The Boardman SLR 8.9 Carbon retains its excellent frameset for 2021, but it's now bedecked with an even better groupset for a wider, 11-gear spread. It only boosts the already great versatility, and it's ripe for longterm upgrades.
Mat tested the previous version of this bike back in 2018 and was very impressed, and now I've ridden the 2021 version I can see why. It's brilliant!
At the heart lie Boardman's C7 frame and fork, which use the same aerodynamic design and geometry as the rest of the SLR range, albeit here with a different grade of carbon fibre.
This sacrifices a tiny bit of stiffness around the bottom bracket, although you're only really going to notice when you're absolutely smashing the pedals in a sprint or taking on a power climb. For 99% of riding it's not an issue.
It's a comfortable frameset to ride, which could be a byproduct of that tiny bit of extra flex. Either way, I did a couple of long rides – four hours or so – on the 8.9 and it's a smooth ride. There's no harshness to speak of, and I found the riding position well thought out.
I could get a relatively stretched aero position, with a decent drop from the saddle to the bar, that wasn't too extreme to hold for mile after mile.
This makes it a quick and efficient bike to ride, especially as the front end geometry is on the lively side of neutral. Technical descents can be taken at speed, not only because of the planted feel, but also thanks to the stiff fork and rigid, tapered head tube and steerer.
Feedback is also good, so you get a good sense of what the bike is doing while you're scanning ahead for the next apex or hazard.
The Vittoria Zaffiro Pro G2.0 tyres do mute that feedback a little, so an upgrade here can make a big difference to the overall ride feel. On the whole, though, the SLR 8.9 is a fun bike to ride as hard and as fast as you like.
It's not as aerodynamic as some frames out there, but Boardman has designed the 8.9 to cheat the wind (a bit), although those benefits increase with the addition of deep-section wheels. As I was also testing the Edco SIX-4 wheelset, I bolted them on – and the 8.9 transformed into a very quick bike, boosted still further by a bit of weight loss.
The Boardman's tube profiles have been dictated by CFD (computational fluid dynamics) and subsequent wind tunnel testing. Each tube flows from one to the other and the internal cable routing means that surface stays smooth and clean.
The majority of the frame is quite boxy and chunky for stiffness, but the dropped seatstays are pencil-thin – it's a big help with comfort. Putting the joint so low allows a bit of flex both in the tube and the seatpost, which helps take the sting out of the rough surfaces.
Tyre clearance is limited by the calipers, so you can't go mad like you can with a disc-equipped bike, but the Boardman still takes 28mm tyres. If you want to use the (discreet) mounts for mudguards, you can still get away with 25s, too – the 8.9 is pretty versatile.
This is a bike that works very well as a fast winter trainer or year-round quick commuter/club run steed.
The SLR is available in four sizes, covering a recommended height range of 170cm to 195cm. We got the medium, which has 555mm top tube, 160mm head tube, and a 500mm seat tube. The key angles are 72.5° for the head tube and 73.5° for the seat tube.
All of this gives a reach of 567mm and a stack of 387mm, meaning a ratio of 1.46. That puts it more towards the race end of the spectrum than endurance.
The previous model came with a ten-speed Tiagra groupset comprising a 50/34T chainset and a 12-28T cassette. For 2021, the SLR 8.9 jumps up to Shimano's 11-speed 105, albeit mated to an FSA Gossamer chainset.
It's still a 50/34T, but the cassette with its extra sprocket now offers an 11-30T spread, which gives you a little bit extra at both ends of the range. Shifting from the R7000 derailleurs and gear levers is crisp and precise; it's one of the best groupsets out there for performance versus cost.
To facilitate the mudguards, Boardman has fitted Tektro R315 long arm calipers. They don't quite have the same bite as a set of 105 calipers, but overall, I was pretty impressed. They gripped tight even before the rims and pads could bed in, which isn't always the case.
Speaking of wheels, Boardman provides their own SLR rims on Formula hubs and double-butted stainless steel spokes. It's not an exciting wheelset, but it is tubeless-ready, and robust too. Hammering around local roads clipping potholes here and there has caused no reliability issues.
They aren't the lightest, which saps energy if you spend a lot of time in urban areas pulling away from a stop, but it's less noticeable out on the open roads. Long term I'd be looking at an upgrade to something lighter, and with a bit of an aero edge to exploit the frameset, too.
Continuing the 'not the most' theme, the Vittoria Zaffiro Pro G2.0 25mm tyres aren't the most supple, but they are durable and will keep you rolling through all four seasons. Grip levels are decent, and while I'd also upgrade here eventually, it's not a must-do straight away.
Boardman has tweaked the contact points for 2021, going narrower at the front and reducing crank lengths. Bar width on this medium is just 400mm, 20mm narrower than you'd generally expect, but I like it – a narrower bar makes the steering feel slightly quicker, and that certainly keeps the Boardman feeling lively.
Most bikes of this size get 172.5mm cranks, but the 8.9 wears 170mm long versions. These changes aren't just for the sake of it, either: Boardman took data from hundreds of bike fits, and insights from bike fit experts, to tweak it.
Has it worked? I can ride five different bikes a week, so my position has become a bit 'ballpark' instead of specific, and I must admit the shorter crank length didn't feel any different to me. The Boardman branded alloy components all do a decent job, anyway. I found them comfortable, and the 120mm bar drop makes the lowers easily accessible to most.
The SLR saddle is good too – I got on with it fine, and never really noticed it, to be honest. I like the length, which allows you to shift your position around a bit, and the padding is firm enough that you sit on it rather than in it.
A carbon frame (a good one at that) is quite rare at £1,000, especially one sporting the majority of a 105 groupset. But that's exactly what Boardman has achieved.
The big rivals, such as Giant's Contend SL-1, typically come with a very similar build but an aluminum frame instead. It's not a problem for the Contend, as it is a very good alloy frame, but if you really must have carbon you need to look elsewhere.
Ribble offers its R872 in both disc and rim brake guise. The cheapest rim brake model is £1,099.99 and gets you a carbon fibre frameset, albeit with a 10-speed Tiagra groupset instead.
The Boardman SLR 8.9 Carbon remains a top-level contender for bikes around the £1,000 mark, especially with with its new upgraded groupset. The frameset is high upgradable too, pleasingly aero and also very versatile.
Fast and fun thanks thanks to a great frameset and impressive spec list – especially for the money
If you're thinking of buying this product using a cashback deal why not use the road.cc Top Cashback page and get some top cashback while helping to support your favourite independent cycling website
road.cc test report
Make and model: Boardman SLR 8.9 Carbon 2021
Size tested: Med/55cm
About the bike
List the components used to build up the bike.
Frame: C7 Carbon - Aero-Optimised
Fork: C7 Carbon with tapered steerer
Headset: FSA Orbit C-40 ACB, 1 1/8' - 1.5' Tapered, Integrated.
Bottom bracket: FSA BB-CF86/CZ Pressfit for MegaExo Chainset
Chainset: FSA Gossamer Compact 50-34
Front mech:Shimano 105 braze-on
Rear mech: Shimano 105 11 speed
Shifters: Shimano 105 2x11
Brakes: Tektro R315, long arm
Cassette: Shimano CS-R7000 11 speed, 11-30
Chain: KMC X11
Saddle: Boardman SLR
Seatpost: Boardman Alloy, 27.2mm
Stem: Boardman Alloy, 31.8mm clamp
Handlebar: Boardman Alloy, 31.8mm clamp, 70mm reach, 120mm drop
Bar tape: Boardman Soft-grip
Pedals: Toe strap road, 9/16'
Wheels: Boardman Alloy Tubeless Ready
Hubs: Formula RB-51 front, RB-5711 rear
Spokes: Double Butted Stainless Steel, Radial front, 2X rear
Rims: Boardman Tubeless Ready 28h front & rear
Tyres: Vittoria Zaffiro Pro G2.0 folding, 700x25c
Tell us what the bike is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about the bike?
Boardman says, "The original SLR 8.9 Carbon was our most popular carbon road bike, and for good reason. We think the light, stiff and comfortable carbon frame designed with aerodynamic tube profiles and features is a perfect platform for all-round road riding, and the reviewers agreed with us. For most bike brands, 4.5 out of 5 reviews and comments like 'Blimey, what a corker!' (road.cc) would be a reason to kick back and celebrate a job well done. However, at Boardman, we are always looking for ways we can push our bikes to the next level, and this is what we have done for the new SLR 8.9 Carbon."
This is a very competent race bike that also has the versatility to run full mudguards.
Where does this model sit in the range? Tell us briefly about the cheaper options and the more expensive options
This is the only carbon fibre, rim braked model in the SLR range, although there is an alloy framed 8.6 and a titanium 9.6 at the top of the line-up.
Frame and fork
Tell us about the build quality and finish of the frame and fork?
The frameset looks and feels high quality.
Tell us about the materials used in the frame and fork?
The frame and fork use Boardman's C7 grade carbon fibre.
Tell us about the geometry of the frame and fork?
The geometry gives quite an aggressive ride on a bike which is race orientated. Full geometry tables can be found on Boardman's website.
How was the bike in terms of height and reach? How did it compare to other bikes of the same stated size?
Very typical for this size and style of bike.
Riding the bike
Was the bike comfortable to ride? Tell us how you felt about the ride quality.
Yes, comfort is impressive.
Did the bike feel stiff in the right places? Did any part of the bike feel too stiff or too flexible?
Yes, on the whole the SLR 8.9 has plenty of stiffness for hard efforts and fast riding.
How did the bike transfer power? Did it feel efficient?
Power transfer is pretty good, although improved markedly by lighter wheels.
Was there any toe-clip overlap with the front wheel? If so was it a problem?
How would you describe the steering? Was it lively neutral or unresponsive? The neutral side of lively.
Tell us some more about the handling. How did the bike feel overall? Did it do particular things well or badly?
Fast enough handling to enjoy the technical descents, without the steering being so fast it becomes twitchy.
Which components had the most effect (good or bad) on the bike's comfort? would you recommend any changes?
The saddle offers decent comfort and there's a small amount of flex in the seatpost.
Which components had the most effect (good or bad) on the bike's stiffness? would you recommend any changes?
The majority of the components offer plenty of stiffness, though there is a hint of flex at the rims.
Which components had the most effect (good or bad) on the bike's efficiency? would you recommend any changes?
The increased range of gears makes the bike more efficient at both ends of the cassette.
Tell us some more about the drivetrain. Anything you particularly did or didn't like? Any components which didn't work well together?
As much as I'd like to see a matching 105 chainset for aesthetic purposes, the groupset works well as a whole.
Wheels and tyres
Tell us some more about the wheels.Did they work well in the conditions you encountered? Would you change the wheels? If so what for?
The wheels are pretty solid and have the bonus of being tubeless ready too. Something lighter really transforms the bike, though.
Tell us some more about the tyres. Did they work well in the conditions you encountered? Would you change the tyres? If so what for?
Just like the wheels, they are durable but the bike deserves something faster rolling.
Tell us some more about the controls. Any particularly good or bad components? How would the controls work for larger or smaller riders?
A decent package all round.
Did you enjoy riding the bike? Yes
Would you consider buying the bike? Yes
Would you recommend the bike to a friend? Yes
How does the price compare to that of similar bikes in the market, including ones recently tested on road.cc?
Many £1000 bikes from Giant and Specialized come equipped with similar spec lists, but with alloy rather than carbon frames, should that be an issue.
Ribble's R872 carbon offering is more expensive at £1,099.99 and comes with Tiagra.
Use this box to explain your overall score
With this SLR 8.9 you're really getting a lot of bike for the money. But it is not just the value that impresses – the frameset and pretty much everything else is very good, and highly upgradable.
About the tester
I usually ride: This month's test bike My best bike is: B'Twin Ultra CF draped in the latest bling test components
I've been riding for: Over 20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, club rides, sportives, fixed/singlespeed,
With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!