Ask the experts

My neighbor rides a Tallboy with a 50 cassette. He smoked a tooth and needs a new one. I have a new 50 I can give him, but he avoids some of the long and punchy climbs we have. So I'm thinking a 52 would be a better replacement. Or maybe the 50 with a 30 up front? I'm assuming he's a 32 now.
I just recall dropping my chainring way back on an old bike and it changed the feel of all the gears (obviously!) but I did get used to it.
Aside from top speed which we don't use on dirt, is there a reason to to go with a smaller chainring?

@jackstraw I'm assuming you're talking Eagle. The 52->whatever jump is pretty clunky, I avoided running that cassette when possible, but it does make things a bit easier. The downside to running smaller chainrings (besides top speed) is less wrap/engagement. I found them to be a bit noisier and wear down faster. I have one buddy with a metal knee (courtesy USMC) who prefers to run really low torque setups, like 30x52 with a 27.5 rear wheel and he seems to wear out rings and have more dropped chains than anyone else I know. That said, I feel like 30x50 is reasonable for a 29er rear for someone who isn't super strong and has punchy climbs to contend with.

Yeah, I am talking Eagle.

So my Blur has the 50 and Bronson 52. I noticed a pretty big difference between the two even with a massive weight reduction with the Blur. It's just easier after a long sustained climb to clean the punchy sections. I do climb up stuff that a lot of people around here avoid. I find ups a preferred challenge these days. The downs are super fun, but I'm not always going 110%...as I like living.

I don't have any issues with the 52. It is a long jump up, but my X01 derailleur and shifter handle it with ease.

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Originally Posted by jackstraw

Aside from top speed which we don't use on dirt, is there a reason to to go with a smaller chainring?

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More gound clearance, for all those rocks you don't have. lol. But you will, once you start heading up to the Sierras to ride.

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Originally Posted by evdog

More gound clearance, for all those rocks you don't have. lol. But you will, once you start heading up to the Sierras to ride.

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Ha! Oh, I've got bash guards...but nobody else around here does! [emoji23]

I run 30x50 on all my mountain bikes. I don't like the big jump to th 52. 30x50 is the same for climbing but you can stay in 2nd longer and then have a smoother transition. I'd rather have more usable options at the big side of the cassette than a faster top speed.

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Originally Posted by beaterdit

I run 30x50 on all my mountain bikes. I don't like the big jump to th 52. 30x50 is the same for climbing but you can stay in 2nd longer and then have a smoother transition. I'd rather have more usable options at the big side of the cassette than a faster top speed.

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I like that plan

As a counter opinion, I run a 32 x 52 on everything (29" wheel). Most of my "normal" climbs are 3rd or 4th gear fire roads. But when I need a bail out gear, the 52 is nice. I don't mind the big jump between 1st and 2nd because I'm rarely waffling between those two gears. I'm either spinning along in 2, 3, or 4, or I'm grinding at a snail's pace in 1. And I like the taller overall gearing mostly because it means I'm in a bigger cog on the descents, which keeps the chain a little tighter and it bounces around less. And having a bit higher top speed is nice too.

But there are certainly times when I'm at the end of my rope on some stupid climb and I start talking about how I should put a fucking 30 on this thing.

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Yeah, I still have not cleaned a two mile single track ascent here. There are two cruxes which I've cleaned individually, but not both on one climb. And it's my heart rate just maxing out, not that the punchy sections are that difficult. Although my friend who's been here since college said he's never seen anyone clean the section I did, so I got that going for me [emoji23]...but every one of my EC friends would clean it! So I guess it's slightly techy because of all the roots. If I put a 52 on the Blur or a 30 on the Bronson I'd probably clean the whole thing by now, but hopefully I'll get in better shape a pull it off soon.

So thinking about this a bit more, 30x50 is a bit lower than 32x52 because two teeth is a larger percent change off a 32 than it is on a 50.

Most of our service rd. climbing around here is ski areas and it granny gear or 2nd at best. A lot of the singletrack climbing I do I’m hoping to maintain 3rd gear. I aspire to do most of the steep climbing in 2nd gear and just use 1st as a bailout, the 30t helps toward that end. However in my old age and struggling fitness, I use the 50 more and more haha.

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Originally Posted by beaterdit

So thinking about this a bit more, 30x50 is a bit lower than 32x52

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Correct. Although not a ton lower. To put a number on it, 30x50 is 17.4 gear inches. 32x52 is 17.8.

(That's with a 29" wheel, although it's still a .4 gear inch difference with a 27.5, it's just a lower number for both gear ratios).

The only real argument for the 32t ring is that most suspensions are designed around a 32t. So going down to a 30t is going to affect the bike's anti squat and pedal kickback. Entirely questionable whether that's at all noticeable though. Probably varies a bit from bike to bike.

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I was not told there would be maths.

Hahaha I'd have to look up the gear inches calcs for sure, nice work.

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Originally Posted by toast2266

Correct. Although not a ton lower. To put a number on it, 30x50 is 17.4 gear inches. 32x52 is 17.8.

(That's with a 29" wheel, although it's still a .4 gear inch difference with a 27.5, it's just a lower number for both gear ratios).

The only real argument for the 32t ring is that most suspensions are designed around a 32t. So going down to a 30t is going to affect the bike's anti squat and pedal kickback. Entirely questionable whether that's at all noticeable though. Probably varies a bit from bike to bike.

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Interesting about the anti squat and kickback. It's nice have experts in the expert thread [emoji16]

With that said I'd consider a 52 on the Blur when the time comes. (As I've said, I really enjoy an Up that I cannot clean, but when I do it's satisfying and there are many I'm still trying to solve) Problem is I don't ride the Blur as often, so the cassette is going to last a long time. I also think there's a difference on climbability between the two bikes. Maybe its me and my comfort level, but I like the mullet for climbing. The full 29er I think I get too far forward or something. I have an easier time keeping the rear wheel engaged and stall/start on super steep with the geo of the mullet. By all rights I should climb much better on the Blur do to weight difference, but I don't. I haven't put the Bronson on a scale, but the weight between the two is upwards of 7-9lbs.

For clarity: going to a smaller ring will INCREASE anti-squat and kickback. Probably in the range of 4-5% increase at the low end of the cassette. Example:

https://linkagedesign.blogspot.com/2...-2016.html?m=1

^^^ yup. As a practical matter, it's usually more noticeable on longer travel bikes.

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Considering suspension is designed around a specific chainring size, it is interesting that sometimes the same bike will be offered with a 32t if equipped with SRAM drivetrain and a 30t if the build has Shimano. Current Smuggler for example.

As mentioned, there is not a huge difference in anti-squat and kickback between 32 and 30t, but you would think the manufacturers would be want bikes to go out the door as designed. Of course, maybe it is a reminder for us not to overthink things.

I get zero pedal kickback with 28t and 10-42t …






… on my hardtail. Of course the pedals on that thing aren’t kicking back. They are kicking up and into my ass!

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Originally Posted by g_man80

Considering suspension is designed around a specific chainring size, it is interesting that sometimes the same bike will be offered with a 32t if equipped with SRAM drivetrain and a 30t if the build has Shimano. Current Smuggler for example.

As mentioned, there is not a huge difference in anti-squat and kickback between 32 and 30t, but you would think the manufacturers would be want bikes to go out the door as designed. Of course, maybe it is a reminder for us not to overthink things.

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Seems plausible that transition designed the smuggler around a 31t ring.

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Some really good deals on specialized full suspension bikes... approaching 60% off for some stumpjumpers in S1 and S6 sizes. Not a specialized person but maybe the best thing we can do is buy a bike from them that they take a loss on?

Where are you seeing that? I have a friend interested in getting an S1 Stumpy and the best deal I’ve found online for a Comp Alloy is via Al’s Sporting Goods … not sure if buying from a place that has no idea how to build a bike is a good idea though.

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Originally Posted by tailwind

Some really good deals on specialized full suspension bikes... approaching 60% off for some stumpjumpers in S1 and S6 sizes. Not a specialized person but maybe the best thing we can do is buy a bike from them that they take a loss on?

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No. Buying a bike they take a loss on is a MUCH worse option than NOT buying a bike from them at all.

And fuck Specialized.

Don't worry about it you will soon all be older than fuck riding an Eeb running a 34 T

Cannot quote still.

Agree - fuck specialized. Not a bad way of getting someone on a bike but I won't be buying one.

The sale is on the main website. Just click the sale banner and then mountain bikes. Some are twenty percent off but there are a handful sprinkled in there at a much higher discount.

Specialized is the best bike company in the world, take a hike with the bullshit.

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Originally Posted by Tailwind

Cannot quote still.

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The sale is on the main website. Just click the sale banner and then mountain bikes.

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Ah okay thanks.

I had been looking at the lower end builds (no inventory in S1) but Expert T Type Gx AXS build with Grip2 34 for $3k is a solid deal. This woman is pretty beginner though, upgrading from like an Alivo-level hardtail … so it feels a bit off being like, “you should get this high end wireless transmission on your first bike because it’s a good deal.”

Oh yeah, and you can’t quote from PC web browser but you can quote from the rather shitty mobile app Tapatalk.