Strong Rear Hub

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alexnharvey
Posts: 1923
Joined: 10 Jan 2014, 8:39am

Re: Strong Rear Hub

Post by alexnharvey »

There's no reason why you can't use a mtb rear hub with a rim brake, the disc fitting would just be redundant. You may also still find new old stock rim brake mtb hubs on eBay.

I nearly always use brass spoke washers to improve the fit of the spoke elbow to the hub flanges on my wheel builds. You might also look at a wheel build which equalises dish a bit using asymmetric rim of similar designs to try to reduce the forces on the drive side.
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

iandusud wrote: 21 Nov 2022, 8:42am How about a tandem hub? This one is available in 135mm OLN. I think these are pretty much indestructible, and will certainly cope with your weight as they are made for use with two riders.
https://www.tandems.co.uk/m11b0s32p87/O ... nd-48-hole
This is what we have on our tandem which copes with our combined weights of around 150kg plus 30kg of luggage and 25kg of bike.
Thanks for your advice, I need a 130mm one but will browse around following your link.
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

alexnharvey wrote: 21 Nov 2022, 8:43am There's no reason why you can't use a mtb rear hub with a rim brake, the disc fitting would just be redundant. You may also still find new old stock rim brake mtb hubs on eBay.

I nearly always use brass spoke washers to improve the fit of the spoke elbow to the hub flanges on my wheel builds. You might also look at a wheel build which equalises dish a bit using asymmetric rim of similar designs to try to reduce the forces on the drive side.
Thanks for your advice, I did not think about just leaving the disc rotor part redundant - I am not concerned with weight, just durability - so a good idea! Do you think the brass washer might reduce the stress on the flange?
iandusud
Posts: 1577
Joined: 26 Mar 2018, 1:35pm

Re: Strong Rear Hub

Post by iandusud »

Jim77 wrote: 21 Nov 2022, 8:47am
iandusud wrote: 21 Nov 2022, 8:42am How about a tandem hub? This one is available in 135mm OLN. I think these are pretty much indestructible, and will certainly cope with your weight as they are made for use with two riders.
https://www.tandems.co.uk/m11b0s32p87/O ... nd-48-hole
This is what we have on our tandem which copes with our combined weights of around 150kg plus 30kg of luggage and 25kg of bike.
Thanks for your advice, I need a 130mm one but will browse around following your link.
If you have a steel frame you can spring the frame to accept the wider hub.
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

iandusud wrote: 21 Nov 2022, 8:51am
Jim77 wrote: 21 Nov 2022, 8:47am
iandusud wrote: 21 Nov 2022, 8:42am How about a tandem hub? This one is available in 135mm OLN. I think these are pretty much indestructible, and will certainly cope with your weight as they are made for use with two riders.
https://www.tandems.co.uk/m11b0s32p87/O ... nd-48-hole
This is what we have on our tandem which copes with our combined weights of around 150kg plus 30kg of luggage and 25kg of bike.
Thanks for your advice, I need a 130mm one but will browse around following your link.
If you have a steel frame you can spring the frame to accept the wider hub.
Unfortunately it is a aluminium one.
alexnharvey
Posts: 1923
Joined: 10 Jan 2014, 8:39am

Re: Strong Rear Hub

Post by alexnharvey »

Jim77 wrote: 21 Nov 2022, 8:50am
alexnharvey wrote: 21 Nov 2022, 8:43am There's no reason why you can't use a mtb rear hub with a rim brake, the disc fitting would just be redundant. You may also still find new old stock rim brake mtb hubs on eBay.

I nearly always use brass spoke washers to improve the fit of the spoke elbow to the hub flanges on my wheel builds. You might also look at a wheel build which equalises dish a bit using asymmetric rim of similar designs to try to reduce the forces on the drive side.
Thanks for your advice, I did not think about just leaving the disc rotor part redundant - I am not concerned with weight, just durability - so a good idea! Do you think the brass washer might reduce the stress on the flange?
The brass washers help the spoke bed into the hub flange so i think they do help a bit with reducing stress on both the spoke elbow and the flange.
rogerzilla
Posts: 2887
Joined: 9 Jun 2008, 8:06pm

Re: Strong Rear Hub

Post by rogerzilla »

cromo wrote: 21 Nov 2022, 8:25am Looking at the pictures now posted, could corrosion also be playing a part here?
I'm sure stress corrosion cracking is a factor in some flange failures, the corrosive agent being road salt. Normally the RH flange has a barrier of oily dirt but it also has to cope with much greater spoke tension (the tension ratio on an 11 speed Shimano road hub is a ludicrous 1:2.2).

7075 aluminium is known to be susceptible and may be what Shimano is using, as it's commonly used for strong bike parts. Most riders worldwide won't ride on salted roads, though - the UK winter is very hard on bikes.
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531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Strong Rear Hub

Post by 531colin »

I think alexnharvey's "pardo" link hits the nail on the head.....the spoke flange is drastically undercut, something to do with a different freehub design? Road salt has always been there, unless Shimano are using a different alloy or whatever the effects of road salt shouldn't change from year to year? Historically, Shimano hubs show flange failure very rarely.

If we were to set out to design a rear wheel to fail, what would you put in the list?
Heavy/powerful rider.....check
Maximum differential between driveside and non-driveside spoke tension....check (achieved by minimum OLN width....130mm for a road hub, and lots of gears)

I remember when Shimano "improved" XT hubs with an alloy axle.....except they messed up a new freehub design and the freehubs failed, and also the bearings had to be smaller to accommodate a bigger axle inside the hub shell, which is a fixed diameter.
I laid in a stock of FHM 756A, the equivalent (8,9,10 speed) "disc" hub ....they still seem to be available, they were (presumably) never "improved" to alloy axle. There also seems to be an 11 speed equivalent, I have no experience of it.

If you can't go to 135mm OLN (not advised to bend an alloy frame) I would still give FHM 756A a look, if 10 speeds are enough. You can find the flange spacings on wheelbuilding websites....if you take 5mm of spacers off the left side of FHM756A is the flange spacing any worse than a regular 130mm hub? The flanges themselves are pretty massive. **(just checked my stash...FH5600 a 105 road hub has the same flange spacing just with 5mm less spacers on the left.)

What else can you do?
Asymmetric rim to balance out the tension a bit; yes, somebody already said that.....as wide a rim as you can get, the narrower the rim the less spoke offset you can fit in!
To share the load over as many spokes as possible, butted spokes and the rim needs to be as stiff as possible radially.....a nice deep section, still fashionable I think? (If you think it won't make a difference, get hold of some rims and make like an archer pulling back the bowstring and arrow.....the difference is palpable!

I agree the spokes are a slack fit in the diameter of the spoke holes in the OPs picture. However, spoke washers are normally recommended to take up the slack when the elbow bend of the spoke is longer than the thickness of the flange. Personally, I am not convinced they are of any benefit; as soon as you stress-relieve the spokes properly you re-set the elbow bend and the spokes bed into the soft alloy of the flange, and no further flexing takes place at the elbow bend, which is why properly stress-relieved wheels don't break spokes,
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

531colin wrote: 21 Nov 2022, 11:50am I think alexnharvey's "pardo" link hits the nail on the head.....the spoke flange is drastically undercut, something to do with a different freehub design? Road salt has always been there, unless Shimano are using a different alloy or whatever the effects of road salt shouldn't change from year to year? Historically, Shimano hubs show flange failure very rarely.

If we were to set out to design a rear wheel to fail, what would you put in the list?
Heavy/powerful rider.....check
Maximum differential between driveside and non-driveside spoke tension....check (achieved by minimum OLN width....130mm for a road hub, and lots of gears)

I remember when Shimano "improved" XT hubs with an alloy axle.....except they messed up a new freehub design and the freehubs failed, and also the bearings had to be smaller to accommodate a bigger axle inside the hub shell, which is a fixed diameter.
I laid in a stock of FHM 756A, the equivalent (8,9,10 speed) "disc" hub ....they still seem to be available, they were (presumably) never "improved" to alloy axle. There also seems to be an 11 speed equivalent, I have no experience of it.

If you can't go to 135mm OLN (not advised to bend an alloy frame) I would still give FHM 756A a look, if 10 speeds are enough. You can find the flange spacings on wheelbuilding websites....if you take 5mm of spacers off the left side of FHM756A is the flange spacing any worse than a regular 130mm hub? The flanges themselves are pretty massive. **(just checked my stash...FH5600 a 105 road hub has the same flange spacing just with 5mm less spacers on the left.)

What else can you do?
Asymmetric rim to balance out the tension a bit; yes, somebody already said that.....as wide a rim as you can get, the narrower the rim the less spoke offset you can fit in!
To share the load over as many spokes as possible, butted spokes and the rim needs to be as stiff as possible radially.....a nice deep section, still fashionable I think? (If you think it won't make a difference, get hold of some rims and make like an archer pulling back the bowstring and arrow.....the difference is palpable!

I agree the spokes are a slack fit in the diameter of the spoke holes in the OPs picture. However, spoke washers are normally recommended to take up the slack when the elbow bend of the spoke is longer than the thickness of the flange. Personally, I am not convinced they are of any benefit; as soon as you stress-relieve the spokes properly you re-set the elbow bend and the spokes bed into the soft alloy of the flange, and no further flexing takes place at the elbow bend, which is why properly stress-relieved wheels don't break spokes,
Thank you for your detailed response - I will digest it and have a think on how I will proceed!
rareposter
Posts: 1990
Joined: 27 Aug 2014, 2:40pm

Re: Strong Rear Hub

Post by rareposter »

https://www.stradawheels.co.uk/product/big-fella/

There's a few similar products around (all at that sort of price range)...
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Strong Rear Hub

Post by fastpedaller »

I think the comments above re the flange undercut are correct. If a hub designed for 7 speeds is used, the symmetry will be improved because the freehub width is slightly less (about 5mm IIRC). I don't know how many sprockets you have, but with careful selection of spacers, there is only one sprocket reduction if using a 7 speed freehub. Brucey explained in previous notes how it's possible to use 8 sprockets from a 9speed cassette. I just use 7 myself, and have sources them from 8 speed cassettes (7 from 8), (8 from 9) probably 9 from 10, but my understanding is that some 10 -speed or more cassettes can have fitment issues. Back to wheelbuilding (although as Colin says this probably isn't the issue), a lack of tension in the spokes can (IMHO) make breakage more likely....... I'll wait for folks to say I'm incorrect, and too much tension is bad! But here's my logic (I've been building wheels over 40 years) If the tension is high in the spokes, the rider's weight, road bumps etc are shared between more spokes than if the tension in the spokes is lower. Taken to it's extreme. if the wheel was used without tensioning the spokes at all (and the rim was exceptionally strong) all the stress would be going through the top-most spoke, and nothing through the others. Anyway, I digress... I have a stock of Shimano m290 7 speed hubs put aside for the future. If you can find a m290 hub for sale on Ebay, this could be your ideal candidate - it's a MTB hub (that's no issue) with excellent seals and will benefit from proper greasing before use. that's (I think) in the 'too good to lose' section of the forum
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

rareposter wrote: 21 Nov 2022, 12:23pm https://www.stradawheels.co.uk/product/big-fella/

There's a few similar products around (all at that sort of price range)...
Thank you.
Jim77
Posts: 113
Joined: 20 Nov 2022, 1:13am

Re: Strong Rear Hub

Post by Jim77 »

fastpedaller wrote: 21 Nov 2022, 12:26pm I think the comments above re the flange undercut are correct. If a hub designed for 7 speeds is used, the symmetry will be improved because the freehub width is slightly less (about 5mm IIRC). I don't know how many sprockets you have, but with careful selection of spacers, there is only one sprocket reduction if using a 7 speed freehub. Brucey explained in previous notes how it's possible to use 8 sprockets from a 9speed cassette. I just use 7 myself, and have sources them from 8 speed cassettes (7 from 8), (8 from 9) probably 9 from 10, but my understanding is that some 10 -speed or more cassettes can have fitment issues. Back to wheelbuilding (although as Colin says this probably isn't the issue), a lack of tension in the spokes can (IMHO) make breakage more likely....... I'll wait for folks to say I'm incorrect, and too much tension is bad! But here's my logic (I've been building wheels over 40 years) If the tension is high in the spokes, the rider's weight, road bumps etc are shared between more spokes than if the tension in the spokes is lower. Taken to it's extreme. if the wheel was used without tensioning the spokes at all (and the rim was exceptionally strong) all the stress would be going through the top-most spoke, and nothing through the others. Anyway, I digress... I have a stock of Shimano m290 7 speed hubs put aside for the future. If you can find a m290 hub for sale on Ebay, this could be your ideal candidate - it's a MTB hub (that's no issue) with excellent seals and will benefit from proper greasing before use. that's (I think) in the 'too good to lose' section of the forum
Thanks for you reply and comments - I am using 10 speed Shimano cassette. I will bear in mind your comments about spike tension. I have found that in order to fix lateral true, that the spoke tension has not always been as even as I would like.
fastpedaller
Posts: 3435
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: Strong Rear Hub

Post by fastpedaller »

Jim77 wrote: 21 Nov 2022, 12:29pm
rareposter wrote: 21 Nov 2022, 12:23pm https://www.stradawheels.co.uk/product/big-fella/

There's a few similar products around (all at that sort of price range)...
Thank you.
Hmm, never seen those before...... Interesting, but I didn't find any mention of OLN dimension, and it says 12mm axles (are they reduced at the ends to fit standard R10 F9 (I expect that's the case, but not clear)
rogerzilla
Posts: 2887
Joined: 9 Jun 2008, 8:06pm

Re: Strong Rear Hub

Post by rogerzilla »

There's a broken 105 hub flange here that had zero service life, as it broke during wheelbuilding. No corrosion, no fatigue.

https://bike.bikegremlin.com/10210/brok ... cle-parts/

It seems they are just badly designed or made, in this case.
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