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Thread: ok i tried

  1. #1
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    ok i tried

    i looked and always get "use the gear calculator." i don't know what the heck that thing is saying. i want to convert my hard tail over and avoid a chain tensioner. i don't have track ends but i think we can do this still. ok what gears....i will NOT be doing hard climbing. mostly commuting through an extremely hilly campus and hitting the local trails on the weekends which still arnt real steep. what is the best general use gearing. it is tax free weekend here so i will be hitting up the local shops and getting the parents to get parts from the shops in their town to. using 26" tires and I'm not sure frame size really but it was fitted for me 6'1" its a marin bear valley. 04 i believe. i know i need

    rear cog (bmx cog from what I'm told)
    spacers
    front chain ring
    one brake lever (only running rear brake)

    please enlighten me on gearing and which parts to get from a local shop

  2. #2
    Yeet so hard
    Reputation: tims5377's Avatar
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    I ride 32x18x29 and it is a little light for a very flat campus but works great for hilly trails. If you used a tensioner you could just have a 'road gear' and an 'offroad gear' on the bike and shift by hand whenever you need to
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  3. #3
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    see i thought about doing that since i do that on my full suspension ss....i just love the appearance of that single gear though. now explain what 32x18x29 means so i can get a little better understanding.....i want to be albe to get around easy but still be able to hammer through climbs

  4. #4
    Yeet so hard
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    32 tooth ring
    18 tooth cog
    29 inch wheels

    It whatever you are comfortable riding. Trial and error is what most will tell you to do
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  5. #5
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    32 is his chainring size(the big one in front), 18 is the rear cog size, and 29 is wheel size. I'd recommend starting with something like 32x16 or near equivalent in terms of ratio. It could be hard or really easy to get what is called "Magic Gear" where the distance from cog to chainring with chain around them is perfect to go right into the drop outs without tensioner. You'll need to measure your chainstays by measuring from the center of your cranks to the center of the dropouts. Then use that measurement to mess around with this Magic Gear Calculator. The calculator will tell you what gear ratios you can use without a tensioner.

  6. #6
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    I guess by saying 32x18x29 he means:

    32 Tooth Chainring
    18 Tooth Cog
    29" Wheels

    Personally speaking, I find there are so many things that can influence gearing such as crank length, tire width and tire pressure. I use 42x17 on a road bike with 700c wheels, 34x16 on a MTB with 26" wheels and 35x15 on a BMX with 24" wheels. I use all of these bikes differently.

    Changing the crank length 5mm on the same gear set-up can really alter how hard you have to push the pedals - so you should take this into consideration.

    Depending on your riding style and the flatness of your area, I reckon you can't go wrong somewhere between 32 - 35 for the front chainwheel and a 16, 17,18 or 19 on the back. The exact gear ratio depends entirely on you. What's your favorite gear-inch ratio? Just keep in mind, a rear cog is a hell of a lot cheaper than a new chainwheel :-)

  7. #7
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    Quote Originally Posted by tcazes View Post

    one brake lever (only running rear brake)
    Why would anyone only want to have a rear brake?
    Might be fine for running around your campus, I suppose (and even then, why?) but it won't be such a good idea on the trails......

  8. #8
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    I think the OP's choice is 'magic gear' since his bike is vert dropout and he doesn't want to run tensioner.

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    yes sir kaizer and andy i prefer my rear brake i guess from racing so much i don't like the front to dip and turn id rather slide the rear end or on a trail just pull the back down slower. would you suggest just the front? haha i don't need two. I'm not doing hard riding. i used to but thats just not in my schedule any more. i was thinking 36x18 or 34x18....ill get someone to measure that length up or me from crank to drop out

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    Quote Originally Posted by vaultbrad View Post
    32 is his chainring size(the big one in front), 18 is the rear cog size, and 29 is wheel size. I'd recommend starting with something like 32x16 or near equivalent in terms of ratio. It could be hard or really easy to get what is called "Magic Gear" where the distance from cog to chainring with chain around them is perfect to go right into the drop outs without tensioner. You'll need to measure your chainstays by measuring from the center of your cranks to the center of the dropouts. Then use that measurement to mess around with this Magic Gear Calculator. The calculator will tell you what gear ratios you can use without a tensioner.
    i hate to say it but can you explain this calculator a little bit better?

  11. #11
    nothing to see here
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    I suppose if you pay for your own rear tyres, just having a rear brake is fine.

    Just be sure to attend trail maintenance days to repair the damage you cause.
    I see hills.

    I want to climb them.

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    i am 99 percent sure this thing will not be seeing trails anytime soon. also. a little work in order to play doesn't keep me away from the trails when i do have to work. also, ride well enough and you won't destroy an trails.

  13. #13
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    Quote Originally Posted by tcazes View Post
    i hate to say it but can you explain this calculator a little bit better?
    To make proper use of that calculator, you need to know the exact chainstay length on your frame. Once you enter that, you can then search for a suitable gear for riding by entering a range of chainring sizes/sprockets that would fit your cranks etc.

    Or you can get a ebb for a standard bottom bracket shell, or an eccentric rear hub. Both work well and eliminate tensioners that use derailleur hangers.
    I see hills.

    I want to climb them.

  14. #14
    the discerning hooligan
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    Bear valley chainstay is 16.75" ( from Marin's site) Calculator indicates 36x13 might do the trick ( lightly stretched chain will make the fit.)
    edit: bikes that might be used near cars need both brakes...end of story.
    MERCY! MERCY! MERCY!

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    no cars so i am free and clear and yes i understand the need for both in traffic. also. did you get that for the 04/5 or the current bear valley. seems my guess was somewhat close mojo haha thanks!

  16. #16
    the discerning hooligan
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    Quote Originally Posted by tcazes View Post
    no cars so i am free and clear and yes i understand the need for both in traffic. also. did you get that for the 04/5 or the current bear valley. seems my guess was somewhat close mojo haha thanks!
    Pulled that from the 05 geometry spec. sheet. as 04 wasn't archived on Marin's site.
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  17. #17
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    cool thanks man. will opefully be trying gears out this weekend if i can spare a few hours to drive home and grab the bike. its no tax weekend here!

  18. #18
    Yeet so hard
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    Quote Originally Posted by tcazes View Post
    Its no tax weekend here!
    woooooo!!!!! Buy me stuff so you can save more money!!!!!!
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  19. #19
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    hahahahahaha yea that sounds fair!

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    btw it is a 2002 model bear valley (found the archive) however i don't think i have stock drive train on it...think my brother built it up from the frame. will get a better idea this evening however if it is stock i can keep my current crank and take off the outer and inner rings since the middle is a 32 and then just buy a 13t cog and see how that works


  21. #21
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    32/13 is gonna be steeeep. I run 32/14 on my DJ bike with 180mm crank arms and it's a serious pig on climbs. It'll be fine for your campus duties, but it's going to suck on trails.
    All of the true things I'm about to tell you are shameless lies.

  22. #22
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    We actually have some pretty moderate climbs. Steep access ramps etc. I will be changing the gearing when we are on the trails

    what would you suggest then false?
    Last edited by tcazes; 08-04-2011 at 05:05 PM.

  23. #23
    the discerning hooligan
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    Quote Originally Posted by False View Post
    32/13 is gonna be steeeep. I run 32/14 on my DJ bike with 180mm crank arms and it's a serious pig on climbs. It'll be fine for your campus duties, but it's going to suck on trails.
    Yes, I don't think 36x13 is at all the perfect choice, but it was the best of the magic gear choices. I just dropped my magic gear combo in favor of a tensioner and am getting on with it quite nicely.
    MERCY! MERCY! MERCY!

  24. #24
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    like i said. what would you suggest

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    Personally, if you really aren't sure what gears to get I would suggest you get a chainwheel that will give you quite a few gear-inch ratio possibilities by changing the cog. Cogs are cheap - get a pack of 5 with 14t - 18t. Then I'd hope for the best and throw a chain around the lot. If it is too tight, maybe a half-link added to the chain will help - if it's too loose with the half link then you will have to get aggressive with the frame (drop-out area) or you'll have to get some type of tensioner.

    I mean, 32:13 with 175mm cranks has a gear inch ratio of 64 which is way too high for any type of climbing. For climbing, cruising around and all type duties you wanna have a gear inch ratio of around 56 I reckon - although it all depends how much push you have in those legs.

  26. #26
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    thanks! ill try and do that!

  27. #27
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    Quote Originally Posted by jaykay View Post
    get a pack of 5 with 14t - 18t.
    Where can you get a pack like that?
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  28. #28
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    Quote Originally Posted by tims5377 View Post
    Where can you get a pack like that?
    Cogs Cogs Cogs

  29. #29
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    yup yup yup

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