Alpha - Compatibility

Alpha One Compatibility

General Compatibility

The Alpha One is compatible with nearly any bike that has a standard fork steerer tube of 1-1/8" (or can be used on 1" steerers with use of the included shim). Alpha One uses standard pinch bolts behind the stem, and works anywhere a standard stem works. Most bikes with a standard steerer work perfectly, including the Cervelo P-series, the Felt IA series, the Specialized Shiv Tri, and many more. You need only a minimum of 26mm of available steerer tube for Alpha One to clamp on. If your bike is limited, or you're close to this minimum (such as on the Felt IA bikes with precut steerers), remove your bike's headset dust cover, and use Alpha One directly on top of the bearing and split ring. Alpha One acts as a dust cover itself, so extra covers are not needed, especially if you need the extra steerer tube for clamping.

Raised Top Tubes

The rear portion of the stem is approximately 13.8mm thick. So if your bike has a raised top tube or other frame member such as a bento box, you need at least 14mm of clearance from the back of the steerer tube to the first frame member, in order for Alpha One to fit. Many bikes with raised top tubes provide enough clearance, such as Omni, the Diamondback Andean, the Diamondback Serios, the Felt IA, and others. However, some bikes have a very tight clearance, and Alpha One does not work on the Specialized Shiv TT or the Fuji Norcom Straight. If you have a specific compatibility question, don't hesitate to get in touch and ask.


The Alpha One can accept any aerobar extensions with the industry standard 22.2mm outer diameter. It can be purchased with our own Gamma extensions which allow a variety of different positions to be achieved. However, it can also be purchased without any extensions so that you can use your own. Any standard 22.2mm-OD extension may be used.

Some older extensions use a 22.0mm diameter instead of the more common 22.2mm standard. These undersized extensions may be difficult to tighten down, and we cannot guarantee fit. However, we have successfully tested some 22.0mm extensions in the bar, and they fit well. So if you have a favorite extension in the 22.0mm standard, it should fit just fine work in the Alpha One.

Center Pull Brakes

The Alpha One has an internal cable stop allowing for ultra-clean setups. Housing can be run from the brake lever to the cable stop, eliminating aerodynamic drag from the cable housing. You then run bare cable from the cable stop at the center of the base bar to the front brake. This type of routing is ideal for the Omega X and other centerpull brakes.

Hydraulic Brakes

The Alpha One's internal cable stop can be removed so that your front hydraulic line can exit the base bar at the center of the head tube. This results in less drag than sending the hydraulic line out the back or side of the base bar. The Alpha One is fully compatible with Magura hydraulic brakes, or any other hydraulic brakes.

Other Brakes

For other brakes that require housing all the way from the lever to the front brake (Such as V-brakes, side pull brakes, dual pivot brakes, etc.), you can remove the internal cable stop and route the front brake housing out of the base bar at the center of the head tube. This generally results in less drag than routing the cable out the back or side of the base bar.

BTA Bottles and Cages

The Alpha One comes with an integrated BTA mount that is compatible with any standard bottle cage. Any retail BTA solution that attaches to a standard cage mount (Speedfil A2, Profile Design HC Bottle) should be compatible with the Alpha One. The mount may also be used to mount computers or other accessories.

Fit Guide

This Guide shows you how to set up your TriRig Omni with the TriRig Alpha One or Alpha X aerobars. This Guide can help you replicate your current bike position, or set up your bike based on numbers from a bike fitter. The Fit Chart below shows the actual X/Y coordinates of your arm pads measured from the bottom bracket. This coordinate is the most important number that bike fitters use to determine your position on a triathlon bike. Be aware that some fitters use a coordinate to the top/back of the pad, rather than the top/center. In that case, you can subtract 44mm from all of the reach numbers in the Fit Chart, which yields the back of pad number. The steps below provide an easy-to-follow system for making sure you have the perfect fit with your Omni.

Step 1: Determine your current fit numbers

What we want is the X/Y coordinate to the top/center of your aerobar pads, measured from the bottom bracket. Most bike fitters can provide this number to you when performing a bike fit (although some provide it to the top/back of the pads rather than top/center). If you already know these numbers, you can skip this step. Otherwise, follow the steps below to determine these numbers for your current bike setup:

1-Place your bicycle up against the corner of a room, with the back tire abutting the wall.

2-Next, measure the vertical distance from the floor to the center of the bottom bracket. We'll call this measurement Floor Offset (FO).

3-Measure the horizontal distance from the wall to the center of the bottom bracket, we'll call this measurement Wall Offset (WO).

4-Measure the vertical distance from the floor to the top of your aerobar pads. This measurement will be Pads-To-Floor (PTF).

5-Measure the horizontal distance from the wall to the center of your aerobar pads. This will be called Pads-To-Wall (PTW).

6-Subtract Floor Offset from Pads-To-Floor (PTF minus FO). This is your Pad Stack.

7-Subtract Wall Offset from Pads-To-Wall (PTW minus WO). This is your Pad Reach.

Step 2: Review Frame Geometry

Small Medium Large
Frame Stack
(BB to Headset)
490mm 525mm 560mm
Frame Reach
(BB to Headset)
375mm 405mm 435mm
Front Center 560mm 600mm 640mm
Rear Center 400mm 400mm 400mm
Seat Angle 79° 79° 79°
Head Angle 72.5° 72.5° 72.5°
Fork Offset 48mm 48mm 48mm

Step 3: Select Size, then find your position on the chart

The chart below shows the stack and reach information for the TriRig Omni with the included Alpha X aerobar, complete with the number of extension spacers and stem spacers used for each setup. Here's how to use the chart:

1-Use the dropdown box in the upper-right corner of the chart to select a bike size.

2-Find your Stack in the left-hand column of the chart, or the row that most closely matches your stack. Every cell in this row represents a way to set up the Alpha X on your Omni that will produce this stack number.

3-Each cell states the amount of Pad Spacers as well as Stem Spacers to use in order to hit your stack number.

4-In most cases, there will be multiple cells that can hit your stack. The best setup for your position will generally be the one with additional colored cells above AND below your selected cell. These cells represent room to move up or down in the future, merely by adding or removing Pad Spacers, which is generally the easiest way to make a position change.

5-Cells in blue represent a standard setup with the extensions over the bar. Cells in green represent the special undermount position, where the extensions are mounted below the bar.

6-Once you have selected a cell from your Stack row that represents your preferred position, look at the bottom of that column to the Reach section. The three rows of Reach cells show the reach to the center of the pad based on the three different adjustment positions available on the Alpha X arm cups. Select the one that most closely matches your Pad Reach number, and set up your pads/cups accordingly.

7-Note that fit numbers for the Omni w/ Alpha X are measured from the top/center of the headset to the top/center of the pad. All measurements for overmount hardware include the integrated BTA mount.