The Bottom Bracket That Was Too Good

When I built up this bike in '03 I used a UN series BB

A while back, a reader here asked a question in the comments which has inspired this post. It is about one of my favorite bicycle components of all time - the UN series of bottom brackets by Shimano. 

The Background:

First of all, it may be a good thing to consider the context of the times before Shimano created the cartridge bottom bracket. This was when all bicycles in bike shops generally had some sort of square taper spindle bottom bracket which was "fully serviceable". 

What I mean by the term "fully serviceable" is that the component could be torn apart, inspected, have parts replaced, re-lubricated, and reassembled making the potential for the component to last a long time fairly high.

Diagram showing a cup & cone serviceable bottom bracket

While there were variants on the theme, a serviceable bottom bracket was typically made up of a hardened steel spindle, loose ball bearings, also in steel, two "cups", and usually some sort of lock ring. 

In this sort of arrangement it was absolutely critical for the frame to have clean, straight threads inside the bottom bracket shell and that the faces where the bottom bracket tube faced outward on either side be 100% parallel to each other. If these things weren't true, the bottom bracket would wear prematurely, or be unusable due to poor adjustment capabilities. 

The cup and cone set up of this type of bottom bracket required skill to set correctly or the bearings would wear out, along with the cups and spindle, before they should. This adjustment required various different spanners, specific to certain types of bottom brackets. Additionally, this sort of bottom bracket was prone to contamination from wet weather riding, dust, and dirt. 

Take these things and add the dozens of variants (differing spindle lengths and thread types) and a repair shop could quite literally have a machinist's cabinet full of spares to service these bottom brackets. Not to mention the time required to install and adjust these bottom brackets.

The Cartridge Bottom Bracket: 

Along about 1992 Shimano introduced a new bottom bracket which was sealed up inside a metal tube so you could not see the bearings. They called it a "cartridge" type bottom bracket. While the first cartridge style bottom brackets looked very similar to what you can still buy today, there were a couple of weird quirks regarding the originals.  

Originally the plastic cup was on the drive side.

Oddly enough, the plastic non-driveside cup you might be familiar with on a cartridge style Shimano bottom bracket was actually on the driveside originally. Obviously these are left-hand thread and are exceedingly rare. Because the plastic wasn't quite up to the rigors of drive side pressure, Shimano quickly switched the arrangement to what is currently available today. 

Another oddity was the original cartridge style bottom brackets were serviceable. You could take the bearings out, re-grease the unit, and the cones were adjustable via a specialized tool sold by Shimano. I happen to have the tool, oddly enough! 

Additionally, the cartridges were not specific to bottom bracket shell length originally. This difference between 68mm and 73mm shells was accounted for by the shoulder in the inside diameter of the plastic cup. A wider shoulder was for 73mm shells and a narrow shoulder was for the 68mm shells. You could use a cartridge unit in either shell as long as you had the proper non-driveside cup. This reduced the number of variants Shimano had to make since every cartridge worked with both bottom bracket shell widths.

Finally, and most importantly for mechanics, the Shimano cartridge system reduced the number of bottom bracket variants by a very significant amount. There were less spindle length variants and you didn't have to worry about bearing race variations between similar width spindles either. This made stocking bottom brackets easier for shops and easier for manufacturers as well, since Shimano only offered certain spindle lengths. In fact, now you pretty much only have three spindle lengths which cover almost every application.

The original UN series was split up into three levels matching the old DX/LX/XT hierarchy for MTB and the 105/Ultegra/Dura Ace on the road side. XT, and eventually XTR, along with Dura Ace had metal non-driveside cups instead of plastic and were UN-90 series. The mid-level was UN-70 series, and the original entry level cartridges were UN-50 series. Later on lower series cartridge bottom bracket variants were offered to accommodate entry level MTB/Hybrid applications, and some road bike/touring bike applications as well. 

Image from a recent eBay listing for a UN-71 cartridge bottom bracket

Just Too Good!

As I said, these were made so well they were too good! Shimano sealed the units so well they resisted contamination to a great degree, making the units last far longer. While the UN-70 and 90 series were lighter and had better machining, the UN-50 series was so much better than previous serviceable bottom brackets, and went for such ridiculously low prices, everyone used these when they could. Of course, Shimano eventually made less expensive, lower-tier cartridge bottom brackets and those - while possessing the long-wearing traits of the upper end units - were far less quality in terms of bearings and free-movement. 

Eventually Shimano moved on to pipe spindle type bottom brackets around the year 2000. The square taper bottom brackets fell out of favor as crank sets became two-piece with spindles and bearings were housed in separate cups. This was when I started hoarding square taper UN-50 series bottom brackets. 

I've run the same UN-52 BB in this bike since it was built in '07

I ended up with several since I was a mechanic and when folks upgraded, or thought these were bad, I had first crack at owning them. I used a few on bikes I still ride today like my Karate Monkey, my OS Bikes Blackbuck, and my Pofahl Signature. 

I had to replace the one in the Karate Monkey after 4 Winters of abuse, That one was frozen in the frame! I had to remove it piecemeal. 

I maybe have had to replace one other of my used bottom brackets due to it being worn out. 

So, you perhaps can see why Shimano moved on to stiffer pipe spindle bottom brackets and different designs, but there is absolutely nothing wrong with a square taper crank and a Shimano cartridge style bottom bracket. You can purchase brand new UN-55's yet, and used UN-70 series bottom brackets are out there for right around $35.00 - $40.00 each. 

If you have any further questions about these or other components, let me know in the comments. Thanks for reading Guitar Ted Productions!

No, It Is Not Bottom Bracket Time!

PF-30 is NOT BB 86. (sigh!)

So, last week I mentioned I had this Enduro Bearings PF-30/Shimano compatible bottom bracket in to hopefully solve my noise problem with the older Wheels Manufacturing bottom bracket. The thing is, I ordered the wrong bottom bracket, and well...... There was actually something else going on.

I'll get to the noise issue later, but first off, I don't know why I did not realize I had a BB-86 bottom bracket in the Noble GX5. I remember I ordered the Wheels Manufacturing one in the bike now way back when I was still working for Europa Cycle and Ski, and after I received the Noble GX5, obviously. I believe the Noble came along in 2018, so this would place the Wheels Manufacturing bottom bracket in the six year old range. It wasn't out of the question that my noises were related to the bottom bracket then. I had diagnosed the bike with it in the stand, and I probably should have taken the chain off, but I did not. It just was really rough feeling when I spun the crank set, and it seemed obvious.

Then the bottom bracket came in, again, exactly what I ordered, just to be clear, and I went to work. Once I went to install the new one I realized what was going on, so I had no immediate option but to go back and re-install the old Wheels Manufacturing one. Now, in between the tear down and the re-installation, I checked the bearings in the old bottom bracket, and while there was not a glassy smoothness, it was not rough. But, where was all the noise and roughness coming from before then?

Not a peep or sense of roughness was felt on Monday\s ride.

Well, I also had removed the wheels from the Noble and replaced them with my older set of Irwin Cycling carbon Aon wheels. I did this to mount the Continental Terra Adventure tires on a slightly wider inner rim width than the WTB wheels have.

Interestingly, those WTB wheels would never run quietly in the Noble GX5 frame until I tried them again this year. They used to squeak a lot back when I had tried them a couple of other times in the past. However; now the noise of squeaking has been replaced by a noise more akin to what a bad bearing sounds like, apparently, because with the Irwin wheels the bike is dead quiet. And even more maddening, these WTB wheels are perfect in my other bikes.

I had gotten away with the WTB wheels being quiet for a while, but I am thinking this was the issue, because I hear no noises anymore. By the way, I think those WTB wheels just do not fit the Noble frame quite right. The through axle interface must not be quite right. Perhaps a different through axle would be a fix? 

Now - I had cleaned and re-greased the interfaces with this latest bottom bracket removal and installation also, so if it was the old bottom bracket which was noisy, I would have taken care of it with the cleaning and re-greasing. But I cannot say for certain now. 

The drive train is quiet now. The noises are gone, so what about this new PF-30 bottom bracket? Well, it would fit my Standard Rando v2 just fine. So, one day IF I wear out the Enduro Bearings bottom bracket in that bike I'll now have a ready-made spare. And I will have to order a BB-86 next time for the Noble. 

Maybe I'd better write this down somewhere, eh?

Friday News And Views

5DEV direct mount chain wheel as shared on their social media.

 The Colorful Edition of the FN&V!

Fashion Plates?

I've been noticing a trend of late on social media. Bicycles with derailleur drive trains being shown with 'pie plate' style, solid chain wheels as 1X drive rings. 

I first noted this back in 2022 at the Gravel Cycling Hall of Fame shindig in Emporia, Kansas. I noted a Stormchaser single speed with a brilliant purple, solid chain wheel. 

Then I found out that Absolute Black does a 'pie plate' style ring, which is supposedly aero. It is a rather stark, unusual offering from this company known for its more open designs and industrial looking offerings in several anodized colors. 

Now I am noticing a few custom bikes being shown on the Insta that have silver colored, solid chain wheels. Okay.....something is going on here. I suspect that some more offerings in this style will appear at Sea Otter soon.

I don't know if I am a fan though. Color me jaded by years of working on cheapo BMX kids bikes, but these look like a gussied-up department store bike component. It's hard for me to take the 'pie plate' look seriously. But that's probably just me. What do you think? Let me know in the comments.

Image courtesy of Wolf Tooth.

Wolf Tooth Announces New Colors For SS Cogs:

Now for the other end of the drive train, you have Wolf Tooth announcing new colors for their line of single speed cogs. Gold and Orange are being added to their other offerings in the range. 

These are aluminum, of course, but Wolf Tooth also has a stainless steel single speed cog offering for those of you who want the longest lasting cogs and don't care about fashion. (Ha!) 

Comments: I am happy that someone out there still believes in making single speed stuff. That kind of went away for a while there in the last ten years and for a while I was worried that I'd be scrounging for parts for my several single speed bikes. But Wolf Tooth must be selling these things, otherwise they would not introduce more colors, I would imagine anyway. 

Now I know where to go to replenish the look on my Campstove Green Karate Monkey when I wear out a cog, or want to change gearing, and want a green cog! 

Image courtesy of Wheels Manufacturing.

Wheels Manufacturing Offers Anodized BB-30 Options:

Now on to the bottom bracket! Wheels Manufacturing recently added anodized color options for their range of bottom brackets for 30mm spindles. Now available in seven anodized hues for BSA 30, T-47 internal, T-47 outboard, and PF-30 variants. 

Prices are $100 - $124.00 each. You can check them out HERE along with all their other bottom bracket options. 

Comments: I've used Wheels Manufacturing bottom brackets for repairs and personally for years now and have found them to be very good quality options for a decent price. The anodized colors are just icing on the cake here. 

Image courtesy of Chris Skogen's social media

Almanzo 100 v3?:

Monday a surprise announcement from Chris Skogen, the founder of the seminal and legendary Almanzo 100, came out, via Skogen's Instagram page, announcing that the Almanzo 100 was coming back. 

This would mark the third come-back for Skogen and the second time for the event to come back as well. (A timeline of events documenting the retiring of the Almanzo 100 name and original event can be found HERE) 

In the announcement, Skogen indicated that the 100 mile event would occur this May on the 18th. Other details are yet to be released, but this post will be updated when and if those details become available. 

The announcement reads as follows, taken from Skogen's Instagram:

"***WE’RE BACK***

That’s right, we’re bringing Almanzo back!

WHEN: Saturday, May 18th - 8:00am
WHERE: Starting location will be announced here on May 11th
WHAT: 100 mile self-supported route (no drop bags, no outside support, no GPS)
WHO: Everyone
WHY: Because

See you in a few weeks!!

#nerd #party"

Comments:  Mr. Skogen has been known to make surprise, unexpected announcements at odd times regarding the Alamanzo and its satellite events. (See link above) On April 2nd he posted again saying this was "real" and that he is, "Taking another swing at building community in and around the bike space."

 UPDATED 4/7/24: Mr. Skogen posted on Saturday on Instagram a list of gravel events with some designated as events he will attend. Quoted: "I’ll be at the events in BOLD." One of those events he marked in bold, on May 18th, is The Heywood Ride, the ride that Mr. Skogen handed over to the organizers of The Heywood, when it was called the Almanzo,  and asked that they not use the name "Almanzo" for it. So, they came up with "The Heywood Ride".

So, is the Heywood going back to being called the Almanzo? 

Stay tuned........

Kit for a Cause Jersey image from Gravel Worlds social media.

Jersey To Benefit Cancer Causes:

Gravel Worlds announced recently that they are offering "Kits For A Cause" now through their jersey vendor, Voler USA. 

The first is a design by Kevin Wilkins that features dogs biting one another with a sign on the rear that says "Chase me!"

All profits from the sales of the jerseys are going toward cancer survivor @kevinwilkins and the organization Grind For Life.org which has a mission to provide financial assistance to cancer patients and their families when traveling long distances to doctors and hospitals.

You can check out the kit and order at this link:  www.gravel-worlds.com/kit

Orders for this kit close on April 15th. Gravel Worlds says there will be other efforts similar to this in the future.  

The Guitar Ted Podcast Sponsored by The Spinistry:

A new episode of the Guitar Ted Podcast is up now. In this one N.Y. Roll and I discuss the celebrations of last place, the Sardine Tool, and N.Y. Roll's experience in Texas recently where he rode the Red River Riot.

You can listen to the episode by clicking THIS LINK. 

We are working on new episodes concerning tires and their construction, how gravel roads are made and why, and more. If you have any episode ideas, let me know in the comment section. 

Thanks again to The Spinistry for their continued support of The Guitar Ted Podcast and check out their Gravel 1000 challenge which anyone can engage in from any location. You can find out more about this challenge by clicking THIS LINK.
 

That's a wrap on this colorful edition of the FN&V for this week. Have a great weekend and thanks for reading Guitar Ted Productions!