Customer Reviews

Shimano BB-UN54 Bottom Bracket, 68 X 107mm

5 star:		(20)
4 star:		(6)
3 star:		(3)
2 star:		(0)
1 star:		(0)

 

 

My bottom bracket was wearing out fast. There was lots of "play" in the crank, and when I pedaled hard, it felt sloppy and made a clunky noise. I took my bike to a shop to have the bottom bracket repaired. They must have taken it out and worked on it, but I suspect the original was not a sealed bracket. They did a nice "tune up" of everything else, but only tightened the bottom bracket instead of replacing it. I didn't realize this until I got home and rode it. It was not good enough.

So I decided to do it right. You need an extractor to remove the pedal arms. (It's a kind of gear-puller.) You also need a special socket to loosen up the old bracket, and maybe a good pair of channel locks or vice grips, depending on what's holding it all together. On my bike, I had to turn BOTH SIDES FORWARD to loosen the bracket. (I learned this the hard way.) It rides like new now. I even replaced the bottom bracket on my step-daughter's bike. Remember to tie the bike off the ground, right side up (to some garage rafters, maybe) in order to make it easy to work on. You'll need to measure the overall length of the bracket, to the outer edges of the square ends of the shaft, and the inner length of the cylinder, to get the right part. Make sure you get the right one. Ask a bike expert if you need some help. I did!

As an Amazon affiliate myself ([...]; My AMAZON Site, My STORES) I'd recommend this product.

This cartridge bottom bracket is the now-standard replacement for loose-ball bearing bottom brackets. For square-taper cranks. Easy to install. Note that one of the threads is left-handed, and many torque wrenches do not "click" in reverse. Size is by thread diameter and length of crank axle.

Used the 68-118 to replace a 68-117 cartridge, so it did stick out slightly more than the original, but works well enough. Noticed that some people prefer these to the older style bottom brackets with the adjustable cones and ball bearings. Call me old fashion, but I prefer being able to simply take apart the bottom bracket, clean-out the parts, re-grease, put back together, adjust and go, rather than having to go shopping for a whole new part every time.

I rebuilt a Trek 800 for a friend (it had some serious problems!) and used this BB to replace the stock one (I don't know what you call the style, but it was a square taper). The UN54 fit great! I used the 122.5 which i believe was the stock size. However, one tooth of the inside ring hit the frame. The wear on the frame, however, leads me to believe that it was lightly knocking on the frame all along. However, the chainrings are the long-discontinued Shimano Biopace-- if you know them, you can imagine why only one tooth would hit the frame.

ANYWAY! This otherwise fit perfectly. It was a tremendous upgrade from the long-worn BB. Along with a few other affordable upgrades, this trek 800 is a nice little commuter. I'm probably going to throw one in the Trek 3500 I built up last summer. It squeals and that annoys me. I look forward to replacing it. If you're a harder core rider, heavier, etc, you might consider replacing the plastic non-drive-side cup with an aluminum one (you can buy them online-- just search). They're about as much as this BB, so if you think you can tolerate the plastic, it shouldn't bug you.

I bought this bracket because other reviews, the product photo, and the product description all led me to believe this BB included an aluminum endcap. Mine is plastic. No big deal, but it would be nice if I had accurate information on the site, so I wouldn't have to confirm every detail on the spec sheet with the manufacturer.

These bottom brackets are great. Extremely smooth operation, and you never have to worry about regreasing. This is a must have upgrade if you have a loose bearing bottom bracket, or if you want to resurrect an old ride. Just make sure you get the right size!

I installed the UN54 on my '84 Schwinn High Sierra, which had a 130 mm bottom bracket axle. The plastic cup on the Shimano unit was hard to screw up tight. I stopped with about one turn remaining. It's plenty tight. The plastic cup is rugged. I removed and replaced it twice and it held up to that abuse. There is conflicting advice about lubing the threads on the plastic. I used anti-seize compound on it the second time. Once it was back in and the pedal cranks were on, I had to readjust the front derailleur to compensate for the 2.5 mm shorter axle length. Everything works great now and I don't get grit in the hanger bearings anymore.

This is what I use on all of my bicycles. You will need the special tool to install/change it. I've used this model for years with no problems. As a matter of fact, I have removed new brackets of other models to replace with this one. It's bullet-proof. Just remember to use anti-seize lube instead of a regular lube in case you do want to remove it some day.

I bought this to replace the cup and cone BB on my 1974 Schwinn Le Tour and it fits perfect. Easy installation except for the cup on the non drive side. The picture showed a plastic cup but mine was an alloy. Not sure if the plastic would have been easier since the combination of the taper of the part and the threads fading out down that taper made it difficult to know if i was getting it on correctly. At this point its on and I'll have to wait until i need to replace it to know for sure if i messed up the threads.

installed this in an old Raleigh mountain bike i found for 20 bucks and it is a nice moderate priced upgrade. work very smooth for a mid range quality bicycle.