If you're looking for a dynohub for day-in-day-out riding then the Shutter Precision PV8 Dynamo Hub is certainly one to consider. It's under 400g in weight, puts out plenty of juice and has stood up well to the rigours of the British 'Summer', and at £90 is decent value too.
SP make a range of hubs, including a switchable one that uses the same internals as the Supernova Infinity 8, but this is their lighweight option. This rim-brake option weighs just 387g, about as light as you'll find. There's a disc version too that's just over the 400g mark.
Both of those units use the same basic shell, which means the flanges on the PV-8 aren't as widely spaced as they could be at just 50mm apart. While in theory this means that the wheel won't be quite as strong as a wider hub, in practice (built up with Halo double butted spokes to a Mavic Open Pro rim) the wheel's been fine. It's no more flexible that I've noticed, and I've been bunging it into corners to check.
Build quality looks to be very good, with aluminium end caps protecting the sealed bearings and dynamo gubbins inside. The Shutter Precision dynamos use a different setup to most hubs: there's a metal ring that's magnetised with a number of individual poles around its circumference, and this rotates with the hub in a slot in the stator. It's a clever way of building a dynamo and certainly it's less work than arranging the magnets around the hub shell, the traditional way to do things. It also means you only have to precision-fit one ring rather than 30-odd magnets, so that makes it cheaper too. It's been wet here, like it has everywhere else, and a quick check behind the end caps reveals no moisture inside from a summer of riding. That bodes well for longevity.
Shutter Precision claim a 72% efficiency for this hub, which means you only need to feed about 3.3W in to get your 2.4W out - that's class-leading if accurate. The output from the PV8 is certainly impressive, up to about 5mph the generator output ramps up steeply and then flattens off as you get faster. It's a very similar power curve to the Infinity 8; not surprising considering they share effectively the same internals.
With a Supernova E3 Pro light running up front you get easily enough light for all-night riding, and even when you're running a USB charger as well you get a usable beam, though there's not quite enough light to go at all-out speed.
You'll be seeing a lot of dynamos based on these internals. Supernova use them, Biologic have started to, Exposure's new light is paired with one and there'll likely be more as SP seem happy to license the technology. Most of the third party manufacturers are developing their own hub shells to fit the SP internals in, but from what I've seen there's very little wrong with the original and at £90 it's excellent value. A wider flange version would be a welcome addition to the range but that's really my only gripe.
Well made dynohub with excellent power output; a great option for day-in-day-out riding.
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Make and model: Shutter Precision PV8 Dynamo Hub
Size tested: n/a
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
The SP 8-series hub dynamo incpororates the best technical advancements and seeks to attain perfection in field of hub dynamos. Painstaking innovation has made an optimal hub dynamo reality. The SP-8's technological advances are well hidden under it durable shell.
Numerous simulations were conducted to optimize the mechanical dynamics of the dynamo contained within the SP 8-series concept. At the dynamo's core is a high grade NdFeB permanent magnet designed in line with a single plane concept that is coupled with a unique yoke alignment design strategy. The resulting hub dynamo attained an efficiency of 72% at 15km/hr and proved a novel design. Its 6V3W output meets German StVZO requirements and has received approval number K845. The intelligent light weight design was tempered throughout with painstaking attention to structural performance. The smooth oval shape of the hub was optimised for balance, while attaining an unprecedented weight only 360g.
Tell us how the product performed overall when used for its designed purpose
Very well. Nicely built, faultless in operation.
Tell us what you particularly liked about the product
Power to weight ratio.
Tell us what you particularly disliked about the product
Did you enjoy using the product? Yes.
Would you consider buying the product? Yes.
Would you recommend the product to a friend? Yes.
Age: 40 Height: 190cm Weight: 102kg
I usually ride: whatever I'm testing... My best bike is: Genesis Equilibrium with SRAM Apex
I've been riding for: 10-20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: commuting, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.