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  1. #1
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    Help with BB replacment!

    So I have been slowly turning my wife's old 96' GT outpost trail from a garage ornament. To a SS trail ripper. I still have a ways to go but this is what I have done so far.

    1. New tires
    2. new V-brakes
    3. SS conversion

    Things I would like to change in the near future.
    1. new rims(at least the rear it is a bolt on, would like to have quick release)
    2. new crank, BB
    3.stem & handle bars(not sure on this yet it seem ok as is)

    I would like to switch out the old OEM Shimano Altus crank and BB for something a little more modern, but unsure on exactly what will fit. I suppose I could keep the BB if I have to. There really isn't anything wrong with it. I looked the bike specs up on bikepedia and it says that the BB is Shimano BB-CS11, 122.5 mm spindle, 73mm english. So any ideas on a decent, budget friendly crank that would fit. Thanks for the help.
    Just remember,Where ever you go there you are...

  2. #2
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    WTF are you asking, dude?

    Is that crank riveted? If not just throw a SS ring on it, a "budget" crank is going to be the same junk. If yes, I bought one of these cheap:



    Was OK, the writing comes off with a green scrubby.

    You can always buy a high end used crank, but you really need to look at it, if the taper is ****ed it's toast.

    Don't know of any cheap splined BB cranks that come set up for SS, but that doesn't mean they aren't out there.

    Good luck.


    Tom

  3. #3
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    Yeah I guess I was a little vague in question. I was wondering if I could put anything besides a square taper BB in as a replacment. Like a Race Face w/ external BB. Yes the current crank is rivited, so slapping on a single ring will not work. Right now I just have it in the middle ring and it works fine. Just would like to put something else on it. Also should I be concerned with the spindle length? Bikepedia states the current BB has a 122.5mm spindle, if I go to a different spindle length how will that inpact my drive train? Will I just need to adjust the rear spacing on the hub?
    Just remember,Where ever you go there you are...

  4. #4
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    You're gonna have to play around with the BB length in order to get the perfect line from center sprocket to near middle on rear cassette hub. It should be close to original length though. I'd use a square taper BB and associated cranks since there are plenty of mid 90's cranks to choose from. I currently have 2 SS setups- one uses Cook Bros E-type cranks, the other uses Kooka cranks. No need for a chain tensioner either- use a half link on the chain to get within 1/2".
    Stick with 90's components and you'll do fine on quality and price.

  5. #5
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    you can find square taper cranks for slightly more then the cost of shipping on eBay or just grab something on craigslist. A lot of people drop a bunch of money into an ss, ride it for a month and then leave it. I would put in as little as possible for now- you can find decent cranks for cheap...

    Good luck!

  6. #6
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    Quote Originally Posted by kitts21j View Post
    Yeah I guess I was a little vague in question. I was wondering if I could put anything besides a square taper BB in as a replacment. Like a Race Face w/ external BB. Yes the current crank is rivited, so slapping on a single ring will not work. Right now I just have it in the middle ring and it works fine. Just would like to put something else on it. Also should I be concerned with the spindle length? Bikepedia states the current BB has a 122.5mm spindle, if I go to a different spindle length how will that inpact my drive train? Will I just need to adjust the rear spacing on the hub?
    Your options for a new crank and BB are pretty wide. There are plenty of square taper cranks out there, there's also ISIS drive, Shimano's splined type and there's also the external types. I'd either go with a square taper or an external.

    The external types (for MTB) will be English tread so don't ponder that variable for too long. The other threaded BB type is Italian which has a different diameter and threading, but don't worry about that unless you're building an Italian steel road bike.

    The next issue is the shell width, which you say is 73mm. The other is 68mm (Italian BBs are 70mm but again, that's not relevant). An external BB will be for a 73mm shell and will come with spacers to make it fit a 68mm shell, so you'll be right, just ditch the spacers, but obviously read the instructions and don't take my word for it. Yep, read the instructions. I don't believe I just gave that advice...

    External type BB and cranks are essentially fixed in their chainline, there isn't a lot of option for fettling with the chainline in the same way you would with BB axle lengths. Don't despair, because you can run the chainring in either the middle or outer position, which gives a bit of lee-way. If you're running a single sprocket on a cassette hub at the rear, you have plenty of scope for adjusting spacers to dial the chainline in. If you have a screw on BMX freewheel type rear hub, your rear sprocket position is fixed and you need to adjust the position of the chainring. You can also get spacers for the chainring to fine tune the chainline.

    If you go with an external BB set up, you'll be fine. If you go square taper, then you have options with where you mount the chainring and also using spacers under the chainring to fine tune it, as well as rear sprocket position if you're using a cassette hub.

    Pop in to the Singlespeed board for a search around if you haven't already, the topic is well covered.

    Grumps

  7. #7
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    I have had my 1996 Outpost since it was new, and have some experience with hanging new parts on it. It has a threaded headset, which means it takes a quill type stem. You could get an adapter that will allow you to use a more modern threadless type stem. The BB is definitely square taper, but you can convert to external bearing BB if you want.

    If you're fine with the stock BB, then something like this with replaceable (removable) chainrings, would allow you to remove the inner and outer chainrings, and either get shorter chainring bolts to just keep the middle ring only on there, or just keep the middle chainring, and then add a bashguard:

    Shimano Alivio Crankset M410 Square Taper 175m Black | eBay

    or this:

    New SRAM S600 Triple MTB Crankset 175 mm 42 32 22 Square Taper x 4 x 5 Black | eBay

    Here is an example of an economical bash ring that would fit either crankset above:

    BBG Bashguard Chain Ring | eBay

    If you want to replace the BB too, this is a good deal on a new crankset and BB that would allow you to do the same as above:

    SRAM X5 Crankset 175mm Triple 9 Speed 44/33/22t Mtb Mountain Bike NEW: 351028 Random Bike Parts

    If you want to replace the stem and bars, the threadless adapter is the way to go IMHO. As for the wheels, you're limited to rim brake wheels (but it is the modern 135mm spacing so no problem in that regard), and that frame was originally designed for cantilever brakes, so if you're upgrading to v-brakes, I strongly suggest you use a brace like this to keep the seatstays from spreading as you apply the brakes, but only if you actually want to brakes to stop you ;~)

    New MTB Bicycle Bike V Brake Cantilever Alloy Brake Booster Blue | eBay

    The XT v-brakes I upgraded to back then were useless until I added the booster. After that, they were very good, so I would strongly advise using one if you go to v-brakes.

  8. #8
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    Looking good!

    A Shimano SLX is a very cost-effective upgrade. The main difference to XT cranks is that the latter don't have a steel insert for the pedals and some chainrings are lighter - which doesn't matter because you'll be singlespeeding anyways. You can sell the chainrings unused and get back some of the money you spend on the set. They will fit your 73 mm British BB shell easily with the right external BB cups and should give a good chainline as well.

    Even if you end up scrapping the SS, these are good cranks for any bike so it won't be money spent on a dead end.

  9. #9
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    bling it up. only way to do a retro ss.

  10. #10
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    Thanks, for the help everyone, and Jeffj You wouldn't be the one who ownes the red GT outpost SS were I drew my insperattion from would you?
    Just remember,Where ever you go there you are...

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