Anyone change their rear hub while leaving the front hub stock?

[Underblu]

I’ve noticed a little bit of lag when going from freewheeling (coasting) to pedaling. I also hear something of a clank when re-engaging the pedal under load. I’m thinking maybe it‘s the DTSwiss hub (I believe the 370) that came stock on my 2021 Santa Cruz Heckler MX-S. I’m looking for a hub with a greater number of “teeth” which I hope will reduce this lag. Some of the hubs I’m considering include the Onyx, Onyx vesper, Industry 9.
Anyone have experience with these hubs. And does it matter if I leave the DT front hub and replace just the rear.

Initially I thought it might be the SRAM GX Eagle group set but from what I read this is rather well regarded so I’m leaning toward replacing the hub. My bike has just under 1000 miles so maybe the rear hub should be replaced anyway.

 

[Rod B.]

I’ve noticed a little bit of lag when going from freewheeling (coasting) to pedaling. I also hear something of a clank when re-engaging the pedal under load. I’m thinking maybe it‘s the DTSwiss hub (I believe the 370) that came stock on my 2021 Santa Cruz Heckler MX-S. I’m looking for a hub with a greater number of “teeth” which I hope will reduce this lag. Some of the hubs I’m considering include the Onyx, Onyx vesper, Industry 9.
Anyone have experience with these hubs. And does it matter if I leave the DT front hub and replace just the rear.

Initially I thought it might be the SRAM GX Eagle group set but from what I read this is rather well regarded so I’m leaning toward replacing the hub. My bike has just under 1000 miles so maybe the rear hub should be replaced anyway.

Underblu,

I saw that nobody answered your question. I do not know your level of riding and experience, so I apologize in advance if you already know what I will discuss below. I would rather make the mistake over-explaining as oppose to assuming you know something and leave something important out of the discussion that may possibly help you out. My hope is that you and others who should happen to read this thread will come away with a better understanding of hub engagement and freehub design as it relates to eBikes and thus allow you to make a better informed purchase/upgrade.

I've been mountain bike riding for many years. I switched to eBikes in 2021. Over the years, I've used various wheel hubs on my bikes. I began using Strava in May of 2016 to keep track of my mtb rides. Since May of 2016, I've ridden 24,000 miles on my bikes. My personal opinions expressed below are based on my ride experience and associated bike component failurers. The terrain which I ride differs between Cleveland Forest or Laguna rides, and severe and punchy Utah technical rock riding. I also like to take multiple bike trips every year to various places across the United States.

Let's Begin:
The freehub/drive on a rear hub is a much overlooked component on a bike. I would submit that it's one of the most important components on a bike. Brakes are great, it's nice to stop...however, without a correctly working freehub, you're not going anywhere, ask me how I know. Your drivetrain, i.e. Shimano, SRAM, e*thirteen, Box, etc, will dictate what freehub/driver your bike came with. The most common are Shimano and SRAM.

There are three basic Freehub or Driver designs which are as follows:

SHIMANO HG FREEHUB - Commonly used on older style Shimano drivetrains, i.e. 10 or 11 speed drivetrains.

SHIMANO MICRO-SPLINE - Commonly used on modern Shimano 12 speed drivetrains

SRAM XD DRIVER - Used on SRAM 12 speed drivetrains

Important note:
Both Shimano and SRAM license their freehub/driver designs and allow the design to be manufactured and incorporated into a hub manufacturers design, i.e. D.T. Swiss, Industry Nine, Hope, etc. While the spline and cassette mounting design are the proprietary designs of SRAM and Shimano, the freehub/driver engagement is the proprietary design of the hub manufacturer. In almost all instances you cannot switch a freehub/driver belonging to one hub manufacturer and install it on another hub manufacturer's rear hub. As an example, D.T. Swiss rear hubs can be purchased with either a Shimano "Freehub", Shimano "Micro-Spline" or SRAM "XD Driver." However....you cannot use a D.T. Swiss' freehub or driver on an Industry Nine Hydra rear hub. It's also important to point out that some hub manufacturers will license and allow their freehubs/drivers to be produced by other manufacturers.

While hub manufacturers will utilize the licensed/patented design of SRAM or Shimano, the freehub/drive engagement is where the hub manufacturer's design is unique and proprietary. There are two styles of freehub/driver engagement that are most commonly found on rear hubs. They are the "Ratchet" design and the "Pawl" design. Note that there are other hub manufacturers such as Onyx which utilize a "Sprag" clutch design. Each freehub/driver engagement design has Pro and Cons, i.e. engagement angle, strength, noise, longevity, weight, consumer cost, cost to manufacture, etc.

Here is an excellent YouTube video discussing freehub/driver types:



Freehub/Driver Purpose:
The cassette mounts to the freehub/driver. This is typically done by the cassette threading onto the driver such as with the SRAM XD driver. With Shimano drivetrains, the cassette cogs are stacked and assembled onto the freehub splines and a threaded retention nut is tightened onto the threaded end of the freehub. The retention nut holds the cassette cogs in place on the freehub. When coasting and not pedaling the cassette floats and spins freely via the freehub/driver. When pedal force is applied by turning the cranks, the cassette and freehub/driver engage the rear hub and propel the bike forward.

Below are examplars of two most common freehub/driver engagement designs:

Star Ratchet Design:
D.T. Swiss employs a "Star Ratchet" freehub/driver engagement design. This is a very robust design and can withstand the torque produced by eBike motors. The design works by allowing the star ratchet teeth to disengage and float when coasting and not pedaling. When pedal force is applied, the teeth on the two star ratchets engage each other and the cassette applies power to the rear hub.

Engagement angle, i.e. how quickly pedal force is applied when the cranks are turned is dictated by the amount of teeth on the two star ratchets. The finer the tooth count, i.e. larger number of teeth, will allow a quicker crank engagement. Should the rider desire a quicker angle engagement, D.T. Swiss sells Star Ratchet upgrade kits. which have a finer tooth count.

D.T. Swiss 350 Hub with SRAM XD Driver

D.T. Swiss star ratchet engagement rings for various D.T. Swiss wheel hubs. Note that the finer the tooth count, the quicker hub/crank engagement will be.

Pawl Engagement Design:
The "Pawl" engagement design works in a similar manner to that of the star ratchet design. The freehub/driver on a pawl design will feature pawls located around the circumference of the freehub/driver. The drive side of the hub will have a splined ring which the pawls float over when coasting and not pedaling. When force is applied to the cassette by turning the cranks, the pawls lock into and engage the hub drive ring.

Example of a Stan'sM-Pulse Hub with pawl engagement

Industry Nine Hydra with freehub/pawls and drive ring shown.

The amount of pawls that a freehub/driver has, will dictate how quick the engagement will be when the cranks are turned. As an example, Industry Nine Hydra freehubs have six pawls and offers an immediate engagement, whereas a D.T. Swiss 370 freehub with three pawls will offer a slower engagement.

This is because not all pawls on a freehub/driver will immediately engage the drive ring. This is due to pawl synchronizing with the drive ring. The more pawls, the more pawls available to engage the drive ring and thus a quicker engagement. It should be noted that freehubs with less pawls, i.e. three pawl design are weaker than a six pawl design. This is because with a three pawl design, there may be only one of two pawls that imediately engage the drive ring when the cranks are turned. This places more stress on those few pawls doing the engagement.

The complex machining and moving parts of a pawl design equates to higher manufacturing cost. Therefore a freehub/driver with six pawls will cost more than a freehub with three pawls.

Bike manufacturers are always looking for ways to cut costs on base trim level bikes. Additionally, wheel manufacturers who wish to sell their line of wheelsets to the bike manufacturers, must provide wheelsets at various levels of cost and quality from premium to junk. Lower tier wheelsets which are cheap, equate to thicker spokes, heavier/soft alloy rims, alloy spoke nipples that will corrode and break and hubs with poor engagement. The world's a cruel place.....

Industry Nine Hydra six pawl with Shimano Micro-Spline

D.T. Swiss 370 hub with three pawls

Having owned various "Pawl" designed hubs/freehubs, it's been my personal experience that Industry Nine freehubs do not hold up well long term to the torque produced by eBike motors. Industry Nine hubs however, are an excellent choice for traditional pedal bike drivetrains. While Industry Nine Hydra engagement is excellent, longevity of the freehub is not as good nor as strong as the D.T. Swiss star ratchet design. I've tried both for thousands of miles. It's also been my experience that hub bearing wear and failure is more prevalent with Industry Nine hubs as opposed to D.T. Swiss. This is especially so with the older style Industry Nine "Torch" style hub.

It's been my personal experience that Industry Nine Hydra freehubs/drivers will begin to develop engagement issues after about 1,500-2,000 miles of hard eBike use. The aluminum alloy bore slots which the hardened steel pawls rest and rotate in, will eventually become enlarged. This introduces play into the pawl and drive ring engagement. When this happens, the pawls and drive ring no longer engage correctly and securely. Your cranks will begin slipping/skipping under a hard pedal.

Industry Nine Hydra hub with elongated pawl bores.

I've also encountered issues with the tension springs used in pawl freehub designs. The springs provide tension between the pawls and drive ring. On three-pawl freehubs such as that used on Specialized Turbo Levo base model wheels, the springs will begin to lose temper, i.e. lose their springiness. When this happens, the freehub will begin to skip on the drive ring and eventually fail.

In situations where the alloy pawl bores become elongated, a new freehub replacement will correct the situation. In situations where pawl springs lose their temper, a rebuild with new springs and pawls will remedy the issue. Typically, if pawls start skipping on the drive ring, they will damage the pawls. The pawls should be replaced along with the springs if they are damaged.

I carry multiple medium duty "Zip-Tie" in my fanny ride pack. Should a freehub fail, you can zip tire the cassette directly to the rear wheel. You can then "Gingerly" pedal your way back to the trailhead and avoid a long walk. Note that when you zip tie the cassette to the wheel, the crank arms will continuously spin and you cannot coast with your feet on the pedals.

I personally prefer the D.T. Swiss 350 hub with 54T star ratchet. I have several D.T. Swiss 350 hub wheelsets which have at least seven thousand miles on them. They look like shit from rock strikes, but the hubs are still going strong with only the occasional bearing replacement required. The D.T. Swiss star ratchet design is built like a brick shit house and will hold up to a lot of eBike motor abuse.

I also like that D.T. Swiss hubs are quick and very easy to service, i.e. clean and re-lubricate the freehub on the D.T. Swiss star ratchet design. All you need to do is physically pull/tug the cassette off of the hub to quickly get access to the star ratchet system for cleaning and lubrication purposes.


Rear Hub Bearing Wear:
It's also important to point out that rear hub and freehub/driver bearing wear will create issues with poor freehub/driver engagement and noise. All modern mtb rear hubs will have four bearings. They are the drive and non-drive side hub bearings and the inner and outer freehub bearings.

D.T. Swiss 350 Hub

Traditional generic style mountain bike hub depicting hub bearings

It's been my experience that the torque produced by eBike drive systems will cause the "Drive Side", hub bearing and the inner and outer freehub bearings to wear out at twice the rate of the non-drive side hub bearing. When hub bearing wear occurs, a grinding/creaking noise will occur while pedaling. You'll pull your hair out trying to locate the creaking noise. Furthermore, when railing the bike hard into a berm, the bike's rear hub will be place under hard stress. The rear hub bearing free play will cause the rear brake rotor (Attached to the hub) to rub against the caliper (Attached to the frame)and noise will occur. Lastly, excess worn freehub bearings will allow excess cassette movement and lead to noise and poor shifting.

To determine if your rear hub bearings are worn, place your bike in a bike stand. Spin the rear wheel with your hand. Place your fingertip on the bike's chainstay and feel for roughness or "Notchiness" as the wheel spins. If you feel any roughness in your fingertip as the wheel turns, then you have a rear hub bearing going out. Ideally you want to feel nothing but silky smoothness as the wheel turns. It's a good practice to replace all hub bearings and freehub bearings and not just one individual worn bearing.

I have no experience with Hope, Onyx, and Chris King hubs. Therefore, I cannot comment and their durability. I'm sure they are equally good but have their own unique issues inherent with long term eBike use.

Fixing Your Situation:
You have several options available to you. I believe number one to be your quickest and easiest option to achieve a quicker crank arm engagement and also a more robust freehub engagement.

1) D.T. Swiss sells a conversion kit that will convert your 370 rear hub's three pawl freehub/driver to a star ratchet design. I've included a link to D.T. Swiss' website so you can research the matter. I'd be more specific about the conversion but I do not know what type of drivetrain and freehub your rear wheel has. If you go the conversion from three pawl to star ratchet route, purchase the 54T star ratchet kit.

Ratchet LN Technology | DT Swiss | DT Swiss

The Ratchet LN replaces the pawl freehub system. It is the entry level Ratchet System of DT Swiss and it stands for outstanding reliability.

www.dtswiss.com

2) You can purchase a more robust rear hub to replace the 370 rear hub. It's perfectly okay to mix hubs on a bike, i.e. D.T. Swiss 370 front hub and a rear hub featuring a D.T. Swiss 350, Industry Nine Hydra or Onyx hub on the rear. My OCD won't let me do this, I like my stuff to match, however it's perfectly okay to mix hubs if the budget doesn't allow for a front hub change.

It's also important to note that every hub is different and will have different flange sizes. This will usually trigger a different size spoke. If you wish to replace just the rear hub, I highly suggest you visit your local bike shop/wheel builder. Changing the hub on a bike and going with another brand, will usually require a change of spokes, nipples, spoke tension, etc. Building a wheel requires expertise. If you do not possess the neccesary skills, you may want to have your local bike shop build the wheel for you.

3) Purchase a new or used wheelset. Wheels can give a bike a whole new ride experience. There are so many choices out there. They come in all flavors, builds and budgets. If you are a basic rider, on a budget and tend to favor non technical trails, then maybe an alloy wheelset is your ticket. If you are advancing as a rider and favor technical trails, then maybe a custom carbon wheelset is within your budget.

I like custom wheelsets. I can specify exactly what I want and how I want it. As an example, I can specify a 28 hole front "Nobl" or "We are One" carbon rim with 350 hub and Sapim D-Light spokes to save front wheel weight. Because of the torque and spoke "Wind Up" produced by an ebike motor at full boost, I can specify the rear wheel to be much stronger with a 32 hole Nobl or We are One carbon rim, 350 hub and Sapim "Race" heavier gauge spokes.

The thing is, wheels are a very personal thing. Some riders like carbon wheels whereas others like alloy wheels. I have nothing against alloy wheels, but I prefer carbon rims simply because they hold up better to sharp and square edged Utah rocks.

Here's a link to one of my favorite wheel builders whom I've used in the past:

Custom Wheel Builder

Our MTB wheels are hand built by wheel building masters to give you an exceptional ride. Combine your favorite hubs, rims, spokes and nipples from top brands including Industry Nine, Nobl, Stan's NoTubes and more.

customwheelbuilder.com

Nobl Wheels is a wheelset builder out of Canada. Noble has an outlet store where you can sometimes score a bargain on use wheelsets.

Outlet Store - NOBL Wheels

Save BIG on outlet inventory, demo wheelsets and more! All clearance wheelsets come with our standard warranty unless otherwise listed.

noblwheels.com

We are One is another excellent carbon wheel builder based out of Canada. You cannot go wrong with either Nobl or We are One.

We Are One Composites - Carbon Fibre Mountain Bike Rims & Wheels

At We Are One Composites, we hand make high quality carbon fibre wheels, rims and cycling components. All our manufacturing happens under one roof in Kamloops, BC Canada. Our mission is to connect our customers to where their bike gear came from, how they are made and who made them. See you on...

www.weareonecomposites.com

You can also find used wheelsets on Pinkbike, Offer Up, Facebook Market Place, etc. The only problem with buying a used wheelset is the not knowing what trail conditions the wheelset has been exposed to. Were the wheels beat like a red headed stepchild or ridden around the park once a month? You simply don't know and must reply upon the honesty of the seller and what the wheels look like visually, i.e. rock strikes, dings, etc. In most instances buying a used wheelset is a great way to save money if you do your research and ask questions before purchasing a used wheelset.

https://www.pinkbike.com/buysell/list/?category=12

Here are some examples of wheelsets I've owned on various past and current bikes:

Nox Teocalli carbon rims, Sapim CX Ray spokes, D.T. Swiss 350 hubs with 54T engagement ratchet.

Nobl TR37 carbon rims, Industry Nine Hydra hubs, brass nipples, Sapim D-Light spokes front and rear

Off the shelf Industry Nine Hydra Enduro Alloy Wheelset

Current ride and wheels: Zipp 3Zero Moto Carbon rims, Sapim D-Light front spokes, Sapim Race rear spokes, brass nipples, D.T. Swiss 350 hubs with 54T engagement.

How you ride, the terrain you ride, your power level and your frequency of riding will dictate how long a freehub/driver and hub will last. All freehub/drivers will eventually wear out from use. Some freehub designs are better than others.

I hope the above helps you out. If you have any questions, feel free to ask or send me a private message and we can discuss it more.

Be safe,
Rod

 

[Bear-uk]

My dtswiss 370 hybrid rear hub has the steel star ratchet freehub fitted and it's been faultless.
So if yours is the pawl type you might be able to just swap out the internals?

 

[RickBullotta]

It's been my personal expereince that Industry Nine Hydra freehubs/drivers do not hold up long term to hard eBike use. With use, i'm talking about 1,500-2,000 mile plus. The slots which the pawls rest and rotate in will eventually become enlarged. This introduces play and the pawls and drive ring no longer engage correctly or securely.

It's been my personal experience that Industry Nine Hydra freehub BODIES don't hold up long to any MTB use. After the third cracked hub body (two on a fatbike, one on a regular MTB) went to DT Swiss 350/240 and never looked back.

 

[Rod B.]

It's been my personal experience that Industry Nine Hydra freehub BODIES don't hold up long to any MTB use. After the third cracked hub body (two on a fatbike, one on a regular MTB) went to DT Swiss 350/240 and never looked back.

Rick, trust me when I say I feel you pain...I thought it was just me...

 

[Rod B.]

My dtswiss 370 hybrid rear hub has the steel star ratchet freehub fitted and it's been faultless.
So if yours is the pawl type you might be able to just swap out the internals?

Bear-UK,
You are correct. D.T.Swiss offers a star ratchet conversion kit for the 370 hub.

Ratchet LN Technology | DT Swiss | DT Swiss

The Ratchet LN replaces the pawl freehub system. It is the entry level Ratchet System of DT Swiss and it stands for outstanding reliability.

www.dtswiss.com

 

[whitymon]

Yeah ratchet are pretty nice, but with times you need to apply their special grease (or any other but clearly the quality is there).

But depending on lots of factors, and also without proper maintenance, it is easy to have the spring going too weak. Not common but not rare either, at least it happened only once for me within 3 years.

 

[Rod B.]

Yeah ratchet are pretty nice, but with times you need to apply their special grease (or any other but clearly the quality is there).

But depending on lots of factors, and also without proper maintenance, it is easy to have the spring going too weak. Not common but not rare either, at least it happened only once for me within 3 years.

Whityman, I 100% agree.

I find it always a bit difficult to write an opinion on something, or a review of a part, for the simple reason my riding environment, style, frequency will be different than another rider's environment, skill, terrain, etc. We all subject our bikes to differing levels of punishment, maintenance and exposure to the environment. What works for me in California's dry as a popcorn fart dustbowl will be totally different than a very wet and muddy European environment.

Regardless, I hope the response to the originating question was entertaining and useful. Everytime I look at it, I find a typo and have to go back and correct the response.

Happy New Year,
Rod