Fit your Aerobar Risers: Bolt Sizing and Spacing Guide

In the build up to the Paris Olympics we developed our Aerobar Adjustable Risers in collaboration with Cycling New Zealand. The goal was to end up with a system which gave more adjustability, allowing for better ergonomics and a cleaner setup. This unique design allows for a practically universal riser with ease of adjustability from 15° up to 30°. Internal cable routing is also considered for electronic road time trial configurations. 

We often get questions regarding the mounting and compatibility. This blog looks to answer the most common questions, however, as usual feel free to ask any questions in the comments.

How do I measure my bolt spacing?

Your basebar’s bolt spacing is the distance between the two bolts that attach the aerobar riser to the bar itself.

To measure it:

1. 1. Remove your current riser system (if installed).
      
      

   2. Use a ruler or calipers to measure from the centre of one bolt hole to the centre of the other.
      
      

   3. Our risers are designed to fit bolt spacing from 20 mm to 40 mm, which covers almost every bar on the market.

If your spacing falls somewhere in that range, you’re good to go.

Are my bolts M5 or M6?

This simply refers to the diameter of the bolts used on your base bar:

• M5 bolts are 5 mm in diameter, common on older setups.
  

• M6 bolts are 6 mm, usually found on newer systems.
  

Some bars may clearly state which size they use, but if you’re unsure, the easiest way to find out is to measure a bolt yourself or compare it to one you know is M5 or M6. An M6 bolt will look noticeably bigger than an M5, but we recommend measuring to be sure.

Our risers are compatible with both M5 and M6 bolts — so no matter which your bar uses, our adjustable aerobar risers will likely be the solution for you.

Do I need a hex nut?

That depends on how you’re mounting the riser.

• In a top-down bolt configuration, your bolt threads directly into the bar or a proprietary nut. No additional nut required.
  

• In a bottom-up configuration, a nut is held captive within the riser to secure the bolt (these are standard hex nuts and not included with the riser). You can typically source an M5 or M6 hex nut from your local hardware store.

If your current setup uses a nut underneath, you’ll want to keep that same hardware when installing the new risers.

Conclusion

Our Aerobar Adjustable Risers are designed to fit almost any base bar with minimal fuss. With micro-adjustable angles from 15° to 30° and internal cable routing in mind, they’re built to help you dial in that perfect, UCI-compliant position. If you’re looking to upgrade or adjust your aerobars, our Aerobar Arm Rests are designed for maximum compatibility and adjustability. Check them out here.