Prime Thermal Bidon 500ml

The Prime Thermal Bidon is a compact and lightweight bottle aimed at riders with smaller-framed bikes looking to save grams while keeping your drinks cool. On this basis, it does exactly what it says in the blurb and keeps drinks cooler for longer than some of its competitors. The 500ml size is also a good bet for smaller, compact geometry frames. However, a protective cap to prevent ingesting nasties thrown up by the front tyre would've been welcomed.

Specification

The bottle is made from BPA (Bisphenol)-free plastics, so shouldn't taint your tipple, or cause nasty chemicals to leach into you. Nothing particularly new there, but what's this nanogel, then...? Well, apparently, it's the world's lightest insulating material, made from 5% 'solid material' and 95% air, and it's reckoned to keep drinks cool for four hours.

Given most of us associate the word 'thermal' with heat or keeping a consistent temperature (whether hot or cold), the fact that the Prime Thermal is not designed to keep warm drinks warm might come as a shock. If you haven't clicked away having read that, this is a compact 500ml (about 16.91 oz) bottle, so should fit nicely in most jersey and jacket pockets. It's 74mm (about 2.91in) in diameter if you're wondering whether it will be a snug fit in your cages.

As for the spout, it's a simple push-pull affair, so should be intuitive. Prime makes weight a selling point, but at 116g it's heavier than some other bottles with thermal properties, including the Passport Frostbite Reflective Water Bottle, though it's lighter than the Elite Nanogelite.

Cage compatibility/Security

I've successfully paired ours with traditional and contemporary shapes, made from carbon, composites, stainless steel, aluminium alloys and titanium, which can be a little springy. Release across the board has been faff-free-grab, guzzle and slot back. 

More traditional cages with gripper buttons, the sort featured on the Elite Ciussi and this Van Nicholas Ti bottle cage, were arguably the more secure, vibration-damping hosts, although thankfully, I found reliability with side-entry models, including this Lezyne Flow SL similarly good on and beyond tarmac, which is good news if you ride a bike with a smaller frame

Smaller bottles are a less obtrusive fit in your jersey/gilet and jacket pockets and the Prime is no exception – helpful if you want some cooling relief on hot days or when you're grinding away on the indoor trainer. It's much the same story security-wise – no ejections or similar woes whether exploring green lanes, unmade roads or just hossing along washboard tarmac.

Grip, at least in gloves with leather palms or those dotted with silicone detailing, has been similarly reliable, although some non-cycling-specific, technical gloves made a less tenacious connection – not that I dropped the bottle, but I needed a firmer grasp.

Flow rate and thermal properties

Flow rate is predictable from the spout and the bottle is easy to compress for a quicker delivery. It becomes slicker with use and again, doesn't seem prone to unwanted dribbling, or leaking – I've parked the bottle upside down in a pocket and not had any issues, either.

Now, this would be an absolute boon if the thermal properties were a two-way street. Alas, while it has kept cold stuff chill for the claimed four hours – at least during November and December, when temperatures ranged between freezing and 12°C, the inability to fill it with something warming was a little disappointing – especially given its 'thermal' tag. Minor grumbling aside, drinks tasted authentic and crisp, with no chemical taint.

Care/Durability

The neck is sensibly wide, so most bog-standard bottle brushes should get right into nooks and crannies, purging any stomach-upsetting bacteria. Gentle tickling rather than enthused scrubbing is key here, with no effect upon the bottle's technical properties to date. However, I would avoid powerful cleaners, such as Milton.

Value

The Passport Frostbite Insulated Reflective Water Bottle is 550ml and costs £11.99. Made from PVC, the thermal properties are two-way, and George found it a good fit in his cages. As a side note, it also features retro-reflective detailing for some added night-time/winter presence. However, the bottle walls were less malleable, requiring more effort to get drinks to flow.

The Elite Ice Fly is available in a 650ml version for £11.99 and includes a protective cap to protect spout from getting caked in filth but only keeps drinks chill for two and a half hours

Summary

The Prime Thermal Bidon is a competent bottle and on the plus side, has done what it says in the blurb. It's a good bet for smaller frames, and stuffed in a jersey pocket, could supply some cooling relief on a very warm day. However, there are cheaper alternatives, and a protective cap would be a welcome touch whether you're riding on road or off.

Verdict

Good all-rounder that keeps drinks cooler for longer but would benefit from minor refinement