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-   -   Straight Gauge or Double-Butted Spokes? (https://www.bikeforums.net/bicycle-mechanics/1170277-straight-gauge-double-butted-spokes.html)

Jon T 04-10-19 10:31 AM

Straight Gauge or Double-Butted Spokes?
 
I ride an '84 Peugeot that I bought new with the Helicomatic rear end. About 30 years ago I rebuilt both wheels with DT Swiss spokes. I rode it for about 10 years with zero problems. Then life got in the way and the bike sat un-ridden in the garage for the better part of 20 years. The wheels were on hooks hanging from the rafters, the frame was on a work stand. A couple of years ago I put it all back together, tuned every thing and started riding again (I'm 64). I put on about an extra 50# since I stopped riding. I'm now having a problem with rear wheel spoke breakage. About every 50-80 miles I'll break one. I carry spares so I can fix it on the spot. I've decided that I just need to "bite the bullet" and rebuild it again. My question to the wheel-building guru's out there is: Is there any advantage to using double-butted spokes v. straight gauge spokes? Are DB more forgiving/resilient than straight gauge? The rims are RIGIDA alloy, 36 hole.
Thanks for your input and PLEASE don't tell me to replace the wheel with a new one--that ain't gonna' happen.
Just for the record, I stand 6 foot 6 and weigh 245-just like "Big Bad John".
Jon

Phil_gretz 04-10-19 11:01 AM

I cannot comment on the strength of butted versus straight spokes. Maybe it depends on the failure point that you're observing. Are the breaks all at the same point on the spoke (j-bend near the head, or at the first thread near the rim end)?

This does sound like an opportunity to build a wheel with whatever hub you'd like, like something with English threading, or even better, a Hyperglide 126mm hub.

For the record, I did not just recommend that you buy a new wheel. Just a new hub. ;)

joeruge 04-10-19 11:06 AM

I like to use DB spokes. There is some theory that DB spokes make a more resilient wheel, are easy to bring up to tension and somewhat more forgiving overall.

Your added weight alone is probably not the only factor in breakage . Other than impacts, the major cause of spoke breakage is insufficient spoke tension .This seems counter intuitive, but it is fatigue that is usually responsible for breakage, not total load.

If the wheel is properly tensioned more spokes share the load and individual spokes are not constantly loaded and unloaded.

Anyway, to get back to your question, which in truth I can't adequately answer from an engineering point of view, I like to use Double Butted spokes.

Jon T 04-10-19 11:24 AM

The breakages all occur at the "J" bend.
Jon

fietsbob 04-10-19 11:43 AM

My touring bike used a lot of spokes , so I bought 2mm straight 88 of them + a couple spares of each length..

my C&V Road bike wheel build used 72 15 gauge .

I dip each spoke in anti seize so it does not twist rather than tighten ,
a butted spoke is less resistant to wind up because it is thinner in the middle..

New Front Dynamo hub Wheel from Germany for my Brompton came with 28 DB straight pull spokes..






...

pdlamb 04-10-19 11:56 AM

I bought into the theory that butted spokes are a really good idea, especially on the rear NDS. Supposedly the NDS spokes, running at lower tension than the DS spokes, elongate a bit more when the wheel is tensioned, and therefore have a bit more "give" in them so they don't de-tension and break from fatigue. That theory seems to be holding up on the rear I built, since I think I've only had one spoke break in the last half-dozen years.

Of course, the wheel with straight gauge spokes I bought on a new bike (that the shop wrench worked over before I rode off) only has one broken spoke in the last 10 years.

So my bottom line is to make sure the wheel is correctly tensioned and stress-relieved no matter what kind of spoke's on the wheel.

Andrew R Stewart 04-10-19 12:01 PM

My opinion is to use DB spokes unless there's some reason not to. Don't forget to check the rim's condition by reducing down all the spokes to a similar and low tension. If the rim is deformed from "cycling incidents" it will show that as an untrue rim when the spokes are not pulling it straight. Andy

bakerjw 04-10-19 12:05 PM

I would expect straight spokes to be 14 gauge the entire length.
I built 36 hole tandem wheels with Swiss Alpine III triple butted spokes 14/15/13. 13 gauge required 2.5mm holes in the hub so they are a bit larger than the 14 gauge straight spokes that were on it originally.
My caveat. I am no expert.

WizardOfBoz 04-10-19 12:18 PM

I'd go with the extensive experiences of folks, because the theory is difficult. You draw wire, then swage it to get but narrow part, then upset the end and bend it and thread it. (Not necessarily in that order). How was the initial drawing done? What stresses were induced and changes made in grain structure due to swaging and other operations? How did the post-work heat treatment, if any, affect the spoke? There are a lot of factors.

Given that your breaks are at the j-bend (which is the thick part, right?), and 50 lbs ago the breaks weren't happening, I'm thinking that this may be a weight factor and is not due to aging or corrosion. My thought would be that you might try to get modern butted replacement spokes and continue to replace. Label the the new spokes (nail polish on the upset head? A piece of vinyl tape?). When you get to the point that either the break frequency reduces and none of the new spokes are breaking, you have an answer. Replace all the old spokes. Maybe their heat treat wasn't good or something. Alternately, if breakages continues, and new spokes are popping, that's another answer.

If you don't want fiddle around with this and want to take care of it once and for all, I'd contact DT Swiss and ask what they recommend for heavier riders. Be interesting to know if they suggest butted or straight.

Le Mechanic 04-10-19 07:19 PM

From my experience, the current setup is going through spokes due to mileage and fatigue. You're a big guy. Big guys kill wheels a lot quicker, not just because of your weight, but you produce more wattage as well. Just rebuild the wheels with good new spokes. if you're on a budget, the straight gauge 2mm DT spokes are fine. The Dt Alpine spokes are triple butted with 2.3mm at the J-bend and 2mm at the nipple, but they're more expensive. Probably best to go with new rims as well as over time they will crack around the spoke holes as they get miles on them.

Retro Grouch 04-10-19 07:40 PM

If I ever build another wheel set it will have 13/15/14 triple butted spokes.

1. If the hub flange holes are big enough to take the 14 gauge threads, they'll take the 13 gauge unthreaded end.
2. Spokes most often break at the bend. 13/15/14 spokes put more material there.
3. Price is about the same as 14/15 double butted spokes.

Gresp15C 04-10-19 07:45 PM

I agree with Andy -- assess the rim by itself before stringing it up again. I'm just an amateur, and have maybe 10 wheels under my belt, total. But I've already learned that wringing a round wheel out of a crooked rim can be a boatload of work and possibly not worth it. I'm living with maybe a mm of radial truth on an old rim of similar vintage to yours, because I didn't take good enough care of it long ago. I'd rather have good uniform tension than a perfectly round wheel, and it's only noticeable if I'm on really flat pavement.

Jon T 04-10-19 09:04 PM

Ok guys. Thanks for all the input. I'm just gonna' do it to it. Triple-butted it will be. DT's are gonna' be expen$ive. Does any one have first-hand experience with Wheel Smith or Sapim spokes? They're more in line with my budget. I'll get the 15/13/14 gauge spokes. I know the rims are ok--I'm not hard on them and it only sees/has seen paved trails and streets and I'm anal about trueness. Thanks again to all.
Jon

Jeff Wills 04-10-19 09:22 PM

FWIW: I'm 6-foot-4 and 240 pounds... and I ride a recumbent so the rear wheel takes a beating. I've built my own wheels for 30 years... usually 36 double-butted spokes. I haven't broken a single spoke since I learned to build them with high, even tension. Not one.

The DT Alpine spokes are probably overkill, but go for it...

79pmooney 04-10-19 09:38 PM

I an another who would start with a new rim. Not only would I know I was starting with a round rim, I would also stating with a rim interchangeable with other available rims so if something does happen to it, I could unscrew the nipples and transfer the spokes to a new rim and not have to toss that investment in spokes. (Plus second builds go quite fast. The spokes are already bedded nicely. Also no thought required, Just tape the new to the old with valve holes and labels matching.)

An out of round rim can probably be brought to acceptably round with the build, but you have built into your wheel uneven spoke tensions to do so you have started the process of making those spokes old so you probably won't want to re-use them even if you can find a matching rim.

Ben

ThermionicScott 04-10-19 11:07 PM

Are you stress-relieving the spokes when you replace one or re-true the wheel? That can help them live a longer life, and if nothing else, it's better to break a failing spoke on the stand than on the road. ;)

My vote is pretty much always for double-butted spokes, don't have any experience with triple-butted, but they seem like a good idea.

bakerjw 04-11-19 06:33 AM


Originally Posted by Jon T (Post 20879312)
Ok guys. Thanks for all the input. I'm just gonna' do it to it. Triple-butted it will be. DT's are gonna' be expen$ive. Does any one have first-hand experience with Wheel Smith or Sapim spokes?
Jon

I just built 2 wheels using DTSwiss Alpine III triple butted spokes 13/15/14 for our tandem. PReviously it had 14ga Wheelsmith spokes. They cost $1.55 apiece and I needed 72 of them. DT Swiss recommends them for heavy riders AND tandems. You can't get much more abusive on wheelsets than with a tandem.

The 14gs spokes will likely work but IMHO the extra is worth it due to the fact that the J bend, where most breakage occurs, is 13ga

https://cimg5.ibsrv.net/gimg/bikefor...7616ade46c.jpg

Trevtassie 04-11-19 07:06 AM


Originally Posted by Jon T (Post 20879312)
Ok guys. Thanks for all the input. I'm just gonna' do it to it. Triple-butted it will be. DT's are gonna' be expen$ive. Does any one have first-hand experience with Wheel Smith or Sapim spokes? They're more in line with my budget. I'll get the 15/13/14 gauge spokes. I know the rims are ok--I'm not hard on them and it only sees/has seen paved trails and streets and I'm anal about trueness. Thanks again to all.
Jon

Used DT and Sapim, Sapim are good too. Worthwhile looking in Germany for spokes from places like Bike-discount and Bike-components

Steelman54 04-11-19 08:32 AM

If you are failing spokes in 50 - 75 miles, something is off here. I'm guessing since it is older bike you have 36 spokes per wheel. Also, you did not mention which side fails, DS or NDS, hopefully spoke length is adjusted to account for the difference here. I don't see why you would need to spend $$ for triple butted spokes, DT or Sapim double butted 14/15/14 should be good in a 36 per wheel set up. Weight, as in yours, might be a consideration also, probably plenty of info on weight, # of spokes, rim, etc out there in internet land to gauge what you need. I also prefer double eyelet rims or at least the washers in not double eyelet. Others may have more info. Just my thoughts for use as deemed appropriate.

Bill Kapaun 04-11-19 08:54 AM

Looking at the Helicomatic hub on Spocalc-
The NDS tension is about 52% of DS tension. Not very good. You have to get the DS tension >120 kgf in order to get what many of us consider a minimum of 65 kgf on the NDS.
This is a classic case where using a thinner spoke on the NDS is warranted.
It puts the spoke in a greater degree of elongation and will result in less "elbow flex".
On the NDS only, I'd use a spoke with a 1.5 to 1.6mm "thin" section.

davidad 04-11-19 09:41 AM

I always build with double butted spokes. The stress of riding is on the narrow section rather than the threads or bend.

GamblerGORD53 04-11-19 10:08 AM

Good choice with the 2.3 head spokes. Mine are the Wheelsmith ones. I also suggest using locking nipples, although they cost 3x as much. They ARE worth it to hold solid and they soften the stress, IMO. No goofball spoke prep involved. My GVW is up to 290 lbs on tour. Nothing breaks, my front SA XL-FDD wheel has 24,000 miles. They are heavy IGH drum brake hubs.
My 120 lb tour bike has a Rohloff14 with 32 2.0 spokes, way less stress and problems than derailleurs.

Retro Grouch 04-11-19 10:10 AM


Originally Posted by Jon T (Post 20879312)
Ok guys. Thanks for all the input. I'm just gonna' do it to it. Triple-butted it will be. DT's are gonna' be expen$ive. Does any one have first-hand experience with Wheel Smith or Sapim spokes? They're more in line with my budget. I'll get the 15/13/14 gauge spokes. I know the rims are ok--I'm not hard on them and it only sees/has seen paved trails and streets and I'm anal about trueness. Thanks again to all.
Jon

My go-to source for spokes the last few years has been Dan's Comp. The exact number and length spokes you want and they are both quick and cheap. You have to call on the phone and talk to their spoke guy personally to place an order.

Jon T 04-11-19 12:57 PM

Hey Grouch,
Got contact info?
Thanks
Jon

Retro Grouch 04-11-19 01:19 PM


Originally Posted by Jon T (Post 20880308)
Hey Grouch,
Got contact info?
Thanks
Jon

Not really. You can Google Dan's Comp as easily as I can.


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