140lbs (63.5kg)130 psi16.5-19 mm
160lbs (72.6kg)150 psi16.5-19 mm
180lbs (81.8kg)175 psi16.5-19 mm
200lbs (90.7kg)195 psi16.5-19 mm
220lbs (99.8kg)220 psi16.5-19 mm
240lbs (108.8kg)240 psi16.5-19 mm
260lbs (117.9kg)265 psi16.5-19 mm

Can I put a 27.5 front wheel on the Bronson?

These bikes are designed specifically to use mixed wheels. We do not recommend a 27.5 front wheel for geometry reasons. The XS size is the exception as it's designed for 27.5".

Do all sizes use MX wheels?

The XS size Bronson uses 27.5" wheels front and rear. All other sizes are MX

I see there are different chainstay lengths for each size bike. Can I buy a different swingarm to customize the length on my bike?

The chainstay length change occurs in the front triangles- we vary the pivot locations fore and aft to achieve the different lengths while using a single size swingarm. So no- you cannot get the chainstay length of the small on your size large, for instance.

I'm coming from a 27.5 bike- what will feel different with MX? Any setup tips?

An MX bike will definitely handle differently than a full 27.5 bike. The main difference you'll feel is a more stable and confident front end. The turning will be a bit slower than a 27.5, but the payoff is a more secure feeling in corners and more traction. Due to the taller front axle height and improved roll-over of the large wheel, your chances of stuffing the front wheel or going over the bars is vastly diminished. Use this security to ride challenging terrain with a more aggressive and dynamic body position.

I've been riding 29ers for a while- what will feel different with MX? Any setup tips?

29" bikes provide a ton of front wheel grip- this is partially due to the front wheel itself, but also due to the axle height of the rear wheel which works to keep the front end weighted. This creates a natural position on lower-angle terrain but requires body position and/or setup adjustments to achieve any sort of rearward bias.

On an MX bike, the bias is more rearward. This gives a very natural feeling on steep descents, but requires some body position and setup consideration for a balanced feel on flatter terrain. Compared to a 29er, a slightly lower handlebar and a more forward-biased suspension setup will make an MX bike feel more like what you're used to. Additionally, using the Hi BB setting will lend itself to a more front biased feel. Using these tuning parameters will help you find the sweet spot for your terrain and preference.

You'll know you have it dialed when it feels like you're never making large bodyweight shifts to either lift the front end or keep it stuck to the ground.

What fork offset is the recommended?

The Bronson comes with 42-44mm offset forks, and this is what we recommend for optimal handling. The size XS come with a 37mm offset 27.5" fork

What's the largest rear rotor that will fit on the Bronson?

The minimum is 180mm (direct mount) and the largest is 223mm

Why are there two different measurements listed for BB Drop?

BB drop is the measurement between the center of the bottom bracket and the front and rear axles. Because the Bronson (S-XL) comes with two different wheel sizes the BB drop is greater up front.

Why MX (Mixed Wheels)?