Endurance SL R & SL - What's the difference?

The Endurance SL R & SL both belong to the same family of carbon endurance road bikes. So naturally one of the most frequently asked questions that we hear is; 'I'm looking at the Endurance SL R & SL frames but am not sure of the difference between the two?' If this is also a conundrum that you face, this in-depth guide should help you to decide which road bike best suits your cycling needs.

Designed to offer an exhilarating mixture of speed and efficiency, the Endurance SL R & SL road bikes are perfect for everything; from road racing to ultra-endurance road events or those epic all-day in the saddle century rides. Whether you choose to ride fast for fun, against the clock, or simply to race the group for that next signpost ahead, they deliver a clear performance advantage.

Aerodynamics has been a major consideration in the development of the Endurance SL R and these class-leading features also filter down to the Endurance SL. Consequently, both models share the same aerodynamic drag-reducing features.

• Truncated aerofoil tube profiles generate up to 28.5% less drag when compared to the previous generation of carbon frames.
• Internal cable routing keeps everything neat and tidy while retaining the smooth, uncluttered lines of the frameset for further aero gains.
• Compatibility with the optional aero one-piece LEVEL 5 carbon integrated handlebar system enables all cables to be fully hidden away. Generating up to 40% less drag when compared to a conventional handlebar and stem set-up.
• A truncated aerofoil seat post and integrated seat clamp.

Aesthetically, both the Endurance SL R & SL are almost identical and with good reason. Both platforms are manufactured in almost exactly the same way. Similarly, they also share most of the same cutting-edge design features. With the odd exception, of course, which we will cover in this section.

As befits a flagship carbon endurance road bike that both the Ribble Weldtite Pro Cycling & Le Col Wahoo racing teams have ridden to great success, the Endurance SL R Series features our most advanced carbon construction. It features a bespoke blend of Toray T1000 & T800 carbon fibres. And uses more of the T1000 fibres within its construction than any other frame in our line-up. (except the Ultra SL R)

This unique carbon mixture is layered to an exacting specification over an EPS inner-core system. The EPS process eliminates any weak spots and ensures complete consistency of the structural integrity of the fibres and resin throughout the frame. But what does this represent in terms of actual performance? Well, it allows us to produce a frame with an unsurpassed strength to weight ratio.

A frameset that retains the superior strength and stiffness of one that's constructed using much more carbon material. Yet, is much lighter and offers a featherlight ride quality that delivers dynamic power transfer, instant acceleration, and nimbleness that sets it apart from the competition.

To achieve the SL R's superlight sub 900g weight it was necessary to forego the use of the aluminium inserts that you would normally expect to find on most carbon frames. These are normally situated within the bottom bracket shell and head tubes of most framesets.

As a consequence, the SL R requires a press-fit bottom bracket in place of the traditionally threaded bb. (More on that in the bottom bracket section below).

• Frame Material: Toray T1000 & T800
• Bottom Bracket: Press-fit BB86
• Weight: 850g (rim brake), 890g (disc)
• Colour: Stealth Black only. You can also add your own CustomColour design in BikeBuilder.

Similarly to the SL R, the Endurance SL is also manufactured from a select blend of Toray T1000 and T800 carbon fibres. Albeit with one slight difference. The ratio of T1000 to T800 is slightly less than that of its flagship sibling. However, it also takes advantage of the same EPS inner core system manufacturing process.

The end result is a frame that excels, whether that's leading the pack in a race or setting the pace on the weekend club run. In direct contrast to the SL R, the Endurance SL does have aluminium inserts installed in the bottom bracket and head tube areas. It is these as well as the carbon layup that accounts for the slight difference in weight and bottom bracket standards.

In all other respects, the Endurance SL is identical to the SL R. Thanks to it sharing many of the class-leading design features. Drag-efficient tube shapes, fully hidden internal cable routing (when fitted with the LEVEL 5 integrated handlebar system), aero-shaped carbon seat post and more.

• Frame Material: Toray T800 & T1000
• Bottom Bracket: Threaded 68mm BSA
• Weight: 1150g (rim brake), 1190g (disc)
• Colours: Gloss Black (rim brake) - Black, Red, or Teal (disc). CustomColour in BikeBuilder is also available.

Left: Shimano BB72-41B Press Fit - Note the lack of threads on the outside of the cups. Right: Shimano BB-R60 Threaded BSA - A traditional threaded style bb that offers easier maintenance.

As we alluded to earlier in the blog, the two frames have different bottom bracket standards. With the SL R not having a threaded alloy insert in the bottom bracket shell, it's not possible to use a threaded bottom bracket. Subsequently, a press-fit system is used.

This is to say that the bb shell of the frame and bottom bracket cups are completely smooth. In short, the cups are pressed into the frame to create a perfect seal. This is achieved through the use of a bottom bracket or headset press. The press-fit system allows the bottom shell to be manufactured in larger diameters. Thereby stiffening up the bottom bracket area for improved power transfer.

On the other hand, the Endurance SL does have a threaded alloy insert in the bb shell. Therefore a threaded bottom bracket is required. You can see the difference between the two bottom bracket standards in the images above. On the left is a press-fit bb with completely smooth cups. On the right, are the threaded cups of a traditional 'BSA' bottom bracket.

The advantage of the threaded style of bb is that it is easier to maintain as the cups can be simply unscrewed and removed. The press-fit system will require a specific bb press-fit tool to extract the cups.

Looking for a relaxed bike to explore the city streets and beyond in comfort and style? Check out our Hybrid Collection.

Keep up to date with the latest race results of the Drops - Le Col racing team here.

Thinking of commuting to work by bike? Check out our guide to avoid the most common pitfalls.