If these multi-holed cranks end up getting made I’d be interested in a pair.
OK, I just ordered a bike pedal tap set, Park-6. This includes the 9/16x20 left and right taps. The pilot hole is drilled with a 33/64 or 17/32 drill, which I have.
I have a 150mm set of Prowheel cranks that I plan to drill for 125mm. If that works, I’ll probably do my Moments. The 165 looks like it will also drill out for a 137mm. That would be sweet for Muni on my 24"
Oh, looks like a countersink would also be nice to allow the pedal thread shoulder to fit flush. I’ll see if I can locate one of those, also.
I’ll build a jig to fit my drill press to keep everything in alignment.
I just hope I remember to tap the left crank with the left thread!
Pics in a week or so!
Well, I’ve just been to my LBS (Cambridge Cycle Centre - they’re very good). They’ve offered to drill my frame for a brake and put an extra set of holes in my prowheel cranks for around 20 quid all in - not bad! Or they have a contact in the Engineering department who might be able to do it for me in their big machine shop.
Either way, I’ll think about getting it done at some point and let you guys know how it turns out. If it works out well then I could ask them if they’d do it for you guys too (e.g. cranks sent by post). Asking your LBS might be a good move as well; I don’t know if big chains like Halfords are able to do it, but more specialist shops may have the right equipment.
I have ordered a set of taps for 9/16 x 20" pedal threads, both sides. I have access to my student workshop, which whould be quiet over exams and as projects are completed. I need a drill for the pilot hole, but our workshop should have the correct 33/64 drill, or I’ll use the 13.00mm or 13.10mm metric drill my Zeus chart suggests.
Depending on number of people interested I’ll be willing to make modified Prowheel cranks for around £30 a set. Other cranks can be attempted, but prowheels seem to be the most suitable from the pictures I’ve seen. If you want other cranks doing, let me know and you can send them to me for machining.
I will/can order cranks from UDC, machine and deliver either by hand via conventions/hockey tournaments, or will ship (P&P extra).
I’m going to do initial tests on a set of 150mm prowheel cranks, that Anna can test on her 36.
Register interest now, and I will inform all interested people by PM when I’ve got a JIG and have tested a set and am happy they won’t snap ;). Ballpark estimate: sometime after 1130, June 8th (“Linear Engineering Systems: Control”, 0930, main exam hall, 2hrs)
Loose.
My pedal taps showed up today; now I just need a little time to get the drill press set up and drill and tap my cotterless alum 150’s.
Photos to follow, and a write-up, but by now everyone knows what a crank with 2 holes looks like (don’t take that the wrong way!)
Happily enough I bought a set of 150mm Prowheel cranks at BUC. Keep me updated as to how the testing goes Mr Moose.
Cheers,
Kit
OK, I couldn’t wait any longer, so I went out and modd’ed the cranks. These are Prowheel 150’s on my first uni, a Nimbus.
Everything worked great; the second set of holes is 125, the originals are 152. I rode about a mile and had to snug the pedals down a bit, but they weren’t really loose. Also did a few dead drops from 18-24", and nothing has bent or broken yet.
What do you think?
I think they look awesome! It’s good to hear that they’re holding up to drops well. My one concern with mine was that they might suddenly fail after the alloy gets fatigued; but I’m not going to be doing huge drops on them so I reckon I’ll probably be alright!
Do you think 125 is the shortest those cranks can be drilled to? I took mine to the LBS on monday and basically asked them to make the second set of holes as short as they possibly could - the intention is to have a cruising gear on my 29er muni so that I can quickly ride to interesting places where I can make effective use of the 150mm setting 
My uni is coming back on Friday, so I’ll see what they look like then. I really think that double-holed cranks should take off, they’re just such a simple and useful idea.