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  1. #1
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    Bottom Bracket and Crankset Upgrade... Need Some Clarification...

    So I bought a road bike that came with an FSA Tempo Compact 50/34T crankset. I was wanting to upgrade my crank to find that there are multiple types of bottom brackets that fit certain type cranks. Right now my FSA crank uses a square taper bottom bracket and the crank I was looking at upgrading to uses an external bottom bracket.

    I know the specs of my bike, and to me, it seems that I should be able to use an external bottom bracket in place of the square taper one I have now. So this is the clarification that I need (as I can't really seem to find a definite answer), can I use an external bottom bracket in place of the square taper bottom bracket I have now?

    It seems that a lot of cranksets are using the external bottom brackets. If this isn't possible, is there a place that I can get a square taper crankset that would be considered an upgrade?

    These are the specs for my bike:
    Bottom Bracket Compatibility: 68mm, English Thread
    Bottom Bracket: 68mm, English Thread Cartridge
    Chainrings: 50/34t
    Crankset: FSA Tempo 50/34t Compact
    Crank BCD: 110mm
    Crank Arm Length: 175mm
    Crank Bolt Pattern: 5-Bolt

    These are the specs of the crank I am looking at:
    chainrings: 34/50t
    weight: 776g w/o bb
    material, arms: cold forged aluminum
    material, chainrings: alloy
    bcd: 110mm
    size: 175mm
    color: polished silver
    bb: 70/68mm
    bc: 1.37"x24t
    thread: english

    I also used my digital caliper on the bike frame where the bottom bracket goes, and it measured just under 70 mm at 69.86 mm. Thanks!

    Cole

  2. #2
    Low car diet JiveTurkey's Avatar
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    Yes, you can put an external BB on it.

    Your bike specs say you have 68mm/English threaded BB shell, but you're measuring just under 70mm? 70mm is Italian; completely different threads. Make sure you know which you need. One way is to see which way the drive-side cup loosens. Italian loosens counter-clockwise (normal threading), English loosens clockwise (reverse threading).
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  3. #3
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    Unless your current FSA Tempo crank has an issue, upgrading there isn't going to give your a better ride, if you want a good value upgrade, wheels are normally the place to look at first.

    When you measured your BB, did you do this with it installed or with the BB removed from the frame?, if you remove the BB, it should have a sticker on it giving the dimentions, if you want to keep with square taper, there are still plenty around, but your current one is perfectly good.

  4. #4
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    Quote Originally Posted by JiveTurkey View Post
    Yes, you can put an external BB on it.

    Your bike specs say you have 68mm/English threaded BB shell, but you're measuring just under 70mm? 70mm is Italian; completely different threads. Make sure you know which you need. One way is to see which way the drive-side cup loosens. Italian loosens counter-clockwise (normal threading), English loosens clockwise (reverse threading).
    I am hoping this image will help...


    I measured the length of the edge of the frame where the bearing would mount flush to, across the bottom of the frame to the other edge and that measurement was just under 70mm. I didn't measure the inside where the threads were at. Does this measurement matter in choosing the correct bottom bracket? Or better yet, what measurements do I need to take into account for, if I did this upgrade?

    Thanks for the response, I really appreciate getting some clarification on that matter.

    Cole

  5. #5
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    Quote Originally Posted by jimc101 View Post
    Unless your current FSA Tempo crank has an issue, upgrading there isn't going to give your a better ride, if you want a good value upgrade, wheels are normally the place to look at first.

    When you measured your BB, did you do this with it installed or with the BB removed from the frame?, if you remove the BB, it should have a sticker on it giving the dimentions, if you want to keep with square taper, there are still plenty around, but your current one is perfectly good.
    I was told that a stiffer crank would help me transfer energy better, so I was looking at alternatives to what I have. Also, trying to keep in mind for when the time comes that I need to replace the bottom bracket what my options are.

    As far as wheels go, I have no idea what makes a good wheel. My problem is that I am 6'1" and 220 lbs. and would want a wheel that would support my weight without having issues with the wheel going out of true. That being said, is there a specific model or brand of wheels that you would recommend looking at? I currently am using a set of Alexrims R500 that came on the bike. Thanks for your help! It is much appreciated.

    Cole

  6. #6
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    Quote Originally Posted by ColeJustesen View Post
    I am hoping this image will help...


    I measured the length of the edge of the frame where the bearing would mount flush to, across the bottom of the frame to the other edge and that measurement was just under 70mm. I didn't measure the inside where the threads were at. Does this measurement matter in choosing the correct bottom bracket? Or better yet, what measurements do I need to take into account for, if I did this upgrade?

    Thanks for the response, I really appreciate getting some clarification on that matter.

    Cole
    Is that really what you have! as that is a pressfit BB30 bottom bracket, and has never worked with square taper like your FSA Tempo; at present, would suggest either a picture of your actual bike, or go to your LBS where they can clarify exactly what you do have. for the external BB giving a stiffer crank, yes it does, but will you notice, that's another matter.

    For wheels, lighter = better for speed; wheels going out of true is more about the build than components.

    Would use caution with replacing any parts, if they aren't worn out, if your bike was a budget to mid range one to start with, throwing money at it won't make the bike as a whole much if any better.

  7. #7
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    Quote Originally Posted by jimc101 View Post
    Is that really what you have! as that is a pressfit BB30 bottom bracket, and has never worked with square taper like your FSA Tempo; at present, would suggest either a picture of your actual bike, or go to your LBS where they can clarify exactly what you do have. for the external BB giving a stiffer crank, yes it does, but will you notice, that's another matter.

    For wheels, lighter = better for speed; wheels going out of true is more about the build than components.

    Would use caution with replacing any parts, if they aren't worn out, if your bike was a budget to mid range one to start with, throwing money at it won't make the bike as a whole much if any better.
    Not that is not my bike... It was the best picture I could come up with showing the bottom portion of the frame... It would be nice to have something like that though

    I will take a picture of my frame and post it here... As far as the bike goes, it would be considered budget to mid range (although my wallet says otherwise). That is a good question on whether I will notice or not. When I was talking to a tech at my LBS, he suggested that I put my bike up for sale (as he thought I could get at least $600) out of it, eat a few hundred and get into a newer bike that has better components on it. This particular shop carries Raleigh and Felt bikes. When I bought my current bike, I opted for buying it online, as I felt I got a better bang for my buck. I felt I was getting a lot better components for a lower price than what I could get at a bike shop. To get the same setup at my bike shops, I was looking at prices around $1200-$1400. I was able to get mine for $700, so being budget conscience I went with the cheaper option.

    I was wanting to upgrade components on my current bike, which I love to ride, but he (LBS tech) started to talk about if you put so much money in components into a bike you will eventually get to a point where that money could have bought a whole new bike with the same components on it. He mentioned that Raleigh and Felt had a change in their marketing scheme and realized that people wanted better components at a lower price range, so now I am able to get into a full 105 group on a CAD designed bike frame for just under $1K. Which was what I was looking for initially, and why I opted to go to an online retailer. I really don't want to sell my bike, as I feel like the bike fits me pretty good! Though it is something I am keeping in mind.

    Cole

  8. #8
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    The first picture is to show where I got the 70mm measurement...


    and some angle shots of the bottom bracket shell...




    Cole

  9. #9
    Low car diet JiveTurkey's Avatar
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    What's the make of the bike?
    Quote Originally Posted by slopvehicle View Post
    Not wearing a helmet makes me more aware of my surroundings. I find myself anticipating the hardness of concrete 50 or 100 feet in front of me, it's almost a zen-like connection between my face and the pavement.

  10. #10
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    Quote Originally Posted by JiveTurkey View Post
    What's the make of the bike?
    It is a Tommaso Monza...

    http://www.giantnerd.com/tommaso-mon...-beginner.html
    http://www.tommasobikes.com/update/bikes.html

    Cole

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