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Trek 4300 bottom bracket
#1
Anyone know the make/size bottom bracket for a 2005 trek 4300 bike.
It has the stock crank set SR, 24/34/42 teeth.
The BB SHELL measures 73mm and is square tapered fit.

Thanks..
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#2
if you have it, just measure it. A Shimano UN54/55 is a good replacement for not a lot of money.
Nigel
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#3
The 73 mm is correct. To add to Nigels advice, make sure you get a BB with English Thread and not Italian. The UN54 can be had in both.
73 is your shell width. The next important number is your axle (spindle) length. It might say '73-113' in the description. You'll have to pull the crankarms to measure this. If the crankset were Shimano, we could easily find what length was required. As it's SR, a bit more difficult.
If I were a betting man, I'd bet on 73-122. SunRace stuff seems to run wide. What diameter is your seat tube? What front drlr?
Wheelies don't pop themselves. (from a QBP fortune cookie)
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#4
Impossible to have a Italian thread on a Trek, it should be English...
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#5
(04-02-2012, 08:44 PM)bobtravers Wrote:  Impossible to have a Italian thread on a Trek, it should be English...
But, but, but Bob! It's not impossible to have an unknowing LBS rat just pull a BB off of the shelf and sell you the wrong item and then want to charge you to clean up the thread damage that YOU did by attempting to install the wrong BB. Never happens in my shop but, I've heard stories. Just looking out for rocky. Dig?
Wheelies don't pop themselves. (from a QBP fortune cookie)
  Reply
#6
Euh, that's why people are asking question on this forum when they do not know the answers... Officially, a Italian thread BB wouldn't fit installing it with your hands...

Your answer is almost the same as: is it possible to run a car motor with sand instead of oil inside, cause the mechanic didn't look at the right bottle to put in???
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