Best Square Taper Bottom Bracket – The Ultimate Guide


As an Amazon Associate I earn from qualifying purchases.

Why do you think we need to change our bottom square taper bottom bracket? The bottom bracket so far is called the heard of the bike. Without it, you can’t rotate your crankset. This spindle bike bracket helps the crankset rotate easily. So, if you feel any kind of discomfort rotating the crankset, changing the crankset is a must.

This unit plays a vital role in your bike riding. With a worn and damaged square taper bottom bracket, it’s not possible to pedal the bike with ease. It’s a tough job to find out the best square taper bottom bracket among the numerous numbers of the bottom bracket.

Here, we will try to give you the best possible review of the best square taper bottom brackets. Besides, we’ll cover up the square taper bottom bracket vs hollowtech. So, stay tuned with here.

What is Square Taper Bottom Bracket

The bottom bracket on a bicycle allows the crankset to rotate freely. It means the bottom bracket has a connection with the crankset. It has a spindle, which helps to connect the crankset. In a square Taper bottom bracket, the best part is it comes with a cartridge sealed bearing, which allows the spindle and crank to rotate.

Now let me share some knowledge about the square taper. The other name is cotterless as the design came after the introduction of cottered spindles. Square taper is the most popular bottom bracket around the bicycle world. From the name, you can have a clear idea about the square tapper bottom bracket. The square taper bottom bracket spindle has a square taped shape around it, and this spindle fits perfectly into square taped holes in each crank.

You’ll see some square tapered bottom brackets have threaded axles to use nuts. Also, there is a hollow square taper bottom bracket. This type of axles allows crank bolts to thread into the ends.

If we talk about the building material and durability of the square taper bottom bracket, then you should know the history first. From the beginning of the bicycle era, manufacturers tried to make the bike lighter. For that, they tried Titanium to make a light bottom bracket, which is known as Titanium square taper bottom bracket. But those efforts didn’t bring any success. Furthermore, several manufacturers tried to build a bottom bracket with Titanium spindles and alloy cups. But nothing couldn’t beat the durability of the steel.

Square taper bottom bracket sizes

Several parameters are used for determining the bottom bracket size. For example, spindle length, shell width, shell diameter, and threading.

Shell Width

68, 70, 73, 83, 100 mm ( 2.7, 2.8, 2.9, 3.3, 3.9 inch) are the standard shell widths. The new modern mountain bikes use 68 mm (2.7 in) shell width square taper bottom bracket. Also, the mountain bikes before 1995 use 73mm shell width. Road bikes and Italian road bikes use 68 mm and 70 mm respectively.

Spindle Length

Spindle length depends not only on the shell width but the type of crankset. But most of the bikes support 102-104 mm spindle length. Also, to determine the Q factor or tread, both spindle length and crank’s shape has a vital role.

Shell Diameter

There is no specific shell diameter for a bike. You will see 34.798-36 mm shell diameter most commonly. Furthermore, thread pitches 24-28 tpi.

Best Tactical Square Taper Bottom Bracket

We have gone through all the square taper bottom brackets we will review here. We have selected them because every one of them has specific reasons to get on the list. So let me show you the best features of them.

Top 5 Square Taper Bottom Bracket

Here, you’ll get the review of the top 5 square taper bottom bracket. Going through the reviews, you’ll get which bottom bracket will be suitable for you and your bike. Also, we will give the Advantages and limitations of the bottom brackets. So don’t skip anything.

Best Traditional Chainset: SHIMANO UN55 BB Square Taper Bottom Bracket

From the specific features to look at, you can easily understand the role of this bottom bracket of world’s one of the best cycle parts manufacturers. It is one of the best square taper bottom brackets. The Shimano UN55 BB doesn’t use plastic material or any kind of cheap material. By going through almost all the reviews from Amazon, it’s quite clear that many customers tried this BB on different bikes and older bikes, and most of them are still using it. 

Features at a Glance

  • It came with a well-made spindle and sealed bearing, which ensures durability.
  • Good quality bottom bracket for the traditional and single-speed drivetrain.
  • The sealed bearing ensures smooth operation.
  • Cartridge bottom bracket is durable and hard-wearing.
  • Square tapered spindle fitting and hollow spindle.
  • Quick and easy installation. 


  • Easily reliable for 15 years.
  • Quick and hassle less installation.
  • Cartridge sealed bearing.
  • Aluminum made and lightweight. 


  • Not commendable for modern bikes. 

Best Plastic Left-Hand Cup: SHIMANO BB-UN26 Square Taper Bottom Bracket

BB- UN26 is one of the best BB of Shimano though it has a plastic left-hand cup. But it’s not for traditional bikes around the year 2000. We have gotten a review from a customer who said he confirmed the shell size 3 times before ordering the BB. Shell width was 73mm, and spindle length was 113mm. But when the BB arrived, it was 3 mm shy, threading in all the way. When he investigates further about the matter, he finds out that UN-55 would be suitable for his bike. 

So make sure before purchasing either you need UN-56 or UN-26. 

Features at a Glance

  • Shell size 68 mm
  • Spindle length 109.5 mm.
  • Sealed bearings.
  • Plastic left-hand cup.
  • English Thread
  • Octalink V1 Bottom Bracket. 


  • Easily lasts for years.
  • sealed bearing.
  • Fits without any hassles


  • The plastic cup makes it less durable.

Best Lightweight Bottom Bracket: VP Components BC73 Square Taper Cartridge Bottom Bracket

We all know about accessories and spare parts VP components make. All are durable and fulfill the demand we seek from the spare parts of VP components. This BB is both suitable for traditional bikes and modern road, mountain bikes. 

We have seen a customer’s review, he said he didn’t face any difficulty installing the bottom bracket. Furthermore, his bike is running completely okay now. Like him, others have done a mostly positive review about the BB. 

Features at a Glance

  • Anodized sheath and Phosphated cups.
  • Made in Taiwan and 280 g.
  • Cartridge sealed bearings.
  • Come in different sizes. 


  • Very much affordable.
  • Silent operation.
  • Cartridge sealed bearing.


  • Doesn’t last long like Shimano BB.

Best for Mountain Bike and Road Racing Bike: Fuerdi VP-BC73 English Square BB Bike Bottom Bracket Set

From the title, you can guess who are the targeted customers of this BB. Fuerdi didn’t try to cover up all types of the bottom bracket for all types of bike. They just focused on the mountain bike and road racing bike for now. 

From the customer’s review from Amazon, you have come to know that this Bottom Bracket’s spindle is a bit thick. So they think it’s a JIS bottom bracketed. So every measurement of this bottom bracket will be on JIS rules. 

Now come to point, what will be the problem if you JIS crank on an ISO spindle? Simply they won’t fit perfectly no matter how much you try. 

Features at a Glance 

  • Made for mountain and road racing bike.
  • Cartridge sealed bearings.
  • Aluminum Sheath.
  • Cold-Forged steel cup.
  • English thread.
  • Phosphated cups with anodized sheath. 


  • Cold-Forged steel cups makes it durable.
  • Silent operation.
  • Cartridge sealed bearing.


  • A little bit expensive.

Best among Shimano: Shimano Alivio BB52 Mountain Bicycle Bottom Bracket

From the specific features to look at, you can easily understand the role of this bottom bracket of world’s one of the best cycle parts manufacturer. Its is one of the best bottom brackets.

Features at a Glance

  • Its hollow part is made of plastic/ aluminum.
  • Covers all the features of more expensive Deore model.
  • English thread.
  • It comes with 2 screws.


  • Durable structure.
  • Easy installation.
  • Silent operation.
  • Cartridge sealed bearing.


  • A little bit heavier.

XLC Cotterless Bicycle Crank Arm Remover Tool for Square Taper Bottom Brackets

Have a square taper bottom bracket? Then this is the tool you need! In term of performance and durability XLC Cotterless Bicycle Crank Arm remover tool is the best. Its does a great job of removing the square tapper bottom bracket. 

This Cotterless Crank arm remover may cost few more than the cheaper ones but at least it won’t be stuck onto your bottom bracket for good. 

Before going to the features, I want to alert you about potential damage from the XLC Cotterless crank arm remover. It may damage the thread pattern on your crank arm. There has a push pin hidden inside the side that screws into the crank arm. You have to ensure the pin is in the same position when introducing XLC Crank arm remover to your crank arm. 


  • Durable structure.
  • Easy operation.
  • Doesn’t stuck with the crank arm too tightly or loosely.


  • A little bit heavier.

Things You Should Look at Before Buying a Bottom Bracket

Things You Should Look at Before Buying a Bottom Bracket

Here we will discuss the things you should understand and know in details before purchasing a square taper bottom bracket.

Compatible or not

The Square taper bottom bracket is the connection between pedals and crankset. Also, it helps to rotate the pedals with the help of sealed bearings. But one thing you must check before buying is, in most of the case, one bike’s taper bottom bracket won’t fit on other bikes. So before buying the bottom bracket, find out it will be really compatible with your bike.

Buildup Material

Bottom brackets can be made with many materials like titanium, steel, aluminum, and even plastic.

In that case, don’t try to purchase anything plastic built. Also, aluminum made bottom brackets are mostly hollow. Their durability doesn’t inspire us to buy them. Ceramic and steel made bottom brackets will be a great option for all type of riding.


Actually, most of the brands offering pretty same price range. So don’t need to worry about the price. But at least don’t buy a plastic square taper bottom bracket at the same price as steel made square taper bottom bracket.

Customer’s review

These square taper bottom brackets have fewer details in their link on amazon. So you can’t have a good idea from amazon about them. What you can do to read the reviews from verified customers. Customer’s review will give you the best idea about the product. You’ll find many people who applied these bottom brackets on their different bikes. Those reviews will help to understand the suitable bike for any specific bottom bracket.


We always tell not to buy any bike accessories from an unknown store or online place. Brands produce quality accessories most of the time, even if someone gives any bad review about their product, they will try to solve the problem, and also brands have customer support center, which will help you to solve all the problems with bikes.

Square Taper Bottom Bracket vs Hollowtech

Hollowtech bottom brackets are stiffer and lightweight. On the other hand, Square taper bottom brackets are solid and a little bit heavier. Also, square taper bottom brackets sometimes create creaking noise. But it doesn’t mean your performance is going down. But to be honest, if you think using hollow tech will increase the ride performance, then I will say it won’t. If you want to get a better riding experience from the bike you have, you just have to replace the bike’s frame with a carbon frame, hollow tech cranks, and other modern accessories.

Different Bottom Brackets type

So far, we have learned about top sic bottom brackets and how to choose the right bottom brackets. But do you know the common bottom bracket type? Let’s find this out.


These bottom brackets are the cheaper and older version of the bottom bracket. They use bearings that are located inside the frame. Also, to tighten the crank arms there, you’ll find an axle. Square taper bottom bracket is also a type of threaded bottom bracket. But usually, we see 3 different designs of square taper bottom bracket. On some square taper bottom bracket, you will see large diameter bearings on the outer shell of the bottom bracket. The major advantage we get from this large diameter bearings is it lasts longer.


Doesn’t need any frame for a threaded shell. That’s why most of the manufacturers prefer to build this bottom bracket. Also, manufacturers can make frames according to their needs, which doesn’t need any tough inserts where the bearings sit.



– Bottom bracket on a bicycle allows the crankset to rotate freely. It means the bottom bracket has a connection with the crankset. It has a spindle, which helps to connect the crankset. In a square Taper bottom bracket, the best part is it comes with a cartridge sealed bearing, which allows the spindle and crank to rotate.

2. What is an ISIS Bottom Bracket?

– ISIS drive is a non-proprietary splined specification for the interface between bottom bracket spindle and bike crankset. The bottom brackets are certified from ISIS is known as ISIS bottom bracket.

3. How do you take care of bottom brackets?

– For having durability and performance, every accessory of the bike should be taken care of. Like you can untie the threaded bottom bracket once a week or every 15 days and check the anti-slip compound if it is get stuck permanently. Also, checking the bearing as much as possible and clean the grease dirt properly. Also, don’t use other tools to install or uninstall a bottom bracket. Use the proper tools.

Final Thought

Already you have known bottom brackets help the crankset rotate freely. That’s why you guys find the pedaling so easy. But like other accessories of a bike, bottom brackets are also worn out. They need to be replaced after a certain period. That’s why we are here to give you the best possible suggestion about bottom brackets. Hopefully, you have learned the details and exquisite parts of bottom brackets. Don’t forget to read the product reviews from amazon.