OldBike876

I am a very heavy rider with a Norco aluminum frame bike that I ride every day on pavement, some gravel paths, and longer trips on weekends. I had the local shop build me a 36h rear wheel and it came with an FHM8000, DEORE XT hub. The prior wheel, also custom made, snapped spokes incessantly.

My current wheel does NOT snap spokes, but since August of 2020, I have fiddled with that bloody hub 4 times (actually, this started in May of 2022, so 4 times since then). The shop that built it can't explain why this is. I tried a different shop, and they agreed that it was unusual for the hub to act up, but had no advice other than "replace it".

The problems with the hubs have been: loss of the freewheel function (so the chain whips the chainstay and bunches up on the cassette), self-loosening, a crack along the body of freehub, and an absurdly loud creak. I have gone through one entire hub and 4 freehub bodies. This January, the LBS that built the wheel looked at it for losing the freewheel function again (the hub had been installed 5 months prior). They installed a FH-M770-S freehub body as a solution. They said that the old one was crunchy (they showed it to me, it was), and they would try for a warranty claim with Shimano. Shimano refused, for some reason. Anyway, now I have symptoms again: it's losing its ability to freewheel.

I think that I am just too heavy for it. I found some similar complaints on the internet, all based on heavy use. I can either get a supply of cheaper parts and suck up frequent replacement (that I am confident I can do myself), or upgrade components.

Does anyone else find the Shimano hierarchy inscrutable? What is a Shimano product stronger than what I have? Are there other brands to consider? What about something from a tandem, would that be stronger?

Any thoughts?

maddog34

M756, M8000, M9000 Hubs having Freehub issues... and this isn't the only thread found... One response lists a fitment issue solved with a tap in the right place during assy.. it appears that there's a problem with the freehub body seating up to the main hub body.... intermittent grabbing of the freehub shell to the main hub.... "loose axle bearing adjustment" is one symptom seen...

https://www.mtbr.com/threads/shimano...-2017.1058985/

DiabloScott

I don't think this is a weight issue.
Cassettes generally don't feel your weight - they feel how much power you put into the drive.
If the cassette sticks like you're describing, that's usually some kind of internal lubrication issue or maybe damaged pawls.
So it could be a factory defect, or it could be that something got in there on a ride that did the damage.
And that's a fine hub, I think you just got unlucky.
I suggest more frequent maintenance - take off the cassette, check the splines for nicks and gouges, drizzle some oil behind the body.

Bill Kapaun

Are you super mashing with a small chain ring and extra large cog in the back?

OldBike876

There are two hills I really work on regularly, and so I do spend a few kilometers in small/big. I didn't know to avoid that.

OldBike876

I suppose I could start cleaning/lubricating on short intervals, and see what happens. I would at least be aware of trouble when it starts.

veganbikes

A very heavy rider tells us little as very heavy to one person could be not as heavy to another. However as DiabloScott suggested some more regular maintenance could be a good way to go.

If you are looking for a good durable hub this is one to look at: https://www.whiteind.com/product/mi5-rear/
The titanium freehub is nice because it won't get damaged like aluminum and while it doesn't matter in our case is a tiny bit lighter but very durable, The MI5 is their heavy duty/touring rim brake hub. If I needed Disc then CLD or XMR would be the go to same sort of set up.

You could also look at the DT Swiss 350 Hybrid hubs which are designed for E-bikes and heavy duty solutions as well.

Trakhak

Try asking those same questions in the Tandem subforum. They have lots of experience in addressing maintenance issues with heavily loaded bikes, including freehubs.

maddog34

tight budget? get a DEORE m525.. they just plain Work correctly and do it for years on end.

Got lots of cash? DT240.. not a fan of DT, but the 240 is rated as "the best rear hub" by many... the DT350 is right up there too.
and the Shimano XTR hubs have had zero complaints, from what i found...

Availability in your chosen configuration was not checked.. 32h/6 bolt is easy to find.. centerlock/36 is not easy, IMO.

Kontact 

I'm wondering if the axle and hub body are flexing, putting a lot of side load on the juncture between the shell and hub body.

Shimano hubs don't have a bearing close to the right flange like other freehubs do, and if the verticle load is high enough...

Bill Kapaun

If you need low gears, you need low gears.
You didn't mention how many teeth on the ring/cog you are using, but if you are heavy and really pushing a lower than normal (whatever that is) gear, it simply may be too much for the Free Hub mechanism?
I'm just throwing that out there.....
Maybe a Free Hub using more pawls than the Shimano has?

OldBike876

The freehub body has some indents in it, nothing looks obviously horrible there. The f/h itself seems ok, no lateral movement if you try wiggling it and spins smoothly enough. I couldn't remove it, I need a bigger Allen wrench (15mm?) than I currently have. Anyway, I greased the axle bearings and cleaned the chain and cassette, so it's not a totally futile project.

Russ Roth

I've heard of intermittent issues with the newer hubs though not this one in particular and my own experience with this model has been great. From the sounds of things there's something just not right with your hub which I suspect has nothing to do with your weight. Not certain what heavy qualifies asfor you but when I took mine on a gravel backpacking trip the combined weight of rider, equipment and bike was about 340lbs, so not too light. The previous generation I built into a wheelset for a friend who weighed close to 350lbs and that wheelset has survived 7 years of regular use. If you want stronger, someone else already mentioned white industries, they're probably the next best thing for the price and I'd make sure that whatever spoke was used was 13 gauge, (2.2mm) at the bend to make sure there's no breakage.

OldBike876

It's odd to me that it seems ok, when there is obviously a loss (slight, for now) of tension between the cassette and chainrings. I don't really know what I am looking for, I guess, but I didn't see anything that looked like it would cause a malfunction.

Clyde1820

Another one to consider: the Clydesdale line of hubs, from Zinn Cycles (@ BigAndTallBike.com).

Zinn Clydesdale Rear Hub (disc brake) -- #BX207R, 36H, rated to 450lbs rider, steel bearings, steel freehub components, $225:

https://www.bigandtallbike.com/clyde...b-36-hole.html



I'm no svelte athlete, anymore. Been riding the White Industries MI5 hubs, front and rear. Bomb-proof professionally built through Rodriguez (R&E Cycles) in Seattle WA. Along with DT Swiss Champion 13ga 2.34mm spokes. Silent, without creaks or noises or frequent adjustments. Of course, with old leg injuries I don't put down much power, but still. (The White Industries XMR hub is their disc equivalent.) These hubs support up to 48H builds.


https://www.whiteind.com/product/mi5-rear/


And White Industries also makes a tandem rear hub (assuming you've got the rear hub spacing to accommodate it.

https://www.whiteind.com/product/xmrt-tandem/


Another choice that might be worth considering: Bitex Hubs, with a tougher steel 6-pawl design for the freehub.

Bitex BX207R heavy-duty rear hub, disc (6-bolt), 32H, QR135 or 12mm thru-hub, 6-pawl:
https://www.bitexhubs.com/htm/pd_detail.php?no=BX207R

icemilkcoffee 

That is generally true for a lot of hubs- the hub body takes all the weight and the cassette is just free-riding on the axle. BUT Shimano hubs are different. The freehub is bolted to the hub body, and the bearing is between the freehub and the axle. So the freehub is definitely weight bearing.

Lombard

Careful. Some of the DT hubs have an alloy freehub body which isn't a good choice for a heavy rider.

These are all good choices. And while Bitex has an alloy freehub, it also has "anti-bite" splines, so these would be good. Just be sure to choose the ones with a steel axle, not alloy.

OldBike876 , I know weight can be a touchy subject, but you didn't actually tell us how much you weigh. You say "very heavy". Some describe 250lbs. as very heavy while others describe 300lbs+ as very heavy. It would be helpful to know this in order to give advice.

Clyde1820

Hm. So, what design features/specs does one look for, when comparing various hubs? Most makers don't make such a distinction clear. Do diagrams make it evident, or what? (White Industries does (on their MI5 hubs), though, specify a hub bearing set, and a separate freehub driver bearing set ... which I'm assuming would signify bearings for the freehub supporting weight; but not all makers seem to make this apparent.)

Kontact 

You could look for three bearing locations rather than just two. But better still would be a hub recommended for heavy loads.

Clyde1820

So, which make/model of specific hub is a good example of having this "three bearing locations" configuration? Would like to compare diagrams with a couple basic hubs that I am familiar with. (Not sure what to look for, as I'm no bike mechanic.)

Kontact 

This is a typical modern hub - a DT 350. Note the right and left bearings in the hub shell and two in the freehub body. Shimano hubs don't have the middle bearing. Some hubs of this style just use one bearing in the freehub.



Doesn't mean that this hub is stronger overall, just that there is less stress at the body/freehub junction because the axle can support that area through those extra bearings.

davidad

The reason for the freehub in the first place was to put the right-side bearings nearer to the dropout to eliminate axle flex that caused broken axles on freewheel hubs.

davidad

The reason for the larger diameter axle is to solve the problem caused by freewheels. Campy and DT both have glorified freewheels with the right-side loaded axle bearings inboard. The two bearings on the freewheel body don't support the axle.

davidad

More pawls actually won't solve his problem. He needs to be able to remove the body and soak it in solvent and drip heavy oil into it.

davidad

Shimano, old Suntour, and some older DT hubs have the right-side axle bearings out board to minimize axle flex. Cassette or Freewheel Hubs by Jobst Brandt (sheldonbrown.com)