The bottom bracket, what is it and what does it do?

We decided to get some bottom bracket help from C-Bear (www.c-bear.com), one of the high tech players in the market and suppliers by choice to the Lotto Soudal Pro cycling team. We asked Robin Corder from C-Bear UK distributors, Velotech Services, for some expert advice on one of the most neglected performance upgrades.


C-Bear are a Belgium company who have developed bottom bracket (BB) solutions to help the end user navigate the difficult issues with bottom bracket selection, offering BB to crank specific bearings so you can’t go wrong when it comes to choosing the upgrade to your particular bike.

TRI247: The bottom bracket, how important is it to the bike?

Velotech Services: The bottom bracket refers to the bearing inside the frame that holds the cranks and pedals in place. It has to transfer all the power from your legs into power at the wheels, and so any unwanted movement or inefficiencies in this part of the drivetrain can seriously compromise your performance.

TRI247: Why would you want to upgrade your bottom bracket?

Velotech Services: The BB and the pedals are doing so much more work than any other item on the bike (except you maybe)! And yet when you buy an upmarket bike it probably comes with the same BB quality as a standard lesser value bike. The performance enhancement you expect to get from better gears, brakes, bars, and wheels is generally overlooked with an upgraded BB. So the most obvious upgrade to make on a bike is often ignored by the manufacturers, and the customer.

TRI247: So what upgrade should I be looking for?

Velotech Services: There are a few options to look out for with BB standards, which are a result of the bigger factories developing separate standards and hoping others would adopt. And then there are the derivatives of these, like the BB-Right from Cervelo using a single side spacer, and the BB30A with Cannondale requiring double side spacers, Specialized use a narrower BB, which needs spacing as well.

TRI247: So why are spacers an Issue?

Velotech Services: Any location a spacer is used increases the chance of error in the BB unit and introduces creaks and wear.

C-Bear bottom brackets use housings that replicate the spacer width and bring the bearing as close to the crank arms as possible. The result is increased life, reduced wear and during this time the rider is getting better performance. The wider the platform for the BB the more stable the BB becomes and allows potentially better power delivery from the rider.

TRI247: And the reason for choosing a ceramic bearing?

Velotech Services: A ceramic bearing is much harder than a steel ball and if used in conjunction with a hybrid race (the surface it rolls on) results in substantially less pressure resistance under load. This is widely accepted as a performance enhancement. C-Bears housings are high precision machined and feature a highly accurate internal seat, which ensures the bearing cannot rotate or move in the cup.

TRI247: So why doesn’t everybody use ceramic bearings?

Velotech Services: Well, previously price and bad wear have been an issue, stainless steel bearing races can be worn easily by hard ceramic bearings and lead to a short life, bad seals allow moisture ingress and it all goes bad very quickly without regular maintenance.

TRI247: So how are C-Bear different?

Velotech Services: C-Bear use a hybrid race that complements the ceramic bearing and specific long run ceramic grease, along with a double labyrinth seal on the bearing.

Because of the perfect marriage of crank and BB the unit becomes a solid structure and without unwanted movement leads to super long life and great performance.

TRI247: Is there a decent warranty with their bottom brackets?

Velotech Services: Yes, C-Bear offer a two year warranty as long as it’s fitted by a reputable store and has a six month re-grease/service interval. So a bearing that is super smooth, silent and gives hassle free performance for two years has got to be worth the upgrade cost?

If you ride a Cervelo, Cannondale or Specialized, we have specific bearings for these, also the Giant standard PF41 can be replaced with our new bearing for 24mm and 30mm axles. You can check compatability on the C-Bear PDF chart C-Bear compatibility chart PDF.

And along with the ceramic pulley wheels your bottom bracket would be an upgrade worth considering; pulley wheels are another story!

You can find out more by speaking to the guys at Velotech Services or visit their website HERE or contact your local bike shop and get their expert help.

C-Bear