# Thread: 29er SS Gear ratio question 42/20 vs. 32/16

1. ## 29er SS Gear ratio question 42/20 vs. 32/16

Math equations are not my strong suit plus first hand experience goes a long way.

Back story: I had a Rockhopper SS 29er a couple years back that I used on mostly XC type flatter trails in my region. I usually had the gearing 32/16 or 32/15 and it felt perfect for me. I could stand up and mash when it was tougher but wasn't spinning too fast in the flats. I sold it to fund a F/S Stumpy to tackle the more knarly daredevil style trails in my area. Well I miss my Rockhopper SS and sold the F/S Stumpy and have the "I don't care if I die as long as I'm having fun" craziness out of my system and would like to go back to my old ways. I have a Stumpy SS 29er on order and I plan to run it 32/16.

In the interim for 2-3 weeks I have a backup Motobecane Outcast SS 29er with stock gearing which is 42/20. I have yet to take this bike to any off road trail. It has been my neighborhood beater/around the block bike. How close would the 42/20 be compared to 32/16 or 32/15 seat of the pants feel? I'm trying to avoid buying a chainring/cogs if this is only gonna be temporary.

2. I think I may have answered my own question after checking out Sheldon Brown's site.

Calculating gear inches: Wheel diameter times front chainring size divided by rear sprocket size.

29X42/20=60.9

29X32/16=58

29X32/15=61.86

Gear inches means nothing to my seat of the pants feel but it looks close enough to give it a try on the flat XC trails as is. It looks like 42/20 is somewhere in between 32/15-16

3. That's pretty tall for xc riding.
Last weekend was the Landmine Classic in Hingham, MA. Only about 1000' of climbing over 25 miles. I race Cat 1 and used a 53" gear. Before the race I ran into a Cat 2 with his brand new Outcast with it's stock 44x18 gearing. I said "good luck with that"!
Unless your trails are real flat and straight, I'd suggest a somewhat shorter gear.

4. I live in Central Florida. It's not known for actual "MOUNTAINS" but we have some awesome off road trails. Alafia River State Park and Balm Boyette Scrub Preserve are built on old Phosphate mines and have a few hundred feet of steep elevation changes at times but nothing ridiculous. Most of the trails I plan on riding are pretty darn flat with only very short or gradual inclines. I rode fine with 32/16-15 gearing for a couple years here.

Here's some of our fun local trails :

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