First Impressions: Absolute Black 28-to-40 tooth cassette cluster adapter

Written by Tyler Benedict Jan 28, 2015 12:19 p.m. ET

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If you’re looking to put together an expanded range 1×10 system from your current setup, this provides a good alternative to single cog adapters that make a big jump at the top of the cassette. This one provides a smoother transition onto the larger cogs and a more subtle change between the top four cogs, too.

And, it’s a fairly reasonably priced way to do it. The SRAM 1050 cassette retails for $85 and the AbsoluteBlack adapter for $122, putting you all in at $207. Your alternatives for bumping up to a 40T or 42T cassette are either Shimano XTR or SRAM XX1/X01/X1. With Shimano, the cassette is about $300, and it’s 11-speed only, which requires new chain and chainrings, too. SRAM’s is also 11-speed only and requires a new freehub body, chain and chainrings. Either way, it’s going to cost you a lot more.

As for the range only being 40T and not 42T, you could just opt for a slightly smaller single chainring to compensate, which makes even more sense if you’re dropping the 11T cog off the bottom of the cassette as I did. I found the new range to be very good for our local trails, keeping me mostly in the middle of the cassette.

Another benefit? It can add up to a lighter system than the stock cassette…

The Absolute Black cassette cluster is CNC machined from 7075 Txx aluminum alloy and replaces the largest three cogs on your cassette with a four cog unit consisting of a 28-32-36-40 combo. Because of that, you’ll need to remove either the 17t or 11t cog to make it work.

AB only recommends using it on the SRAM PG1050 or Shimano XT/SLX cassettes. I tested it on the SRAM PG1050, which has a three-cog cluster at the top, making it an easy swap. Since I wanted to keep the smooth transition across all gears, I opted to remove the 11t cog at the bottom, made easy thanks to AbsoluteBlack’s 13t lock ring:

The oversized lock ring retails for $18 and is a beautifully machined piece of metal with a larger diameter to hold the larger 13t cog in place securely. Now, there’s a catch to setting it up this way, but first let’s take a look at the parts and weights…

ACTUAL WEIGHTS & DETAILS

The cassette cluster weighs in a 149g and the oversized lock ring at 6g.

For comparison, the 3-cog cluster of a stock SRAM PG 1050 cassette is 177g, so you’re saving 28g even with the larger cogs. Most likely you’ll want to use the 13t in place of the 11t, so there are a couple grams gained back…but it’s still a lighter system overall. They have a complete weight savings comparison chart on the product page showing a lot of different stock and competing 3rd party options.

The adapter basically just adds a 40t cog to the end of your normal 36t cassette, but presents it as a solid unit for crisper shifting and lower overall weight.

The front makes it look pretty chunky…

…but the rear reveals the beautiful CNC work AbsoluteBlack is known for.

The teeth are ramped and shaped to facilitate chain movement, but they do warn that shifting won’t be quite as quick as with the stock steel cassettes, and that they shouldn’t be shifted under extreme loads. The rider-plus-bike weight limit is 200lbs (90kg).

So much detail on such a small piece.

INSTALL NOTES & OPTIONS, OPTIONS, OPTIONS

If you’re wanting to ditch the rarely used 11t cog from your cassette, AB recommends going with the XT or SLX cassette, saying the SRAM 13t cog doesn’t have the proper spline interface to ensure adequate purchase on the freehub body under hard pedaling. Therefore, they recommend removing the 17t cog when using the SRAM PG1050 cassette. But, since all I had available to test it with was the PG1050, I took a closer look and have decided to continue running it at my own risk. To be clear, neither I, Bikerumor as a whole nor AbsoluteBlack is recommending you do this as it’s almost certainly voiding more than one warranty, but here’s why I’m fine with the risk: SRAM’s 13t cog actually has larger, wider splines than Shimano’s, providing a broader contact area. But, honestly, I’m not sure that matters…

…since the actual spline contact area on most every hub is going to cut short of hitting the end of the freehub body. So, there’s plenty of overlap and the same if not more contact area as with the XT 13t cog. Proceed with this hack at your own risk.

Why did I risk it? Because I almost never use the 11t cog, and keeping a smooth two-tooth transition across the entire bottom section of the cassette makes for smoother gear changes and better cadence consistency.

Here’s why you can’t just ditch the 13t cog – it has a lip that fits into the recess on the 13t cog and this design characteristic is the same for both SRAM and Shimano cassettes. So, you’d end up with the too-wide gap between the 15t and 11t as shown above.

Other than that restriction, you’re could (again, at your own risk) experiment to find the gearing solution that works best for you. Here’s what a few options look like. And you could always use an aftermarket 16t cog to replace both the 15t and 17t and keep a more natural transition while maintaining the 11t at the bottom. Decisions, decisions.

One final install note: It fit very, very snug sliding onto the Ringlé freehub body, but slid more easily over a few other hubs I tried it on just to make sure it wasn’t a bad fit overall. After a little persuasion, it got past the first 1/3 of the FH body and slid more freely to the edge of the hub.

FIRST IMPRESSIONS

On the trail, shifting was pretty good between cogs on the cluster, even with a well used chain mated to both a brand new cluster and brand new PG1050 cassette section.

There’s a definite tinging sound to let you know you’ve gone from the steel to the alloy cogs on your way up, along with minimal hesitation between the two. With a solid push of the shifter’s thumb lever, though, it’s not enough of a pause to be an issue. There doesn’t seem to be any of that hesitation going back down the cassette to harder gears.

Overall, it feels like a solid way to add gear range for the big days in the mountains while dropping a few grams compared to other oversized options. Time will tell if those weight savings come at the cost of durability, but for now it’s behaving just fine.

AbsoluteBlack.cc

Tyler Benedict

11,186 articles

Tyler Benedict is the Founder of Bikerumor.com. He has been writing about the latest bikes, components, and cycling technology for almost two decades. Prior to that, Tyler launched and built multiple sports nutrition brands and consumer goods companies, mostly as an excuse to travel to killer riding locations throughout North America.

Based in North Carolina, Tyler loves family adventure travel and is always on the lookout for the next shiny new part to make his bikes faster and lighter.

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gMoney

9 years ago

So … if I am clear, you went from an 11-36 cassette with a ~3.72 (36/11) “range”, to a 13-40 with a ~3.08 “range” all for only a few hundred dollars?

What am I missing here?

Rotomon

9 years ago

This does seem like a step in the right direction but I just don’t get why they go through the hassle of making adapters and not just make a whole 11-42 10 speed cassette…
We all use the adapters but making the complete cassette seems like a no brainer.

Rob Mantz

9 years ago

Why on earth would you use a well used chain on new new gears????????????????

DGWW

9 years ago

Thank you!

Jo-slow

9 years ago

Losing the 11 is not wise… Losing the 11 takes out the extra range you get from going to 40 or 42. The idea is going from 36/11 = 3.27 to 40/11=3.64 or 42/11=3.82. With 40/13=3.08 or 42/13=3.23 : you end up with less range! Instead of 40/13 or 42/11, get a smaller front ring and keep your 36/11. If you go to 40 or 42, get a 16 t and keep the 11.

9 years ago

The only place i see this as a benefit will be if your limited by a 120bcd sram crank and running a 36T front ring. If you’re not limited on your front chain ring, no reason to give up the 11, just run a smaller front ring and stick with 11-36 cassettes.

Jo-slow

9 years ago

*Instead of 40/13 or 42/13…

9 years ago

Your cost comparison is a bit disingenuous; why not compare the cost of any of the several other hack 10s options rather than an 11s (because this is an ad for AB disguised as a review and it doesn’t compare all that favorably to the OneUp hack).

Gunnstein

9 years ago

@Jo-slow Exactly what I was thinking. If you’re ditching the 11t, it would be better and cheaper to skip the whole 28-40t section and just get a smaller chainring.

@i Yep, was wondering about that too. Surely that’s a more interesting comparison. (And personally, if I’m going to make such a Frankencassette it will have to be an 11-42t, otherwise the 1x gearing range is too small.)

slyfink

9 years ago

I fail to understand the weight limit number. it’s not like we’d be standing on the darn thing. Are they assuming Clydesdale’s are stronger? (which of course we are!)

Derek

9 years ago

What Jo-slow said. If you lose the tooth range (i.e., 40 to 11) there is absolutely no point in using a cassette of that size. A normal 11-36 offers more range than a 40-13, and the gaps in gears are smaller. Just alter the front chainring size to adjust the gearing.

What most people THINK they need for gearing and what they actually use are usually very different. This is a foolish product if you can’t use the 11.

Derek

9 years ago

Durability is definitely not going to be good compared to steel, especially on the smaller cogs.

Ol' Shel'

9 years ago

There’s a reason cassettes are made of harder materials, like steel and Ti.

James S

9 years ago

Jo-slow and Gunnstein are absolutely right. The only caveat is that if you have a 104BCD chainring, you can’t go small enough. But I’d rather get a new crankset that allows for a smaller chainring – that way you get to use standard cassettes that work well with your derailleur.

Just keep the 11-36 and get a 28 teeth chainring.

Here’s the relevant math assuming you start with a 32 tooth chainring (as you can see, this expensive Absolute system with 13-40 actually has LESS range than a 28 tooth chainring and 11-36 cassette):

32/11 = 2.91
32/13 = 2.46
28/11= 2.55
32/40 = 0.8
28/36 = 0.77

Tyler

9 years ago

All – true, if you want the range, just keep the 11 and get rid of the other cogs. The 16t add-ins are a good option to minimize the effect on cadence. If that’s the plan, this provides a more gradual change to a larger top end if you’re starting with something smaller like an 11-32 that wouldn’t work as well with a single oversize cog. I just wanted to show all the various ways I could think of that this could be used.

Jay

9 years ago

The new XTR 11-40 cassette can be purchased for under $200, I just got one from the UK for $192.

Not directly related to this story but I thought I’d mention my recent franken-drivetrain on my touring bike. I am using SRAM 11-speed road shifters, a 10-speed long cage MTB Type 2 rear derailleur, 46/34 10-speed chainrings, a Shimano 11-speed chain and the new Shimano XTR 11-40 11-speed cassette. It works well and the gear steps are nice.

Johnny

9 years ago

@Jo-slow is right. You get less range on 40/13 than 36/11. I’m surprised the author missed this. Keep it simple and get more range. Win-win.

A_Donch

9 years ago

Can someone please explain the 200lbs Rider + Bike weight limit?

What exactly does that mean and why would a cassette have a weight limit?

Joe

9 years ago

You can get a wolf tooth 42 tooth adapter for like 80 bucks. I’ve got 1500 miles on one and 1000 on another. I’ve also got an AB oval ring with a few hundred miles on it and it is really nice. 10 speeds are enough. Truly 1 speed is enough. If you can’t make the climb, try harder.

Mr Durable

9 years ago

Per post #131 here form Abs Black you have to be careful how you shift: http://forums.mtbr.com/drivetrain-shifters-derailleurs-cranks/absoluteblack-chainrings-thread-874053-6.html

Kinda like when some phone maker told us we weren’t getting good reception because we were holding our phones wrong =)

You should expect the shifting to the 28t to deteriorate quickly (other replies in that thread confirm this) and the 28t in general won’t last long (to someones point earlier why all other cassettes us Ti or Steel other than 36, 40 and 42t cogs).

Jesse Edwards

9 years ago

I use a wolftooth 42 and the 13T lockring on my 29er (wheelsize is a factor here) and have never once missed the 11T cog while on dirt as I don’t pedal down hills much and am not racing. Sure, I go a bit slower on the road to the trail, but not nearly slow enough to negate the benefit of a relatively cheap 1x setup that gives me all the gears I need to spin up all the hills on my trails. I think this is a great option for a good portion of trail riding society. if you’re on a 26er though, the loss of the 11T will be a bigger deal.

gmats

9 years ago

Warning. I have used this piece. It’s great, it’s light but be careful as the teeth bend easily and wear pretty quick. If you are going to use this piece in a rocky, wet, muddy environment, it will wear quickly.

pile-on

9 years ago

200 lb. bike+rider/gear weight limit…so it’s women specific right?!

Jo-slow

9 years ago

@ A_Donch. When you go up a hill, torque in the cassette is proportional to rider+bike weight (at constant speed, minus friction.) Up hill speed is not a factor for the torque. So, your power does not influence the torque transmitted to the rear cog going up a steep hill. (again, without frictions forces)

Also, the torque you are able to transmit to the rear wheel is proportional to the rear cog diameter. In other words, with a giant (40+) rear cog you generate a lot of torque.

So, they are afraid that a 200+ lbs rider+bike will damage the aluminum cluster in some way.

Tim A

9 years ago

@Jesse Edwards,

It sounds like you should revisit your math too. A 42-13 will give you a 324% range- slightly less than the 11-36 you likely upgraded (327%). Coming from a 32, a 28t cog would have yielded similar gearing. Not always a possibility as others have noted, but a direct-mount or XX1 chainring would have done the same for less cash. More recently, there are chainrings that mount to the inner bolt circle of most doubles to go smaller than a 30t.

Dude

9 years ago

Jo-slow – torque is proportional to power, not rider weight.

Power is work per unit of time, which in a rotating system means power = torque x angular velocity.

At any given speed on a 0+ deg slope, a heavier rider has to put out more power than a lighter rider. Side by side, the increase in power requirement is a factor that is more or less linearly proportional to total system weight (if we’re just talking rolling resistance and energy expended to gain potential energy). Of course, being heavier doesn’t always mean you are more powerful, so lighter dudes often go faster because power-to-weight ratios… but that’s an aside.

Dude

9 years ago

Also, at any given power, using bigger cogs mean lower angular velocity and thus higher torque. Even a “weak” rider can put a lot of torque into the hub if the gearing is right.

Mindless

9 years ago

Dropping smallest ring from cassette is an utterly idiotic thing to do when the whole point of the upgrade is RANGE.

ING

9 years ago

shorter range??? why???

Tim J

9 years ago

This must be the worst thought out wide range cassette adaptor ever.

You pay more money than all the others to get yourself:
– worse shifts across more of the cassette
– a greatly reduced lifespan on multiple commonly used gears
– a reduced gear range from a standard cassette when setup as per this article
– exactly the same jumps between the top cogs (28-32-36 is standard) despite what Tyler claims in the article and his comment above.

At least it’s lighter….

Chader09

9 years ago

It costs more and does less, what’s not to like :/

Jo-slow

9 years ago

@Dude

My dynamics classes date 12+ years… Here is my logic…

In a hill, were the grade is the prime acting force, the force opposing the rider’s movement is = mass * sin (grade deg.) *g. That force (gravity) is constant regardless of speed. The wheel’s torque is the opposing force to gravity, so if gravity and mass is constant, wheel torque is constant. Since the wheel is not moving relative to the cassette, the torque is the same.

Power kicks in when you consider speed. 0 speed means 0 power but torque is not 0 unless you hold the brakes… When you move power is proportional to speed. But torque is constant, angular velocity increases.

Sorry Dude, I just convinced myself that I am right… Rear wheel torque is only a factor of weight at constant speed, up a hill.

Tom

9 years ago

I had two of these. In no time at all they start to shift poorly, then wear out. I bought them because they seemed like a more elegant solution that would work better than the single 40t ring from OneUp or Wolftooth.

I was wrong. The OneUp and Wolftooth rings, while having their own (relatively minor) issues, are a better way to go.

Jesse Edwards

9 years ago

@Tim A Had I known companies would be offering the narrow-wide inner rings I would have gone this route. But, that would have made the 11T cog easier to pedal as well, so I’m not sure how this gives me more range?

Jesse Edwards

9 years ago

@Tim A Had I known companies would be offering the narrow-wide inner rings I would have gone this route cause I’d rather stick with a complete cassette, and it’s cheaper. But, that would have made the 11T cog easier to pedal as well, so while there would be a slight increase in range, I’d be left with essentially the same gearing. Is the difference in a range of 324% vs 327% that great?

Padrote

9 years ago

oh god LESS RANGE! so many meaningless numbers

save your money and buy a properly designed drivetrain setup.

mike

9 years ago

@Jay – do you actually get 11 speeds out of your franked-system with a 10 speed derailleur?

absoluteBlack

9 years ago

thanks for the comments.

I will start from the end.
@ Jesse Edwards – we already have narrow wide 64BCD chainrings since almost 8 months in 26, 28 and 30T. These are the sizes lots of people ride these days to be fair.
http://absoluteblack.cc/xx1-style-shimano.html

What we found over time is people are already in favor of smaller than 32T rings. To be funny 32T these days is considered LARGE ring. So tons of our customers already use 28/26 chainrings up front in 64bcd or spiderless version for Sram/cannondale. More over there are more and more inquires about 24T as 1X.

Now if you think that way – these are not peope who race. People who race use 32-36T ring on daily basis. For trail warriors/people who ride for fun, it is far to big of a setup.

So when most of you here speak about Range it only matters when someone is competitive and ride in various terrain on one bike. If you have few bikes you specialize them to certain tasks.
So imagine that if someone already have 26/28T up front there is nothing to drop lower. Then usually such people want one more cog at the top and find they do not need 11T at all as terrain is or up or down.

Who said this proposition is for everyone? It’s not. Hence we also offer single 40T cog and it also can be used with our 13T lockring.
For every day rides 40T plus 13lockring is far better option as it will last you more than a season or as long as cassette.

I think most of you guys forget that you think only from your local perspective. What may look wrong for you for someone else in different place will be a great solution. I already wrote that some time ago, but it is always a good quote. Henry Ford (car inventor) once said “If I had asked people what they wanted, they would have said faster horses.”
This is still true in many aspects.

Chris

9 years ago

Put your money into a crank that can handle a 30t. If it’s over $200 for this set up, that would suck every time you wear it out. Which will happen. With a new crank, you will just be replacing standard parts afterwards instead of killing your visa.
OR! Just ride whatever you have. 2x or 3x…. Or single speed. That works the best.

danedownhill

9 years ago

Instead of making this product for just a few consumers,

Please make a 42t cog and spacer kit to convert 11-36t 10 speed cassettes to 11-42 11 speed cassettes that will fit a standard free hub body. I know you can do it AbsoluteBlack. I dont mind spending the money on 11 speed, I just hate spending 400 plus bucks on a cassette.

Tim A

9 years ago

@Padrote:
Gear range is anything but meaningless. It’s the difference between a mountain bike and a singlespeed. Dividing the tallest ratio by the shortest allows one to compare any of the solutions on the market before spending money to make performance worse. Speaking of which,

@Jesse:
That’s the point- the 13-40 solution nets a (small) decrease in range while making shifting noticeably worse. Run what you’ve got, but once the aB cogs wear out it would make more sense to go to a smaller chainring and restore your cassette to stock. It’ll shift better and last longer and you’ll get some extra chainring:ground clearance as part of the deal.

Chris

9 years ago

Mine lasted maybe 180 miles before the “28” (actually 27 tooth) ring stripped out. Avoid.

salsarider79

9 years ago

Now you can see why I just want to get on my ss MTB and ride. I don’t have to worry myself sick over gear ratio’s, $200+ for cassettes that wear every five minutes…don’t worry, just ride!

Wic

9 years ago

I don’t know anyone with a rider + bike weight below 200 lbs/ 90kg… o_O

BJMelin

9 years ago

Trickstuff makes a 10 speed 11-41 cassette at 259 g.

collin gundersen

9 years ago

I am running the oneup 42t cog and it is awesome, was able to switch to a 1x up front so I have more clearance over logs and don’t have to worry about what chainring I am in.