Raptor: the Ultimate Aero Gravel Rig
Mar 8, 2020
article & images by Nick Salazar
So, after all the research and careful comparisons, I just took to eBay and nabbed a cheap, generic frame. Or to put it a little more nicely, I bought an open-mold frame sold by a trading company. This frame, the Spcycle "SP-R119" has geometry very similar to the 3T Exploro. Spcycle is not exactly a brand, nor a factory itself, but merely a reseller known in the business as a trading company. They buy from the factory, give you some custom paint options, and drop ship to you quickly and at a smoking-good price. I paid $503 for the whole thing INCLUDING shipping. That brings me to the inevitable questions about the quality and reliability of a generic frame. I've seen opinions on these range a wide spectrum from "generic frames are EXACTLY the same as the expensive branded ones" to "generic frames are garbage, and will crumple beneath you like tinfoil on your first ride." Of course, neither of these extremes is remotely accurate. I've bought close to a dozen no-name generic frames. And in general, I've been very pleased.
The materials, the fit, and the finish of open-mold products are, in my opinion, on a similar level to that of standard branded bike offerings. That is, if you buy a generic carbon frame, you'll receive a carbon frame, and it will work just fine as a bicycle. But it's not all perfect. Open-mold frames generally suffer a few common problems. First, the design is ALWAYS subpar compared to top-shelf offerings. Head tubes are going to be fatter; cable routing won't be as clean; you may find yourself chasing threads that weren't properly tapped, etc. And if you have any questions or troubleshooting to do, you'll find that customer support is ... completely nonexistent. This is a no-name bike. There's no brand, and therefore no one behind the scenes to support that nonexistent brand. Again, I've had good experiences, because I know a thing or two about building bikes, designing bike parts, and tinkering in general. But if that's not the kind of person you are, and/or you need the bike to be plug-and-play from day one, then open mold frames are not for you.
But for me, open mold frames are fun! They're cheap, they work, and any tinkering I have to do is just part of the fun. Your mileage may vary. Analyzing the geometry of the frame, I realized I could hit very acceptable fit numbers. Essentially, I'd be taking my tri position and just rotating it backwards a few degrees relative to the bottom bracket. Same position, same biomechanics, just rotated back and up a little bit. That's nice, because it improves visibility while in aero, a must-have for riding around trails. And of course, the other must was putting the Alpha One up front, complete with a set of Scoops for ultimate adjustability and a dead-simple time dialing in the position. Ultimately, it's a little slower (higher head = more drag), but I'm not trying to set the hour record with this rig. I'm just out to have a good time, and Raptor sets me up to do exactly that.
Ok, now that we've covered the frame and its geometry, let's talk about the standards and interfaces this guy uses. It features disc brakes, 700c wheels, a BB386 bottom bracket, a full Alpha One cockpit with Scoops, and a 1x mechanical drivetrain (SRAM Force 1).
First and perhaps most controversial: the disc brakes. Hath hell frozen over? Has the world's biggest proponent of keeping rim brakes on tri bikes changed his tune? In a word, no. Horses for courses, my friend. If your typical riding conditions are likely to slop a whole lot of mud onto your brake track (for example, riding a dirt-turned-mud road in springtime after a rain), disc brakes can offer a significant benefit, giving your caliper a clean alloy surface to grip. In other scenarios (like regular road riding), disc brakes have little to offer other than weight, complexity, and drag. Moreover, I absolutely despise hydraulic calipers. So we sourced these TRP Spyre brakes, which are cable-actuated disc brakes. They're actually somewhat difficult to find, as everything is going the way of the hydro caliper. This is a shame, because hydraulic bicycle disc brake calipers are absolutely AWFUL things to work with, and force the designer to try to hide that monstrosity of a master cylinder within the lever. And the hydro calipers don't do anything that their cabled counterparts can't. But I digress. Anyway, there are the brakes. TRP Spyre Disc. They work just fine, but so do the Omega brakes they replaced for this build.
Bottom bracket is a BB386. I've always been a big fan of press-fit BB's, including BB30, PF30, BBRight, and BB386. In fact, Omni uses PF30 for this reason. BB386 is identical to PF30, albeit with a wider shell. This maximizes the amount of frame that holds cups, resulting in the stiffest possible system. I really like BB386, and it works very well here. SRAM has dedicated BB cups just for it, and they work brilliantly. In went the Quarq Prime crank in 165mm, with a 48t X-SYNC ring. Brilliant.
Wheels are 700c! Although there are a lot of different wheel options out there, many gravel riders size down a bit, going for 650b or other wheels. I wanted these wheels to match my road hoops, for the closest apples-to-apples riding experience I could manage. I finally found a semi-aero 38mm-deep carbon clincher wheelset in 700c from a company called ICAN, with some nice beefy 36c tires. I like this as an all-around wheelset. Still, I would have liked a set from FLO or Zipp, both of which make some lovely 45mm-deep hoops with disc brakes. But the frame will accept a lot of other wheel + tire combinations, so in the future I could definitely check out some other sets. There's lots of room and clearance for almost any combo up to 700x40C, or 27.5x2.1" . That's massive, and it also happens to be exactly what the Exploro can clear. There's a lot about this bike that screams "Exploro Knockoff," right down to the dropped drive-side chainstay designed to maximize wheel clearance.
With our wheels and tires sorted out, the last step in drivetrain is the actual gearing. Again, as I'm not using this bike for serious racing, we don't need to make the ratios perfect. I put an 11-36t cluster in back, with a 48t chainring up front. That's more than enough gear on either end, for me, for most of the riding that I do around here. And given that it's a 1x group, all I have to think of is "harder" or "easier," and move just one hand. I've always loved how SRAM's R2C Shifters work, so they were the natural choice for this build. Although it's been nearly ten years since I wrote that review, everything I wrote way back then is still true. As far as mechanical groups go, they are still a "must have" piece of kit.
Ok, let's get into some more nitty gritty of the build, including a couple custom bits we made just for Raptor.