View Full Version : TECH: Install a Tapered Roller Bearing Conversion Kit - DIY Tech Tips from Lowbrow

08-13-2009, 11:57 AM
Once you remove the front end off of your Triumph or BSA motorcycle you will likely have the stock races and loose roller bearings that will fall all over the floor and roll out of site. A nice upgrade, which also makes installing your front end very smooth, is a tapered roller bearing conversion kit. These modern bearings and races will give you smooth steering and will last for many years. In addition to being an upgrade for stock frame / front end combinations, we also produce bearing conversion kits to fit any front end with a 1" stem (many girders and springers, HD big twin and Sportster forks) to your Triumph or BSA motorcycle.

Shown below is the stock top race with a few remaining ball bearings.


The stock races have to be knocked out of the neck. There is one both top and bottom. A long drift held at an angle so it will catch the inside lip of the race makes the job easy (usually). Sometimes they can be seated really well and take a good amount of effort to remove. Move the drift around as you knock it out so it comes out evenly to make it easier.



Once you remove the stock races, you will want to place your new tapered bearing races on the neck, and using a deadblow hammer or a piece of wood and a hammer, drive the race into the neck.


08-13-2009, 11:58 AM



Before you insert your bearings you want to pack them with grease. Work them around in your hand and really get it in there, you want to get the bearings thoroughly greased.


08-13-2009, 11:59 AM

Depending on what bearing set you are installing, the dust cap would go over the top bearing, and you slide your forks in from the bottom. It can be much easier to install your forks if the front wheel is off of them. Also, if you are rebuilding your front end, you can put the trees on the frame, then insert your fork legs.




08-13-2009, 1:19 PM
Great tech article! When I changed mine out on my stock CB750, I couldn't believe the difference. It liked to shake its head a bit when decelerating. Not full on speed wobble or anything, just a bit of shimmy that you wouldn't want to take your hands off of. Now with the new bearings, there is no wobble at all, and you can take your hands off at any speed (not that I recommend it). It also feels better turning and stuff. It's an amazing difference for such an easy fix.

I saw my dad pack wheel bearings on cars and stuff when I was a kid. When packing the grease in the bearings, put a pile of it on the palm of your left hand... It's nasty feeling but it will wash off later. Hold the bearing at an angle (45 degree or whatever works) in your right hand, with the larger side down. Now try to scrape the grease off of your palm, not a back and forth motion, but one way. Basically, you are forcing grease up between the outer metal part and the inner part. The scraping is what forces the grease in there. This works real well, keep it up till it comes out the top real well and then turn it to a place with no grease. Repeat till it's full.

This works real well to get the old grease out when you want to change grease too... just scrape till clean grease comes out the top.

Now if all that sounds like too much hassle there are bearing packing tools that may work, but a wad of grease in your hand don't cost ya a thing for tools.

EDIT: Good old YouTube! This guy taps it, but its the same way to hold it, I like scraping better. http://www.youtube.com/watch?v=agxjGtmHV_4

08-13-2009, 2:40 PM
+1 for this post. I put new tapered bearings in my kz650 not to long ago. but god damn, getting the old ones out is a bitch! for anyone who has not done this allready i highly suggest it.

08-13-2009, 7:30 PM
Thanks for all your tech articles. they are always very clear. I hope to be placing an order with you real soon.

08-13-2009, 7:57 PM
figured I would help this thread out... this is how to take the tapered 1" conversion kit from LowBrow and cross breed it with a pro 1 internal fork stop kit. enjoy!


this is what I started with... Neck bearing conversion kit (low brow sells these) to run a 1" HD style stem on a triumph (dave bird in my case) neck, and a pro-one internal fork stop kit FOR HOUR GLASS STYLE NECKS. (PN# 103413T)


lucked up, bearing fits race perfectly!


installation of the pro-one kit requires swapping out the lower bearing race, but on the triumph conversion kit, notice the "bushing" on the out side of the race which makes it fit snugly in the neck... if the "bushing" actually has a proper name, I don't know it...


time to get em' apart for the swap! I used a 2" trailer ball, and my shop vise. just ran the vise up to hang the lip of the "bushing" put the trailer ball on the race, and gave it a few blows with a ball peen. came right apart, didn't even mark anything up... (you wont need the race anymore anyways if you screw it up...)

08-13-2009, 7:58 PM

time to mate them together...


slather red loctite on the knurled area per Pro-one's instructions. I used a block of wood on top, with the new race/bushing sitting on my wooden work bench, and beat them to seat with a hammer.


this is what you end up with... just drill and tap bottom tree for the stop ring, and ready to go! you'll end up with an extra dust cover, and the old race, feel free to drink beer and play washers with them when your done...

hope my experimenting helps someone out!


08-14-2009, 9:09 AM
that is awesome. Thanks for posting the how-to!

08-14-2009, 9:23 AM
looks easy enough thanks!

08-11-2015, 10:39 AM
Hi, I know this is an old thread but I'm looking for a bearing set to install a set of Ceriana/Arces forks/trees on an OIF Triumph, and I'm having trouble finding the bearing set. The stem on the trees mics out at just over 1". Thanx in advance for any help. (or direction to the proper post) Mark