Shimano’s RP4 cycling shoes sit on the lower end of the brand’s range but shouldn’t be overlooked for triathletes seeking all-day comfort.
Sole
The RP4’s glass-fibre reinforced nylon sole has a stiffness rating of six on Shimano’s scale (as opposed to the pro-peloton level RC9’s stiffness of 12). This might put some off, but the idea is that it equates to more comfort and efficiency for longer rides.
It’s part of Shimano’s Dynalast technology, which features a springer area under the toe box, which is designed to promote a smoother, more energy-efficient upstroke and decrease tension in the plantar, calf and hamstrings.
While we can’t attest to feeling suppler muscles through riding in the RP4s, we can confirm that they’re some of the most comfortable shoes you’re likely to find. The RP4 feels stiff under power yet not completely unyielding and after hours in the saddle, feet feel fresh and run ready.
Another boon of the sole for triathletes is the extended cleat adjustment area. Most shoes feature three fixed bolt holes, meaning setting the cleat’s fore and aft position is down to the cleat itself. By contrast, the RP4s feature a sliding plate built into the sole that allows for the more set-back position favoured by many bike-runners.
There’s also a large rubber heel pad and while it’s not replaceable, its chunky design should provide plenty of life and extra traction at coffee stops. At the other end of the shoe is another rubber bumper plus sizeable vents under the toebox to aid airflow and help avoid overheating.
Upper and closures
In recent years, Shimano has updated the styling of its lower-end shoes to make them look racier and more professional. That’s certainly the case with the RP4’s sleek synthetic upper, which is thick enough to be supportive in itself but also perforated in several places, so it breathes well.
There’s a great balance of padding inside to aid comfort while the Shimano insole lifts the arch slightly for an extra sense of support without wresting the foot unnecessarily.
The shoes are secured by a combination of Velcro straps and a single BOA dial closure. The straps are offset to reduce any hotspots across the top of the foot and stay put once fastened. In fact, since setting the tension on our first ride, they stayed locked in place with all other adjustment coming from the BOA.
The BOA dial is a great addition and marks the difference between this shoe and its cheaper siblings. As the dial is turned, tension on a wire is ratcheted up, cinching down over the instep. It’s a great design that works really well.
While there’s no heel loop on the shoes to easily hold them horizontal in transition, opening the BOA dial fully allows easy insertion of the foot in T1. You can then wait until you’re on the bike before turning up the tension – all without fear of a strap to get in the way of your chain.
The only downside to the BOA is that this model doesn’t allow ratcheted loosening. So, if you find things are getting a little tight as the day warms up, it takes a couple of extra seconds to pull the BOA out – releasing all tension – then dialling back to your preferred level.
The heel cup is reinforced giving stiff support that kept the heel from slipping but also well padded. Combined with the thickly cushioned tongue, this makes the RP4s an extremely comfy place for your feet no matter the distance.
Wide fit option
For those with feet wider than the traditionally slim profile most cycling shoes seem to be made for, finding a good fit can be tricky. Shimano’s wide fit option is only available on certain models and luckily for our spread-toed flippers, the RP4 is one of these.
The wide fit here also means more volume in the shoe, which will aid comfort for those with larger feet or high arches. In our low-profile case, adding a simple insole under the stock Shimano one gave a great fit and lasting comfort.
A quick word on sizing – we’ve never been above a size 45 before in Shimano shoes but we had to swap out to a 46 in the RP4s, so it’s probably best to try before you buy.
On the bike
Given Shimano’s pedigree, it shouldn’t really be a surprise that a mid-range shoe like the Shimano RP4 performs exceptionally well.
No matter the length of the ride, the secure yet very comfortable fit meant hour upon hour of foot happiness. The shape of the last allows the toes to stay spread and relaxed, letting your feet do their thing without the excessive pressure that comes from ‘racier’ designs.
The fact the shoes don’t have the stiffest sole in the world certainly adds to that endurance comfort, allowing a more natural movement. Don’t mistake that for a sloppy, soft feeling though – there’s no sense of lost power, especially when pulling hard out the saddle.
At the end of rides, we’ve experienced zero pain, numbness or irritation after releasing our feet – making brick sessions a breeze.
