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Discussion Starter · #1 ·
Has anyone modified the chaining on a new 2019 JEFFSY CF PRO RACE 29 with the 1X11? I am considering dropping to 32 tooth to a 30 tooth to help on climbs. My local trails are brutal and with 8,000 ft elevation a smaller chainring will feel nice.

Any idea on a compatible/best fit chainring?
 

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I have the 2019 27 Pro Race. Went down to a 30t from stock 32t eThirteen SL Guidering. I just stuck with the same chainring to avoid messing with chainline. It works fine... still drop chains backpedaling in the lowest 3 gears.
 

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Discussion Starter · #3 ·
Thank you for the reply. I've been looking to get an E13 30T as well but they are sold out in the US at least.

Was there a noticable difference pedaling uphill? Did you remove any links from the chain?
 

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Thank you for the reply. I've been looking to get an E13 30T as well but they are sold out in the US at least.

Was there a noticable difference pedaling uphill? Did you remove any links from the chain?
Not sure on the chain as I had my shop install it (don't have BB tool yet and wanted them to bleed new brakes anyway). It is noticeable for sure, two benefits: first is you stay in the 28/33/39 cogs more often and don't sit in the 46 as much. Second benefit is the 46 is about 6% easier than on the 32t which is noticeable when sitting and spinning on steeps. Doesn't sound like much but it's the difference of getting off and pushing on shorter 15% grade pitches to me.

28t would really help and you probably won't spin out 28/9 but I was worried about impact on rear suspension of such a small ring up front.

Keep an eye on eBay for the e13 chainring or maybe ask e13 USA when they will restock their webstore.
 

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Curious about concern over 28t chainring and suspension. I have the 28t ring, haven’t installed it yet, thinking I’ll need to pair it with a chain shorter by 4 links. Math says 28t chainring is about the same as a full bump in large cassette (i.e., 39 will be almost as low as 46/w 32t ring). I want lower gearing, but did I screw up somehow? (Thought about going with 30t, but that only equaled half a gear)
 

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It's not a massive concern and I don't have the math on hand, but anti-squat/rise is designed around a certain chainring size so significant changes (due to changing where the chain is located in relation to main pivot and instant centre) can change those values from what the frame was designed at. I am probably overstating the impact though.
 
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