are single-walled rims obsolete?
02-02-17, 02:38 PM
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are single-walled rims obsolete?
I recently wrote a post about a wheel in the mechanics category that had a second part that wasn't addressed so I thought I would post the inquiry here. The wheel of attention without a tire or skewer weighs in at 1188g while any other rear wheel I weigh hovers around 1400g average. I figured this is mainly due to a single-walled rim having less material and therefore being lighter. So I asked at a LBS if racers still use single-walled in favor of double-walled rims for this reason and they seemed to think double-walled rims are always favored. Is strength more important than weight in the case of wheels for racing?
02-02-17, 02:53 PM
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yes
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02-02-17, 03:23 PM
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02-02-17, 03:27 PM
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The hidden spoke nipples are a big advantage of double-walled rims. In single-walled rims the nipple head is exposed. If the spokes are even a little too long this is a problem that even rim tape won't fix. With hidden nipples the spoke can stand a little proud, and there will be no problem.
Last edited by rpenmanparker; 02-02-17 at 08:26 PM.
02-02-17, 05:04 PM
#8
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1188g versus 1400g?
When you consider that a typical double walled rim weighs around 450-500g that would mean you had some 212-262g rims (all else being equal)?
I can't see anything on weight weenies anywhere near that (at least in a clincher and alloy, but with tubular and carbon fibre you can get the x-treme nano elite at 225g but tubulars are never single walled are they?)
What make and model of rims do you have?
When you consider that a typical double walled rim weighs around 450-500g that would mean you had some 212-262g rims (all else being equal)?
I can't see anything on weight weenies anywhere near that (at least in a clincher and alloy, but with tubular and carbon fibre you can get the x-treme nano elite at 225g but tubulars are never single walled are they?)
What make and model of rims do you have?
02-02-17, 08:28 PM
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1188g versus 1400g?
When you consider that a typical double walled rim weighs around 450-500g that would mean you had some 212-262g rims (all else being equal)?
I can't see anything on weight weenies anywhere near that (at least in a clincher and alloy, but with tubular and carbon fibre you can get the x-treme nano elite at 225g but tubulars are never single walled are they?)
What make and model of rims do you have?
When you consider that a typical double walled rim weighs around 450-500g that would mean you had some 212-262g rims (all else being equal)?
I can't see anything on weight weenies anywhere near that (at least in a clincher and alloy, but with tubular and carbon fibre you can get the x-treme nano elite at 225g but tubulars are never single walled are they?)
What make and model of rims do you have?
02-02-17, 09:48 PM
#11
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1188g for a rear wheel is nowhere near lightweight. There are aluminum rimmed clincher wheelSETS available at that weight. Tubular wheelsets with carbon rims can go far lower.
02-03-17, 12:43 PM
#12
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I recently wrote a post about a wheel in the mechanics category that had a second part that wasn't addressed so I thought I would post the inquiry here. The wheel of attention without a tire or skewer weighs in at 1188g while any other rear wheel I weigh hovers around 1400g average. I figured this is mainly due to a single-walled rim having less material and therefore being lighter. So I asked at a LBS if racers still use single-walled in favor of double-walled rims for this reason and they seemed to think double-walled rims are always favored. Is strength more important than weight in the case of wheels for racing?
Are there any high-end single wall rims? No. I have some single-wall Bontrager BCX rims on an old mountain bike that are very light, and have gone through hell and back, but out of hundreds of wheels I've worked on in the last 30 years, these are the exception. All high-end rims are double wall.
At the highest level, as in elite, pro-level riding, tubulars completely dominate. So on a grand-tour stage race, or during the spring classics, every rider will be on tubulars, all of the time.
Since tubular rims are necessarily 'double wall', then it is true that 'racers use double wall rims'.
About the very lightest you can build a alu-rim clincher wheelset is 1,300 grams. I own a set of these, and they are sketchy light, and require frequent truing. Plus they are not the most confidence-inspiring during high-speed cornering. With carbon clincher rims, maybe you could drop another 100 grams.
With tubulars, you save about 100 grams per wheel over clinchers, simply due to the inherently superior rim profile. You can produce a fairly robust carbon rim tubular wheelset weighing less than 1,000 grams.
Last edited by Dave Mayer; 02-03-17 at 12:45 PM. Reason: Speling
02-03-17, 12:47 PM
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02-03-17, 01:30 PM
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1188 grams for the front wheel? Wow. I thought my Campagnolo Shamal wheels at 2,000g for the pair were porky. That's why I eventually sold them.
Are there any high-end single wall rims? No. I have some single-wall Bontrager BCX rims on an old mountain bike that are very light, and have gone through hell and back, but out of hundreds of wheels I've worked on in the last 30 years, these are the exception. All high-end rims are double wall.
At the highest level, as in elite, pro-level riding, tubulars completely dominate. So on a grand-tour stage race, or during the spring classics, every rider will be on tubulars, all of the time.
Since tubular rims are necessarily 'double wall', then it is true that 'racers use double wall rims'.
About the very lightest you can build a alu-rim clincher wheelset is 1,300 grams. I own a set of these, and they are sketchy light, and require frequent truing. Plus they are not the most confidence-inspiring during high-speed cornering. With carbon clincher rims, maybe you could drop another 100 grams.
With tubulars, you save about 100 grams per wheel over clinchers, simply due to the inherently superior rim profile. You can produce a fairly robust carbon rim tubular wheelset weighing less than 1,000 grams.
Are there any high-end single wall rims? No. I have some single-wall Bontrager BCX rims on an old mountain bike that are very light, and have gone through hell and back, but out of hundreds of wheels I've worked on in the last 30 years, these are the exception. All high-end rims are double wall.
At the highest level, as in elite, pro-level riding, tubulars completely dominate. So on a grand-tour stage race, or during the spring classics, every rider will be on tubulars, all of the time.
Since tubular rims are necessarily 'double wall', then it is true that 'racers use double wall rims'.
About the very lightest you can build a alu-rim clincher wheelset is 1,300 grams. I own a set of these, and they are sketchy light, and require frequent truing. Plus they are not the most confidence-inspiring during high-speed cornering. With carbon clincher rims, maybe you could drop another 100 grams.
With tubulars, you save about 100 grams per wheel over clinchers, simply due to the inherently superior rim profile. You can produce a fairly robust carbon rim tubular wheelset weighing less than 1,000 grams.
02-03-17, 02:22 PM
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That is the problem: all of the weight gains on the rims are more than negated because of the disks.
02-03-17, 02:28 PM
#16
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I admit it in advance. I am just being an asshat, but theoretically speaking why couldn't a tubular rim be just a single strip of aluminum of some thickness as required to provide the necessary resistance to flex and twist. As in single wall clinchers the spoke nipples would be exposed, but there could be a channel down the center for them to sit in. There should still be plenty of surface area to provide good adhesion to the tire. And the cloth tape on the backside of the tubular should protect the tire from being punctured by it. Like I said, I'm just fooling around here, but I think it ought to be feasible. Unfortunately the stiffness would then not have the benefit of the geometric constraints of the box design, so the strip of metal would need to be thicker and heavier than desirable. Kind of like trying to replace an I-beam with a solid square girder. You can do it, but it is heavy and wasteful.
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
02-03-17, 03:42 PM
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Hadn't thought of this - it is actually a brilliant concept. Not with alu, but with a single strip of curved carbon, with a shallow spoke channel in the middle. The result may actually be lighter than the conventional tubular rim profile. Of course, there would be no place for a brake track; this implies the use of disks.
That is the problem: all of the weight gains on the rims are more than negated because of the disks.
That is the problem: all of the weight gains on the rims are more than negated because of the disks.
Remember the rim is in compression because of spoke tension. Single strips of aluminum for a rim will just collapse. And if you thicken it so it doesn't collapse, you can get the same strength for less weight by hollowing out the middle... and then you are back to double walled rims.
02-03-17, 05:44 PM
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I guess that answers the OP's question though. Everyone uses double walled alloy (or carbon) because they prefer rear wheels that weigh 800g.
02-03-17, 07:23 PM
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Walk into any bike shop, I'm reasonably certain that the rear wheel on EVERY road bike in the store will be <1200g. That's pretty much the definition of obsolete...
02-03-17, 10:03 PM
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so, I forgot tubulars are for racing .. which are probably the original double-walled rims -- I was just trying to figure out how to get the weight down because the wheel I built and rode a lot weighs 1445g and is composed of a Sun CR-18 700c rim, Shimano 105 hub, 32 14/15/14 DT spokes, and a SRAM PG-850 cassette. Then I found this other bike that was high-end for the 80s/90s era and had the said 1188g wheel, making the former wheel foreboding to ride, while I know the rotational weight does most of the damage with accelerating. The later wheel is built with a single-walled nashbar 27" aluminum rim, shimano 600 hub, 36 straight-guage (14) spokes, and a 7-speed cassette. I am wondering where more than half a pound was dropped in this wheel and how I can improve the weight of future builds.
02-03-17, 10:52 PM
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Never heard of single or double wall.
What is a double wall rim?
I doubt it matters. The best sets I have have hidden / internal nipples. They are also the lightest, and tubulars. Weight front and rear in 20h/24h 50mm profile / 25mm wide 1120g/set bare.
What is a double wall rim?
I doubt it matters. The best sets I have have hidden / internal nipples. They are also the lightest, and tubulars. Weight front and rear in 20h/24h 50mm profile / 25mm wide 1120g/set bare.
02-04-17, 12:37 AM
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Are you including the cassette?.
Last edited by GeneO; 02-04-17 at 12:41 AM.
02-04-17, 03:25 AM
#23
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so, I forgot tubulars are for racing .. which are probably the original double-walled rims -- I was just trying to figure out how to get the weight down because the wheel I built and rode a lot weighs 1445g and is composed of a Sun CR-18 700c rim, Shimano 105 hub, 32 14/15/14 DT spokes, and a SRAM PG-850 cassette. Then I found this other bike that was high-end for the 80s/90s era and had the said 1188g wheel, making the former wheel foreboding to ride, while I know the rotational weight does most of the damage with accelerating. The later wheel is built with a single-walled nashbar 27" aluminum rim, shimano 600 hub, 36 straight-guage (14) spokes, and a 7-speed cassette. I am wondering where more than half a pound was dropped in this wheel and how I can improve the weight of future builds.
DT competition spokes x 32 = 191g
Nipples x 32 = 32g
Shimano 105SC hub (the old 8 speed) = 421g
SRAM PG-850 cassette = 295g
Total = 1399g
Usually the cassette is not included in the total wheel weight so if we subtract your cassette that would be 1104g for the rear wheel.
Modern 105 hubs weigh 353g. While a Dura ace rear hub is 247g and a DT Swiss 350 rear hub comes in at 265g.
I can't tell you what the other parts in your other wheel weigh but if the rim is a bit lighter, and the hub is a bit lighter and the cassette is a bit lighter and the spokes are a bit lighter then that could easily add up to 212g.
It's not necessarily going to be one single component and as has been pointed out, single-walled rims are pretty much non-existent in road cycling nowadays.
02-05-17, 06:55 PM
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It's not a single/double wall issue, lots of variation even among modern double wall rims
eg
double wall Mavic tubular ~300g, the ones Merckx used were probably lighter, maybe 250g. Very thin rims by modern standards, ERD 613
They (pro racers) used thin and narrow (ie soft and flexible) rims for light weight and plenty of spokes to make up the rigidity.
There is something to be said for this, I would much rather have a 300g rim and 50g more worth of spokes than a 450g rim....
A modern classic, the Stan's alpha 340/400 clincher
the 340 (~380g) is double wall, the 400 (~415g) triple wall. ERD: 592mm
I have a set with 340 rims at ~1340g for both wheels, and with the 400 rims ~ 1390g. Even the stan's 340 with 28/32 spokes is about 1450g total. Highly recommended!
eg
double wall Mavic tubular ~300g, the ones Merckx used were probably lighter, maybe 250g. Very thin rims by modern standards, ERD 613
They (pro racers) used thin and narrow (ie soft and flexible) rims for light weight and plenty of spokes to make up the rigidity.
There is something to be said for this, I would much rather have a 300g rim and 50g more worth of spokes than a 450g rim....
A modern classic, the Stan's alpha 340/400 clincher
the 340 (~380g) is double wall, the 400 (~415g) triple wall. ERD: 592mm
I have a set with 340 rims at ~1340g for both wheels, and with the 400 rims ~ 1390g. Even the stan's 340 with 28/32 spokes is about 1450g total. Highly recommended!