Specialized Tarmac SL6 S-Works Ultralight Rim 49cm - 5.86kg with pedals

[OtterSpace]

This is such a solid lightweight build with no compromises.

Thanks. It has been fun to see how far I can push a rim build.

It likely will remain my main non ebike until the current crop of more polished disc frames pop up used at what I'd consider acceptable depreciated prices ($2k for S-Works level frameset). I likely will have to wait years and years for those prices to happen but I already have all my use cases fairly well covered with my fleet.

I think bikes like SL8 have now almost totally surpassed the performance of a high end rim build for the kind of riding I do but most of my miles are on the ebike now. The ebike has been a total game changer for me and is a much bigger difference than this bike to a top end disc build but the ebike has a lot of teething issues so not for everyone.... yet.

However, the 12 speed HG+ cassettes are so bloody good there is no way you'll get that same level of shifting on the ZTTO unit. I have the all steel Gen 2 version 11-34 11 speed cassette (R9100 mechanical RD) and it's much clunkier than my 12 speed HG+ Dura Ace cassette (R8100 electronic RD). The shifting performace is not even close - the HG+ shifts so smoothly that some gear changes are imperceptible.

Yeah I'm not expecting to like the ZTTO on this build. However, I like playing around with things and challenging my expectations. Thankfully this is a fairly cheap one to try. Also it will be nice to see what a black cassette looks like to see if I want to pursue cerakote for the Dura-Ace cassette. I like the idea of colored cassettes to better hide wax but also better show teeth wear.

After many builds the more I play around with aftermarket shifting stuff the more I end up back with OEM which just works. Many are fine with slightly worse shifting to save some money or grams and that used to be me on past builds, but I've aged out of that as I've tried more stuff and gotten pickier with time. Long term I've only been happy with YBN chains which shift a tiny bit worse but are technically imperceptibly more efficient.

I read in the other thread that you're replacing the XG1190 11-32 unit with the ZTTO Gen 3. In my experience the XG1190 11-32t shifts better than the ZTTO Gen 2 11-34t. I still have my XG1190 at 199g, but I like the 1:1 gearing of the 34/34.

Yeah, I have much better expectations for the ZTTO there and would be fine with slightly worse performance than XG1190 without the o-rings which I might migrate to the ZTTO. That build is a round tube external routing round tube mech rim build with tubulars at 4.4kg (sub 10lbs) and almost everything is optimized down to the last gram regadless of price. The only things that would save weight that I would run is THM ($$$$$ / ~50g) & xpedo sonik (12g). It is fairly compromised by 2024 standards but no crazy sacrifices by 2014 standards. By this I mean there is no drillium, no slow tubulars, no 1x, no chopped bars, no removing of stock hoods, no round carbon spokes attached to standard hubs, and the gearing is actually usable and not something just for show. On that build I am hyper fixated on being under 10lbs which in the hiking world they call ultralight. There I am using Red22 mech which just barely works and the front shifting has to be babied and carefully coaxed into place. If ZTTO works well enough there I might be able to go Dura-Ace shifting, which I already have ready, and stay under 10lbs which would be a massive improvement in front shifting quality. I decided to stick with 11-32 there because I only like going one step away from Shimano specs which support 11-30 on that gen and as a bonus I get a direct gearing swap for a more direct comparison.

Its because I have the 10lbs bike that I have kept this SL6 more generally focused. I could have built this SL6 with similar parts as that build and gotten it to somewhere around 4.6kg but I dont think it leans into the strengths of the SL6. Back in 2018 I lusted over the SL6 ultralight expecting it would be the best super weenie bike but that just isn't the case given inherent platform weight so its more like a emonda or TCR with their platform limitations than an extralite, RCA, or Izalco Max.

[justinfoxphotos]

I'm super happy with the final weight of my SL6, but yeah for sure, I agree that the frame itself isn't amongst the lightest out there for a full on weenie build (S-Works Aethos is calling!).

[mrlobber]

Thanks, Otterspace, for this thread, a ton of useful info in here, also nicely linked from other threads , and I really enjoy your methodical no-nonsense approach to all of this

I still run my SL6 rim 54cm @ 6.1kg config for those mass start races where I don't want to show up with carbon-spoked disc brake wheels or an all-out straight aero setup, but even to myself, I reluctantly admit that the latest gen disc brake bikes have surpassed any rim builds for performance for any riding scenario out there, so the only reason to ride rim is for sort of sentimental value, keep depreciating the accumulated rim components, and enjoy building/tweaking some bits here and there, for which the platform still remains ideal. Moreover, it somehow doesn't seem right to ride tubs for a disc brake bike, but for rim, they still roll nice and (fairly) fast.

[OtterSpace]

S-Works Aethos is calling!

Kind of hot take but I'm not interested in the ÆTHOS at all in 2024.

I remember when it came out I was working on my now 4.4kg Izalco Max and was awestruck by the bare frame weight and cost of the Aethos.

That time (Oct, 2020) was peak rim vs disc forum flame wars era and a strange transition era for road cycling with tons more people getting into the hobby, supply chains strained, and prices through the roof for anything that was the latest tech. I didn't engage much in the forum then outside of my build thread which started out as $/g super weenie before going all in sometime in 2022. Looking back it seems like it was just a terrible time to moderate with everyone all pent up and huge rifts of knowledge in the community as everything was shaking up.

From googling the founders edition was $12k @ 5.9kg claimed (without pedals) which is kind of trash for that cost really. Sure there were easy wins like the crankset but it also forces electronic shifting so as a platform its not as light as it seems for a super weenie build. I think it would also end up somewhere around 4.7kg if I had a similar build to my Izalco Max and weenied down the discs as much as possible.

So at a high level for a similar component build cost what is the æthos platform vs a round tube rim bike, SL6 rim, and SL8 in 2024 for dry riding?

Round tube rim: Slow aero, narrow tires so least confidence inspring for descents, good low to medium braking force performance, bad high braking force performance, bad braking in the wet, lowest weight, best adjustability & serviceability. Fastest uphill, slowest downhill, slowest on the flats.

SL6 rim: Hot take here but I think it can be as aero as SL8 if you shroud the front caliper and use the same level of bars but lets just say its second most aero. Second worst tire clearance at 30mm stated. Good low to medium braking force performance, bad high braking force performance, bad braking in the wet, weight simlar (+/- 150g) to all but lowest, second best adjustability & serviceability. Basically bang on the middle performer for uphill, downhill, and flat riding but will be way slower than good disc with wide tires for crazy downhills.

SL8: Most would say most aero, best stated tire clearance, best braking, weight simlar (+/- 150g) to all but lowest but most would optimize for speed over weight, worst adjustability & serviceability. Techincally slowest uphill from weight but many will recover those weight losses from other optimizations, fastest downhill, fastest on the flats.

ÆTHOS: Slowest aero, tied for best stated tire clearance, can be tied for best braking, claimed frame & fork weight 150g lower than SL8 but at least 300g heavier than round tube rim platform weight when build up, second worst adjustability & serviceability. However, this comes to where it falls apart.... Most intentful æthos builds I've seen tend to try and focus on leaning into the low weight side so light tires, shallow wheels, tiny rotors. Most of this tech is old from the teething era of disc bikes and then got weenied down further reducing performance. From my view all of this stuff severely sacrifices the strength of discs to chase a weight target it will never be first in. So as built it would end up second lightest but to get that it would become: Slowest aero, tied for worst tires, braking in the same ballpark as rim but better in the wet, second lightest, second worst adjustability & serviceability. Which gives you... Slower than round tube rim uphill, second slowest downhill, slowest on the flats. Sounds like an Icarus build that flew too close to the sun to me. Even if you build it up more sensibly in 2024 you will always be fighting the bad aero. So it just isn't worth the 150g platform savings (vs SL8) in almost all circumstances.

From this I'd take a weenied round tube rim bike with mech shifting over a weenied æthos with electronic for hill climbing easily. To me the æthos would be best for a n=1 build that you don't try and fight inherently higher disc platform weight on but I'd take an SL8 over it all day.

With that said I personally wouldn't go SL8 either as I don't think bikes are done evolving to fit wider tires yet and I'd personally be fine with a slightly heavier platform for better aero. To me the latest canyon aeroad is what I vibe with more although I'd never buy it new personally and there likely will be a bigger aero focus on the next crop of bikes given UCI frame spec changes.

Also ebikes are way faster than anything without a motor for those who don't race. So that's where the bulk of my money is going now and into the future. All other bikes are just occasional use for me now but I love having a quiver of bikes without motors that cost around $5k each to pull from when the mood strikes. There definitely is a gap in my stable for an optimzed disc build but the tech advances haven't settled down yet, which is a good thing, and prices are way too high for me to fill that gap yet.

/rant

[OtterSpace]

Thanks, Otterspace, for this thread, a ton of useful info in here, also nicely linked from other threads , and I really enjoy your methodical no-nonsense approach to all of this

I still run my SL6 rim 54cm @ 6.1kg config for those mass start races where I don't want to show up with carbon-spoked disc brake wheels or an all-out straight aero setup, but even to myself, I reluctantly admit that the latest gen disc brake bikes have surpassed any rim builds for performance for any riding scenario out there, so the only reason to ride rim is for sort of sentimental value, keep depreciating the accumulated rim components, and enjoy building/tweaking some bits here and there, for which the platform still remains ideal. Moreover, it somehow doesn't seem right to ride tubs for a disc brake bike, but for rim, they still roll nice and (fairly) fast.

I'm glad you like it.

Its mostly just me ranting to pass time and stay somewhat sane while at my window seat purgatory big company job before I go back to another startup after certain dates pass.

I personally think SL6 rim can be built just as fast as SL8 for everything except rides that require very heavy speratic braking or rides over serious chop that you would want a clutch for. Sure claimed clearance is 30mm instead of 32mm so you are giving up a bit but that is just one step not five so not a massive loss. Its the next crop of bikes, wheels, and tires that likely go wider still (which SL8 descending will benifit from an aero matched tire & rim around 34mm WAM which should fit) and new UCI aero regulations that should fully displace what this platform can do. The SL6 rim is one of the few that still barely holds on for overall performance while most rim bikes fell out for at least one performance reason awhile ago.

From a speed perspective the super narrow flared bars are great and I couldn't recommend them highly enough. This is probably the best platform to play with super narrow bar fit on before you transition it to another bike. Front Dura-Ace brake and the widest aero matched tires and wheels are also a big part of getting within spitting distance to stock modern disc performance. Tubulars are well dead in 2024 but I love them on my weight optimized build, no idea how long term I'll be able to source them and keep that intended forever bike riding though...

[justinfoxphotos]

That was an EPIC Aethos rant!

I've had many of the same thoughts and after watching and reading a LOT of reviews on the Aethos I can't say I'm any clearer on many of those thoughts as some people have so strongly praised how well it descends and many have praised just how uniquely different it feels to their SL8's, but what I most disagree on is that the external cables make life easier (I hate them and would most likely have bought one by now if it featured fully internal cabling).

SO many people praise it for it's classic lines, but I disagree with this as nothing screams modern more than a sloping top tube.

Where your rant (and my own thoughts) fail though is that it's all theory. End of the day you can theorise as much as you like but nothing beats experience, and I don't mean a ride around the block on someone else's bike. I mean ownership.

That said, it's all that theory that ended up convincing me to not buy an Aethos and instead buy an SL8.

[OtterSpace]

Where your rant (and my own thoughts) fail though is that it's all theory. End of the day you can theorise as much as you like but nothing beats experience, and I don't mean a ride around the block on someone else's bike. I mean ownership.

Fair point.

There are some things that are objective truth and there are some things that are fully or partially subjective which is good to keep in mind. For the subjective stuff its good to also figure out why as much as you can both about the thing discussed and the frame of reference of the feedback.

We can't try or own all the bikes so we have to decide what to engage with and what to let go.

Parsing through the æthos feedback its clear that the rear has something extra done through layup which makes it more compliant and less stiff compared to bikes of that time. Some love it and some think its a noodle but in trying to pull as much out of it as you can without testing I think its good to go back to the frame of reference of the feedback.

Some bikes have an x-factor like this and are ahead of their time in ways tough to capture on a spec sheet but other designers can likely pick out the details and decide what to intigrate going forward for the next gens. In a way all bikes are a product of their time and the needle shifts for future gens which is a good thing.

Something to keep in mind is a lot of this æthos rear end feedback is fairly old now so much of it is comparitive to when the bike first came out and what people used before. Big people, or more spirited riders, seem more likely to consider it a noodle and small people, or more steady riders, seem to favor it.

Clearly Specialized knows the more objective details of the æthos rear and they decided to migrate some degree of it to SL8 but not the full noodle. How important is this x-factor? Thats up to each person to decide if they try both bikes but I doubt its a massive game changer for the same WAM between SL8 and æthos for most riders. Was it a game changer at the time of æthos launch? Maybe... but a lot of disc bikes had terrible ride feel back then and rim brake bikes of the time often were at 25WAM or less.

I'm not trying to rain on anyones parade just trying to compare platforms as well as I can behind the keyboard.

The Crux 1x UDH... now thats a bike with some froth if you have the terrain to run it with a big chainring to mittigate efficiency losses. Hopefully they move that line of thinking to something more aero but still with long chainstays and very wide clearance in the future.

[justinfoxphotos]

Yup agreed, subjectivity is HUGE.

100-150g savings in a frame is huge to me if I was aiming to build the lightest bike possible. For example it's starting to cost me a LOT to shave even 10g off my SL6 and the fact that my SL6 frame weighs around 850-870g really hurts.

I find the Aethos attractive as it's literally aimed at the weight weenie in me. That's about it though as visually I don't think the Aethos is beautiful (the way a bike looks might not matter at all to a lot of people but being an artist and retired graphic designer it means a LOT to me).

[OtterSpace]

Yup agreed, subjectivity is HUGE.

100-150g savings in a frame is huge to me if I was aiming to build the lightest bike possible. For example it's starting to cost me a LOT to shave even 10g off my SL6 and the fact that my SL6 frame weighs around 850-870g really hurts.

I find the Aethos attractive as it's literally aimed at the weight weenie in me. That's about it though as visually I don't think the Aethos is beautiful (the way a bike looks might not matter at all to a lot of people but being an artist and retired graphic designer it means a LOT to me).

Sounds like you need a rim Cannondale Super Six Hi-Mod or Focus Izalco Max to tune on. Sand them down and equip them with tubulars and mechanical groupsets and you are off. Raw carbon on those builds is just.. chef's kiss.

They are truely special bikes but entirely impractical by 2024 standards and I love them.

edit: in this vein the extralite SCR-058 seems amazing too but not many of them around and little posted on it. It also looks like the BB changed at some point. Given your extralite addiction it might appeal more than the other more general round tube rim options. Weight is amazing but looks are well... an acquired taste to be kind. The tube shapes just seem a bit unbalanced from one to the next.

[justinfoxphotos]

Sounds like you need a rim Cannondale Super Six Hi-Mod or Focus Izalco Max to tune on. Sand them down and equip them with tubulars and mechanical groupsets and you are off. Raw carbon on those builds is just.. chef's kiss.

edit: in this vein the extralite SCR-058 seems amazing too but not many of them around and little posted on it. It also looks like the BB changed at some point. Given your extralite addiction it might appeal more than the other more general round tube rim options. Weight is amazing but looks are well... an acquired taste to be kind. The tube shapes just seem a bit unbalanced from one to the next.

Ahahaha yup I've looked into the Extralite frame as my local bike shop has it listed on their online shop. Have definitely looked into a Cannondale too as I have a history with the brand (my first MTB was a Cannondale and I loved it, and I'm a huge fan of clean typography).

[OtterSpace]

Got a ztto 3rd gen SLR cassette to try out. Not going to claim the weight savings yet as I don't know how long I'll run it. This cassette does save a decent chunk of weight at around 93g bringing the build total down to somewhere around 5.77kg as ridden. However, this build is focused on overall performance so if the Dura-Ace feels better I'll swap back given I have a much lighter build to soak up my super weenie tinkering.

More photos including one with a test fit of a black chain from my other bike

[justinfoxphotos]

The black chain looks SO much better!

[OtterSpace]

The black chain looks SO much better!

Thanks for the kind words. I'm much more on the fence about black chain but certainly like it more that I typically would.

Setup wise it was easy to mock up as the black YBN chain is in a waxed rotation for my other 12s bike. However I want to start off trying the "aftermarket cassette" with its best shot on goal so my Dura-Ace chain and a new quick link went on after taking the pics.

Pivoting back to visuals to me black chains are the hardest color to make look good as I would deploy them. I always run waxed and the latest speed additive wax seems to be getting thicker with a graphite color which makes a chain more of a lighter color matte finish even if the chain itself is closer to a dark black mirror. This bike is a mix of matte and glossy so it works but close inspection of the chain the wax stands out quite a bit.

I have a lot of batman bikes, as they are the lightest frames, but there always are a few bits of silver here or there that you just cant do without that the chain can help balance. My visual goal isnt just to have the S-WORKS logo in silver and everything else blacked out but its harder to say what exactly should be silver, what glossy, and what black vs my lightest bike where I just go with whatever is the lightest weight I can find. Fun but a bit of a conundrum.

Chains are a good place to add a pop of color with gold or oil slick to balance a build, provided they match pops of color elsewhere, but black is kind of removing something. The black cassette certaintly helps here vs other black chain deployments I've seen before. I set the black pic as my desktop background and will continue to ponder it which for me is fun.

My personal favorite black chain deployments so far have been when there are pops of color eleswhere and the chainset is all matte like I have on my travel brompton.

[justinfoxphotos]

PS: I found a product made by 3M to remove the logos on tyres. I got a tiny bottle of it on eBay and some applicators for it too on eBay (had to buy a big bag of them), and 1 month in and it's doing amazing (I'm very happy).

3M product: https://www.3m.com/3M/en_US/p/d/b40065466/

The product can be seen in this YouTube short: https://youtube.com/shorts/fGB_oo26sbw? ... td-pp37lHn

[OtterSpace]

PS: I found a product made by 3M to remove the logos on tyres.

Nice I'll certainly try it on my black walled SCHWALBE||||⇂1||||PRO ONE, RenéHERSE BARLOW PASS 700c x 38 TC, and the worst offender GRANDPRIX(grey) 5000(white)tire info(grey) which looks like a war crime when you look at it vs the valve and they have a conti logo opposite so you cant just line it up with the 5000.

The TT TR logos are quite balanced along the valve, only on one side, and one color so I dont think I'll touch these but most tires are just terrible. Also with the tubulars on my super light build there was no tread polarity and they only had logos on one lateral side so I just glued them backwards to hide to logos.