Is it possible to redrill a 24hole hub for 36holes?

[Audax1]

Hello

Just wondering whether it is possible to get a 24 hole small flange hub redrilled for 36 holes? Not an engineer but wondered whether the 12 holes could have a hole drilled in the middle, so a further six added each side so the holes are evenly distributed.

Does anyone have any ideas or suggestions for how to approach this please? Grateful for any guidance, thanks in advance

[hubner]

If the 24 hole hub was designed for that number of holes, adding extra holes could weaken the hub.

But I suppose actually drilling the holes would be quite straight forward, best to use a pillar drill and a jig to hold the hub upright.

[mzjo]

Given that 36 hole small flange hubs are (or at least were ) a lot more common than 24 hole small flange hubs I don't suppose that there has been much incentive or need to do this. Unless you want some sort of weird spoking pattern (which probably will not match very well to existing rims) there doesn't seem much point in weakening hub flanges with extra holes. A large flange hub would be a better prospect for this sort of thing.
I would measure very carefully how much metal will be left when you put a 2.4mm hole between the existing ones. It might be so little as to make the whole thing unviable.

[Wowbagger]

In order to do this, I think you would need a deep understanding of the theory and practice of wheelbuilding. And if you have that deep understanding, I don't think you would do it.

I'm thinking about the practicalities. Each flange of a 24 hole hub would have 12 holes, so that would be 30° between adjacent holes. The 36 hole hub would have 18 holes per flange, therefore 20° between adjacent holes. You would have to drill two holes only 10° either side of alternate existing holes. How much flange would be left once you'd drilled the holes and allowed for the countersinking of the spoke heads?

[Audax1]

Hi

This is the hub, had held back on sharing the link as it’s still up on eBay but would appreciate the guidance and seems you guys know alot more about this than I do! Grateful for the comments, the hub does seem to have a medium size flange, and looks like a reasonable amount of space between the holes but will see what people think

https://www.ebay.co.uk/itm/204456897886?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=vCFEmB0lSUi&sssrc=4429486&ssuid=rwcEtwo8Qgy&var=&widget_ver=artemis&media=COPY

[Wowbagger]

At that price, I certainly wouldn't. You could buy something perfectly decent at half that price and I doubt you'd notice a difference in performance.

[mzjo]

Eating has refreshed my memory. Back in the 70's or early 80's Chris Juden reported having built a 72 spoke rear wheel for his tandem (this was in the Tandem Club Journal). The process involved taking a brand new Campag large flange hub and drilling a second lot of holes (he reported IIRC "with great trepidation"), then obtaining an undrilled rim and drilling that to have 72 spoke holes with the correct offsets (it is the offsets that make this impossible to do correctly by drilling an existing 36h rim). So it can be done, if you know what you're doing!
In the case of this hub I don't see the point. You either build it up as a 24 spoke wheel or you look for a suitable hub to build a conventional 36 (or 32 if you like) wheel. Now if you wanted to do the thing correctly you would drill it to 48 holes!

[LittleWheelsandBig]

If it was actually a small flange aluminium hub, I would run screaming from the thought of drilling extra spoke holes. You would run a high risk of a zipper failure through the new holes due to lack of metal either side.

You are proposing to drill extra holes in a (possibly unique) titanium hub with medium flanges. It might actually work without failing (enough stronger metal in the flanges, so probably ok) but it would be such a waste to bodge such a lovely hub when there are so many other hubs out there that don’t need to be drilled.

[Peter]

Drool:  Engineering as art.

[nextSibling]

If you add a further 6 holes to either side you would have 18 unevenly spaced holes (one new hole between every other initial pair).

I mean, sure, you could drill and (importantly) countersink the new holes, carefully, if you have the appropriate tools and machining skills. Building the wheel with uneven spoke holes at the hub wouldn't be too challenging for an experienced builder. But why? There are plenty of nice 36 hole hubs already available.

[giropaul]

Why not ask the manufacturer? They still have a Facebook page.
If it’s a possibility they might even do the job for you.

[Audax1]

Thanks everyone useful to read people’s views and ideas. Have emailed Royce and will see what they say, think it would perhaps need them to do it due to the precision required, will wait and see whether it’s possible and what they say.
Thanks again

[robgul]

Thanks everyone useful to read people’s views and ideas. Have emailed Royce and will see what they say, think it would perhaps need them to do it due to the precision required, will wait and see whether it’s possible and what they say.
Thanks again

I would be surprised if they gave the idea their blessing . . .  I think the additonal holes would substantially weaken the hub flange, and as mentioned above give odd spoke angles.

[fruitcake]

Don't do it. You'd f**ck up the hub, and you'd end up with something unusable because the holes would be unevenly spaced.

[aidan.f]

how heavy are you? a 24 spoke un-dished wheel with a sensible rime is pretty strong

[grams]

Ignoring everything else, drilling titanium isn’t something I would do casually.

[Audax1]

Hi,

Have realised my maths was well out, drilling between each of the twelve holes would actually make 24 holes in total so would be a 48 hole hub. Would have been a bit of a disaster! Drawing it out made a bit more sense…

Have been trying to decide about a 24hole wheel, whether it would be strong enough. I’m 6ft6 and about 195lb/14ish stone.

Have been reading the Roger Musson book he seems to suggest 24 spokes is enough for a carbon rim but to use stiffer spokes to reduce side to side wobble under high load…

Not too sure about it, seems abit risky just having 24spokes, interested in others ideas on this

[LittleWheelsandBig]

I have 28 hole 700C wheels on my tricycle (lots of side load). The front wheel has a disc brake and all wheels have DB spokes and 32mm deep Al rims. No problems with them. I am in excess of 80kg.

[markcjagar]

Have been trying to decide about a 24hole wheel, whether it would be strong enough. I’m 6ft6 and about 195lb/14ish stone.

you're really underestimating the strength of 24 hole wheels, I rode on them without issue at 17+ stone

[Audax1]

Ok thanks much appreciated.
Just noticed Sapim do a ‘strong’ spoke which may provide some additional strength too! https://www.sapim.be/spokes/butted/strong

[Dickyelsdon]

Might be too late if youve bought it, but not sure the 'strong' spoke would fit correctly as they are 2.3mm at the head. Might work but you wont really know until you try to build it.

A standard butted spoke (2/1.8/2) will be fine when built properly. You could splash for CX-ray which have better fatigue, but more for show than go.  The rim will dictate the wheel strength/flex more.

[vorsprung]

Not an engineer but ...

Neither am I but this is an insane idea
What 36h hub do you want?  I'm sure someone has one in their shed

[mzjo]

Of course if you really need strength there are 48h hubs and rims out there if you want to look. SJS were doing a 48h wheel with a Halo hub. 26" wheel, my daughter has one to cope with a juvenile heavyweight bouncing in a child seat but I am sure there are 700c rims in that drilling as well. (48h might have been overkill but 32 was giving spoke problems and I am a bit too far away to hop over and fix them.)

[iandusud]

If you're really sold on the idea of using this hub I would suggest building it up using a good quality rim and maybe single butted spokes. Modern rims are much stiffer than they were 30 years ago. I've used a set of Shimano wheels, with the rear dished for 11 speed, with 16 spokes front and 20 rear. They remained perfectly true throughout their life. Eventually the rims wore out and replacements were impossible to find.

[Audax1]

Thanks everyone , very grateful for the comments and useful suggestions. I managed to move on from the idea of the hub, there are easier alternatives and solutions but was a nice looking hub.

Just to give something back, as people have been very generous with their knowledge…

It turns out that there is a rare vintage Airlite hub, a British manufacturer c. 1940-50’s who produced a small flange hub and riveted a large flange onto the small flange. Not sure it’s a length that would need to be gone to in this situation but thought it may be worth a share. Perhaps of note it was also an intentional design rather than an adaption.