Merlin Nitro SL review

The Merlin Nitro SL comes with WorldTour credentials and a UCI sticker. We've tested its lightweight and climbing capabilities

Merlin Nitro SL 2017 road bike
Merlin Nitro SL 2017 road bike
(Image credit: chris catchpole)
Cycling Weekly Verdict

Merlin has pulled off something of a coup by sourcing a frame ridden at WorldTour level in 2016 and offering it as a great value package. You can feel the frame’s racing heritage in its ride performance, but it delivers without sacrificing comfort. Indeed the Nitro SL is a bike which can happily be ridden for long periods, rewarding and encouraging extra effort. The bike is nicely specced for its price too. A complete Ultegra groupset is a bonus: too often there are swap-outs for cheaper components – particularly brakes and chainset – but these have been avoided by Merlin. The choice of Fulcrum’s Racing Quattro LG wheelset should give plenty of trouble-free miles too. So we’re impressed by the Nitro SL. With its low weight and quality spec it’s a bike which would serve an enthusiastic rider well. A wheel upgrade would add even more to its appeal. With its WorldTour pedigree it’s a bike that wouldn’t look out of place on the start line of a hillier race either. And currently discounted to £1,750 it’s something of a bargain.

Reasons to buy
  • +

    Impressive frame

  • +

    Well specced

  • +


  • +

Reasons to avoid
  • -

    Quite high geared for UK all-round use

You can trust Cycling Weekly. Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.

Lancashire based Merlin Cycles has grown steadily since its inception as a mail order business in 1993. It’s also got a retail shop attached to its warehouse in Chorley.

Alongside selling bikes and kit from the well known brands, it also distributes Dutch brand Sensa’s bikes in the UK. And it has a well regarded own-brand offering of bikes and kit. Although Merlin is coy about it, some of its bikes are sourced from Belgian bike manufacturer Ridley, among them the Nitro SL, the top of its road bike range.


Ridley has upgraded its Helium SL road bike this year to the Helium SLX, but the rebadged Helium SL frameset lives on in the Nitro SL. It’s a frame which the Lotto-Soudal WorldTour team, including its star climber Thomas de Gendt, have used as their climbing bike and has survived being ridden by sprinter André Greipel. It bears the UCI approval sticker to indicate that it is authorised for use in races sanctioned by cycling’s governing body.

Nitro SL comes with a full Ultegra groupset, including brakes and chainset
(Image credit: chris catchpole)

Made with a mix of 30 and 24-tonne high-modulus carbon and with an all-carbon fork, it’s the basis for an impressively light build. Merlin claims 750g for the frameset. It has neat internal gear cable routing, although the brake cable runs externally along the top tube. There’s a BSA-threaded bottom bracket mounted in a shell with wide junctions to the down tube and seat tube.

>>> Ten climbs from around the world you haven't heard of

Nitro SL comes with a UCI sticker showing its racing heritage
(Image credit: Merlin Cycles)

The frame has plenty of clearance for the fitted 25mm tyres, although 28mm might be a tight squeeze.


Merlin has kitted the Nitro SL out with a full Shimano Ultegra groupset, including brakes and the 52/36 semi-compact chainset, which is coupled to an 11-28 Shimano 105 cassette. It functions as sweetly as you’d expect, with the internal routing protecting it from the elements during winter rides.

Nitro SL's neat cockpit comes from Ridley's 4ZA component sub-brand
(Image credit: chris catchpole)

Bars, stem and alloy seatpost come from Ridley’s 4ZA component brand. The marque is well regarded and used extensively on is own machines. Bars are quite wide at 42cm centre to centre and have a shallow drop. There’s a San Marco Ponza saddle which is narrow and sits on chromoly rails. I didn’t find it comfortable for longer rides: it’s the only component I’d swap out for something that suited me better.

>>> The best bike saddles

Watch: Aero versus lightweight bike - the climbing test

Merlin has fitted Fulcrum Racing Quattro LG alloy wheels with Continental Ultrasport II tyres. The Racing Quattro LG is a slightly deeper section design at 35mm and sits between the Racing 5 and the Racing 3 in Fulcrum’s range. It shares the quality build and 2:1 rear spoke pattern of Fulcrum’s other wheels.


The Nitro SL offers an interesting and rewarding mix of efficiency and comfort. You can feel the stiffness of the bottom bracket area and the rear triangle. It’s among the stiffest rear ends with the greatest feel of efficient power delivery that I’ve encountered.

At the same time, it’s really very compliant by the time you reach the saddle and the cockpit, so it’s comfortable to ride. There’s clearly enough flex in the fork and the skinny seatstays to smooth out road imperfections very well.

Fulcrum Racing Quattro wheelset suits the Nitro SL well
(Image credit: chris catchpole)

The bike tracks exceedingly well too, with positive steering leading to assured descending and handling at speed. Braking from the Ultegra calipers married to the Racing Quattros’ alloy rims is excellent.

>>> Is the compact chainset dead?

The 36-tooth smaller chainring and the 11-28 cassette obviously gives a taller bottom gear than a standard compact would. This makes very steep climbs a bit of a grind, although the light weight and efficient frame means that you do feel that your effort is pushing you forward rather than being dissipated by a flexy bottom bracket and stays.


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