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Three spoke questions (wheel building)(11 posts)

Three spoke questions (wheel building)NewDayNewWay
Nov 22, 2003 2:16 PM
My single speed cross build is coming to fruition. Only one more item to buy - spokes. Any help with the following is greatly appreciated.

Per SpoCalc, I need spokes lengths of 290.2 mm and 295.4 mm. Obviously, I will round down to 290 and 295, but should I go down 1 mm or 2 mm more as insurance? My measurements were sufficiently accurate so I'm tempted to stay with 290 and 295, but a voice in the back of my head says to be conservative.

I have a basic understanding of 3X pattern. I'm going with 2X pattern on front, however, and cannot find any web references that describe lacing of 2X. Can someone easily explain how to lace 2X given my understanding of 3X, or give a web reference?

For cross-type riding (gravel roads and smooth single track) what gauge spoke should I go with? Can I go with a 15 gauge? (14 gauge seems a little too much)

Thanks!
NDNW
2xMike Tea
Nov 22, 2003 3:03 PM
For 2x you.....wait for it....drumroll.....cross your spoke over two instead of three spokes! Actually it's over one and under one.

14/15g double butted would be the best spoke for you. Well CX-Ray would be the best (in my opinion) but at 3x the price.
Why is shorter more conservative?...TFerguson
Nov 22, 2003 3:15 PM
Is there a reason to think you measured long? I would use the results or re-measure.

TF
Why is shorter more conservative?...NewDayNewWay
Nov 22, 2003 5:06 PM
No, my measurements were accurate but as my wife says "sometimes I'm too accurate" meaning that I sometimes measure so closely things barely fit, although in this case there are two directions to error, so my thought was to avoid the potential that I would "bottom out" the spokes. However, I assume the lengths from SpoCalc allow ample room in this regard, assuming measurements are correct.
Why the heck would you round DOWN?russw19
Nov 22, 2003 10:40 PM
You've never built wheels have you? Don't round down. Always round up. Otherwise you won't be able to properly tension your wheels. Are you using a double wall rim? If so you will have about 4mm of extra clearance before you have to worry about the spoke poking thru to your tube. Round up (unless you have single wall rims, and then you should still round up, but file down the spokes after the wheel is built and tensioned.)

Also, do you plan to use alloy or brass nipples? If alloy you MUST go longer! If brass it's not as big a deal, but with alloy if you don't thread the nipple almost to the point where it bottoms out, you will strip it out while riding. If you used a good spoke calc chart, it should have told you to round up. If on the rear both drive and non-drive are near to one size, you could round one up and one down to use the same size, but I would still always round up.

As for Spoc Calc... it will give you the exact correct length.. not a length with room for error and it bases the number on a certain tension (although I forget the tension value) so if you need to error, go long. Spoc Calc also assumes a perfectly relieved wheel as well for that length. If you screw up and go too short you can get long spoke nipples, but the overall wheel strength will suffer and it will be harder to get the tension correct.

You don't have to take my advice, but I would at least double check it with some local wheel builder you trust before you discount it.

Russ
Why the heck would you round DOWN?NewDayNewWay
Nov 23, 2003 3:05 PM
I have no reason to doubt what you indicate, and in fact your advice makes perfect sense at face-value. You provided many solid arguments for rounding up. Thanks for the input!
does SpoCalc calculate spoke stretch?cyclopathic
Nov 22, 2003 6:00 PM
Some calculators don't and on drive side of dished rear DB stretch up to ~1mm, sometimes if you're "too accurate" there might be not enough to tension rear wheel properly.

DB14 gives the strongest wheel, it can take more tension then 14G and it's stornger at J-bend then 15G. My pers favorite WheelSmith DB14, you can pick 290 and 294 at JensonUSA for .34$ in silver.
Lacing made easy....Alexx
Nov 23, 2003 12:30 PM
The rule for lacing is quite simple: You only go over the LAST spoke before you hit the rim. 1x means one over. 2x means one under, one over. 3x is 2 under, one over. 4x, 3 under, 1 over.
Lacing made easy....NewDayNewWay
Nov 23, 2003 3:09 PM
Thanks all for the input!

FYI Jenson appears to be virtually out of spokes. They do not even have enough in stock for one wheel build for the sizes I need.

I'm going with 15/14/15 for spoke size. I suppose a road bike would typically have 15 (not sure off hand because my 2300 has the aero-spokes), and I'm assuming that a MTB might use 14, so this seems best given the type of riding.
I meant 14/15/14 (nm)NewDayNewWay
Nov 23, 2003 3:10 PM
Spokes, go to www.oddsandendos.com.jw25
Nov 24, 2003 8:54 AM
Unless I'm buying other parts at the same time, I use Mike at oddsandendos for my spokes. Great prices, outstanding customer service, and it's nice to support the little guy.