Sealed Bottom Brackets
- Thread starter wwarnke
- Start date
hi,
what i would do is take out the old bottom bracket and either measure its length or take it with you to the bike shop, you need to make sure the sealed one is the same length because if there not it will alter the position of the cranks (closer or further from the frame). Also tell them the model of you bike, eg. Trek 1500. They might need to know the diameter so bring the "CONE" (it holds the bearings) with you. though im pretty sure all road bikes (im guessing its a road bike) have the same diameter bottom bracket.
cheers
what i would do is take out the old bottom bracket and either measure its length or take it with you to the bike shop, you need to make sure the sealed one is the same length because if there not it will alter the position of the cranks (closer or further from the frame). Also tell them the model of you bike, eg. Trek 1500. They might need to know the diameter so bring the "CONE" (it holds the bearings) with you. though im pretty sure all road bikes (im guessing its a road bike) have the same diameter bottom bracket.
cheers
it's actually a MTB and it is a Royce Union FS. I know its a cheaper bike and probably not worth putting a lot of money into...blah....blah.....blah.
But, it does me fine. I have been putting good parts on it as i destroy the parts that are on it. I regularly take it off of 3-5 foot drops and fly over some fast jumps.
I know need a new set of front gears. Are they universal or do they come with their own cranks. My bottom bracket is the square type with a nut holding the cranks in place.
But, it does me fine. I have been putting good parts on it as i destroy the parts that are on it. I regularly take it off of 3-5 foot drops and fly over some fast jumps.
I know need a new set of front gears. Are they universal or do they come with their own cranks. My bottom bracket is the square type with a nut holding the cranks in place.
The spindle type you're referring to is a "square taper". The other pieces of the puzzle you need to know are:
* the BB shell's thread type (English or Italian -- almost all frames these days are English thread)
* the bottom bracket shell size (either 68mm or 73mm)
* the spindle length.. these come in all sorts of lengths, it's usually something between 100-115mm or so. When the cranks come off it might be stamped on the spindle itself; if not, you can measure the spindle and get a new BB with a matching length.
What front chainrings you want to get is dependent on the bolt circle diameter (BCD). Usually this is stamped on the chainring somewhere, otherwise you can measure it: use a ruler and measure the distance between two diagonally opposite bolts that are holding the rings on. Common MTB standards are 58/94mm (smallest ring is 58mm, the other two is 94), and 74/104mm.
* the BB shell's thread type (English or Italian -- almost all frames these days are English thread)
* the bottom bracket shell size (either 68mm or 73mm)
* the spindle length.. these come in all sorts of lengths, it's usually something between 100-115mm or so. When the cranks come off it might be stamped on the spindle itself; if not, you can measure the spindle and get a new BB with a matching length.
What front chainrings you want to get is dependent on the bolt circle diameter (BCD). Usually this is stamped on the chainring somewhere, otherwise you can measure it: use a ruler and measure the distance between two diagonally opposite bolts that are holding the rings on. Common MTB standards are 58/94mm (smallest ring is 58mm, the other two is 94), and 74/104mm.
It's usually not that easy because most cranks have 5 arms. Usually the easiest way it to measure the distance between two adjacent holes and to find a chart that will convert that distance to bolt circle diameter.rek said:
