Strong Rear Hub

[slowster]

Comparing the photographs in the pardo and bikegremlin links, the depth of the undercut looks significantly greater in the latter. The dates of the articles, respectively 2014 and 2020, suggest to me that the hub with more undercut is likely to be an 11 speed hub, whereas the other hub is 8/9/10 speed.

Pardo - 2014 Sora FH-3300 hub

Bikegremlin - 2020 new 105 hub

[531colin]

Here in Yorkshire its dark, raining and cold; I'm sitting by the fire thinking about bike stuff

https://spacycles.co.uk/smsimg/195/4130 ... 9r-195.jpg

Thats an asymmetrical rim from Spa which looks to have a decent amount of spoke hole offset; its also fairly wide and deep. My ugly mug is still pictured as the wheelbuilder at Spa, despite the fact I retired more than 10 years ago, but I'm well and truly out of date. I recommend you phone up and speak to Bobby if you want to know about wheels.

I also had a look at one of my stashed MTB disc hubs, and its got an obvious washer about 3mm thick between the left cone and its locknut. If you remove that, the OLN comes down to 132mm, and I would be happy to fit that in an ali. frame built for 135mm.

[Jim77]

Here in Yorkshire its dark, raining and cold; I'm sitting by the fire thinking about bike stuff

https://spacycles.co.uk/smsimg/195/4130 ... 9r-195.jpg

Thats an asymmetrical rim from Spa which looks to have a decent amount of spoke hole offset; its also fairly wide and deep. My ugly mug is still pictured as the wheelbuilder at Spa, despite the fact I retired more than 10 years ago, but I'm well and truly out of date. I recommend you phone up and speak to Bobby if you want to know about wheels.

I also had a look at one of my stashed MTB disc hubs, and its got an obvious washer about 3mm thick between the left cone and its locknut. If you remove that, the OLN comes down to 132mm, and I would be happy to fit that in an ali. frame built for 135mm.

I think that was the rim that was used to build my wheel by Spa Cycles with 105 Shimano Hub - it was about 4-5 years ago!

[ANTONISH]

I've had the same happen with a Sora hub.
I had an incident on a winter audax - it was dark and the passenger in an approaching car was leaning out of the window shouting abuse (probably didn't like my front light).
As the car passed it appeared that something had struck my rear wheel.- I found I had a broken spoke and trued it to get to the finish.
I didn't use that bike for ages and when I came to ride it I found the flange damaged in much the same way as other posters.
It's the first time I've experienced this.
I've built similar wheels with Ultegra hubs , Shimano deore and Miche.
I've recently built a wheel with a 105 hub - I'd better not rely on that for touring

[fastpedaller]

Crikey - that photo from Bikegremlin shows what can happen That one's certainly not due to spokes being too tight or too loose!
As is often said "they were better before the improvements"

[Jim77]

I suspect the problem is partly due to a) having 36 holes in a small flange hub, which places the spoke holes pretty close together, leaving less metal to resist the pull of the spokes, and b) modern hubs being made with higher strength but less ductile alloys than older hubs, and so the flanges are more likely to break rather than just deform slightly.

You could look for hubs with a slightly larger flange. We've been using Phil Wood hubs on tandems for over 40 years and have yet to break one. The flanges on them are ~10mm greater diameter than those on Shimano hubs. But they're a) fiendishly expensive, and b) when I look at their website, all the rear hubs show as sold out: https://phil-wood-co.myshopify.com/coll ... -hub-parts.

The White Industries MI5 is another hub that has larger flanges, and I've used those also without problem.

Out of interest - how often do you service the MI5?

[NickJP]

Out of interest - how often do you service the MI5?

Other than checking the preload when I received the hubs, I haven't serviced them yet. They've probably done a few thousand kilometres since I built them up. Adjustment instructions in the video below, or White Industries have PDFs on their website covering complete service and adjustment: https://www.whiteind.com/wp-content/upl ... CTIONS.pdf and https://www.whiteind.com/wp-content/upl ... STMENT.pdf.

[Jim77]

Out of interest - how often do you service the MI5?

Other than checking the preload when I received the hubs, I haven't serviced them yet. They've probably done a few thousand kilometres since I built them up. Adjustment instructions in the video below, or White Industries have PDFs on their website covering complete service and adjustment: https://www.whiteind.com/wp-content/upl ... CTIONS.pdf and https://www.whiteind.com/wp-content/upl ... STMENT.pdf.

Thanks NickJP.

[Barrowman]

I have had a similar looking failure on a wheel (I fear I had over done the spoke tensions (whilst still a not well practiced wheelbuilder) on straightening a significant bend on a secondhand wheel I didn't know the history of. The hub was a large Flange Norman (which aren't high end hubs)
Have never had signs of this problem on Shimano hubs but the largest ones I have are only 7 speed .
The comment on corrosion may be relevant too.
I used to run a Tandem with Suzue (?) Tandem Hubs , the wheels were built with washers under the spoke heads
and I recall reading that this helped in minimising the wear at the hub /spoke interface .
I have seen 'old school' racing wheels where the spokes are soldered and tied .
And I have seen back wheels built with plain gauge spokes on the block side (perhaps the ex Spa wheelbuilder could comment on this ? ) although your problem doesn't seem to be where the spokes cross.
Don't think you have mentioned the rims you use, do you need something more robust than you currently use?

[Jim77]

I have had a similar looking failure on a wheel (I fear I had over done the spoke tensions (whilst still a not well practiced wheelbuilder) on straightening a significant bend on a secondhand wheel I didn't know the history of. The hub was a large Flange Norman (which aren't high end hubs)
Have never had signs of this problem on Shimano hubs but the largest ones I have are only 7 speed .
The comment on corrosion may be relevant too.
I used to run a Tandem with Suzue (?) Tandem Hubs , the wheels were built with washers under the spoke heads
and I recall reading that this helped in minimising the wear at the hub /spoke interface .
I have seen 'old school' racing wheels where the spokes are soldered and tied .
And I have seen back wheels built with plain gauge spokes on the block side (perhaps the ex Spa wheelbuilder could comment on this ? ) although your problem doesn't seem to be where the spokes cross.
Don't think you have mentioned the rims you use, do you need something more robust than you currently use?

Thanks for your comments - the rim is a DT Swiss TK540 36hole so very robust from what have been told.

[Jim77]

For completeness here are the photos for other 105 hub with the two points of failure.

[531colin]

...........
And I have seen back wheels built with plain gauge spokes on the block side (perhaps the ex Spa wheelbuilder could comment on this ? ) although your problem doesn't seem to be where the spokes cross.
Don't think you have mentioned the rims you use, do you need something more robust than you currently use?

Plain gauge (or 13/14g single butted) driveside and double butted left side is something which has been done for years....Hewitts were the first people I came across.
The theory seems to go like this; driveside spokes are under more tension than left side, if you use the same gauge spokes both sides there is more "stored" stretch in the driveside spokes than the left spokes. If you use thicker spokes driveside, the "stored" stretch will be more similar each side.
OK so far.
I have never seen a convincing reason why this should necessarily make a "better" wheel. I don't think it does any harm with a big strong rim, but I would advise against it using a lightweight rim because of the local loading at the nipple. I can't imagine what "where the spokes cross" has to do with it.
At Spa it was standard practice to build (touring) wheels with thicker spokes driveside; that was what the boss wanted, and that was what he got.....unless the customer wanted butted both sides, when that was what the customer got.

I have already posted my thoughts on hub spoke washers (to quote the Hitchikers guide....mostly harmless)
For rims, (as previously) a heavy rider using a highly dished wheel needs a rim which is radially stiff and has offset spoke holes.
While I'm in a cynical mood, I'm a bit un-convinced by rim eyelets. A single eyelet is like a boot eyelet, "rivetted" into the bit of the rim which faces the hub. I guess they increase the area which takes the tension load, and probably help the nipple to sit straight to the spoke in some cases.
Double eyelets are supposed to spread the tension load to the bit of the rim under the tyre. Except i have seen too many rims where I could get my fingernail under the "top hat washer" . In that case, the double eyelet is just acting like a washer to spread the tension load.
I wouldn't be surprised if the modern approach of putting a bit more metal in the extrusion where the spoke holes go isn't a better idea.

[Barrowman]

The 'where the spokes cross' is a reference to tied and soldered wheels which I realise was a thing in racing circles and probably not relevant to this problem.
( Wrap wire around where spokes cross and solder it for those who haven't come across this)
I am an enthusiastic amateur just expressing my thoughts and experiences here.
Good to get an expert on the case.

[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.

[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?