Strong Rear Hub

[fastpedaller]

I believe that high spoke tension will not cause a breakage of the flange, more likely to be low tension - the explanation is in my earlier note. To add an extra 'discussion point' or maybe 'evidence' ...... For a tyre/tube combo (so not the racing tubulars of old), if the tube is inflated to its usual pressure eg 70-90 psi, the tension in the spokes is perceptibly lower than before inflation. This has always convinced me to tighten spokes to a level many might intuitively say is too tight. I have only had one spoke breakage in over 40 years, and never a hub breakage. Over the years I've built radial front Campag record small flange hubs, track wheels (used on the road) with Campag C-Record large flange hubs, and many other regular wheels. One pair, in particular, was 24 spoked Campag large flange wheels laced 'crow's foot' pattern and tied and soldered as requested by the customer. He never reported any issues.

[rogerzilla]

The 11-speed 130mm hubs need an unreasonable amount of tension on the RH side to stop the LH side being unacceptably slack. Let's say you don't want to go below 80kgf on the left, which is a good value to avoid the bottom spoke ever losing tension completely. That means 170kgf on the RH. Many rims are only rated to 100kgf, although they don't specify whether that's an average or a maximum for a rear wheel.

[Jim77]

According to your OP you have had two rear 105 hubs crack like this. What is not clear is who built the wheels. Your various posts refer in passing to Spa, to truing wheels yourself (including building wheels from scratch?), and to a DT Swiss rim (which I don't think Spa sell).

If you built them yourself, what was the final tension of the drive side spokes?

Where exactly are you going with this Slowster?!

[Jim77]

The 11-speed 130mm hubs need an unreasonable amount of tension on the RH side to stop the LH side being unacceptably slack. Let's say you don't want to go below 80kgf on the left, which is a good value to avoid the bottom spoke ever losing tension completely. That means 170kgf on the RH. Many rims are only rated to 100kgf, although they don't specify whether that's an average or a maximum for a rear wheel.

From memory the DT Swiss TK540 Rim has max spoke tension of 122kgf. Therefore not sure I would be comfortable putting 170kgf on the drive side…

[rogerzilla]

122 kgf on the RH means 55 kgf on the LH, which is quite a lot less than most riders' weight. These hubs have far too much dish.

[gfk_velo]

NDS tension whilst it's related to rider weight, isn't a direct metric for it.

55 kgf on the LH, which is quite a lot less than most riders' weight

There's any number of factory built wheels with max rider weights quoted at 100kg plus where the NDS spoke tension is a lot less than the quoted max rider weight.

I've got 2800 pairs of wheels and 800 plus singles in my wheel book since I started building in the late 1970s and I doubt many of those I built before I started using a tensiometer as a matter of course in 2008, had NDS tensions much higher than 80kgf.

Some probably did because track wheels built for the Sixes and the like came apart at the rim after quite a short service life ... counted in 100s of km ... but in those cases, we were building on light rims (Super Champion Arc en Ciel or Mavic OR7), fitting the tub., pressuring it and and then whacking the tension up a bit more.

Relatively few after I started using a tensiometer do - that I know for sure as I record that type of thing now.

Spoke failure is far more often too little tension, than too much it's true. However, you don't need NDS tension to exceed rider weight, or anything like it.

Hub flange failure, though - too much tension might often be to blame. It's the specific reason that Campagnolo and Shimano et al all refuse to warranty hub flanges when radially laced (in some cases making hubs specifically for radial lacing) as the tension needs to be relatively high and is at more or less 90 degrees to the intended load path. I've certainly had failures in Campagnolo and Mavic in years gone by - nearly all on radially-laced fronts.

In modern hubs, another additional problem can be the method used to make the hub shell. Aluminium alloy billet, CNC'd, does not always have the directional strength that can be introduced during a forging process, such as was used by traditional hub manufacturers, one reason why hubs in general have become somewhat "chunkier" in recent times. I spoke at some length to the design team at a large OEM in Italy about this several years ago and since have had a similar conversation with a manufacturer here in the UK (as I know these things are all subject to change with new processes etc) ... they confirmed it as the reason why they machine hub flanges with a significantly greater radius outside of the spoke hole PCD ...

[slowster]

According to your OP you have had two rear 105 hubs crack like this. What is not clear is who built the wheels. Your various posts refer in passing to Spa, to truing wheels yourself (including building wheels from scratch?), and to a DT Swiss rim (which I don't think Spa sell).

If you built them yourself, what was the final tension of the drive side spokes?

Where exactly are you going with this Slowster?!

I am doubtful that the key issue is the strength/quality of 105 hubs, even in combination with your weight. I think the main factor is likely to be the wheelbuild, not least because that is the biggest human element in the manufacture of a wheel and its constituent parts, and introduces the greatest scope for variability and human error, mainly in the actual process, but also in the choice of parts.

The more information you provide, the better the responses you are likely to receive. I suggest you tell us:

1. Who built the two wheels?.

2. If you built one or both, what were the drive side tensions?

3. What rims are they? / Are they both DT Swiss TK540?

4. 130mm OLN is a road standard which I would normally expect to be used on a race or sportive type bike. The TK540 is a rim which I would expect to be used on a touring bike, including heavily laden touring. What sort of riding are you using the wheels for?

[531colin]

Tying and soldering's only value is that it stops a broken spoke causing injury. It dates from the days when spokes weren't much good and often broke even in a decently-built wheel.

Looking at the photos of the broken hub, one spoke has sheared out singly and the other has a radial crack. The mystery deepens, as the undercut wouldn't cause these. Unless the spoke tension was absolutely psychotic, it looks like really poor metal was used in the hub shell.

Which photo, please?
Jim's photos posted 20 Nov both show unequivocal flange separation at the undercut.... don't they?
Jim's photos posted 23 Nov, the bottom one shows a fairly clear crack at the undercut....the top one is more difficult due to shadow and dirt, but isn't there a crack in that one as well?

I'm only 75, I wasn't riding when tying and soldering was fashionable, but I thought both tying and soldering and large flange hubs were favoured by track sprinters looking for a "stiffer" wheel.

[531colin]

The 11-speed 130mm hubs need an unreasonable amount of tension on the RH side to stop the LH side being unacceptably slack. ......

Well, I don't disagree, but OP is running 10 speed.

............- I am using 10 speed Shimano cassette. .........

[531colin]

I have been retired from Spa for 10 years, and I was there 10 years or thereabouts.
In my time at Spa, I saw more Hope hubs with broken flanges than Shimano; I couldn't guess how many more Shimano hubs are in use than Hope. (I think I saw about 2 Shimano broken flanges)
The reasons for flange failure have been touched on; Forged vs. machined from billet; stress-corrosion cracking; "improved" design; unsuitable alloy
At the end of the day, we have a hub manufacturer whose hub flanges were extremely durable now suddenly with a rash of flange failures all over the internet.
This is a hub problem.
Now, come on all you internet-savvy young people....I'm definitely too old for this.......

But just as a "f'r'instance".......
heres a section of a hub

from here https://bikerumor.com/shimano-patent-sh ... -dura-ace/

Is this the design which is failing? the right flange is pretty well undercut, compared to this...

from here https://bicycles.stackexchange.com/ques ... ce-6-speed

which looks to me like the good old pattern

[slowster]

At the end of the day, we have a hub manufacturer whose hub flanges were extremely durable now suddenly with a rash of flange failures all over the internet.

I am not sure that is the case. So far we have the two links which alexharvey provided, one of which was in 2014 and the hub was 8/9/10 speed ('the good old pattern'), and now the OP's two wheels.

heres a section of a hub

from here https://bikerumor.com/shimano-patent-sh ... -dura-ace/

Is this the design which is failing? the right flange is pretty well undercut, compared to this...

from here https://bicycles.stackexchange.com/ques ... ce-6-speed

which looks to me like the good old pattern

The first image looks like a design drawing, but the second and third images look to me more like simplified illustrations. Moreover the link for the first image is an article about a Shimano patent for a silent ring drive ('Scylence'), which I don't think is representative of current Shimano hubs like the 105.

[ANTONISH]

I'm very much an amateur wheebuilder.
After a couple of disapointments with professionally built wheels I decided to try my hand.
For several years now I have used Sapim spokes (Strong drive side,standard DB non drive)
I've managed to produce perfectly serviceable wheels and have had no real problems until the breaking of the Sora rear hub.
I've used Campag, Miche,Shimano Ultegra, Deore, parallax hubs.
I've never usd a tension meter because I seem to get by without one.
When this thread strted I had just built a wheel with a new 105 hub - I'm keeping my fingers crossed.

[rogerzilla]

Tying and soldering's only value is that it stops a broken spoke causing injury. It dates from the days when spokes weren't much good and often broke even in a decently-built wheel.

Looking at the photos of the broken hub, one spoke has sheared out singly and the other has a radial crack. The mystery deepens, as the undercut wouldn't cause these. Unless the spoke tension was absolutely psychotic, it looks like really poor metal was used in the hub shell.

Which photo, please?
Jim's photos posted 20 Nov both show unequivocal flange separation at the undercut.... don't they?
Jim's photos posted 23 Nov, the bottom one shows a fairly clear crack at the undercut....the top one is more difficult due to shadow and dirt, but isn't there a crack in that one as well?

I'm only 75, I wasn't riding when tying and soldering was fashionable, but I thought both tying and soldering and large flange hubs were favoured by track sprinters looking for a "stiffer" wheel.

I was looking at the "dirty" hub photos. The first spoke looks as if it's sheared out. The only flange failure I've suffered, on a Goldtec rear track hub, took a chunk out with 4 spoke heads attached and looked quite different.

On the 10/11 speed question, you're quite correct. The tension ratio for 10 speed is still pretty horrible at 2:1. Rear spacing should really have been increased by now, but I can see the counterarguments - no upgrades of older frames (unless steel), wider Q-factor. And they'd only use it as an excuse to cram in 16 sprockets a few years later.

[531colin]

"My era" 105 8/9/10 speed hub was FH-5600. https://si.shimano.com/en/manual/search ... el=FH-5600
It has a smooth fillet between the hub barrel and the spoke flange. https://www.walmart.com/ip/Shimano-105- ... /164555251
When did the angular thing seen in Jim's photos appear?
FH-5800 has the angular business...https://bike.shimano.com/en-US/product/ ... -5800.html

[531colin]

http://pardo.net/bike/pic/fail-001/FAIL-195.html

I didn't pick up that "Pardo" link was from 2014. However, it does show that where the bit of flange has pulled off the hub barrel the broken surface is about as thick as the flange.

https://bike.bikegremlin.com/10210/brok ... parts/#1.2

The bike gremlin one is 2020, I think?
It looks to me that the broken surface there is less than the thickness of the flange. (possibly 2mm?)

I put the vernier on a FH-5600.
Right flange is 3.3mm thick at the spoke hole. (left flange is barely 3mm....sounds deliberate?)

It seems to me the new hubs would be a lot stronger if they simply increased the diameter of the hub barrel.