Triban RC120 Disc vs Rim Brake: Which Entry-Level Road Bike Is Worth It?

Introduction

The Triban RC120 has become one of the most accessible ways into proper road cycling, and the disc brake version asks only a modest premium over the rim brake model. That premium is roughly £50, which raises a fair question: does the disc bike justify the extra spend, or does the lighter rim brake version make more sense?

This comparison looks at both bikes as they arrive from the shop, covering weight, gearing, tire clearance and the details that matter once you start riding regularly.

What Both Triban RC120 Models Share

Both bikes are built around an aluminium frame paired with a carbon fork, a combination that is genuinely uncommon at this price. The geometry is relaxed rather than aggressive, which keeps the riding position comfortable for newcomers, and there are spacers under the stem that can be removed later if you want a lower, faster position. The frame also carries mounts for racks and mudguards, so commuting and light touring setups are straightforward.

The drivetrain is a Microshift 8-speed groupset with a 50/34 chainset and an 11-34 cassette. That pairing delivers a 1:1 easiest gear, which is enough to get up genuinely steep climbs without grinding. Shifting is crisp, and the shifter ergonomics are comfortable even if they do not match the feel of far more expensive groupsets.

Finishing kit comes from Decathlon’s own B’Twin range, including the handlebars, stem and saddle. The saddle sits on a standard 27.2 mm seatpost, so swapping it for something lighter or differently shaped is easy. Bar width is matched to frame size, with the size small using 40 cm bars. The small frame tested here suited riders around 5 ft 8 in to 5 ft 10 in, so taller riders should look at a medium.

Bikes arrive fully assembled by a mechanic and include lights, reflectors and pedals. The lights are adequate for being seen in traffic, though they are not bright enough to light the road ahead.

Triban RC120 Disc: Disc Brakes and Bigger Tire Clearance

The disc version is the more versatile of the two, and the differences go beyond the braking system. Tire clearance is the headline: the frame is officially rated for 36 mm tires, but 38 mm and even 40 mm gravel tires fit with room to spare. That opens up comfortable commuting rubber, light off-road riding and cyclocross-style setups on a single bike.

The wheels are tubeless ready, something the rim brake model does not offer. They ship with tubes because sealant has a shelf life, but converting later is an option if you want the puncture protection that tubeless brings. The 28 mm Triban tires fitted as standard held their grip well, including on wet, slippery climbs.

Weight is the trade-off. On the same scale and with the shop extras removed for a fair comparison, the disc bike came in at 11.1 kg against 10.72 kg for the rim brake version, a difference of roughly 400 g. Most of that sits in the brake hardware. In everyday riding the extra weight is not something you notice, and the disc brakes themselves offer strong, predictable stopping once they are bedded in. Expect the first 15 to 20 minutes of riding to bring them up to full performance.

A couple of small details are worth checking early. The rear wheel can rub slightly if it is refitted a little off centre, and the cable clip on the fork can work loose over time, so a cable tie is a sensible replacement. Neither is a reason to avoid the bike, and both are quick to sort.

Triban RC120 Rim Brake: Lighter and Around £50 Cheaper

The rim brake version keeps the same aluminium frame, carbon fork, 8-speed Microshift drivetrain and friendly 1:1 climbing gear, but trims the price by roughly £50 and sheds a little weight. At 10.72 kg it is the lighter bike of the two, and for riders who rarely leave smooth tarmac that saving is easy to live with.

What you give up is flexibility. The rim brake frame has noticeably less tire clearance, so the wide gravel and commuting tires that fit the disc version are off the table. The rims are also not tubeless ready, which closes off that upgrade path.

If the goal is simply the lowest possible cost of entry into road cycling, this version still delivers the same comfortable geometry, the same gearing range and the same relaxed handling. It suits riders who know they will stay on paved roads and would rather put the £50 towards a helmet, lights or a better saddle.

Practical Ownership Notes

One frame detail deserves attention before you buy. The derailleur hanger is built into the frame rather than being a replaceable part. If the bike goes down on the drive side and the derailleur takes a hit, the hanger can bend with no way to swap it out, which can mean replacing the frame instead of a small bracket. Higher-end frames in the range use a replaceable hanger, so it is worth knowing the limitation and being careful when parking or transporting the bike.

Ride quality is firmer than on very expensive road bikes, which is expected at this price. It is not uncomfortable, just less cushioned over rough surfaces, and fitting wider tires on the disc model is one way to soften that. The saddle has no pressure relief channel, which some riders prefer to change; the standard seatpost diameter makes that straightforward.

The tires can be removed by hand without levers, which is reassuring if you puncture at the roadside. Carrying a set of tire levers is still a good habit.

Overall Buying Advice

For most riders, the disc version is the one to choose. The extra £50 buys disc brakes, tubeless-ready wheels and tire clearance that turns a road bike into something you can ride on gravel paths and rough commuter routes. That flexibility is worth more than the small weight penalty.

Choose the rim brake version if your budget is fixed at the lowest possible figure, you are confident you will stay on tarmac, and you value the slightly lighter build. It is still an excellent first road bike, just a less adaptable one.

Whichever you pick, budget for a few small extras: tire levers, a spare tube and, if you go for the disc model, a cable tie for the fork cable clip. Fit matters more than spec, so try to sit on the size you are considering. Riders around 5 ft 8 in to 5 ft 10 in were well served by the small frame, and anyone taller should look at a medium.

Conclusion

Both versions of the Triban RC120 deliver a level of equipment and ride quality that feels well beyond their price. The disc model is the more capable all-rounder thanks to its brakes, tubeless-ready wheels and generous tire clearance, while the rim brake version remains the lighter and cheaper way in. If the budget reaches around £400, the disc bike is the easier recommendation.