After noting a faster-than-normal wear-down period in his bottom bracket bearings, John, with the help of his local bike shop, figured out a simple Bike Hack that has increased both bearing longevity and decreased maintenance in his rigid, hardtail, and full-suspension bikes. In our world, we call this a win-win. Read on for an in-depth look at bearings…

I’m not really sure I’d call this an official Bike Hack, but hear me out. A few years ago, my Moots Womble bottom bracket bearings needed to be replaced more frequently than usual, like every three months. After the third bearing replacement, Bailey at Sincere Cycles had an idea.

Side Load Bearings

“Why not try suspension linkage bearings in the shell?” He proposed. His line of thinking was that linkage bearings are designed for side-loading applications, which might increase the bearing’s longevity.

This reasoning makes sense with bikes that are “flexy,” i.e., some steel and some titanium frames. The Womble was flexy. As is my Black Cat Swami. My Sklar Ti PBJ is very flexy loaded down. And even my Starling Murmur is flexy. These bikes all take a good amount of abuse, and once the factory bottom bracket bearings wear out, I’ve been pressing in Enduro MAX pivot bearings.

To my surprise, this doubled, if not tripled, the life of the bearings. Prior to this “hack,” I had to replace them every three to six months, and now I’m replacing them maybe once every eighteen months or in some cases, even longer. I found this to be helpful on my titanium or steel hardtails and even my full-suspension bike.

The Starling Murmur uses two 6902 2RS Enduro MAX suspension pivot bearings for the main pivot, and for the past four years, I’ve been running the same style of Enduro MAX suspension pivot bearings (above with the red cover), albeit a different size, 6806 for the bottom bracket cups on that bike and all of my 30 mm spindle bikes.

Wondering if this was just snake oil in a cartridge bearing or some sort of hardware placebo, I reached out to Dustin from Enduro Bearings to see what it was all about. Dustin used to work for Phil Wood and has always been super helpful with bearing questions I’ve had with my numerous vintage Ritchey restoration projects. He’s also a great wheel builder if you need any wheels built up.

So Much More to Bearing Tech

I began our conversation by saying, “I mean, bearings are bearings, right?” knowing this would elicit a reply worth recording.

Dustin grew with excitement in his voice and enthusiastically chimed in with, “There is soooo much more to bearing tech!”

I explained our rationale and my previous experiences to Dustin. His response hinted at Bailey and my assumption…

“The reason they are probably lasting longer is that MAX bearings are designed for the high load presented by suspension linkages. You know, they’re not ever fully rotating 360º. They’re just grinding back and forth and taking side load every time you land on your bike at an angle. Because our MAX bearings are full-compliment bearings, we usually cram as many as required in there. Sometimes it’s up to 30% more balls per bearing, compared to other bearing models. And we use a pretty thick grease in our MAX bearings.”

A full complement bearing has no separation between the ball bearings; i.e., no cage holds the number of ball bearings together. In some cases, the bearings are stuffed in there, potentially touching each other, even. They’re then suspended in a grease, depending on friction requirements. Phil Wood only uses full compliment bearings in their hubs and bottom brackets.

MAX Bearings for Side Loads

I asked Dustin if we had cracked some sort of code with bottom bracket bearings, and he replied:

“I’m not saying it’s the wrong thing to do, but we wouldn’t officially tell you to do that. MAX bearings aren’t going to spin as freely as some of our other bottom bracket bearings.”

Knowing I’m not a performance-minded cyclist and that I usually ride metal bikes, I asked if this was something that someone like me would even notice. He paused and said:

“… You know… It would be hard to measure, to be honest. The drag you would feel from MAX bearings being in your bottom bracket cups. They are used in places where side load happens, and they work really well for that sort of load. If your frame is flexing a lot, the MAX bearing is load-bearing and could potentially last longer. Also, on a mountain bike, you’re not putting a ton of rotation on the bearings, so that could contribute to why they’re working better. If you’re just grinding up a long climb and then coasting down a steep trail, then yeah, it sounds like the MAX bearings would do the trick.”

Dustin then explained that if we’re upgrading the factory bearings from a manufacturer’s bottom bracket, there are other options they’d recommend to start off with.

“Abec 5, 71806 angular contact, or XD-15 ceramic hybrid bearings could potentially solve this problem, too. We even make high-end ceramic bearings with a lifetime warranty. The XD-15 bearings are comparatively expensive ($89), but if you’re looking for maintenance-free bottom brackets, that’s your ticket.”

As our conversation was coming to a close, Dustin interjected,

“You know what? You ought to talk to Matt, our bearing engineer. He’ll be really interested in this…”

MAXhit left, radial standard, right

A Chat with Matt from Enduro Bearings

We hung up for the evening, and the next day, I connected with Matt, who offered up some more precise engineering data on why I was experiencing longer lifespans on MAX suspension pivot bearings. We determined the bearings that were wearing out quickly in stock bottom brackets were most likely radial bearings.

“Radial bearings have play in them. Sometimes, there is not enough preload (30-35%) of 16 balls in the 6806 bottom bracket bearing, so maybe only a few more balls are engaged at a time. MAX bearings have 30% more balls. If they’re not fully engaged, the balls going around the top of the bearing are floating, and the load is being transferred to the bearings on the bottom. A MAX bearing could be giving you more ball bearing contact. MAX bearings also use 62 Rockwell stainless steel, which is 20% harder than 58 Rockwell bearings found in many radial bearings.”

I began to pry and asked why Enduro doesn’t recommend MAX bearings for MTB bottom brackets if they seem to be working for me.

MAXhit: Bigger Ball Bearings

“The reason we don’t push MAX in bearings in bottom brackets is we grind a fill slot into the shell to load the bearings. So, if the ball hits just right, it can shear it, causing a catastrophic failure in the bearing. This is why they aren’t intended to do full rotations. However, our MAXhit bearings do not have a fill slot.”

So that was the Achilles I’ve been gambling with (and will continue to gamble with, to be fair.)

Overlap between the MAXhit bearings, which have the bearing ring incorporated into the bottom-bracket cup and a standard radial bearing…

“Normal bearings like our MAX bearings are 2.5-3 mm wide. Meanwhile, the ball bearings are up to 5 mm wide with the MAXhit bearings. We machine part of the bottom bracket cup to act as a big external bearing race, allowing for the increase in bearing size. When you double the diameter, the mass increases, and the ball is more corrosion-resistant and has a better load rating. Then, if the shell or something isn’t completely straight, it can count for better misalignment.”

Bailey’s hunch was correct, and while the MAX bearings had worked for me for almost five years, talking to Dustin and Matt from Enduro led me to one-up this Bike Hacks with a conclusion: try out a MAXhit bottom bracket.

Bearing Longevity

Matt said he was sold on the longevity of Enduro’s MAXhit bottom bracket bearings after he met Josh Ibbett, the ultra-endurance athlete who uses MAXhit bearings. Josh pulled his bottom bracket apart to show Matt the condition of the bearings after two full years of training and racing. When I asked what they felt like, Matt said, “They still spun like they were brand new.”

Bike Hacks and Tinker Tantrums aren’t always about finding a final solution for a problem. Sometimes, it’s the process of experimenting and conversing with people who know a lot about a subject that can lead you to the best solution. It’s the journey, not the destination, so to speak.

While the MAX bearings pressed into my aluminum bottom bracket shells have worked great for the past five years; I’ll be testing out the Enduro MAXhit bottom bracket for a long-term review, so stay tuned! Matt from Enduro is also going to inspect an old set of LLB bearings from my Murmur to see how they were wearing.

TL;DR

• If you want to extend the life of your standard 30 mm bottom bracket bearings, use the Enduro MAX bearings, but with a warning: the fill slot in the bottom bracket shell could shear a ball bearing catastrophically. So caveat emptor!
• Enduro makes a 71806 Angular Contact Bearing, which handles side load better…
• If you’d like to extend that life even longer, use the MAXhit Bottom Bracket.

Many, many thanks to Dustin and Matt from Enduro Bearings for this chat. This Bike Hacks post was not a paid advertisement; it was just a recent realization I wanted to share with you all that can hopefully guide you through your next bottom-bracket installation. If you have any pointers or anecdotes related to this particular discussion, please drop them in the comments!