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Spin Unobtanium Monobloc Cassette



Superlight cassette for weight obsessives looking to shave grams and add some bling

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Our first question about Spin's Unobtainium Monobloc Cassette was, is it really made from Unobtainium? Sadly no. Our second was, £250 for a cassette. What's so special about it?

Well, the main draw here is the weight. Our 10-speed 11-23 tooth test product, including the lockring, is 96g. To give that some context, a Shimano Dura-Ace 7900 cassette (£179.99) of the same size weighs in at about 163g and a SRAM Red one is about 155g. Superlight, then. To give some more context on price, list on a Campagnolo Super Record cassette is over £300 and quite a bit heavier so while the Spin cassette is a lot of money it's certainly not out of line.

This is a one-piece unit that's milled from a solid block of aluminium. Well, that's not exactly true; the smallest two sprockets are milled separately on the 11-23T cassette. The other cassette sizes are each milled from a single block.

The aluminium in question is what Spin call Spindustrial Unobtainium alloy because they have a special name for just about everything; it's actually 7075-T6, which is strong, high-quality stuff.

The amount of work involved in creating this cassette is amazing. Spin reckon it takes half an hour on the CNC machine to make one of these bad boys. We can easily believe that. Everything that possibly could be removed has been removed, so much so that you can see right through to the freehub body underneath the middle sprockets.

In use, the Spin cassette works just fine. I took off a Dura-Ace cassette to fit this one, and to be completely honest I couldn't make out any change in the function. It shifts up fine. It shifts down fine. Um, that's it. If you can discern any difference, you're more in tune with the subtleties of bike performance than I am. It does its job well and that's good enough for me.

The gold coating is titanium nitride, designed to improve the shifting and durability as well as enhance the looks. The looks thing is a matter of taste, obviously, but I likes it, me.

Speaking of durability, that's just fine too. I've been running this cassette through all sorts of bad weather and the drivetrain has been filthy half the time, but the sprockets are looking in decent nick for the amount of use. If longevity is your number one concern by all means go for steel sprockets but it's not as if this lightweight number can't handle plenty of use and abuse.

The one negative point I would make is that if you do get lots of gunk off the road into the cassette, it can be difficult to clean because of all the milled out space in there. I had to take the cassette off the freehub after a few weeks to remove the gradual build-up of waxy lube and general winter debris. That's not a major problem, but it's worth noting (and I probably won't use waxy lube with this cassette again).

This cassette is compatible with Shimano/SRAM 10-speed drivetrains and comes in 12-25T and 12-27T as well as this 11-23T model. A ceramic gunmetal silver-coated version is available £10 cheaper and Campagnolo 11-speed models are available too.


Superlight cassette for weight obsessives looking to shave grams and add some bling

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Make and model: Spin Unobtanium Monobloc Cassette

Size tested: 11-23T

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?

Spin say, "Spin QuickLight cassettes are at the cutting edge of bicycle component design and engineering. Sculpted by our multi-axis CNC SpinBots, these beautiful cassettes are the lightest on the planet from just 94 grams in 11-23T ratio.

"Available in 11-23T, 12-25T or 12-27T. The lightest, smoothest and most seriously trick cog set in the world."

The main point is that this is an extremely lightweight cassette with no discernible reduction in performance. It's for people who are willing to pay a premium to drop a small amount of weight.

Rate the product for quality of construction:

The level of machining involved here is nuts. Spin have put in loads of work to shave off the grams

Rate the product for performance:

Shifting across the cassette is as smooth and reliable as with any other cassette but the weight is considerably lighter. I did wonder whether a smaller amount of surface area in contact with the freehub body would result in notches to the splines, but there are no worries on that front.

Rate the product for durability:

The aluminium sprockets probably won't last as long as steel sprockets but they're going fine so far

Rate the product for weight, if applicable:

The lightest cassette I've ever used by a long way.

Rate the product for value:

Depends how you look at it, I guess. You can get a Shimano 105 10-speed cassette for £55, a Dura-Ace one is £180 and the list price of a Campag Super Record cassette is over £300.

The Spin cassette is much lighter than any of those. You're paying a lot of money to drop a small amount of weight. It takes a lot of work to drop those grams, hence the price.

Tell us how the product performed overall when used for its designed purpose

It works well. I didn't notice any difference in function over any other cassette I'm currently using, and it's considerably lighter.

Tell us what you particularly liked about the product

The benefit is the weight reduction. It's a very small amount in the overall scheme of things, but if every gram matters to you, check it out.

I think the gold finish looks pretty neat too.

Tell us what you particularly disliked about the product

There's no avoiding the fact that this is a whole lot of cash to spend on a cassette.

Did you enjoy using the product? Yes

Would you consider buying the product? Too pricey for me

Would you recommend the product to a friend? Yes, wealthy friends

Overall rating: 7/10

About the tester

Age: 41  Height: 190cm  Weight: 75kg

I usually ride:   My best bike is:

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: time trialling, commuting, club rides, sportives, general fitness riding,


Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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