Geometry and Sizing
Ready to rally the World.
A 1:25000 scale map, a weather forecast and the Roubion. Three things you shouldn’t hit the high mountains without. And while we can’t guarantee you won’t get lost or soaked, we’re pretty sure there’s no better bike to tackle ancient alpine terrain.
And whether blind racing or just blindly enjoying the trails as they come, the Roubion’s MX wheel combo feels like the best mix since Aperol met spritz. A 29-inch front wheel serves up high-speed stability and high-rolling confidence. Meanwhile the 27.5-inch rear makes for an intuitive and highly maneuverable rear end that loves to get sideways around the most ragged of switchbacks.
This bike is rapid, so when it comes to stopping power and control we’ve mixed things up here also. A 200mm front and 180mm rear brake rotor pairing ensures you shouldn’t overcook the corners no matter how hot you’re coming in. The Roubion’s chainstay lengths are all specifically sized for the XS, S and M frames too, meaning handling remains consistent across the range. And like all Juliana’s, each shock is tuned to work better for slightly lighter riders than equivalent Santa Cruz models.
|Head Tube Angle||64.7°||64.7°||64.7°|
|Seat Tube Length||370mm||380mm||405mm|
|Head Tube Length||110mm||100mm||110mm|
|Top Tube Length||536mm||570mm||599mm|
|Seat Tube Angle||77.6°||77.2°||77.1°|
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.
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.
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.
1 / 5
Travel for Days
150mm of VPP® lower link rear travel and a 160mm fork
Best of both Worlds
High-speed stability and confidence are fixed variables of the 29-inch front wheel, plus you get the 27.5 rear maneuverability for snappy moves, playing for style points, and negotiating hairy switchbacks
Geometry to match
The Roubion's chainstay length is matched to frame size so every rider, no matter their height, gets the same balanced geometry and bike fit
Low standover height
Juliana's sloping top tubes always assures confidence for shorter legged riders
More options for smaller riders
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.
If you have any other questions or would like to follow up on a warranty claim, contact our Warranty Department.
Roubion Tech Support
|Front Derailleur||No compatibility|
|Eye to Eye length||230mm|
|BB Shell||73mm Threaded|
|Max Tire Size||2.6"|
|Max Chainring Size||36t|
|Water Bottle Mounts||1|
|Shock Mounting Bushing Front||30x8 (standard bushing)|
|Shock Mounting Bushing Rear||30x8 (roller bearing)|
|Brake Mount||180 PM|
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 Weight||Air Pressure||Shock Sag|
|100lbs (45.5kg)||105 psi||16.5-19 mm|
|120lbs (54.4kg)||125 psi||16.5-19 mm|
|140lbs (63.5kg)||145 psi||16.5-19 mm|
|160lbs (72.6kg)||165 psi||16.5-19 mm|
|180lbs (81.8kg)||185 psi||16.5-19 mm|
|200lbs (90.7kg)||205 psi||16.5-19 mm|
|220lbs (99.8kg)||225 psi||16.5-19 mm|
|240lbs (108.8kg)||245 psi||16.5-19 mm|
|260lbs (117.9kg)||265 psi||16.5-19 mm|
RockShox Super Deluxe Ultimate
|Rider Weight||Air Pressure||Shock Sag|
|100lbs (45.5kg)||85 psi||16.5-19 mm|
|120lbs (54.4kg)||105 psi||16.5-19 mm|
|140lbs (63.5kg)||130 psi||16.5-19 mm|
|160lbs (72.6kg)||150 psi||16.5-19 mm|
|180lbs (81.8kg)||175 psi||16.5-19 mm|
|200lbs (90.7kg)||195 psi||16.5-19 mm|
|220lbs (99.8kg)||220 psi||16.5-19 mm|
|240lbs (108.8kg)||240 psi||16.5-19 mm|
|260lbs (117.9kg)||265 psi||16.5-19 mm|
Can I put a 27.5 front wheel on the Roubion?
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 Roubion 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 Roubion 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 Roubion?
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 Roubion (S-M) comes with two different wheel sizes the BB drop is greater up front.
Why MX (Mixed Wheels)?
Mixed wheels provide the stability and traction of a 29" front wheel with the agility of a 27.5" rear wheel. The smaller rear wheel and its comparatively lower axle height allows the rider to more easily unweight the front wheel- this makes for confident yet agile handling on the steepest of descents.
If you know the difference between a wrench and a spanner then we have a host of simple-to-follow guides for the basic service jobs.
We design our bikes to last, to be easy to work on and we make sure to provide the parts and information so you can make your bike last for many lifetimes.