Freehub pawls failure? Is this common 3kw+

I always hear people talking about wearing out cassettes and chains with 3kw plus mid drive setups but has anyone ever destroyed the ratcheting mechanism of a rear MTB hub? How strong is the average freehub pawl setup?

Sorry if this has been covered a bunch times but I don't ever recall seeing it mentioned.

I was thinking of trying out a freewheeling bottom bracket setup with an LMX motor I have. I'm peaking at 4.5kw. I can turn it down a little bit. My main motivation is not to pedal along at speed but instead its just a convenient way to package everything. The stock derailleur keeps the chain on quite well and its a full suspension bike. I'd like to run close to 1:1 on the final chain so pedaling is similar to my trials bike at low speed. I was thinking something like 38-40tooth chainring and 42-45t cog. So technically still overdrive but not by much.

Is an average Shimano Deore M525 freehub ratchet up to the task? I really don't want to build a $400 wheel so if 3-4kw will be certain death for this hub then I'll probably rig up a LH drive solution.

I had one die in about 1100 miles on a BBS02 on lipos.... On 14s, 24A. 750w. Lol. Stock controller, homemade battery... One day going up a hill it just let go.

I am not a chainline cexpert, nor am I gentle. The freehub was impacted one too many times. (Kachink! spinspinspin). The chain grease and the cold and the hub didnt like each other... I solvent soaked it and got to engage a few times since, but it is really done, and the reason my BBS02 has sat for about a year. Engages about 1/3 of the time, and not reliably.

In the defense of the cassette, I was doing lil wheelies, climbing like goat without regard to gear, and liberally spraying wax on the chain wherever I walked by in the garage in the name of lubrication. I had shreadded the Bafang nylon in the first 200 miles also, incidental.

I think it was the grease vs the snow vs the abuse vs the dirt. I started with a brand new bike from Bikes Direct. I think the cold+grease kept the pawls from engaging the cassette freehub until one day there was just one pawl on it and got damaged. I had the program set up to deliver as much "umph" as I could at start. You can adjust that, probally wasnt best idea.

Front was 44T and the rear was a 34-11 cassette. Chain doesnt even sit on the full sprocket anymore, and I started with all new parts. ( Motobecane and BBSO2) . I need a whole new drivetrain, I was hoping to get more longevity.. but did not. I am sure the worn chain did not help.


Hell I have seen pics of others fold the rear sprocket over with quality components before the freewheel gave up with BBSoHD and a external controller. My freewheel was probably the cheapest design cassette that Bikes Direct sold on the bikes... My whole bike was 300$ shipped... and there are much better quality ( freewheels) available in this world that might actually take 3Kw, let alone 750w... on nicer bikes. But that is my experience.

I blew up a Mavic hub in a couple thousand miles on a pedal bike, but they're known/were known to be somewhat fragile. I've had the same dt on the rear of my BBS02 for five years, no problem, but only 22 amps at 52V.

Oh man! You guys are not telling me what I wanted to hear. I already own a white industries flywheel I was going to use on the crank. I think maybe I'd be better off building a cheap ish threaded FW wheel and using the WI freewheel back there. That way if I blow it up with too much torque I can just replace it. Shredding the internal guts of a nice hub and having to lace a whole new wheel each time sounds no fun.

For me a freewheeling rear sprocket is a big priority once there is a spring loaded tensioner/derailleur involved. My goal was just to experience my suspension bike with a mid drive motor to see if that is the direction I want to build in. I'll probably have close to $150 just in the FW crank to try it. Bummer that everything fun costs money.

Pawl hubs are terrible for ebikes. They are way inferior to star ratchet systems like Dt swiss has. Dt swiss wheels containing star ratchet hubs 240 or 350, NOT 370, are cheaper than if you bought a hub and got it built.

Thanks! That is super useful info. I'll look into it.

Tommm said:

Pawl hubs are terrible for ebikes. They are way inferior to star ratchet systems like Dt swiss has. Dt swiss wheels containing star ratchet hubs 240 or 350, NOT 370, are cheaper than if you bought a hub and got it built.

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Why not 370?

Looks like the 370 had pawls not the star ratchet.

Having used 3 different hub motors , and now a mid-drive, I would not own a mid-drive if I lived in a mostly flat area of the Country . I have very steep hills and mountains around me so I must use that bike for the Hills .
I use the Hub motor bike most of the time ,
since on the Mid-Drive bike I have destroyed one cassette, and chewed up the freehub body , in only 350 miles of use !
and that is taking it easy, and a quality Mavic Hub/wheel at that . so far I have never used my mid-drive motor over 1.5 kw at the most , usually 22 and under amps , only on the very steep hills do I go up to 30 amps and 1.5 kw watts , I have done those hills only 4 times now .
Having a mid-drive is proving to cost more and more maintenance , which is time and money spent .

After having both systems I feel a Good Strong rear hub motor is better for 80% or more of the people on this Planet .

DanGT86 said:

For me a freewheeling rear sprocket is a big priority once there is a spring loaded tensioner/derailleur involved. My goal was just to experience my suspension bike with a mid drive motor to see if that is the direction I want to build in. I'll probably have close to $150 just in the FW crank to try it. Bummer that everything fun costs money.

Click to expand...

OK, so for ebike hubs,

freewheel is better than freehub

and the DT Swiss star ratchet is ? best?

350 vs 240 which is more robust wrt torque?

Is the 240 convertibility a real advantage for ebikes?

7 speeds is plenty?

Depends on where you live , go up mountains and you will find that the more cogs you have on the rear cassestte/freewheel , the Better for your motor .

john61ct said:

7 speeds is plenty?

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Yes long steep mountain climbs, heavy loads too. But an 18mph top speed on the flats is fine too.

Any way to pair a Rohloff with a powerful rear hub motor?

Or is a mid drive required, like the Lightning Rods?

How long and how steep are the roads you are going up ?

I have not looked into any type of internal hub much since early on a few years back people here on E.S. were saying that internal gear hubs ( Instead of a Cassette or Freewheel ) did not last long with the power and torque of e-motors. Grin Technologies has the answer , I am sure they have experimented with IGH's .

Depending on how long and steep your hills are . ( What state are you in and where in that state ? )
then you probably are in the 20 or so % that will be better off with a mid-drive .
A mid-drive is a must have for me to go up the mountains I live near . If a person here just wants to commute or ride for pleasure on mostly flat areas then a hub would be better . I ride 80-90% with my rear hub bike and the other 10-20% on my mid-drive bike, depending on where I go that week .

What are you using now for your motor on your e-bike ?

john61ct said:

Yes long steep mountain climbs, heavy loads too. But an 18mph top speed on the flats is fine too.

Any way to pair a Rohloff with a powerful rear hub motor?

Or is a mid drive required, like the Lightning Rods?

Click to expand...

john61ct said:

OK, so for ebike hubs,

freewheel is better than freehub

and the DT Swiss star ratchet is ? best?

350 vs 240 which is more robust wrt torque?

Is the 240 convertibility a real advantage for ebikes?

7 speeds is plenty?

Click to expand...

The ratchet system for 240 and 350 is the same, they are interchangable.
7 speeds is plenty for an ebike yes.

According to the internet the 370 hubs can be converted to the star ratchet design. Some googling lead me to a forum post that said the following:

"The freehub is about 50 bucks. The ratchet rings are about 90. The tool to remove the star drive is about 40... that alone exceeds the cost of a 350 hub if you hunt around, and that doesnt include in the inner star drive you'll need too."

There is apparently a seal that is less than perfect when you do this but is functional. So if you already have a 370 hub and don't want to build a whole new wheel then there is a way.

I don't want to get too deep into a general mid-drive vs hub discussion but I can say from experience that I don't like the way my hub acts during most of my riding. It is awesome for blowing people's minds with raw acceleration but that is about it. I have also Pac-manned a really heavy duty rim build riding it hard off road. From what I have seen Mountain bike rear shocks absolutely cannot control the weight of a hub motor. A hub wheel is 4-5x the weight that bike suspension was designed to control. Too much inertia when a bump shoots the weight upwards at you.

Here are the 2 bikes that lead me to this question. The Hub motored bike was my primary project. It gets all the nice high end parts. I would like it to be more playful offroad. I've ridden it on motorcycle trails and its fun but limited by the hub weight. The 2nd bike is a cheap genesis with a custom swing arm. Its a perpetually unfinished test platform for anything I want to try. I mounted an LMX 30mm motor to the swingarm. Its awesome! The reduced weight in the rear wheel is immediately obvious. The suspension is garbage and is the best walmart has to offer yet it almost feels better than the fancy specialized suspension on the hub bike. Lightweight rear wheel is the secret to happiness.

Now that I am convinced of the awesomeness of the mid drive I need to get it on that Specialized (first pic)! I was able to use the genesis frame to get the brake rotor and the sprocket to play nicely together with 219 chain and a 203mm rotor. The downside is that this will only work with 150mm rear dropout spacing. My Specialized (hub bike) is 135mm. So the easiest thing I could think of is to go FW bottom bracket. This would require almost no custom parts for the rear end. No engineering of brake mounts or possible fixed chain derailments. At the same time I don't really want a FW bottom bracket enough to spend $300 on a wheel build that will hold up and another $150 on the FW BB. If it would be semi reliable with the shimano hub I have then it's worth a shot just for the experience on the nicer frame.

There are plenty of used DH bike frames out there that I could pick up for the cost of a DT swiss wheel. For $300-500 something like this Commencal DH supreme would work great. I would mount the LMX motor in front of the BB then use the swing arm pivot (red arrow) as a jackshaft to a LH disk brake rotor mount large kart sprocket. I could keep my 219 chain and have zero tensioners or chain growth under suspension movement. This would be my ideal situation. Stock weight rear wheel, no chain growth, no power compromise to keep hubs or freewheels alive, least amount of noise, properly engineered adult size MTB suspension etc. The downside is shipping on used bikes is expensive. The Specialized bike is already in my possession and is already a complete running bike.

So that is my conundrum.

Well Dan,

If you can get someone to make a swing arm for you , then that would be the best solution possible.

Keep in mind you will want a bike with more modern head tube angles the faster you go.

Most all the new DH / Enduro bikes are around the 60 degree mark these days .

I have been wanting someone in my area to make a custom rear swing arm for a couple of years now. California is so expensive that
anyone with the talent to make a custom swing arm ( that is much like a motorcycle swing arm ) is so busy
working 50 or more hours a week or 2 jobs just to pay for Business Work Shop Space and High Taxes that they do not have time for a bicycle part job.

If you can find someone in your area that can produce something for a reasonable price let me know, Even a whole frame is would be good. we have a need for a U.S. made e-bike frame .

I have been running DT Swiss 350 190x12 fatbike hubs now for 1000 kms.

1. The 18-notch ratchet that comes standard is the most durable on the market.

2. The freewheel parts are interchangeable. This hub is modular. If something fails you don’t need to rebuild the wheel.

3. I installed an aftermarket steel freehub body. No bite-in problems anymore!

By far the best hub for ebikes. Not the lightest but really durable and maintenance and upgrade friendly.

FlyingFinn said:

3. I installed an aftermarket steel freehub body. No bite-in problems anymore!

By far the best hub for ebikes. Not the lightest but really durable and maintenance and upgrade friendly.

Click to expand...

Yes don't forget to buy the steel freehub body with the DT star ratchet hubs.

The splines on my steel freehub still look perfect after thousands of km with the 40:1 tangent gearbox.

Awesome! Sounds like the DT is the clear winner. I am not as concerned about the steel freehub body because I plan on running an aluminum adapter hub with just one sprocket on it. I can make the adapter as wide as the entire FH body if I want. That way I wont have narrow steel gears trying to cut into the body. I've given up on the idea of pedaling along. Its nice to know that the steel body is out there though in case I ever feel like trying a standard shiftable drivetrain.

You only need to make the adapter thick towards the base.

Btw cheapest steel dt freehub on the net by far:
https://hollandbikeshop.com/en-gb/branded-bicycle-parts/dt-swiss-bicycle-parts/dt-swiss-hub-parts/dt-swiss-freehub-body/dt-swiss-cassette-body-540-shimano/

Bought 2 already, they are legit.

Thanks for the link. Glad to know there is that option. I just bought a DT 240 hub yesterday with an 18 point ratchet.