This new FAIR Bicycle IPA Rim Tech story is quite obviously another April Fools’ exercise, right? But frankly, their spoke tension adjusting rim concept is bike-nerdy enough that it’s worth sharing anyway. We know FAIR mostly for their unique seatpost & dropper head toppers, bringing more seat angle adjustment and even lower stack height to the bike you already have. But obviously, their engineers can get pretty creative when they think outside the box.
FAIR IPA adjustable pressure rim concept is out there, right?
Actually, Fair says this was them thinking inside the box. That is, inside the box section of your mountain bike rim.
“Is it really possible that we live in the 21st century, yet in mountain biking the top riders / mechanics still have to hand tune their spoke tension to get the desired ride feel out of their wheels?“
That’s the underlying thought that led to this out-there concept. They derived the solution a bit from the problem Schwalbe had with ProCore a decade ago, when their high-pressure inner tire liner actually detensioned a wheel’s spokes when fully inflated to its max 90spi operating pressure. So, if that could happen by accident, why not do it on purpose to fine-tune a wheel’s stiffness?
Enter IPA – Internal Pressure Adjust
Fair wanted to create a solution to use pressure to quickly and easily wheel stiffness. They said riders had a difficult time sensing changes in wheel vertical compliance, but could easily differentiate a wheel with extra lateral deflection from lower spoke tension. So maybe fine-tuning that lateral stability through adjustable tension could be the path to finding a sweetspot in stiffness, grip, and control. And maybe add the possibility to tune for different tracks – say buff flow trail berms vs. DH track ruts?
So they developed an inflatable air chamber inside a concave rim section. Increasing pressure inside the rim would expand the rim, decreasing its ERD – the effective rim diameter from the spoke bed – thus decreasing tension in the spokes.
It’s rather simple.
Add more air, ERD and stiffness decrease. Remove air pressure, ERD and stiffness increase.
It’s just a concept, though
“First of all, IPA TECH is not a commercial product yet. It is still being developed and refined. FAIR bicycle has filed patents for the air chamber and the rim profile – Swiss Pat. 20240633 & Swiss Pat. 20248421 (Bikerumor was unable to verify the authenticity of any Swiss patents). The IPA TECH system is composed of a proprietary rim (profile) design and nipple/secondary valve technology. As an added benefit, the rim bed is natively tubeless ready / air tight.“
Maybe it’ll show up on the race scene. Maybe it’s just vaporware. Or maybe it ends when the calendar clicks over to April 2nd.
Who can guess these days, what craziness will happen tomorrow!
In the meantime, we’ll leave you FAIR’s UnFair IPA Tech Pros & Cons…
THE PRO’S:
- fast and infinite adjustment of spoke tension, to fine-tune ride feel to rider preference/track characteristics
- natively tubless rim bed
- roughly equivalent rim/wheel weight
- you could inflate your rim with helium, to reduce bike weight AND unsprung mass. just kidding
THE CON’S:
- more involved wheel builds due to captive nipples
- slightly more expensive rims
- you have earned yourself an IPA only after reading and thinking through all of this
- helium is very expensive!
