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Discussion Starter · #1 ·
For XC racing, would a 32T or 34T chainring suffice? I previously used a 2x setup with a 38T as the bigger ring. I used this mainly, as I very rarely switch to the smaller gear for climbs. Do most XC racers use 34T or 32T chainrings? I also plan on using an oval chainring, if that changes any opinions.
 

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Discussion Starter · #2 ·
I just found the thread from 2015 but I am still undecided as I will have to test my biggest gear. Does the oval chainring lean anyone specifically towards the 34T or the 32T? I'm thinking that when running oval the 34T is better because people feel as if they are spinning a lot faster during climbs, but I wouldn't know. Any help would be very much appreciated.
 

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The answer is, "It depends."

Where do you live, what are your races like, etc?

I'm on a 34t on a 10-42 cassette. I live at 7200ft in the Front Range. Racing pro/open, 120/100mm FS. Not a lot of steep climbs, just long ones. Also, not a lot of XC races in general. Lots of marathon/endurance and stage races though, oddly enough.

Sent from my XT1585 using Tapatalk
 

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Le Duke answered it damn good.

I run a 34T oval and a 11-40 XTR on my 20lb XC bike.
I run a 32T oval on my SS due to the 34T oval drains my legs too fast.

Some of the fast guys here are 34-36T chain rings and Eagle

But like Le Duke said. It depends on your area. go test both and see how it feels.
 

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29er? If you're not one of the best cat1s or better a 32 should be plenty big, unless you prefer a really low cadence. A couple of years ago I took off my 44 (iirc) and just left the 32 and smaller ring to give me some more clearance on a course with some logs, on my 29er. I never put the big ring back on because I have never needed it, - lots of cat1 masters podiums with the 32 since then. I've raced that bike in cx too with the 32x11-34, plenty big for cat1 masters. If it's a steep enough descent that you 'spin out' on a 32, you're probably better off tucking and resting. 27.5 may equate to needing a 34?, I don't have a 27.5. I use the big ring/44 on my 26 er all the time, 32 would be too small on a 26er.
 

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Just a note on your thinking about an oval chain ring. There are different degree of angles on different brand ovals that can make a difference on how they feel. And generally people that have a slower pedal rate tend to like oval better than spinners. I have one bike with and one without, both the same tooth count. I don't race, so not sure how an oval works for racing. For me, I feel it helps me on the hard punchy climbs. My bike with the round chainring has much lower gearing, so I will probably not change to oval on it.
 

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I post this every time someone talks about how big of a chainring they need:

Interview: XC racing legend Tinker Juarez - Mtbr.com

"When it comes to equipment, I want anything on my bike carbon. It's light, it's strong, and it works. With components, we have the 1×11 now. I think that's the best thing that ever came out. It took a little while to figure out the front chainrings because you have some options. When I was first using it, I raced with a 34-tooth chainring and I was getting passed up the climbs. I was thinking, 'This is not right.' I realized the problem was my gear so I got a 32 tooth and it made the night-and-day difference. Now I know what works best for me. When I race, I race with either a 32 or 30 depending on how much climbing there is."
 

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My geared 29er runs 28t with 10-42. That works good for me for general riding, bike packing and endurances races. For sprint races it all depends on the course. With that gearing I can pedal and put down good power to about 21 mph. Beyond that I can still pedal, but it gets spinny and not as efficient. For the 24hrs of Old Pueblo I will be on 5 person team and there is one section of the course where I will be at 23 mph for 3-4 minutes. Slight downhill grade and pretty smooth. So I need crank out the watts and go fast. My 28t will not work, but running the numbers the 34 will be much better. Since there no long steep climbs I won't need the low end. This applies to 11spd as well as 10 speed set-ups. The think you need to do is understand you ratios and what you need for the courses you want. I can't tell you what to run since I don't know you our your courses.
 

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32T Oval. It feels like 34T on the mash...then it doesn't. I don't race. I do see an appreciable improvement in my climbing times with 32T Oval over 32T round when riding my usual XC trail network on my SS. I feel it, too, but mostly when I haven't been on the SS for a bit.
 

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Discussion Starter · #10 ·
Thank you everyone. I will be going with the 32T oval chainring. I live in Illinois and the terrain I ride on is mostly moderate climbs and the occasional steep short one with not too many downhills. As I am still racing in the sport class, the 34T doesn't seem too fitting considering there are pros answering my question :eek: Once I get faster I will definitely try out the 34! Thanks again for the responses.
 

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So probably 32x42 if Tinker is talking about the original SRAM XX1. Which would be a 36T on Eagle. I have 32, 34, and 36 in my toolbox depending on the course but in my experience the 36 just feels faster. Maybe it’s spending more time in the middle of the cassette for better chain wrap, maybe it’s the slightly longer pull when spinning out of a corner. I’m not a single speed rider but I was told by one that chain wrap and not having too small of a diameter gear is actually a real benefit.

Overall my point is get a few sizes and swap around to see for yourself. It’s typically not hard and pretty cheap. The clock won’t lie about which is faster for you.
 

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another opinion on oval; I have an absolute black on my cyclocross bike (39x11-32), I only notice it on the steepest climbs, and it feels just a little easier than a round ring, I don't notice it anywhere else. My xc bikes are both 2x, if I were to convert to 1x I would get an oval ring.
 

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So if you really want to get nerdy about all of this, you'll probably want to break it down into gear-inches. Find your wheel circumference (incl tires), then find an online calculator that will give you inches per crank revolution. I run a 38t front ring, 11x46 cassette, 27.5x2.35 ikon (r). It works super well for me. But if I ran a different wheel size my choice would be different.

On the ovals fwiw: used one for 2 weeks, and totally loved it. Then I went to a 3 month road bike training camp (no oval), part of which involved working on pedal technique. Came back to the MTB, took one ride on the oval then ditched it. It was bobbing my rear suspension like crazy.
 
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