R4 Rear Hub

R4 Rear Hub Mountain Bike Chromag Bike Parts
R4 Rear Hub Mountain Bike Chromag Bike Parts
R4 Rear Hub Mountain Bike Chromag Bike Parts
R4 Rear Hub Mountain Bike Chromag Bike Parts
R4 Rear Hub Mountain Bike Chromag Bike Parts
R4 Rear Hub Mountain Bike Chromag Bike Parts
₩322,000 Sale Save

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☛ Hub only with your choice of XD, MS, or HG driver body


Axle Diameter // 12mm

Spacing // Boost 148mm

Driver // XD, HG or Microspline

Engagement// 4-Pawl, 36 Point

Spokes // 32

Disc Mount // 6 Bolt

Click here to view the wheel user guide.
Phase 30 Rear Wheel MTB Mountain Bike Wheels Chromag Bikes


Don't hesitate to reach out with any and all questions!

Contact Us

Worldwide shipping

We ship anywhere in the world with competitive rates from UPS and FedEx. Alternatively you can pickup right here at Chromag HQ.

Service Guide

Need more info on setup, service and spare parts?

Check out our user guides here.


All of our parts are backed by a 1 year warranty.
After that we still have your back with our crash replacement program.

key features

Design Considerations

Oversize Ratchet Ring

The R4 is designed around an oversized ratchet ring, reducing torque on the engagement assembly & thereby improving life span.

This has the added benefit of providing space for larger bearings, which also increases time between service intervals.

Steel Axle

The hardened steel axle gives good stiffness and longevity, while the smaller diameter of the steel axle gives more room for larger bearings in the hub body, again, increasing life.

Thread on end caps make for simple servicing and keep the freehub body securely in place when the wheel is removed.

R4 Rear Hub Parts Mountain Bike Chromag Bike Parts
Spare Parts

We have a wide variety of spare parts and bearings available for the R4 so you can fully service your own equipment at home.

The exploded diagrams are also pretty helpful if you got distracted while pulling everything apart.

Available here

Hub FAQ's

Torque caps are a RockShox product that allow for greater stiffness between the front hub and fork interface. Newer RockShox forks will work with or without them.

All other fork brands will not work with Torque Caps.

Because the bike industry likes to invent new standards by the hour, there are different freehubs to choose from depending on which cassette you run.

HG is typically for older drivetrains and SRAM NX.

XD is for newer SRAM.

Microspline is for newer Shimano.

The R4 is compatible with HG, XD & Microspline, so if you do decide to change your drivetrain, all you need to do is switch out your freehub.

Available here.

Having fewer points of engagement leads to more backlash in the system, this is apparent predominantly in climbing gears and technical situations. That being said, from our experience you very quickly become accustomed to the hub you are running and it rarely crosses your mind when riding after the first ride of a new component.

The more points of engagement, the smaller the area of contact between pawls and ratchet ring, along with the fewer pawls engaging at the same time. This is in order to fit more into the same space, often leading to reliability issues especially as parts start to wear.

With the R4 we have tried to strike the happy middle ground of having enough points of engagement to feel sharp but also leave room for long term reliability.

Of course there is also the topic of pedal kick back and suspension interaction, which could be a full article in itself.

To keep things simple, a higher engagement hub has the potential to give more feedback due to less backlash before it engages. In general, we think there are a myriad of more important things to worry about in how a bike rides.

If you notice any play in your wheel when your axle is tight its time to check things out. Similarly if you can hear or feel the bearings grumble when spinning, an investigation and likely fresh set of bearings would be a good move.

If you are doing a pre-season refresh or just giving your bike a thorough going over then cleaning and re greasing your freehub body is a good move, removing any contaminants and adding fresh clean grease is a good way to reduce long term wear.

All spare parts available here.

Customer Reviews

Based on 3 reviews
Great hubs

No issues with these hubs. Smooth, good sound, good engagement. They're simple and easy to work on, and the exploded view diagrams are very helpful. Been running them laced to BA30s on my trail bike for almost a year. No complaints.

Great Quality

Solid hubs! No issues at all and I have been running them on the BA30 rims for about 7 months in all terrain, all weather. Still smooth as ever. Highly recommend!

James M.

If you're after super duper high engagement, then maybe this isn't the hub for you, but other than that they have been bomber. Having the choice of end caps and freehubs is nice too. And like the other guy said, the exploded diagrams makes it very easy to service and see what's going on.