Wheel builds using 1995 campagnolo chorus hubs

the_one_with_the_big_wang
the_one_with_the_big_wang Posts: 35
edited January 2011 in Workshop
I rode through a massive pot hole at about 30 mph on my way back from work denting my front wheel rim and splitting the rear wheel rim. So I have decided to rebuild them. The rims I am replacing are Campagnolo Omegas. This will be my first wheel build so I need to know what the specs are for my 1995 Campagnolo hubs which I've had from new. I am trying to calculate the spokes I need using this: http://www.dtswiss.com/SpokesCalc/Calculator.aspx I want to fit them with Mavic CXP 33 black rims. They are 36 spoke hubs. Some of the alloy nipples have become welded to the original DT Swiss spokes so will probably need to cut those spokes to get them out. I have a feeling that some of the spokes twisted perhaps a bit too much when loosening the nipples so I think this may deteriorate their performance which is why I am considering replacing some of them. Basically can anyone please give me some advice as to where to get the hub specs from so that I can use the spoke calculator, what alloy nipples to get, how to prevent them seizing again in the future and whether DT Swiss spokes now have a competitor offering better value for money? My current spokes are double butted. Thanks

Comments

  • balthazar
    balthazar Posts: 1,565
    I'm pretty sure the (deeper) Mavic rim will need shorter spokes than the outgoing Omega, so you'll need all new spokes anyway. Remember to lace the hub the same way, following the deformations made by the current ones.

    Forget aluminium spoke nipples. Use brass ones which are much less likely to bind. 14/15g double-butted spokes are ideal. Narrower ones are strong enough, but difficult to tension because they twist so easily.

    For dimensions, I have used Damon Rinard's Spocalc database:

    http://sheldonbrown.com/rinard/spocalc.htm
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    OK that workbook looks like it contains the correct specs for my hub. I'd better measure them just to make sure but thanks for the pointers. I might still stick to the alloy nipples as some experienced wheel builders appear not to have any problems with them so long as anti seizing compound is used. I'm not sure whether this was the case with my wheels. They are pretty old though so I guess it was bound to happen.
  • crankycrank
    crankycrank Posts: 1,830
    Spoke length calculator here. http://lenni.info/edd/ I didn't check to see if your combo was in the database but hopefully it will be.
  • Wappygixer
    Wappygixer Posts: 1,396
    The One with the Big Wang wrote:
    I rode through a massive pot hole at about 30 mph on my way back from work denting my front wheel rim and splitting the rear wheel rim.Thanks

    Don't forget you can claim for the damage from your local highways agancy.Take a photo of the hole and send it with all the detaIls of what happened.

    If you want to use alloy nipples then use Sapim as these are slightly harder than DT and don't cut up as much.You could use DT hexagonal nipples but they are expensive and require a special tool which is also expensive.
  • Monty Dog
    Monty Dog Posts: 20,614
    Quote: I might still stick to the alloy nipples as some experienced wheel builders appear not to have any problems with them so long as anti seizing compound is used.

    Nope, it's about corrosion of the nipples themselves which can result is stress cracking problems. I weigh less than 65kg and had problems with a front wheel after only a few months - DT Revs on Records/ Open Pro mainly because the wheel was used in winter. Replaced all the nipples (they were DT) and haven't had a problem since (3 year).
    Make mine an Italian, with Campagnolo on the side..
  • balthazar
    balthazar Posts: 1,565
    crankycrank wrote:
    Spoke length calculator here. http://lenni.info/edd/ I didn't check to see if your combo was in the database but hopefully it will be.

    Bookmarked. Thanks, I didn't know about that web app. For others- it's Damon Rinard's spocalc underneath, but about a thousand times easier to use (at least if Excel is an alien planet to you, as it is to me).

    +1 with Monty's comments. Really, use brass spoke nipples. There are no pros with aluminium, only cons.
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    Great Crankycrank, thanks for that link that is really useful and has all the details I need. When it asks me to enter the number of crosses what is it asking exactly?
  • Monty Dog
    Monty Dog Posts: 20,614
    Crosses refere to the number of spoke crossings and I would use the same pattern as your existing wheels to keep the stresses on the hubs the same - count the number of spokes a spoke crosses on the same side from hub to rim - most common pattern is 3-cross. 4 is heavy-duty and 0 = radial - the more crosses, obviously the longer the spoke as it leaves the hub at greater tangential angle.
    Make mine an Italian, with Campagnolo on the side..
  • crankycrank
    crankycrank Posts: 1,830
    The One with the Big Wang wrote:
    When it asks me to enter the number of crosses what is it asking exactly?
    As Monty Dog described but be sure to include the spoke that gets crossed at the hub, usually the next spoke over. As also mentioned most 36 spoke wheels have a 3 cross unless used for super heavy duty such as touring or tandem wheels.
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    Thanks for your help guys. Now I've used both the Sheldon Brown excel spoke calc and the one here http://lenni.info/edd/ and they're both giving me the same spoke lengths but using the DT Swiss spoke calculator http://www.dtswiss.com/SpokesCalc/Calculator.aspx is giving me different lengths from the other two. I'm using CPX 33 rims, DT brass 2.0 14mm nipples (convinced now that aluminium nips aren't worth the hassle), with DT Swiss Competition 2.0 spokes, crossing 3 times. My front hub is Campag 90's Chorus (being 1995) and rear hub is Campag 8 speed. The only reason I can figure other lengths are different is perhaps the nipple length. This is the only thing I am not inputting into the calculators other than the DT Swiss calc. Can anyone explain this?
  • crankycrank
    crankycrank Posts: 1,830
    The One with the Big Wang wrote:
    using the DT Swiss spoke calculator http://www.dtswiss.com/SpokesCalc/Calculator.aspx is giving me different lengths from the other two. Can anyone explain this?
    Well, sorry but I don't know which is correct. Try emailing DT and tell them about the discrepancy. I would bet they"ll give you the correct spoke length and an explanation.
  • ugo.santalucia
    ugo.santalucia Posts: 28,325
    The One with the Big Wang wrote:
    Thanks for your help guys. Now I've used both the Sheldon Brown excel spoke calc and the one here http://lenni.info/edd/ and they're both giving me the same spoke lengths but using the DT Swiss spoke calculator http://www.dtswiss.com/SpokesCalc/Calculator.aspx is giving me different lengths from the other two. I'm using CPX 33 rims, DT brass 2.0 14mm nipples (convinced now that aluminium nips aren't worth the hassle), with DT Swiss Competition 2.0 spokes, crossing 3 times. My front hub is Campag 90's Chorus (being 1995) and rear hub is Campag 8 speed. The only reason I can figure other lengths are different is perhaps the nipple length. This is the only thing I am not inputting into the calculators other than the DT Swiss calc. Can anyone explain this?

    Once I had this problem, then realised I was inserting the NUMBER of holes in the hub instead of the DIAMETER of the hub holes, hence a 32 instead of 2.3... that made a lot of difference! Other than that, they all use the same algorhythm, I would be surprised of any difference
    left the forum March 2023
  • balthazar
    balthazar Posts: 1,565
    Dt might default to the nearest available length (because they sell them), where the others give an ideal but unavailable size, for you to round up or down as you see fit.. How big is the discrepancy?
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    I'm using 14mm to decrease the risk of scratching the wheel rim with the spoke wrench. I read somewhere that when using 14mm nipples you should deduct 1.5mm from the spoke length. I'm assuming spocalc by default uses 12mm nipples. This seemed slightly strange considering there's a 2mm difference between the two nipple lengths.

    I still don't really understand the figures the DT Swiss calculator is outputting though. For example on the Rear wheel Left side DT Swiss advises 288mm and the spocalc says 289.6mm. Now deducting 1.5mm to take into account the 14mm nipple length from the spocalc figure matches up with the DT Swiss figure i.e. 288mm. Now for the Rear wheel Right Side DT Swiss advises 287mm but the spocalc says 287.8mm deducting 1.5mm and rounding down gives me 286mm. That's a whole 1mm out.

    Oh something else...DT Swiss do offer spoke lengths in 1mm increments from 286mm to 292mm so they aren't rounding up or down to the nearest available length

    Anyway here's the DT Swiss calculations 5a43a4970c5f13b41665_1.jpg and the spocalc calculations for your perusal. 5a43a4970c5f13b41665_2.jpg Do these look right?
  • ugo.santalucia
    ugo.santalucia Posts: 28,325
    To be honest, you're being a bit picky here... I though you were talking about real differences...
    Put it in perspective... a 1 mm difference over nearly 300 mm is about 3%, which is well within tolerance...
    It could be DT does not have that particular size and advises you on the nearest available.
    left the forum March 2023
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    So do you frequently build wheels with spokes that are 1mm less in length than advised within one of these spoke calculators because you know that it makes no real world difference? I would like to know since this is my first wheel build and it'll probably cost less to buy 72 spokes that are the same length and 18 of another length rather than 3 sets of spokes of differing lengths.
  • ugo.santalucia
    ugo.santalucia Posts: 28,325
    The One with the Big Wang wrote:
    So do you frequently build wheels with spokes that are 1mm less in length than advised within one of these spoke calculators because you know that it makes no real world difference? I would like to know since this is my first wheel build and it'll probably cost less to buy 72 spokes that are the same length and 18 of another length rather than 3 sets of spokes of differing lengths.

    Yes, it basically does not make much of a difference, within a +1or -1 mm (or even -2, really). When I need 3 different sizes, as it's often the case, then I use "pedalon", they are quick and as long as you buy at least 16 spokes, you can buy singles.
    If you want to save money ACI DB spokes are good quality and cheaper than DT, many builders use them. In my view stay away from DT Revolution, but that's a personal opinion, some swear by them... I've had two broken within one month, while I've never had a problem with the Competition ones. If you are on a budget and don't mind the extra gram, DT Champion are indestructible

    One question... the ERD you use is measured or taken from the manufacturer? I ask you as ERD depends on whether you use 12 or 14 mm nipples, but nobody tells you that.
    left the forum March 2023
  • Monty Dog
    Monty Dog Posts: 20,614
    ~1mm variation in spoke length makes as good as no difference - threads only engage for about 6 turns - anything more is redundant. If you engineered the threads for greater engagement the costs would skyrocket because of the higher tolerances and adjusting spokes would be a nightmare because of the friction in the threads.
    Make mine an Italian, with Campagnolo on the side..
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    The ERD I used wasn't measured it was automatically input by the calculator once I had chosen the rim. From what I understand the ERD decreases with a longer nipple which is why you should then decrease the spoke length required. The socalc has nowhere to tell the script that a 14mm nipple is being used and I suspect by default it runs the calculations based on a 12mm nipple. The DT Swiss calc on the other hand has a drop down for different types of nipples (lengths and materials).

    So you think it'll be OK to replace the 288mm spokes the DT Swiss calc is telling me to use on the rear wheel for 289mm or use 288mm on the front?

    I was looking at Pedalon and liking the fact they sell single spokes but with only 12mm nips. Chainreaction do packs of 36 with 14mm nips for £17.99 which seems pretty good. I think Sdeals which is where I'm getting the rims and tape from do the ACI spokes. Because my wheels were previously DT Swiss I'll be staying with them. Had no problems and I know they work.
  • balthazar
    balthazar Posts: 1,565
    Longer spoke nipples are not threaded any further, as I recall: the extra length is blank bore, allowing better spoke key engagement only. That's why the charts ignore it. As long as the spokes don't stick out beyond the nipple into the rim when tensioned, then you're fine with a variance of a few mm.

    Make sure the spoke nipples are the correct diameter. 2.00mm nipples will thread apparently fine onto 1.8mm spokes, but will then strip at higher tension. (1.8mm nipples will not fit onto 2.00mm spokes)
  • jonmack
    jonmack Posts: 522
    This thread has gotten pretty in depth, but for what it's worth 1mm difference is completely negligible, if it was 5mm difference i'd be worried, but i've built BMX wheels with spokes 2/3mm too short and too long and they still hold up fine.
  • the_one_with_the_big_wang
    the_one_with_the_big_wang Posts: 35
    OK I'm confident I know what to get now. Thanks everyone I'm off to order the parts.

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