Canyon Ultimate CF SLX 8 Di2 review

The Canyon Ultimate CF SLX 8 Di2 is the cheapest of three builds the German brand offers of its second-tier, all-round road race bike.

The Ultimate CF SLX sits between the range-topping CFR and more value-oriented CF SL versions, with this tier said to offer the best compromise of performance and cost.

Whether that’s true naturally depends on who you are, your budget and your ability. That said, the Ultimate CF SLX 8 Di2 is an excellent all-round race bike that I’ve found to be more rounded than the flagship CFR version.

The CF SLX carbon frame might be a touch heavier, but with the benefit of back-to-back testing with the CFR, I’m confident it’s the more compliant of the two bikes to ride – and no slower for it overall.

This specification costs £6,199 / $5,499 / €6,499. Given the build is practically unimpeachable, it’s one of the most well-rounded race bikes available for the money today.

Canyon Ultimate CF SLX 8 Di2 frameset

The Ultimate platform was last updated in late summer 2022, with claims of better aerodynamics, more stiffness and more compliance compared to its predecessor.

Despite the Ultimate CFR grabbing most of the headlines when the updated range launched, the CF SLX version is, according to Canyon, the frameset tier best suited to cycling “enthusiasts”.

Moreover, Canyon recognised its importance by giving it the registry number 100, marking the fact that it’s the 100th frameset developed by the company (the CF SL carries number 101, the CFR 102).

Canyon says the CF SLX’s carbon frame is slightly heavier than the CFR (846g versus 762g in a size medium), but that it’s been optimised to produce a more compliant ride compared to the top-level bike.

That said, the German brand claims it has a comparable stiffness to the CFR.

This latest Ultimate is said to be 5 watts more aerodynamically efficient at 45kph with a rider atop it, compared to the previous version, thanks to tweaks made in partnership with aerodynamics specialists, Swiss Side.

These include flatter, straighter tube profiles, small tidy-ups of the dropouts, plus the use of a D-shaped seatpost. It also adopts the width-adjustable CP0018 Aerocockpit from the Aeroad CFR.

An Acros headset lives above the head tube, with the front end incorporating a design that locks you into using the Aerocockpit, but offers the ability to add 15mm using jigsaw spacers without needing to cut the steerer.

The fork also has broadened shoulders, and is said to be 15 per cent stiffer than before.

Canyon says reinforcement was added to the bottom bracket area to increase pedalling stiffness, and to the top tube and junction with the seat tube to improve frameset reliability.

The frame has clearance for up to 700x32c tyres, and is built around a BB86 press-fit bottom bracket.

Canyon Ultimate CF SLX 8 Di2 geometry

The Canyon Ultimate CF SLX’s geometry is identical to the CFR’s layout.

The only change in terms of rider fit is Canyon’s decision to include a setback seatpost with the SLX (and SL) – the CFR has an inline post – while the CF SLX is also available in a 3XS size.

In the size large here, the frame provides a 583mm stack with a 401mm reach. This is 14.5mm taller than a 56cm (large) Scott Addict RC and 18mm taller than a 56cm Specialized Tarmac SL8. The reach is 6mm shorter than both.

Having said that, Canyon’s take on a size large is broadly closer to an Addict RC or Tarmac SL8 in a size 58cm (conventionally considered ‘extra large’). The sizing discrepancy is worth noting, especially given Canyons are sold direct-to-consumer.

Actual reach-to-hood and stack figures can also vary depending on stem lengths and fitted spacers, but Canyon intends the ride position to be suitable for both racers and less flexible riders.

The angles are all in race-bike territory though: a steep 73.3-degree head tube angle for sharp handling, and a 73.2-degree seat tube angle to pitch the rider over the bottom bracket.

The wheelbase is notably long at 1,003mm, though, compared to a 56cm Tarmac SL8 at 991mm in a nominally equivalent size (compared to a 58cm Tarmac SL8, though, it’s 3mm shorter).

This should improve the bike’s stability when cornering, as well as taming the responsiveness somewhat.

Alongside the non-extreme ride position, this renders the Ultimate well-suited to longer rides as well as shorter speed runs if you don’t need the Endurace’s more relaxed riding position.

Canyon Ultimate CF SLX 8 Di2 build

The Canyon Ultimate CF SLX 8 Di2 features a Shimano Ultegra Di2 R8100 groupset.

Unless weight is your top priority (in which case there’s an £8,299 Dura-Ace Di2 R9200 model or the two CFR builds to consider), Ultegra delivers the best Shimano can offer right now in terms of shifting and braking performance, at a much lower price.

The 52/36-tooth crankset includes a left-only 4iiii power meter.

Bear in mind, though, that because it’s a single-sided unit, it measures the power produced by your left leg, then doubles it to estimate total power. This is unlike the £500 pricier SRAM Force AXS-equipped Ultimate CF SLX, which uses a SRAM power meter spider to measure the total power produced by both legs.

Here, a 50mm-deep DT Swiss ARC 1400 Dicut wheelset is supplied, complete with highly regarded DT Swiss 240 EXP hubs. The rims are 20mm wide internally and 27mm wide externally.

Technically, there are higher-spec road bike wheels, but the ARC 1400 Dicut proved to be an excellent pairing – I couldn’t imagine needing any more from an aero carbon wheelset.

The Schwalbe Pro One TLE tyres are excellent, and while they’ve been around the longest of the latest generation of all-round performance tubeless tyres, they're still very competitive in terms of rolling resistance.

Canyon says it has chosen a 700x25c tyre at the front and 700x28c tyre for the rear, for their relative benefits – more aero at the front and more comfortable at the rear. However, on balance I’d probably choose to have 28c all-round, given the terrible state of many British roads. This is a minor niggle, though.

The rest of the build comes from Canyon, including the proprietary Aerocockpit and seatpost.

The Aerocockpit comes in a 410mm (centre-to-centre, +/- 20mm) width on my size-large bike, offering near enough all the flexibility any rider will need and a 110mm stem length.

If that bar width or stem length doesn’t suit you, though, Canyon says you can get in touch to source a replacement Aerocockpit at extra cost (they aren’t readily available to buy online, though).

By default, Canyon supplies a 10mm-setback seatpost, reckoning this is most likely to suit typical Ultimate CF SLX and CF SL riders.

Again, if this doesn’t suit your fit, you’ll have to purchase the inline post aftermarket (a £218.90 or £219.90 upgrade, including the necessary hardware for oval or round rails, respectively).

Canyon has a well-earned reputation for offering good value with its bikes (thanks to its pioneering of the direct-to-consumer model). The Ultimate CF SLX 8 Di2 is no different.

A Specialized Tarmac SL8 Pro Ultegra Di2 costs £8,000 / $8,500 / €8,500 / AU$11,900, and the Pinarello F7 Ultegra Di2 with carbon wheels is £7,000 / $8,800 / €8,850, without a power meter.

A near equivalently specced Scott Addict RC 15 has a similar price in the UK and other territories.

My Canyon Ultimate SLX 8 Di2 test bike weighed 7.26kg.

Canyon Ultimate CF SLX 8 Di2 ride impressions

To begin with a comparison, the Canyon Ultimate CF SLX 8 Di2 feels almost identical to the CFR Di2 – it’s an outstanding race bike platform.

The stiffness of the frame offered me the platform to really put the hammer down, while the steering responses are sharp and tactile.

The ride position is excellent – aggressive enough to feel involved with the ride, but not too extreme – and the handling and overall behaviour breeds confidence.

Except, here, it feels more rounded than the flagship bike.

For context, since reviewing the CFR Di2, I’ve been able to use it as a mule for other testing.

This has included a couple of mid-depth carbon wheelset reviews, as well as BikeRadar’s recent fast tyre test (for which we used a Hunt 54 Aerodynamicist Carbon Disc wheelset – comparable, if not identical, to the DT Swiss ARC wheels specced here).

I also put the Hunt wheels on the CF SLX for one ride, to help verify my experience.

My conclusion is this: while there’s no doubt the CF SLX 8 Di2 gives up a small amount of weight in the frameset and groupset, this doesn’t make it feel any slower in almost all situations.

The one exception was when riding the steepest ascents in my local area, where I found the CFR marginally easier to whip around out of the saddle, thanks (probably) to the reduced mass. I’ve no doubt all things being equal here, this might translate into a second or two saving on a steep and long enough climb.

But, having controlled as many of the variables as realistically possible in my test period, I think the CF SLX carbon layup offered a more compliant ride compared to the flagship frame, complete with rolling stock that also helps smooth the experience.

This makes the Ultimate CF SLX an easier and more comfortable bike, which over the course of a long day’s ride can translate into more speed and, more importantly, more enjoyment.

The Ultimate CF SLX 8 Di2 isn’t a dedicated aero road bike, but the excellent DT Swiss ARC wheels help boost efficiency in this area compared to a lightweight wheelset.

It’s almost certain that an aero bike will be faster on a totally flat course, but the benefits of being able to ride in more comfort with such a competent wheelset (fitted from the outset) should be obvious.

Canyon Ultimate CF SLX 8 Di2 bottom line

Given that the Canyon Ultimate CFR Di2 is one of the best climbing bikes money can buy today, the Ultimate CF SLX 8 Di2 had a big reputation to uphold.

It manages this, and more. It feels like a slightly more comfortable, easier-to-ride bike than its flagship sibling, without conceding much in the way of weight.

It’s priced competitively, and the component choices are practically impossible to meaningfully upgrade for the vast majority of riders (without, at least, spending a lot of money to obtain only marginal improvements).

Compared to the CFR, the CF SLX frameset packs in outstanding performance, with more sensibly priced and pitched builds.

In the context of the all-rounder race bike market, the Ultimate CF SLX 8 Di2 deserves a spot on the very top shelf.