17 July 2008

bikefix Initial Review: Crank Brothers Cobalt XC Wheelset

Next to tires, wheels are one of the most important components a person can pick to improve their bike’s ride. The right wheelset can make a bike accelerate faster, ride smoother, or steer better. Of course heavy, flexy or fragile wheels can make a bike feel much worse too. I’m happy to report that Crank Brothers’ new Cobalt XC are fast (light & stiff), tough (so far), and really, really nice looking.

I’ll admit that I was pretty confident I was going to order a set of the Cobalt XCs the moment I saw the early photos- before reading the accompanying text. When read more about them, I was even more convinced by their low weight, new spoke design and rim strip-free tubeless compatibility (which I think is imperative), and claimed strength- I was sold.

When the wheels arrived (we were on the company’s waiting list) I mounted a pair of the Schwalbe’s new Racing Ralph Evo UST 2.25 tires with no fuss and started riding. Prior to the Cobalts, I had been riding Fulcrum’s Red Metal Zero wheels and been impressed by their light weight and strength for what’s being called ‘trail’ riding. I mention this because the Fulcrums were fantastic- and the switch to the Crank Brothers wheels didn’t change the feel of the ride much at all- and that’s good. It’s possible that UST rims with about the same weight, quality and dimensions will feel similar no matter who built the wheels.

The Cobalt XCs seem fast when riding and, although I was still chasing the same fast guys I always do, I did feel a bit sprightlier. I could definitely feel the light weight when the wheels turned downhill though- they accelerate very quickly once you pass over the peak of a hill. In fact, I often had to rein them in long before I have to brake on some other wheels.

In order to create a hole-free, sturdy rim [without infringing on others’ patents], Crank Brothers have come-up with what they’re calling Twinpair spoke technology. Instead of attaching each spoke to the rim through a threaded hole [like Mavic, Shimano or Fulcrum], their rims are extruded with a central rib for a Y-shaped profile. This rib is pierced by little metal barrels to which a pair of spokes are mounted. The in the Cobalt XCs’ case, the rib is machined away between the spokes to save weight. There is also a central rib inside the rim itself [like WTB’s LaserBeam rims from the mid 1990s] to stiffen the rim vertically and resist the paired spokes’ tendency to try to collapse the rim. All of this allows the rim’s outer wall to be unbroken and therefore stronger and hold air without adding significant weight or requiring a sealing rim strip. To keep the user from having to remove rotors and cassettes to true the wheels, the nipples are long. Really long. See how the spokes are half blue? The blue halves are the nipples. It's weird, but it works (and makes the wheels bluer).

The other fun new thing about these wheels is the new quick-release design. Crank Brothers have split the quick-release lever into two halves. Crank Brothers claim that it takes less effort to release the lever if you pull one half and then the other. This is probably true but I usually don’t have a problem getting the quick-release lever undone. It may be a boon to all the weak-gripped mountain bikers out there- there must be a few who’ll appreciate the feature. I think that they look nice.

I have only about a hundred miles on them so far, but 60 miles of that distance was two rides of about 30 miles each. Both were punishing rides with a fair amount of wet thanks to New Mexico’s monsoon season. The second ride in particular was vicious, with a 10 mile downhill close to 6,000 vertical feet and filled with rocks, roots, mud, and water crossings. The other was a point-point ride on Taos’ South Boundary and Elliott Barker trails, featuring plenty of technical climbing, fast descents, torrential rain, lightning and hail. Other than some strange “pinging” noises from the spokes over slower technical sections that had me looking down to see if I had busted one, they performed flawlessly, and didn’t keep me from hitting some truly scary speeds on the descents.

After all this, the rear wheel was a bit out of true, but not bad. This is not something I consider a problem on new wheels after some hard use- most need a slight “tune-up” after some early mileage. I’ll have them trued at my local shop and imagine that will be that. If they don’t stay true, that could be an issue and I’ll post that in a later report.

The Cobalt’s are advertised as weighing 1540 grams and mine came out very close to that at about 1550 something grams. That is very light for a tubeless wheel that can handle the kind of rides that it has proven it can. They have a two year warranty and retail for a whopping $1,000.00. I like them and will post an update as I get more miles on them.




Anonymous said...

Hey, so how is that crank brothers wheelset workin' out for you. And one question, if you bust a spoke does the blue nipple still stay there, or does the wheelset come with extras?

bikefix said...

My wheelset didn't come with extra spokes. I would think that if you bust a spoke, you could replace just the half that broke, but perhaps that is a question better left to the folks at Crank Brothers. They have been very responsive to e-mails in the past. The wheels are holding up fine. They make some noise on medium-speed rock gardens- but no problems yet. They need a truing after the first ride or two though. I have to admit that they havn't been getting as much use in the last few months because I have been testing some 15mm QR forks that don't work with the Cobalts (yet). I have faith in these wheels though. Don't forget that I am close to 215 lbs with all my gear.


tjdayney said...

I am looking at a set of these wheels. I am selling a set of Notubes ZTR355s to replace with a set of cobalts or possibly the Mavic crossmax SLRs. I am wondering if you have any advise or comparison of the cobalts vs the SLRs for stiffness and strength.

bikefix said...

I ride both those wheelsets and I don't have a definite feeling on whether one is stiffer than the other. If I had to pick which one is stiffer just from the way it rides- I would guess the Mavic, but the Rim on the Cobalt is likely stiffer (no penetrations whatsoever). If I'm right about that then that means Mavic's spokes are probably the reason it feels slightly stiffer. I like both these wheels. I weigh in at about 220 lbs with my gear and they both feel good. I had one freehub issue with the Cobalt which they promptly fixed, and in their defence, my wheels were one of the first 50 produced so perhaps that was part of it. The Rep said he had never seen that before. In the past I have had some Mavic freehubs go down too, but I think they have largely fixed that problem. I think they are both great choices and you cant go wrong with either. FYI- the Mavic Crosmax SL weighs the same as the SLR so keep that in mind when shopping.


Dan S said...

Hey I might be buying a pair of these wheels soon and i am wondering about how they hold up in aggressive riding and slight drops like 2 feet, i just want them to be strong enough to handle some gnarly trails, i dont want them to fail and spend alot of cash on a weak wheelset. I have heard some differant thinks and i am just curious

bikefix said...


The short answer is that you are probably going to be just fine with the Cobalts. They seem very very tough for their weight. The long answer: they are on the light side for the riding you are describing. They are still a new product and as such it is hard to tell how they will weather repeated rides over tough terrain. Also, to be honest with you, I pulled them off my bike shortly after the review in anticipation of a frame that was coming and have since gotton very few miles on them (I am still waiting for that frame). However, my buddy kills all his equipment and his Cobalts are still surviving (including a trip to Moab) and he is also a very accomplished downhiller. I don't know your weight so if you are between 145lbs. and 170lbs. then you might be able to get away with it for a long time. If you are heavier than that, then you might be pushing it a bit. If you have extra cash to spare and you like the look, I might encourage you more. The reality is that it's alot of money to spend on a product that may not last as long as you like. I would probably er on the tougher side and get a pair of Mavic Crossmax ST wheels- they are almost as light (around 1670ish grams) and I know they are strong enough for what you have in mind. We may get to the point where 1540 gram wheels are the norm for "aggresive trail riding" but right now they are sitting on the fringe and although I think you would be fine, I find it hard to tell you to spend the cash without being sure. It is safer to go 100 plus grams heavier and be sure. Plus, Mavic has (or used to have) a crash replacement program- but you have to pay a premium when you buy them- basically it's insurance. Other posible suggetions: Fulcrum wheels are looking good. I am tying the Red Metal 0 and so far it is fine, but it has the same problem as the Cobalts (light/new). You could also have a DT 190 ceeramic hubset laced to 819 rims- that would be light and strong. I still t hink the Crossmax ST's are the best all-around trail wheel out there right now-and the 9mm axle version is also cabable of 15mm axles should you upgrade your fork.

Good Luck,


Anonymous said...

I am just 125 pounds. Do you think that I can use them for long-term trail use (rocky trails, 1-2 foot drops) or do you think that in building an XC wheel, Crank Brothers sacrificed on quality compared to an all-mountain wheel? Also, will this wheel require more maintenance than a typical all-mountain wheel?


bikefix said...

First, let me say that your question seems more like a question about categories- it comes down to the core differences between XC and All Mountain (AM) and where exactly "trail riding" fits in between the two. These genres are a bit different from region to region, and if you value strength, durability and low maintenance over weight and speed, then you probably have your answer already. If you are willing to try an XC componant for trail use, then realize that you may encounter a problem when you exceed the item's design limits. That being said, I have not had a problem with mine yet and am more impressed with them every day. If you didn't read it on the website, I weigh over 220lbs. with my pack on, so I think they will last a very long time under the use that you describe and given your weight. Will they last as long as an All Mountain wheel? Probabbly not, but they are considerably lighter than any AM wheels and that will make your life much better. Crank bros did not sacrifice any quality to build the Cobalts, they did sacrifice a little durability and strength over their AM wheels (the Iodine), but that is the name of the game when you make any product. The Cobalts may need to be trued a bit more often than AM wheels but that's it for possible extra maintenance. Crank Bros is also very good about warranty issues.


ProEdgeBiker said...

we went thru 5 rear hubs total on 2 sets of Cobalt Wheels, CB took care of the problem each time but it was a PAIN IN THE ARSE specially because it happened during our racing season. I hope they have fixed the problem and do a massive recall for the rest of the wheels.