In a quest to maximize aero gains, every shape in the clean air or on a leading edge was optimized for maximum advantage. The steer tube is moved to the rear of an incredibly deep head tube, resulting in the Speed Sniffer nose cone. By moving the steer tube – the tube that determines head tube width – backwards, the leading edge of the head tube can be much sharper, delivering a much lower drag shape.  Ahh, the sweet smell of victory.

The Rapide Cockpit (available on S-Works models and in aftermarket) shaves four watts of drag vs the already quick two-piece Tarmac stem and Rapide bar combination by removing the cluster of hardware on the leading edge. To ensure every rider can still get their perfect fit we used Retül data to create 15 different bar/stem combos. We also shaved 50 grams of weight while we were at it. 

Where we find meaningful aero gains beyond the leading-edge we optimize for them. Utilizing new UCI rules, the Tarmac SL8 seat tube is the same size as the SL7 seat post. The result? The SL8 has the narrowest, most aero seat post we’ve ever made ensuring fast moving, dirty air around the legs can more easily flow backward. 

“Aero where it matters, not just where it looks good,” has delivered the most aero road bike we’ve ever made – 16.6 seconds faster than the SL7 over 40km. It also allows our engineers to make attacking weight and ride quality across the rest of the bike priority one.

“The lighter the bike, on a steep climb, it’s super important. You really feel it. It can be one or two seconds, but that can be enough to win a race.”

Remco Evenepoel, 2022 World Champion  

685 Gram Frame: Lightest Race Bike on the World Tour

With the Aethos, we learned how to make the lightest production road bike in the world and saw how it could marry blistering response in the mountains with a supple, all-day ride. Thanks to our Ride Science team, we can also quantify just how much faster lower weight can make a bike over today’s demanding racecourses. 

Tarmac SL8 Advantage after 60min

The goal then became simple, deliver the most aero bike we’ve ever made, to be easily built at the UCI minimum with power meter, pedals, and all the other things necessary to actually race a bike. With the ability to make lightweight a top priority in the down tube, seat tube and rear of the bike, lessons from Aethos were applied. The frame’s shape carries load so efficiently that extra carbon stiffness layers become redundant. The overall frame surface area can also be reduced to lower weight when the frame isn’t trying to ‘look’ aero with deep tubes in dirty air. Using an all-new process called Front Loading Development (more about that later), iteration after iteration was tested virtually.

This is what it takes to make SL8 and SL7 equal on the scale

The team delivered a mind bending, scale tickling 685 gram frame – 15% lighter than the Tarmac SL7 and lighter than anything on else on the World Tour*.  

*Unless of course you count the time Kasper Asgreen raced our 585 gram Aethos frame during a Tour stage. 

Unprecedented Ride Quality and Handling

The Tarmac has been the winningest bike in the modern era thanks in no small part to its legendary, telepathic handling and aggressive, instantaneous responsiveness. Now, the Tarmac SL8 sets a new standard when it comes to pinpoint handling in the most demanding situations and aggressive, efficient response to pedal input. Ambitious – some would say fool-hardy- benchmarks were set for the new Tarmac based on decades of data born from decades of working with the best riders in the world. The team surpassed them all. Reaching these bottom bracket, head tube, and front end stiffness targets with incredibly lightweight delivered a stiffness-to-weight ratio improvement of 33% over the SL7.

Of course, hyper reactivity at the pedals and iconic handling are Tarmac trademarks. But what this new Front-Loading Development process and our breakthroughs in shape understanding from the Aethos have delivered is the most-supple Tarmac ever. While the areas that deliver power transfer and precision are stiffer than ever, in the saddle the Tarmac SL8 is 6% more compliant, floating over rough road and diving into corners with a supple, balanced feeling unique in the high strung world of race bikes.

The new Tarmac SL8 retains the identical geometry, proven across every parcours in road racing, with the same generous 32mm tire clearance to ensure the flexibility to choose a high-volume tire when needed.

33% Improved Stiffness-to-Weight , 6% Smoother

*Measurement criteria used above

Lightness: Frameset Grams
Speed: CdA x Weight
Mountain Stage: +/- 5000m elevation gain
Flat Stage: +/- 500m elevation gain
Comfort :Compliance at the saddle
Responsiveness: Stiffness-to-Weight

Front Loading Development: Innovate Or Die

Creating a bike more aerodynamic, 15% lighter, with an 33% improvement in stiffness-to-weight over the 4X World Championship Tarmac SL7 took more than our obsessive commitment to our Innovate or Die philosophy, it took an entirely new process called Front-Loading Development. This workflow utilizes a loop between virtual carbon modeling and a virtual FEA and CFD test lab with using ply-by-ply numerical models. In this virtual world up to 500 separate layers can be modified in a few hours, then put to the test. Our engineers can then move to physical testing with thoroughly vetted ply-books removing a huge amount of time and uncertainty, delivering prototypes closer to the benchmarks than ever before. 

We began by simply applying our 585 gram Aethos layup strategy and our top spec FACT 12r carbon to the new Tarmac SL8 shape, then got to work. We amplified stiffness where it mattered – at the bottom bracket for explosive power transfer, and at the head tube for pinpoint handling. We tackled creating a supple ride in the saddle, ensuring a balanced ride front to back. All the while keeping a watchful eye on our weight targets – every step of the way.

Over 53 separate iterations, testing ply-by-ply numerical models, we created more and more performance by chasing an unprecedented combination of aero, lightweight, stiffness, and compliance. On the 54th iteration, we had achieved our targets – 16.6 seconds faster over 40km, 685 gram frame weight, 15% lighter, 33% improvement in stiffness to weight, and 6% more compliant than the 4X World Championship Tarmac SL7. The Tarmac SL8 was born.

Rider First Engineering: Data Driven Design

But we didn’t just go through this process with a size 56cm and make assumptions about how to scale the Tarmac SL8 up or down for riders of different size. Using extensive data acquisition of forces through every part of the frame during real world testing, the Rider-First Engineered Tarmac SL8 delivers an optimal balance of stiffness, weight and ride quality at every size. It means every rider, regardless of size, can ride faster everywhere with Tarmac SL8. 

The Creators: Aren’t You Glad Some Kids Stayed in Science Club?

Engineers, Aerodynamicists, Sports Scientists, and Product Managers. This is the team that took performance targets considered unreachable just a few years ago, fused aero, lightweight, and ride quality in a way previously thought impossible, and created the world’s fastest race bike. 

ColourStory: Heightened by Adrenaline

Inspired by the emotions we feel in moments of adrenaline and heightened senses on the bike, the new Tarmac SL8’s colors and design breath energy and life into the frame’s shapes. Our team pioneered new techniques and pigments to create these effects with as little paint – or added weight – as possible. Our Strata Red frames for example use very little paint to create a sense of movement with gorgeous texture. 

High end pigments are edge faded to get as much color as we can, but at the same time remaining super light because of the quality of material, the placement of the pigment, and the raw carbon base. Our in house team painted frame after frame to perfect these techniques. It’s no easy task to create a frame rich in color but light in weight. 

Beyond Gender: Informed by 10,000 + Retül Fits

Thanks to our partners at Retül, we know there can be more differences between two male cyclists than between a male and female. Gender alone doesn’t provide nearly enough data to specialize and that means creating male or female bikes is arbitrary and outdated. Every rider can get the next level advantage of Tarmac SL8. It’s time to go Beyond Gender.

Made In Racing

Since day one at Specialized, the rider has been the boss. When we decided it was time to take on European road racing it wasn’t to win races – hey, who are we kidding, we love winning – but it was to develop the best race bikes in the world with the best riders in the world and make them for everyone. Pros like Tom Boonen, Fabio Cancellara, and Peter Sagan put our race bikes through a torture chamber mere mortals can only imagine and provide feedback that makes the next model better yet.  Developing the Tarmac SL8 was no different. The best all arounders in the world – Remco Evenepoel, Demi Vollering – the fastest sprinters in the world – Fabio Jakobsen, Sam Bennett – classics stars and climbers alike, all had a hand in helping develop and refine the targets for the Tarmac SL8. Ultimately, they helped us co-create the fastest race bike in the world. 

Picture by Zac Williams/SWpix.com- 17/06/2023 – Cycling – 2023 Tour de Suisse – Stage 7 – 

FAQs

Is the Tarmac SL8 Rider-First Engineered?

Yes. Every frame size of the new Tarmac SL8 has the same responsiveness and ride quality our performance road bikes are known for.

How much does Tarmac SL8 weigh?

The S-Works FACT 12r frame tips the scales at 685g in the lightest Satin Carbon/Chameleon Snake Eye colorway (56cm). The FACT 10r frame used on Pro and Expert models weighs only 780g.  

Complete bike weights are roughly as follows: S-Works Di2 – 6.6kg | S-Works eTap – 6.8kg | Pro eTap – 7.4kg | Pro Di2 – 7.2kg | Expert eTap – 7.7kg. These weights may vary based on colorway, size, and final fit configuration.

What’s the difference between the FACT 12r and 10r frame levels?

Both levels share the same shape, geometry, and handling targets. They only differ in the material selection and layup, with the S-Works version utilizing the most premium material and layup techniques available. As a result, the S-Works 12r frame is just about 100g lighter than the 10r frame.

How much faster is Tarmac SL8 compared to the previous generation Tarmac SL7? Is it faster than the Venge?

The Tarmac SL8 is 16 seconds faster than Tarmac SL7 over a flat 40km course. It is even faster than the 2019 Venge over that same flat 40km course.  If there is any elevation gain or accelerations/changes in speed, Tarmac SL8’s weight savings would mean even more time saved. Reference the Tarmac Whitepaper for a detailed breakdown of our performance claims and the methodology we used to arrive at them.

Do professional teams use a special version of the new Tarmac SL8?

The Tarmac has been developed with input from our professional riders over many generations. The S-Works Tarmac SL8 that you can purchase is identical to the bikes raced by pros like Remco Evenepoel, Julian Alaphilippe, and Demi Vollering.

What is the geometry of the Tarmac SL8?

The Tarmac SL8 features the same, trusted race fit and handling geometry as the outgoing Tarmac SL7. Detailed measurements can be found in the geometry chart.

How is stack and reach measured on the new Tarmac?

There are two stack and reach figures displayed on Tarmac SL8’s geometry charts. Stack and reach to frame show vertical/horizontal distance from bottom bracket to center/top of headtube. Stack and reach to stem accounts for the headset cover height, and measures to the center of stem base in the lowest position. Stack and reach to the stem are identical between Tarmac SL7 and Tarmac SL8.

What sizes does the new Tarmac come in?

Tarmac SL8 comes in seven sizes: 44cm, 49cm, 52cm, 54cm, 56cm, 58cm, and 61cm.

What handlebars is the new Tarmac compatible with?

The Tarmac SL8 has a 1 1/8” steer tube and was designed for use with the one-piece Roval Rapide Cockpit or the Tarmac SL7 stem. Riders can use any handlebar with 31.8mm clamp diameter with the Tarmac SL7 stem.

S-Works bikes ship with the Rapide Cockpit. Pro models ship with the Tarmac SL7 stem/Roval Rapide handlebar while Expert models ship with the Tarmac SL7 stem/Specialized Expert Alloy handlebars. 

What do I need to know about the Roval Rapide Cockpit and the Tarmac SL8? 

The Tarmac SL8 was optimized for use with the Roval Rapide Cockpit. It is a key part of the performance story and is the setup we recommend to maximize aerodynamic performance while still being incredibly light. 15 cockpit sizes are available with stem lengths between 75-135mm and bar widths of 380-440mm.

S-Works complete bikes ship with the Rapide Cockpit. Reference the geometry chart for the specific bike model to understand which size cockpit ships with a given bike size. 

Framesets and other models ship with the required spacers to easily upgrade to the Rapide Cockpit. There is a short one-piece cover for a “slammed” stem position which effectively changes cockpit angle from -6 to -12. The other spacer setups emulate a -6 stem setup.

What fit options are there with the Tarmac SL8 seatpost? 

All Tarmac SL8 models ship with a 15mm offset seatpost. A 0mm offset seatpost is available as well. Both are available in 300mm or 380mm lengths. 

What goupset and drivetrain configurations is the Tarmac SL8 compatible with?

The Tarmac SL8 is only compatible with electronic drivetrains and hydraulic disc brakes. It can fit a maximum of 55/42t chainring set and has room for power meter pods on left and right crank arms.

How much stack adjustment is there on the Tarmac SL8?

There is 35mm of stack adjustment on the Tarmac SL8 in 5mm increments. This comes in the way of spacers that come apart for easy installation and removal without having to re-install the stem or redo cable routing. There are dedicated spacer configurations for the Rapide Cockpit and Tarmac SL7 stem. Please refer to the user manual for full build instructions. 

What’s the biggest tire size you can fit on the Tarmac?

While Tarmac models ship with 700x26c tires, Tarmac SL8 can fit tires that measure up to 32mm with 4mm of clearance.  Tire widths can vary based on rim width and tire pressure, so be sure to thoroughly check for clearance if you’re changing to a bigger tire.

Can I remove the front derailleur hanger?

Yes, Tarmac SL8 comes with a removable front derailleur hanger. There is also a cover that can be installed for the cleanest 1x setup. Reference the user manual for installation or removal.

If I want to run 11 sp Shimano Di2, where should Junction A go?

In order to run 11 sp Di2, you should install Junction A in the handlebar end. The Tarmac SL8 seatpost does not have a location for the A Junction.

Where is a Di2 battery installed?

The Di2 battery for the Tarmac SL8 lives in the seat tube and is installed under the seatpost using a special clip. Reference the user manual for assembly details.

What are the other tech specs of the Tarmac SL8?

All Tarmac SL8 models have a 68mm BSA threaded bottom bracket. The Tarmac SL8 has 142×12 and 100×12 dropouts and follows the Shimano flat mount disc brake standard for 140/160mm rotor in the rear. The front brake is only compatible with 160mm and with flat mount brake calipers.