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Discussion Starter · #1 ·
Who makes the largest 104 symmetrical BCD oval chainring?

I'm interested in using or at least trying an oval chainring for BMX racing, but BMX racers can be luddites in some areas, so I'm checking over here to see if anybody knows who makes the largest Oval chaining in the symmetrical 104 BCD pattern that is used by DH and BMX cranks (saint and DXR). I know that they make large tooth count rings in asymmetrical road crank patterns. The biggest that I have found is 36t by wolf tooth I think, and they only have every other tooth (32t, 34t, 36t). It would be better if I can find one that has every tooth so I can fine tune it for different tracks.

I don't necessarily need a huge tooth count, but the bigger the better.

Thanks!
 

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Discussion Starter · #2 ·
Well, I just found garbaruk makes up to a 52t. That should be sufficient, but they still only make every other tooth count. I'd still appreciate any thoughts or ideas.
 

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since 4/10/2009
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you're not likely to find odd tooth counts on mtb rings.

Since mountain bikes in 1x configurations nowadays pretty much exclusively use chainrings with narrow/wide tooth profiles, even tooth counts are all you're going to get. An odd tooth count simply can't work with that kind of tooth profile.

Other than that tidbit, I'm not sure about the answer. I'd have to google it just the same as you already have.

I suspect you're going to run into limitations because of a couple of factors. Both are related to the fact that the manufacturers who produce these oval rings are doing so with mtb use in mind. And so with the situation framed that way, chainstay clearance is one major issue that will limit chainring size. A lot of frames nowadays (with room for big tires, and with wider hubs) simply won't fit a chainring bigger than a 32-34t. Another issue is a bit more general, but related to the combo of factors going on. Most manufacturers produce these rings out of aluminum, since that's easier to produce all the fancy shaping and whatnot. Put a big alu ring on a crank with a smaller bcd, and you're going to increase the risk of folding that ring over. I've seen folded over alu 1x chainrings where the rider just hit a half rotten log. It's why I'll never NOT run a bash guard with a 1x drivetrain.

I dunno if a cyclocross crank could be made to fit a bmx bike at all, but if you could, that'd get you into a bcd where you'd find larger chainrings. Still not likely to find odd tooth counts due to the narrow/wide tooth profile limitation. I think odd tooth counts are only going to be available on traditional bmx rings, or on track rings.
 

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Discussion Starter · #4 ·
Thanks, I wasn't thinking about the N-W profile even tooth count limitation, but that makes perfect sense. I was thinking the N-W profile would be a good thing since I may have to run the chain at a somewhat lower tension if I don't want to add a tensioner (which I don't). I guess the rear cog doesn't have to be a N-W, which would limit my gear combinations even more if that had to be an even tooth count, too.
 

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since 4/10/2009
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Thanks, I wasn't thinking about the N-W profile even tooth count limitation, but that makes perfect sense. I was thinking the N-W profile would be a good thing since I may have to run the chain at a somewhat lower tension if I don't want to add a tensioner (which I don't). I guess the rear cog doesn't have to be a N-W, which would limit my gear combinations even more if that had to be an even tooth count, too.
In your case, honestly, neither HAS to be. But if you want to try an oval chainring, not sure you have much choice in the matter.

Meh, singlespeed riders don't have problems with oval rings. Assuming you can work around the other limitations of using one, you shouldn't have problems with chain tension.
 
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