Middleburn, gearing, and BB help- Mtbr.com
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  1. #1
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    Middleburn, gearing, and BB help

    I've finally decided to get some Middleburns. I've been riding Sugino XD300's and they've been just fine. However the Middleburns are lighter and I think I deserve nice cranks for my SSing.

    Their site says I should use a 113mm BB. Any reason not to go with that recommendation?

    As for gearing... I'm not sure what to do. I've been running 36x24 on my 29er, and its just a little too easy. When I get the Middleburns I will be looking to use the Uno ring in either 34 or 32 tooth. How much difference would I feel between 32x21 and 34x22?

    Gear chart using Gear Inches
    For 29 inch (nominal) tire with 175 mm cranks
    With Custom Sizes Cassette

    32 34 36
    20 46.4 49.3 52.2
    21 44.2 47.0 49.7
    22 42.2 44.8 47.5
    23 40.3 42.9 45.4
    24 38.7 41.1 43.5

  2. #2
    Mtbr Forum Sponsor - Homebrewed Components
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    i think if you go narrower you might have chainstay/chainring clearance issues. They seem to have a weird offset to their uno rings.

  3. #3
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    Quote Originally Posted by ISuckAtRiding
    i think if you go narrower you might have chainstay/chainring clearance issues. They seem to have a weird offset to their uno rings.
    Well as soon as I figure this out, I'm ordering a cog from you.

  4. #4
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    Quote Originally Posted by Wish I Were Riding
    How much difference would I feel between 32x21 and 34x22?
    Almost none. If you are really tuned into your bike, you might just be able to identify them correctly in a blind climb test.

    I'd go 34:21, for just under 48 gear inches. That would be equivalent to a 36x22, 'the next gear', so to speak.

  5. #5
    achiever
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    They recommend 113 for a 50mm chainline.

  6. #6
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    Quote Originally Posted by redwarrior
    They recommend 113 for a 50mm chainline.
    What does that mean though? Isn't 50mm wide? Wouldn't a narrower chainline be better?

  7. #7
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    Quote Originally Posted by sunset1123
    Almost none. If you are really tuned into your bike, you might just be able to identify them correctly in a blind climb test.

    I'd go 34:21, for just under 48 gear inches. That would be equivalent to a 36x22, 'the next gear', so to speak.
    That's interesting. How do you define "the next gear". Maybe 32x20 would be good as well?

  8. #8
    achiever
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    Chainline is the distance from the center line of the bike to the center of your chainring and cog. They need to be equal for the chain to be straight.

  9. #9
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    Quote Originally Posted by redwarrior
    Chainline is the distance from the center line of the bike to the center of your chainring and cog. They need to be equal for the chain to be straight.
    I know what "chainline" is, I was wondering if 50mm was wide. I don't use freewheels with fixed chainlines.

  10. #10
    achiever
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    Here's a thread with a few good links about how to measure. I tried with a tape measure but that didn't work. Ended up getting a set of calipers which made it way easier.

  11. #11
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    Quote Originally Posted by Wish I Were Riding
    I know what "chainline" is, I was wondering if 50mm was wide. I don't use freewheels with fixed chainlines.
    I'd just make it as easy as possible...

  12. #12
    Yo.
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    Quote Originally Posted by Wish I Were Riding
    I know what "chainline" is, I was wondering if 50mm was wide. I don't use freewheels with fixed chainlines.
    Paul Components notes that the WORD ended up having a 52mm chainline, and as it was the first purpose-built 135mm-spaced singlespeed freewheel hub, all the Johnny-come-lately hub manufacturers followed suit.

    Middleburn notes that other factors may affect the length of the BB spindle you ultimately end up with. Since the components are all interchangeable, it makes sense for them to define a starting point to work from depending on your specific needs.
    Quote Originally Posted by JonathanGennick View Post
    I am a poser. But forums.poser.com doesn't seem to exist, so I come here instead.

  13. #13
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    Quote Originally Posted by Wish I Were Riding
    That's interesting. How do you define "the next gear". Maybe 32x20 would be good as well?
    'the next gear' ie: on a gearie bike, if you were to shift up once from 36:24, depending on cassette, you would be in a 36:22.

    32:20 will be in the same range, within 0.5 gear inches of 36:22 or 34:21. You are looking at an increase in the range of 3 to 3.5 gear inches, which is a good amount to change. I'd favor the 34:21 just because of the greater tooth count.

  14. #14
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    I think I could get behind a 34x21. Kinda depends on how easy you thought 36x24 was.

  15. #15
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    Quote Originally Posted by umarth
    I think I could get behind a 34x21. Kinda depends on how easy you thought 36x24 was.
    While I thought the 36x24 felt easier then the 38x24 and 36x22 I've also recently run, I would say to was totally easy. I do think that going to a harder gear will be okay. I like to make all my climbs, but some in my area can be very tough. I think 34x21 sounds pretty good, and I'll probably go this route. I still want to make most of my climbs without walking, but occasionally having to walk can either mean I need to get in better shape or I've got just the right gear. Would you agree?

  16. #16
    Ovaries on the Outside
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    Sure. The only person that will know the right ratio is you. I think Sunset did a good job of picking out a good next step to take. The only thing I'm sure about is that you will have a sweet crank.

  17. #17
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    RS7 or RS8....which ones hombre'?
    Click Here for Forum Rules

  18. #18
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    Quote Originally Posted by CHUM
    RS7 or RS8....which ones hombre'?
    You talkin to me?

    Does it really matter? Since I don't do jumps or drops and the they are a midge lighter, I'll probably get the RS8. That cool?

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