Originally Posted by
cyccommute
“Stronger rims” are a misnomer. “Stronger” usually just means wider. The extra width means that they are heavier but the weight increase is what would be expected with the increased volume of metal used in association with the increased width. They don’t have thicker walls or more metal in places that would really increase strength. Even if they had thicker walls, aluminum is a soft material that would return only marginal increases in strength.
Nor have I found that wider rims allow for any higher tension than narrower rims. Because the amount of metal at the spoke bed hasn’t increased, the spoke tension is about the same. For some rims that are much wider (aka “stronger”), the amount of tension would probably have to be less since the top of the rim is a flat plate which isn’t as strong as something that is more like a tube.
Comparing single walled aluminium rim, to a double walled one. The double walled ones allow a lot higher spoke tension before they get out of true when stress relieving the spokes.
Similarly, not all the double walled rims can take the same amount of total spoke tension. Some are just, well, stronger.
One of the locally very popular rims is outragously heavy, with about 2.5 deep aluminium section (box?), and very thick walls, including the place where the spokes go.
These, rather cheap (under 10$) rims can take a lot of beating and wheels built can allow even for the cheap, low quality spokes to survive a lot longer.
That's what I've observed - and, while I'm not 100% sure why exactly this helps, it does seem to help, noticeably.
Originally Posted by
cyccommute
And, again, there is the way in which the spokes at attached to the rim. In cornering, the rim can shift on the spoke nipples. Think of how the rim slides around on the spokes when you build a wheel and it hasn’t been tensioned yet. Once tensioned, the rim is only held in place by the tension of the spokes. Decrease the tension and the rim slides on the spokes. That occurs every moment the wheel is turning and even when the wheel is stopping. Tension decreases in one part of the wheel and increases in the others. That’s because the rim isn’t attached to the spokes. It just holds the spokes. A “stronger” rim doesn’t change that dynamic.
You mean that, at the ground contact point, a more flexible rim will not flex more?
And thus let the spokes at the bottom loose more tension - compared to a thicker (stronger?) rim?
Haven't done any measurement and comparing (it would take making two wheels with very similar spoke tension, and the same tyres at the same pressure, I suppose, to measure and compare).
Could be wrong, but I would expect the weaker/more flexible rim to bend more and have fewer number of spokes loose more tension, while a more rigid rim might be able to spread that load over more spokes (perhaps/probably not by the same amount, but still have a bit more spread).
Am I missing something there?
I would also say, not sure if you'd agree, that most stress and fatigue (resulting in spoke elbows breaking) comes from a wheel just turning, under the rider's weight. Those loads get taken by bottom spokes loosing tension (and, adjacent spokes, at both sides, gaining just very little extra tension).
Originally Posted by
cyccommute
In my experienced, I haven’t had any issues with using light...and supposedly “weak”...rims. I don’t find myself replacing wheels all that often. I don’t break spokes even with supposedly “weaker” rims. My first wheel to use the Alpine III’s lasted me 10 years with Mavic XC717 rims. The only reason that the wheel didn’t last longer is because I loaned the bike to a student intern who somehow sucked the derailer into the wheel and tore out spokes. He replaced the wheel without telling me about it until he returned it. If he had told me about it, I could have replaced the spokes and would probably still be riding it.
I use strong spokes because I recognized long ago that spokes do all of the work of strength in bicycle wheels. The rims are just along for the ride.
Even straight spokes of good quality are very, very durable. Using swaged spokes, especially the ones with more beefy elbows (triple butted, like Alpine III), might take the rim out of the equasion.
When using cheap spokes, for heavy riders, on rough terrain - I have noticed the "stronger" rims making a difference.
Can't put my finger on the exact reason why. Maybe it's just because spokes can be run at a higher tension (so the rear, left hand side ones are less likely to become loose). Maybe the load distribution does come in play and make some contribution as well (as I have explained my line of thinking above). Not sure.
Originally Posted by
cyccommute
Pillar is a Taiwanese company (I think) and it doesn’t have a huge footprint in after market spokes. The only place I’ve been able to find them is through
BDop Cycling which is another Taiwanese company. The Pillar spokes from them are relatively inexpensive when compared to DT Alpine III, at least here in the US. They cost $0.89 each instead of $1.50 each.
Rose Bikes sells Alpines for $0.60 each but shipping costs for me can drive that price up to close to $1.50 each. I have ordered silver ones from Rose because silver Alpine III are hard to find in the US.
Wheelsmith is an American manufacturer and don’t have as large a foot print as DT. They’ve been around since the mid80s. Ric Hjertberg started the company but he has moved on. Pillar spokes have a “P” on the head. Wheelsmith has a “W”.
I’ve never seen nor used Sapim. I’m aware of them but they just aren’t that prevalent in the US.
Sapim is rising in popularity (and availability) where I live (not sure about the rest of Europe).
Gave them a try - quite good. I would say they compare to DT Swiss in terms of quality - both spokes, and nipples.
However, just like Wheelsmith, they have missed the mark with their 2.3 elbow wide spokes - not making a thinner mid section. That at least is my opinion. I'd always choose DT Swiss Alpine III, over those other two options. Even at a bit higher price. I'd even choose double butted spokes over those (not over the Alpine IIIs).
Originally Posted by
cyccommute
That’s something I’ve noticed about them too. I see that as an advantage even if strength isn’t considered. The holes of the hub have to be drilled large so that the threads of the spoke can pass through. For regular 2.0mm spokes, the spoke hole has a lot of extra space for the spoke to move around in. Since the spoke is tensioned and detensioned all the time, the spoke can move in that hole which puts extra flex...and thus fatigue...on the head. The 2.3 mm spoke just fits tighter so there is less stress on the head. Fasteners work better if they aren’t put in a hole that is 25% larger than the fastener.
Agreed. Those wider holes make lacing a bit faster and easier, but that benefit is not worth the cost, in my opinion. 2.3, perhaps even 2.2 mm wide holes would allow for the threads of 2 mm wide spokes to pass.
Originally Posted by
cyccommute
I didn’t phrase what I was trying to say so you misunderstood. Sorry. I agree that double butted spokes are stronger than straight gauge. But if someone has a problem with broken spokes, in all likelihood, they are going to break double butted spokes as well. They may not break them with the same frequency as straight spokes but they will probably still have problems with double butted. They could try the double butted but it would probably be best to skip the mid level solution. It’s cheaper to build a wheel once than twice.
I see. Agreed. Tripple butted as an extra "safety margin", just to be on the safe side?
If the price difference isn't huge, or if availability isn't a problem - it's perfectly logical, makes no sense doing otherwsie IMO.
P.S.
In my practice - if even straight spokes of decent quality can be sourced, and people can afford, that's an exception, unfortunately.
Double butted - hardly ever available, and the extra cost (1 euro per spoke for DT Swiss Competition, compared to 0.5 euro per spoke for Sapim Leader, locally) makes them often beyond the budget.
Tripple butted - those are like the unicorns.
Only available abroad. And very expensive - with nonsense shipping costs and import taxes that make the price effectivelly doubled. So it's practically impossible to use them, or recommend them locally.
Wrote to both Sapim and DT Swiss about the availability problem, just for laughs. DT Swiss even replied, suggesting I try buying from the Check Republic. Not sure if they knew how ridiculous that sounds from my perspective (oh, so you're thirsty in Sahara, well hop to the Alps, plenty of water there) .