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I really should lose some weight, but I like carbs too much, so I put the bike on a zero carb(on fiber) diet instead.
Total weight 6.800kg as pictured (including handlebar and seatpost mounted ballast)
The build goals, in addition to being a non-carbon-fiber (completely non-carbon-fiber) sub-UCI limit bike, were to use normal bottom tier consumables, not super exotic stuff, and include things like pedals, a pair of cages, computer, power meter, quick releases, etc. I also tried to keep most weenie parts from not exceeding $1/g versus the next available option.
It is currently a fully-rideable bike, and has no carbon fiber, but not final. Some parts still need changing.
There's a lot of places I could have easily cut weight or cheated to fudge the numbers, but I didn't.
2x bottle cages (~-50g)
Chain catcher (~-6g)
Padded saddle (~-30g)
Stainless inner cables (~-20g?)
Power meter (~-60g?)
Double crank (~-175g?)
Quick releases (~-10g)
Non-carbon fork (~-275g)
Clinchers and butyl tubes (?)
The Rival 22 short cage RD comes in at only 179g. That's only 1g heavier than the Force 22 with a carbon cage.
It's also about half way between Dura-Ace and Ultegra weight, despite being third-tier.
You might be wondering, how is this possible?
First, lets start off with what makes a SRAM rear derailleur different from the rest. Yes, it has 1:1 actuation and that funny looking cam, but there are significant differences in the way a SRAM RD is constructed.
Several bicycle mechanic authorities claim that Shimano invented the modern derailer, which all modern derailers are patterned off of. This isn't true. A SRAM RD actually has more in common with a Suntour derailer than a Shimano one, because it uses a single sprung pivot design. Modern Shimano, Campy and Microshift road rears have a sprung b-knuckle (copied from Simplex), where the RD attaches to the hanger which helps a derailer adapt to a wide range of cog sizes. A single sprung design on the other hand does not have a spring there, it is essentially rigid in operation, and moves out of the way when removing the wheel. The path of the jockey wheel is rigidly defined by the parallelogram geometry. It's also popular in MTB because it helps reduce chain bounce, since the pulley cage isn't floating. That's another reason SRAM shares another design feature with some Suntour designs, it features an upper jockey that is concentric with the lower pivot, because otherwise front shifting would change the location of the pulley (and this is why 1x has lots off off-set instead of a slant parallelogram).
Basically, it's simpler, and lighter, because they didn't copy Shimano (they copied Suntour)
SRAM also uses some interesting choices of materials on the Rival RD. It has an alloy inner plate, like what is traditionally found on Ultegra derailers. It also has an alloy fixing bolt, which saves a significant amount of weight over a steel one, although after market ones have had a reputation for cracking and the bolt is softer and easier to strip. This is why Shimano uses steel fixing bolts, or the funny looking 2-material bolt on Dura-Ace. SRAM also uses a plastic bottom knuckle for the Rival, that's right, plastic. Shimano used to do the Same on older Sora and Acera, and still makes Tourney with plastic knuckles. However, it's something Shimano has phased out of Sora, while Shimano copied the Simplex dual sprung pivots, they didn't share Simplex's affinity for plastic derailers. Plastic is cheap, but it's also light. For things that won't require lots of strength, but need to take a certain shape, plastic is about as light as carbon fiber. SRAM also uses aluminum for the cages, because the truth is, aluminum really doesn't cost much more than steel. It's not all weight-saving corner-cutting for SRAM though. SRAM put ball bearings in their jockeys (13g ea), which makes them higher quality than bushings, but with a thick grease and an undemanding job, they don't necessarily spin better. It does add weight and cost though.
Shimano trickles down technology, but not weight, weight is a key defining factor for product differentiation as well as perceived quality of construction. SRAM is willing to keep the weight weenism going in the lower tiers, and will use use whatever mix of cheap and expensive processes based on how much it can help reduce weight.
And the last bit, why is the Rival 22 RD only 1g heavier than the Force 22 RD, even though the Force 22 RD has a carbon cage? That requires a look at Force 10. It's basically the exact same thing as the Force 22. Same weight, same construction, same design, different color. Moving over to the Rival side, Rival 10 was 188g, 10g heavier than Force because of the metal cage. However, unlike Force, Rival 22 was redesigned, with a new front plate, and possibly other changes, reducing weight by 9g. It's very likely a Rival 22 RD with a Force cage would be ~10g lighter than a Force 22. However, because Rival 22 is only 1g heavier, they had to cripple it, by intentionally painting it with ugly glitter silver paint (like older Sora) even though the shifters use white paint.
So, Rival 22 RD is quite competitive with Force 22 because it got a revamp coming from 10 speeds, unlike Force.
The yaw FD is a nice piece of kit, it yaws and stuff, you can read about it in the marketing material. It can be finicky to set up.
Anyways, it's 76g without the bolt (79g with bolt, SRAM catcher is 10g without mounting bolt, not used here)
It's also exactly the same as the Force 22 unit. They are identical, except for the paint and labeling. Rival is black. Force has flashy graphics and $15 more expensive. Mechanically, they are the same, weight-wise they are identical. Both are 79g +10g for the catcher. I couldn't tell you the actual weight of the RED unit. It's not clear to me if they changed RED production at some point in time. Early versions have actual weights of 77-78g, within a couple grams of Rival. SRAM used to list RED as 74g without chain catcher, although now they say it is 69g. So a Rival FD is only 1-10g heavier than a RED and identical to Force.
So for the RD and FD, despite being "third-tier" there's basically no weight penalty (0.2g listed) compared to Force.
The shifters are a whopping 5g over list (+1.5%) at 337g instead of 332g. That being said, they're still very light. There's only about a 25g penalty compared to Force (carbon levers), and substantially lighter than Dura-Ace, and still lighter than Super Record. SRAM makes the lightest shifters. I'm not the biggest fan of double-tap, but it is clever. It saves weight.
I suspect that Ultra-Shift actually weighs more than Power-Shift, as the escapement mechanism in Power-Shift is simpler. Power shift, in addition to having a separate thumb lever, needs separate engagement mechanisms for both shift levers so they don't interfere with each other (push one lever in, then other other so they're engaged at the same time, and you can see what I mean), and SRAM doesn't have the thumb button, and it doesn't need an engagement mechanism, because there's no thumb button trying to turn the pulley the other direction. I suspect a ratchet and escapement mechanism is also lighter than the sprung detent system used by Power-Shift. Athena Power-Shift of course is crippled by needing to be heavier and inferior. If Campy can't have any real product differentiation between SR, Record and Chorus, they can at least do so for Athena and Centaur.
Shimano only has 2 levers, just like SRAM, a brake lever and a shift lever. But Shimano needs a heavy duty gimbal that can withstand braking forces, and with the advent of hidden shift cables, it also needs a gimbal mechanism that keeps the brake and shift inputs separate and transfers them to the shifter body. It also needs to transfer the input from the dedicated shift lever. Shimano's control system really wasn't designed to house the shift internals in the shifter body, but on the lever itself. The mechanism to get all the lever inputs into the body of the shifter is not uncomplicated. SRAM's gimbal is simple, it only needs to take low forces (and some of them still snapped) and it only has to keep and pass on a single input to the shift internals. Again, it also doesn't need a second lever for the escapement.
So if you were wondering why SRAM levers are so light, that's why.
179g + 79g + 337g = 595g for the shifting bits, and these are the only parts that strictly have to play nice with each other. That's only 5g more than the equivalent Dura-Ace parts, and 2g heavier than the equivalent Record parts.
So despite no carbon bits in Rival, at least for these 3 parts, it's still extremely competitive with other top shelf shifting parts.
It doesn't make any sense for me to buy a Force chain over a Rival chain. The weight savings is an entire 3g on a consumable. I wouldn't pay the price differential even if a chain wasn't a consumable. PC-1130 is 259g, PC-1170 is 256g. SRAM RED or a KMC SL would be a bit light, but I'm not inclined to spend extra money on consumables for very marginal gains in excess of $1/g. If I remember correctly I removed 8 links, which is 18g worth of chain. So 241g for the chain.
The current cassette is a Shimano 105 CS-5800 12-25 which lists at 269g, minus, I'm guessing, 7g or so because of an Ultegra lockring. So 262g. Generally most of the weight savings between second and third tier cassettes the lockring, and sometimes the spacers, which can be recycled from an old cassette. The loose cogs are identical. The spider may have some very small differences, but not enough to justify buying a 2nd tier cassette twice to me. Shimano is a bit better than SRAM in this regard because they have 2 spidered clusters for Ultegra.
The plan is to replace it with a take-off SRAM PG-1130 11-28 (because I don't like Shimano 11-28) eventually, because a light bike should have climbing gears. That will be a ~2g weight penalty. But for the time being CS-5800 12-25.
That's it for the SRAM bits.
2lo8 wrote:Force has flashy graphics and $15 more expensive. Mechanically, they are the same...
I've read the the Force FD has a stiffer cage, but have never been able to confirm it. Do you think that Rival has the same stiffness as Force?
Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)
The weights are the same. They look (minus the graphics) the same. I'm about 99% sure, like Campy, they re-use lots of common sub-parts between different groupsets. They aren't like Shimano with the volume to make a separate production line and tooling for every tier. I seriously doubt SRAM would even bother to make new tooling when they otherwise look identical. If they chose to use thinner(flexible) steel (Young's modulus says steel is as stiff as steel), Rival would be lighter, but it isn't.
There might be slightly worse tolerances on Rival. But I doubt it. SRAM appears to have a history of releasing the same parts with different looks, and using the same sub-parts in different assemblies, only changing the graphics and a few other bits. Maybe they don't ream the holes and just drill them or something. But I doubt it, because that would complicate production. I'm pretty sure they're assembled the same way, on the same assembly line, the parts just get different graphics at the branding stage. The plating is a bit different. Maybe Rival's plating is a little less durable, or maybe the bright chrome finish just shows scuffing on the inner cage more than matte blasted. But all the metal bits look to be shaped the same. That's just how economies of scale work if you aren't Shimano. I'm pretty sure they're identical. But when you're working a bike shop, you have to explain why something costs more, and you jump to tried and true platitudes.
As far as I can tell, Rival is a non-carbon Force, with an updated RD design. And with SRAM's trickle-up model, the next generation of Force is probably going to look at lot like Rival 22 but with the carbon cage.
Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)
istigatrice wrote:had a quick glimpse at the website, sram claim the material for Force is ' Steel outer cage, Steel inner cage, Composite tail' while Rival is claimed to be 'Steel cage , Aluminium links' I don't know if that means anything to you though...
Force 22 was released the same year as Red 22, because SRAM wanted to get Force 22 out the same year as Ultegra 6800. Steel outer, steel inner is more compare-and-contrast to RED, which uses an aluminum outer cage and a tool-steel inner cage. Technically a tool-steel (a steel designed for cutting tools) should be harder and more wear resistant to abrasion (great for cogs) but how many times have you actually worn through a FD cage, or even through the plating? Short of constantly riding with chain rub, the only time I've seen deep scratches or wearing into the steel have been on really cheap no-name FDs.
Composite is a fancy name for plastic, it means the little plastic bit that helps reduce the clang of chain noise.
Rival was released later, so the description isn't really consistent with RED/Force. Aluminum links just means the parallelogram links are aluminum, which is also the case for RED and Force. Steel-inner and steel-outer is kind of redundant, and it still has the little plastic piece even if it isn't mentioned.
This isn't really a fair comparison, because it is SRAM with an 11t lockring vs Shimano with a 12t lockring.
That makes a difference of 14g. I don't have a PG-1130 on me to compare, but list weight for a 11-28 PG-1130 is 271g, for PG-1170, it's 257g, a difference of... 14g. To be fair, the SRAM 11t lockring and spacers might be a couple grams lighter. But pretty much all the weight difference is in the spacers and lockring. There's almost no difference in the cogs. Meaning if you already have a PG-1170, save the aluminum bits and buy a PG-1130.
It's hard to tell for Shimano, partially because I can't find consistent numbers and don't have an assortment of cassettes to weigh. The weight difference seems to be from 15-25g depending on size. But most of the weight loss is still probably spacers and lockring. That's because Ultegra uses 3 + 2 spidered cogs, versus 3 for 105, Rival and Force. So converting cogs 7 and 8 to spidered versions saves more weight the bigger they are. More importantly it helps reduce freehub notching because those tend to get notched the worse since larger cog means more torque. Ultegra also has more gearing options. So Ultegra isn't that bad.
PG-1130 is on the wishlist so I can say the bike is equipped with base level consumables (even if I use the alloy bits, not actually consumables)
Obviously these come in way below the weight of the big brands, and are pretty much the lightest dual-pivot alloy brakes out there.
The brakes have a number of quirks. The first you might notice is the symmetrical dual-pivot design like current Shimanos, which came out after the KCNC brake. What you might not realize is the design is far older, and dates back to the 60's with the introduction of Altenburger Synchrons. I have a one of these in my parts bin somewhere. Lots of people like to credit Shimano with the invention of the dual-pivot brake, because Campy was still using single-pivots when shimano was using dual-pivots (and Campy still makes single-pivot brakes to this day). As advertised by GB who made Synchrons under license, "A side-pull fitting brake with centre-pull brake action." A very accurate description. They look pretty much like old center-pull Weinmann brakes that were ubiquitous on bike-boom bikes, except modified for side-pull actuation. These were the original dual-pivot side-pulls.
Unfortunately, they were poorly constructed brakes, found only on the trashiest bikes, and people got sick of poorly set-up center-pulls with flexy cable hangers. Campy didn't invent the single-pivot side-pull, but they certainly made them lightweight and raceworthy, and soon trends dictated side-pull brakes on racing bikes. Shimano later introduced a hybrid one-and-a-half-pivot side-pull, which is commonly known today as a dual-pivot side-pull, where the left side is a side-pull and the right side is off-set like a center-pull or a Synchron, and it uses a cam to synchronize the arms like a center-pull (Mafac not included) or a Synchron. It provided the self-centering (or rather non-floating) action of a center-pull or a dual-pivot, with the simple compatibility of a side-pull and compromised on weight. This allowed the pads to get closer to the rim for stronger leverage. Note that a single-pivot brake tracks an out of true wheel better and generally provides more tire clearance (to compensate for the lack of a rigid linkage defined action), and dual pivot brakes could only really take off when wheels were reliable enough to stay true.
The CB1 has some other quirks, it is known to be flexy, have low power and friction from the arms rubbing together when they flex. They also feature a barrel adjuster that doesn't fit high quality brass ferrules. To make up for these shortcomings I used Kool-Stop salmon pads and Odyssey Linear Slic[sic] outers.
Kool-stop salmon pads also trace back their history to the bike-boom era. The compound was created by Mathauser. The secret ingredient was rust (the normal industrial purpose is jewelers' rouge, a metal polish). Back then, bikes were made from steel, and they used the rusty remains of bikes killed by water and rust, and imbued their vengeful spirits in brake pads to offer superior braking in the wet. Or something. They have a reputation for being grippy. They're also ugly and red, so they got the sharpie treatment. Technically, I should have used Dura 2's, which are a bit lighter* due to cut-outs and also wider, which would have helped compensate for a narrow rim, and thinner for thin brake tracks. All of these things would have helped. But I had plain Dura's on hand, so for the time being, that's what it gets. The spare sets of black Dura and Dura 2 I have are both 20g for 4, although there is some variation between individual pads.
For the cables, I used Odyssey Linear Slic. They are advertised to "to prevent the cable from binding when the cable is twisted around during barspin or tailwhip tricks" when doing mad BMX tricks. That's cool, but trying to do that on a road bike means a dented top tube. While BMX might have their own purposes for compressionless brake housing, it also have benefits in improving brake performance. It's commonly specified and recommended for mechanical disc brakes for this reason. Compressionless housing does not improve power, although it might feel like it. A pound of pull on the cable is a pound of pull on the brakes. What it does is it reduces the lever throw to apply the same force (without changing the leverage ratio, nothing is flexing when the pads aren't on the rim) by making the system less spongy and springy, and more rigid, giving a snappier feel, more pad clearance, and prevents the brakes from bottoming out as easily. In other words it helps compensate for the flex found in the calipers by making the cables more rigid.
The braking isn't too bad since they're used on alloy rims, but the action of rough with lots of friction. I'll try lubricating the cables later, although I speculate it may have to do with having to use cheap stamped steel brake ferrules, so I'll see if I can turn down some metal ferrules to fit.
KCNC C7s have a small weight penalty, but supposedly work a lot better because of revised geometry, a roller cam, the cable clamp being supported on both sides by a forked lever arm. So C7s with Dura 2's are on the wishlist if I can get a good deal on some (and completely ignoring the high performance eebrakes, because there is a 0% chance of getting a deal on those)
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From my notes, weights are:
Rotor 3D+ Inpower
Crank arms: 530g
BB: 96g (list)
Chainring bolts: 9g
Current chainrings: 140g
AA Battery: 15g (WW note: You can save 10g vs a 25g alkaline with a longer lasting lithium battery)
A Shimano 105 FC-5750 would have actually been just as light with a BB-9000, and presents more turning opportunities (-15g for alloy CR bolts, -2g for pinch bolts, lighter rings) and kept consumables standard, but obviously would have lacked power, which is where all the weight savings go.
Some quick notes, because they don't fit in anywhere else:
Inpower is nice because it takes a standard battery and user changeable. But if you have a high-capacity NiMH AA in your Inpower, you should take it out, although rechargeable, they're heavy and lower capacity. If you have to change one away from home, you have to carry your battery around with you and end up with a cheap disposable anyways. The power consumption is so low you might as well use a long lasting high quality lithium battery at half the weight.
If you have SRAM crank arms, for some reason SRAM feels inclined to include green(!) loctite on their chainring bolts, presumably to prevent squeaking and torquing problems some people with alloy chainring bolts. Also SRAM chainring bolts at all levels are aluminum, so don't count on losing any weight there. If you need to remove them, consider heating them, or using a soldering iron to apply heat directly to the chainring bolts. That or just go for it, green is stronger than blue, but it is not red.
If you wonder why Shimano sticks with 24mm steel, it's because BB30 isn't really much lighter once you factor in the larger bearings. BB-9000 BSA is considerably lighter than the BSA30 BB, and PF86 BBs are lighter than PF30s. However, SRAM GXP needs a SRAM NDS cup, not just because of the 22mm ID bearing, but because the bearing is held in with a c-clip to prevent the bearing from coming out. The DS can be matched with a BB-9000 cup if you so desire. The people hurting are people who have BB30 frames, with BB30 bearings, and have to run additional BB30 to 24mm spacers. There's nothing inherently wrong with 24mm. It's just heavier when you use parts designed for BB30 adapted to 24mm. Steel is also inherently stiffer than aluminum, the larger diameter of the aluminum spindle just helps compensate for aluminum's inherent flexibility.
Rival OCT is a much lighter crankset than the YAW crankset. Yes, technically there are compatibility issues, but the move to separate arms and spiders, as well as the heavier chainrings. From my notes, a Rival OCT weighs as much as a Force 22 Yaw. Apex is lighter than Rival 22. Also note that chainrings getting closer to each other with increasing numbers of speeds is not true, and have not been true for some time. This was true when they moved to 9 speed and then 10 speed, but then there were issues with interference during cross chaining, and the teeth were moves out, but the ramps on the chainrings moved in so the ramps bridge a bigger distance. YAW actually has the rings spread farther than before.
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