Bruce on ceramic bearings: I’ve replaced the stock Catrike bearings with ceramics bearings on both of my Speeds. Front and rear. In a year and a half I’ve burned up two of the stock bearings, so I was looking for something that is more durable and that I wouldn’t have to worry about again. It just so happens that they really improve the coasting abilities of a trike, which also means they reduce pedaling effort. But, they ain’t cheap! PRH has just done the ceramic swap in the rear of his trike, and is awaiting the arrival of his new fronts. He felt the improvement from just the rears. If I recall, they are about $50/bearing, and there are four of them in the two front hubs. It takes about ten minutes to replace them in each front hub. Here’s a link to my section on Flickr where I keep my pix of the guts of a front hub, showing the bearings and how they fit. For information on how to remove these bearings, check out this post. It’s easy!
ABEC stands for Annular Bearing Engineers’ Committee. This committee works to determine the standards for bearings for the Anti-Friction Bearing Manufacturers Association (AFBMA).
The ABEC scale classifies different accuracy and tolerance ranges for bearings. The first column of this table lists the five ratings in the ABEC scale.
ABEC Ratings ISO Class
ABEC1 Class 0
ABEC3 Class 6
ABEC5 Class 5
ABEC7 Class 4
ABEC9 Class 2
The ABEC rating of a bearing is determined by the following (for a 608 size bearing):
1. How close the bore is to 8mm in microns
2. How close the outer diameter is to 22 in microns
3. How close the width is to 7mm in microns
4. The rotating accuracy in microns
Thanks to PRH for this latest info on these bearings! These are the bearing and part numbers to order them from VXB Bearings. You will note that these are also ABEC-7 bearings, as well as ceramics.
Kit8041 6904-2RS Bearing 20x37x9 Si3N4 Ceramic:Stainless:Sealed:ABEC-7 Quantity 2
same bearing from BOCA Bearings
Kit7660 6805-2RS Bearing 25x37x7 Si3N4 Ceramic:Stainless:Sealed:ABEC-7 Quantity 2
same bearing from BOCA Bearings
Each front wheel uses one 25x37x7 bearing, and one 20x37x9 bearing, so you need two kits, each with 2 bearings, for a total of 4 bearings for the two wheels.
For standard Catrike rear hubs you need one of each of these kits from vxb.com:
Kit7653 6000-2RS Bearing 10x26x8 Si3N4 Ceramic:Stainless:Sealed:ABEC-7 (about $30)
Kit8160 6200-2RS Bearing 10x30x9 Si3N4 Ceramic:Stainless:Sealed:Nylon:ABEC-7 (about $33)
I believe that all current Catrikes use the same hubs and bearings. The older front hubs used two of the 6904 bearings, but all of the current models use one each of the above bearings in each hub.
An excellent step up from the stock bearings on a Catrike would be to good stainless steel bearings. The next step would be to stainless ABEC-7 bearings. The next step would be to non-rated ceramics. The top of the line (well, almost!) would be ABEC-7 ceramics. You will note that “Stainless” is listed in the description. That’s because the globes (balls) are the ceramic component, but the races are stainless steel.
The best analogy I can give of the difference in ceramic versus steel balls is the difference between a golf ball and a ping-pong ball, as far as smoothness.
Unless you just have a bunch of money to spend, I would recommend running the stock bearings until one of them gives you trouble, then replace them all with ceramics, keeping the stock ones for spares.
Concerning sealed bearings, they can be lubed. That process is discussed in a separate post located here.
My experience (Bob’s) with ceramics has been that they make a 2-3 mph difference in my riding. I found a roll out hill with a straightaway below it, and I coasted my trike on the test track before and after installing ceramic front bearings. Over about a 300 yard run, the trike went 40 paces (120 feet) further with the ceramics. On all the “go fast” sections of my regular route to work, over the next week I set new personal best times on every section, by about 3 mph. On one section, the new speed ability made me try to complete a 6 block section at speeds above 20 mph. I was successful at that. My usual speed over that route is more like 17, and on some areas I usually drop down to 13 or so.
Bruce says the bearings will get better after 200 miles of run in, so I’ll retest them later.
If you install ceramics looking for speed, you should remove the seals, clean out the grease they come with, add replacement grease, and replace the seals. Excess grease would be displaced by the bearings as they rotate, and would come to rest on the bearing cage. During use, oil from the grease would seep out and lubricate the bearings. But if there is so much grease that the bearings have to continually push it aside you will lose any speed advantage the ceramic bearings might have given you. When you replace the grease, you can also make a batch of “thin” grease to pack the bearings with, made of 70% grease and 30% 3-in-1 oil. The picture below shows how much “thin” grease I added.