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• #4352
If they are 700c (622) I wonder if you could use a 27" (630 or 635) rim that would fit snugly on the outside, and use the holes from that as a guide for the drill (drill press/pillar drill would be most accurate, but the "guide hole" should keep a hand-held drill fairly straight). 27" rims probably tend to have higher spoke counts though, so you might not be able to get the spoke count you want. If you haven't worked with it much, aluminium can be quite grabby with some drill bits, which sometimes affects the finish on the exit.
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• #4353
How about using a protractor with a long stick nailed to the centre to give you where the holes should be.
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• #4354
@jdmitch @n/a I think measuring the holes from the outside of a pre drilled rim would leave with more of a margin for error. There must be a mathematical equation to work out the spacing, im guessing something along the lines of -
(Random carbon tubular 700c rim) ERD 584mm divided by 2 = 292mm
Circumfrence rounded up is 1834mm, then divided by 28 (hole count) = 65.5mm
So basically saying that it should be 6.5mm per hole for that ERD? Anyone have a 28h 30mm deep rim then could verify this please? -
• #4355
I'd put some dot stickers on every 65.5mm and see if you end up back where you started after 28.
http://www.whsmith.co.uk/products/whsmith-self-adhesive-small-dot-coloured-labels/37255749 -
• #4356
You definitely wouldn't. The risk of accumulated error is way to big, you need a system than measures from a fixed point each time. Having said that I don't know how accurate drilling actually has to be, I suppose the wheel builder compensates automatically for discrepancies, if there are any.
You'd probably get pretty good accuracy by using your method, but only up to three holes or so, then re-measuring from a fixed point for the 4th. Saves time but keeps reasonably accuracy.
This is all random conjecture, I've never built a wheel or drilled a rim.
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• #4357
Sounds like a challenge. I'd bodge the last few to make sure I did :)
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• #4358
The problem with doing it based on ERD (spoking diameter) is that you may not be drilling from that point. Not sure how these rims are constructed (ie the cross-section), but lots of rims would be a bit further out where you would be drilling from. Using another rim allows you to do everything effectively in degrees, a relative measurement, rather than mm, an absolute measurement. While I can imagine that in this particular instance, the methodology may fall short, I think the general principle of doing this by relative measurements rather than absolute ones are likely to be more accurate. I think this operation likely to have very fine tolerances (more so than spoking, where a few mm of play is permitted), and given the number of rims you are doing, it is worth setting up a jig of some sort...
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• #4359
Easy peasy. Make one of these :-D :
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• #4360
I think you could actually build something pretty similar with a lazy susan (you can pick up the essential bearing components on ebay for a few quid ), with a drill carefully mounted at the right height. It would be in your interests to do the rims all at once, or at least in batches, and determine in advance which numbers of holes you'll want, as the setup will be the most challenging bit. PM me @BigH if you want to follow up - I could probably build the jig/lazy susan, but as I say the setup is the crucial bit...
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• #4361
I remember tester mentioning disc specific road rims which are cheaper alternative to Stans Grail .. maybe Disc version of R460? Anyone know where I can get them cheapest?
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• #4362
DT R 460 DB. Dunno about cheapest, try Google
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• #4363
Diff between stans grail build and DT build is about a tenner .. with DT comp spokes.
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• #4364
£60 from Bike24.
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• #4365
not in stock (32h)
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• #4366
24h working fine for me
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• #4367
yeah it would for me too but the hubs I am after only come in 32h
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• #4368
SJS says 32h in stock, £35 per rim
http://www.sjscycles.co.uk/dt-swiss-r460-db-700c-622-road-disc-rim-black-prod40748/ -
• #4369
Sorry, I'm being real lazy:
Is there a modern rim (disc or machined) that has a similar ERD as a CXP33, to the point where I could do a straight swap? Assuming the spokes on the original build were sensible, which I expect they were given that the originals are Arup builds.
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• #4370
Everything you need is here.
http://weightweenies.starbike.com/forum/viewtopic.php?f=113&t=133744 -
• #4371
The rrp is 34.99 and that will be a shipped price. They are in stock at madison. In hospital at present so i cant help.
With this rim dont be too fussy about a very round and straight wheel the rim wall wobbles a bit but it is no problem either.
The ither alternative us the kinlin xr22rts ocr. Same money but proper offset drilling. Lighter too.
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• #4372
Built up my r460 rim last night with cx rays, 24 hole 2x all around last night. Real happy with it, Used a tension gauge this time so hopefully I'll go longer than 6 months without pinging a spoke.
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• #4373
In hospital at present so i cant help.
Called your shop yesterday and came to know this. Hope you heal up soon!
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• #4374
Check ERD on CPX33 (should be on rim, and no it's not the same for all models you will have to check...can't do it for you :)
Google ERD (within a mm +/- should be fine, but check how much spoke thread there is/how high spokes are under tape before you buy...if they're nearly poking out better to take a mm off. Perhaps you can even take 2mm off)
Success result profit.
You can also play with spoke pattern here if you fancy something quite different:
https://leonard.io/edd/ -
• #4375
Oh oh, get well soon :)
Sigma doing a 14% discount until midnight WLY14. Makes Archetypes £42.50 per rim.