Crankbrothers have a new line of rims with the curious name of Synthesis. After examining these rims I came to the conclusion that they were aptly named. Here are a few synonyms for the word synthesis. Union, amalgam, blend, mixture, compound, fusion, coalescence, composite, concoction, conglomerate and alloy.
Keep these in mind as we begin to explore the attributes of these rims to see if the name suits.
When I unboxed these lovely rims I immediately thought of an obvious comparison that stood out . There are slightly raised hubs at every spoke hole exit point that are quite similar to those found on the Reserve rims by Santa Cruz. But the approach with the Synthesis is far more subtle and refined.
I have built the Reserve rims and I feel that they are too stiff, so the approach by Crankbrothers here is superior.
The next thing that struck me right out of the gate was the weight. I didn’t need my trusty scale to know I was holding a very light rim. Curiosity got the better of me and I pulled out the scale to see just how light they really were. The front was 370 grams and the rear was 379 grams.
Synthesis XCT 29er’s primed and ready for some tires!
If you are familiar with carbon rim designs you would acknowledge that’s quite light, especially for anything that will be required to survive on the trail! The specs on the rims are as follows. Front: 31.1mm wide - 26.5mm internal Rear: 29.5mm wide - 24.5mm internal with a 19mm depth.
Right off the bat you’ll notice that there are some intentional dimensional differences between the front and rear rims. Each rim has been designed to excel at its assigned task. The role that a front rim plays is very different than the role of a rear so why should they be identical.
The front rim with its wider internal dimension was designed with a slightly wider tire in mind and the rear with a potentially narrower tire.
I chose a pair of 29er’s with a 32 hole rear and a 28 hole front to see if I could build up a very light pair of MTB wheels that would still hold up to a proper thrashing in the outbacks!
My choice for the ultimate hubset was Hadley. These beautiful Californian hubs have nice big flanges that will help to keep things both stiff and strong. You really need to have a pair sitting in hand to see just how well made they are. I also had an all gold colour theme in mind, so gold anodised hubs were the order of the day.
Flawless CNC workmanship and gorgeous gold anodisation.
The Synthesis XCT carbon rims could hardly find a more suitable match than these stunning Hadley hubs!
Gold Hadleys, gold Sapim double square 3.2mm alloy nipples and gold titanium tubeless valves from the guys at Lindarets. You’d think their destination was Fort Knox!
I thought I would opt for some bladed spokes for this build and Sapim’s CX Sprints were a great choice. I have used them extensively for many gravel wheels to good success and I felt they would do the trick nicely with the Synthesis XCT/ Hadley combination.
They are a little bit more stout than the ultralight CX Rays and that extra metal will go a long way in providing some additional lateral strength for these wheels. A tried and true cross 3 lacing pattern was the obvious choice as well. If it ain’t broke, don’t fix it.
I decided that there was no real need for spoke nipple washers. Normally I am a big fan of the stainless steel HM washers from Sapim. They are immensely helpful at staving off rim cracks and providing some extra support for rims with thin spoke beds. In this case the Synthesis had a generously thick spoke bed which removed any concern about a potential crack in the rim.
So, how did these uber light rims react when being brought up to a final tension of over 100 kgf?
In a word, impressive! You have to work carefully when building with carbon rims that are under 400 grams. So I take my time and very gradually increase the overall tension while working through the build. This gives me the chance to monitor how the rim is responding with successive increases of tension. The Synthesis responded wonderfully as the tension climbed, showing no signs of “carbon fatigue” as I like to call it. This bodes well for the lifespan of a rim which reminds me of the fact that these rims come with a lifetime warranty to the original owner. A very rare offer in the world of carbon rims, highlighting the confidence that Crankbrothers obviously have in this product.
Even at the finished tension of 105 kgf for the front and 110kgf in the rear they were holding their own perfectly. The final de-stressing step was a very positive indicator of this rims intrinsic strength. When they went back into the truing stand they were still dead true, requiring no additional work to bring them back into shape. That’s quite impressive and is a testimony to the rim designers abilities and those who determine the specific carbon layup at the factory. Very few rims attain this ideal marriage of design and build quality.
Some might be curious about the respective weights of each wheel. The front tipped the scales at 739 grams without a tire and similarly the rear was 910 grams. So, 1649 grams for the pair.
I always learn a ton about a rims potential just from building it up, but the real acid test of course will be some miles on the trails. You’ll have to wait for the next instalment that delves into the ride quality of these beautiful rims. Stay tuned!
If you would like to discuss a set of custom wheels with Crankbrothers new Synthesis rims just give me a call. You have numerous excellent hub options at your disposal. My favourite MTB hubs are from several distinguished makers like Onyx, Chris King, White Industries, Industry 9, Trailmech, Hope and Hadley of course.
Hadley are arguably one of the finest MTB hubs currently being made. Incredible quality replete with a titanium freehub.