One of the most common questions we receive is “what’s the widest tire that fits the Decathlon Triban RC 520?”. While some versions of Decathlon’s websites list the maximum tire clearance to be 700×36, several people on a couple of bike forums have claimed to go higher. Wider tires not only have better grip but also offer a smoother ride in part to the lower pressures they require and taller side walls. This additional cushioning means that wider tires can soak up potholes if you’re commuting on rough city roads or provide more grip off road. Thanks to some help from Hutchinson, we’re excited to test out some wider tires to see whether they cleared the frame and how it affected the ride. Decathlon ships the RC 520 with their own Triban branded 700×28 tires so we decided to test 700×35, 700×38 as well as a 700×40 tire on our RC 520 (note the frame is the same as the RC 500). 

We chose the Hutchinson Override tires in the 700×35 and 700×38 variations as they offer an excellent blend of on-road compatibility by incorporating a dual tire tread. The center is semi-slick for less rolling resistance while the sides are knobby for improved grip. Hutchinson offers the Override tires in both standard tube and tubeless ready variations as well as a tan walled option. For the larger 700×40 tire, we chose Hutchinson’s new Touareg tires which is one of their most versatile tires and excellent for everything from bikepacking, commuting, to gravel racing. Using the same 127 TPI construction and a small-block knob design, the Touareg tires offer a great blend of puncture resistance, grip and speed.

STOCK TRIBAN PROTECTLIGHT TIRES

Before we get too far, we wanted to take a second to talk about the stock Triban PROTECTLIGHT 700×28 tires that the RC 520 ships with. The tires have a semi-slick design with L shaped groves to improve mixed weather riding. Decathlon has designed the tires with economics in mind, so they are quite heavy at 365g each and stiff. This becomes very obvious once you remove the tires from the rim (a very difficult task as they appear to be glued from the factory!) and feel how rigid they are. Compared to the 127 TPI construction of the Hutchinson tires which easily deform to pressure, the Triban tires are very rigid. Whether you want to go wider or not, we definitely recommend upgrading the tires as we discussed in our review of the 700×28 Hutchinson Sector 28 – as high quality tires really improved the speed and feel of our RC 520.

RIM WIDTH CONSIDERATIONS

Although you can theoretically install any tire on a wheel if the diameters are compatible, the general advice is to use similar sizes. For any given inner wheel width there is an ideal tire width to ensure optimal performance. If you run a very wide tire on a narrow wheel or a narrow tire on a wide wheel, there is a higher risk of flats or tire/wheel damage. The stock Triban Tubeless Ready Light wheels that come with the various Triban bike variations have a narrow internal width of 17mm. According to some trusted conservative online sources, the Triban wheels can be matched with tires ranging from 25-37mm. While you can still go below/above this range as we did with the 700x40s, you should consider a different wheelset to avoid potential issues. Also note that as you go wider some with a tubed setup – you may need to use a wider tube to accommodate the larger sized tire.

DOES IT FIT? YES!

All the tires we tested had no clearance issues. You heard that correct, even the 700×40 Touareg tires did not rub on the frame even at different tire pressures on and off the road. As you can see in the photos, the Triban RC520 looks quite impressive with the tan 700×38 Override tires and the almost fat bike sized 700×40 Touareg tires. Despite the more aggressive knobby tread and wider widths, there were no clearance issues on the fork, seat stays or chain stays. The narrowest points are the chain stays though, and with the 700×40 Touareg tires and our slightly out-of-true rear wheel, we measured about 1-2 mm clearance on each side of the tire. 

Widest tire that fits the Decathlon Triban RC 520 - 700x38
The tan walled 700×38 Override tires not only make the Triban more capable off-road but also make it Instagram ready.

Note, the big caveat here is that our testing was only for the Triban stock tires and the Hutchinson tires combinations. Using our calipers, we found that the Hutchinson tires were consistently 1mm more narrow than the claimed width. The discrepancy is due to how the wheel/tire combination fits, so the same tire may fit differently on a different wheelset. Although there was room to spare with the 700×40 Touareg tires, we’d be hesitant to recommend using them with the stock Triban wheels due to the narrow tire width and would recommend using wider wheels or 700×35 tires.

Widest tire that fits the Decathlon Triban RC 520 - 700x40
Surprisingly the 700×40 Touareg tires fit on the Triban without clearance issues at the seat/chain stays or fork.

RIDE QUALITY

Once you’ve ridden with wider tires, it’s easy to see why they’ve become so popular. Compared to the stock 700×28 tires, the wider Override and Touareg tires were more supple and smooth off-road or on rough city streets. The more aggressive tread design of the tires have more grip on gravel or dirt providing more confidence to ride faster. However on the road, the wider tires (particularly the 700×40) felt more mushy and less responsive than the Sector 28 or even stock tires. Depending on what type of terrain you ride in, it’s easy to adjust the feel of the tires by playing with the tire pressure. Use a higher tire pressure for more road riding and a lower tire pressure off road to improve the grip.

THE VERDICT

Overall we found that not only were we able to run a wider tire than the 700×36 maximum width Decathlon recommended but were able to run the 700×40 Hutchinson Touareg tires as well. The aggressive gravel tires not only cleared the fork and seat stays, but they also had additional space between the narrow chain stays. Just because you can fit the wider tires doesn’t mean you should. With the narrow 17mm inner width of the stock Triban wheelset, the general advice is to stick to more narrow tires or upgrade to a wider wheelset. Also, we’d recommend choosing your tire width based on the type of terrain you ride on. Stick to 700×35 or similar size and a higher tire pressure if you plan to do primarily city commuting as you get the benefits of a smoother ride and can still find tires that are lighter than the stock tires. Choose wider tires with lower tire pressure if you plan to ride off-road to take advantage of the additional grip and contact surface.

Disclaimer:  The tires for this review were provided by Hutchinson. The views expressed on this website are solely those of the authors and are here to help people make an informed choice before a purchase. The authors or the blog itself does not get any monetary compensation from the product manufacturer or third-party websites/vendor links that are posted here.

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