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Chainring Contact with frame - Please Help

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Chainring Contact with frame - Please Help

Old 01-17-09, 01:36 PM
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Chainring Contact with frame - Please Help

I bought an old GT frame the other day and found an extra chainring lying around and I figure I'll put it on the frame but for some reason the bigger cog rubs agains the frame. I dont have the brand or the model of the chainring. It is just a regular 48 tooth 3 ring cog. So, Im wondering is there different sizes mtb chainrings and what would my options be.
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Old 01-17-09, 01:38 PM
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Your frame might be designed for a 44 or 42T biggest chainring. You would need a longer bottom bracket spindle to move the crank further away to let a larger ring clear.
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Old 01-17-09, 01:38 PM
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How old? If it's an old mtb 48 was the standard big ring size. You probably need a longer BB.

Read This and adjust accordingly.
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Old 01-17-09, 01:39 PM
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Either the frame isn't designed for that big of a chainring or you need a longer bottom bracket. Standard MTB cranksets have a 42 or 44 tooth big ring so you are going larger than typical but 48 tooth big rings aren't unheard of for MTBs either (I use one though it's on the road with a MTB frame).
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Old 01-17-09, 01:40 PM
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There are several sizes available, in one to two tooth increments. A smaller tooth count ring would likely fit, and if you have the original ring you won't have to guess. Make sure you get the right size bolt circle diameter.
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Old 01-17-09, 02:41 PM
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Depending on how much additional clearance you need, a spacer like these might work. Your LBS should have them-
https://www.loosescrews.com/index.cgi...id=70323611650
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