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Opinions on bottom brackets...(8 posts)

Opinions on bottom brackets...texsun
Aug 3, 2002 3:23 PM
I'm replacing my bottom bracket on my Trek 5200 and would like opinions on whether or not it's worth going to an after market bottom bracket. The bike is full Ultegra (non splined crankset) and the only Shimano bottom brackets I can find that are square tapered are the UN72's (XT). The UN72 is not the same quality as my original...wondering if it's worth going with a Phil Wood or other after market instead of the UN72????
re: Opinions on bottom brackets...Rusty Coggs
Aug 3, 2002 3:27 PM
Un-72 is ultegra. What was your original??
re: Opinions on bottom brackets...texsun
Aug 3, 2002 4:07 PM
The original ultegra bottom bracket was made closer to the specs of the XTR btm bracket (I think it was UN 90).
Aug 3, 2002 8:03 PM
Had a 5200 with 8 speed Ultegra - it really is just a UN-72 style that is sold today as an XT in the MTB world. Anywho, they're certainly cheap enough that it would be a no brainer and you could buy quite a few of them and never even come close to the cost of a Phil. I seriously wouldn't consider any other aftermarket brand - there's always some catch as to why you're going to have problems, be it chainline, durability, keeping it adjusted, etc. Shimano is good value for the $$$ and Phil is simply the best that $$$ can buy. I've had a Phil in my old Motobecane for over 20 years and have been more than halfway around the world and back and have never taken it out. You really can not easily kill them and if somehow you do you can just send it back and have them rebuild it with a new set of bearings (or whatever for minimal cost). It will be the last BB you'll ever buy for this drivetrain setup which brings up the point - are you going to stay 8 speed forever? The minute you decide to go 9 speed you'll need to enter the splined BB world and buy a Shimano unit. Is it worth it to go Phil? Not strictly based on cost, but if you want to put an end to hassles it's a good way.
" go 9 speed you'll need to enter the splined BB world.."trimble
Aug 4, 2002 2:57 AM
Uh, no.

I've upgraded from 8sp Ultegra to 9sp Ultegra (shifters, rear derailleur, chain), but my BB and crankset are from the 8sp gruppo. As far as the crankset goes, the only thing you need to change is the inner chainring as the older ring doesn't work well with 9sp chains.

The UN-72 BB is bombproof, per my LBS. While I wouldn't go that far, for the money (~$20-$25), it's easily a bargain. And they last for years.
Going from eight to nine.Juanmoretime
Aug 5, 2002 5:24 PM
The above poster mention about replacing the inner chain ring when going from eight speed to nine speed. This is Shimano propaganda at it's best. I rode a eight speed crank with the eight speed rings with a nine speed cassette and chain for over two years and didn't wedge my chain once between the chain rings.
Going from eight to nine.texsun
Aug 5, 2002 9:49 PM
I too have upgraded to nine speed, but have kept my old Ultegra crankset. As others have mentioned, upgraded shifters and other drivetrain components...still using square tapered crank.
Yer, right!!grzy
Aug 7, 2002 5:30 PM
Yup, kinda spaced that you can run 9 speed on an 8 speed crank, doh. Replacing the inner chain ring is advised not b/c the 9 speed chain gets wedged but it can actually not quite make the shift and slide. Then Mr. Happy gets to meet Mr. Crossbar.

Probably the biggest long term problem with the whole square tapered BB approach is that if you remove/replace your crank enough it starts to wedge further and further on the spindle an affects chainline.