Hambini Roasts: Cervelo

If you are about to buy a Cervelo bike, watch this video. It shows the appalling tolerances the bike frames are made to. The bottom bracket pressfit specification is so bad, neither NTN or SKF will warranty their bearings in it. https://youtu.be/GWDztuezn0g Cervelo Bike Frame fixed This particular frame had misalignment between the two halves of the frame body.

0 Comments

Warning: Counterfeit/B Grade SKF and NTN bearings

I have had a number of cyclists contact me with issues around NTN and SKF bearings being fitted at bike shops and failing within a fairly short period of time. A number of these cyclists have sent me the bearings back to look at and I have found a large number of bearings to be counterfeit or B grade. Counterfeit Bearings These bearings are units that have been made by a third party and then subsequently badged with a named brand eg SKF,…

0 Comments

Specialized OSBB – Engineering Guide

A question that crops up frequently is with regards to Specialized's OSBB bottom bracket and what size it is exactly. The short answer is OSBB comes in 3 variants which are all called OSBB. 46x61, 42x68 and 46x73. A summary table is below, with the detailed drawings below that. Variant (Diameter x Width) (mm)ApplicationDescription46 x 61RoadFrame tolerances are the same as PF30. It is extremely narrow42 x 68RoadThis has exactly the same dimensions as BB30 and is designed for 6806 or 61806 bearings…

0 Comments

Bottom Bracket Pressfit and Creaking, an Engineering Analysis

If you are reading this you will have probably already come across the numerous posts by various individuals in Internet forums across the web. The issue of creaking bottom brackets has been blamed on the introduction of pressfit and directfit bottom bracket standards, where bearings either push directly into the bike frame or push into cups which are then pushed into the bike frame. General guidance varies from taking everything out and regreasing it to installing with extreme measures such as epoxy resin.…

0 Comments

Ceramic Bearings vs Steel Bearings… An Engineering Analysis

One of the most controversial topics in the cycling industry is with regards the topic of Ceramic bearings and whether they do or do not reduce friction dramatically in riding. This article will address some of the concerns and topics associated with this debate and quantify the numbers. Internal Bearing construction - Ceramic bearings are not 100% ceramic Ceramic bearings are in actual fact hybrid. They use ceramic balls and usually a steel inner and outer race. The ceramic balls are often silicon…

0 Comments

BB86 Bottom Brackets with a 30mm or SRAM DUB Crankset

30mm cranks into BB86 bike frames - Avoid if you can... A common question I am often emailed about is asking if I can supply a bottom bracket that will allow a 30mm crank to be fitted into a BB86 bike frame. This post will talk through the many problems associated with this. BB86 uses a bottom bracket with a diameter of 41mm and a width of 86.5mm (Drawing shown below). In practice these are nominal dimensions and have a tolerance on them…

0 Comments