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29er and 26er
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Assuming a tier size of 2.35" on your 26" wheels and the same size tire on your 27.5"

26" Wheels = 53.4 Gear Inches @34x17T
650b Wheels = 54.4 Gear Inches @34X17T

I would not change your gears. You will be running a slightly higher gear ratio but the difference is not really that much unless you are having a hard time pushing your current 34X17 on 26" wheels. If your current ratio is too steep for you swap out to a 34X18T.

Good Luck.
 

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Discussion Starter · #5 ·
thanks, yeah came to the same conclusion.. but 2.35" tires!!! Im running 1.95 front and 2.10 rear.. lol
probably run 2.1's on the 27.5.
Ive never had any problems pushing the gear on my 26" so hopefully it won't feel much different on the 27.5, if anything the little extra top end will be nice.
 

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NedwannaB
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was riding 26 with 34x17 and want to stay with the same overall gear.. what would be the equivilant gearing for 27.5/650b?
any help would be great..:thumbsup:
As always with these generic inquiries, you'll get a lot of varied responses. Typically for starters it's 1 tooth jump up on cog for 650's, 2t for 29er's. It really does depend on terrain and riding abilities. If not a lot of ups/grunts and more rolling on your reg rides then leave it in your current 2:1 gearing setup like you've mentioned. You may adjust to it with the big(er) wheels right away.

My current 650 SS setup is 34/19 running the 2.2 WTB Wolverines and BeeLines which are not huge per say but quite abit bigger than the 2.1 CrossMarks I had on before. Although they add a tad more roll once up to speed on the flats/rollers etc, I'm finding a tad more effort on climbing which I like and my rides tend to have a good amount of lately. Could be the change in tires or just me getting old too tho.... Thinking about going to 34/20 or maybe 32/19. I'm running an SS kit with individual cogs on a geared hub and tensioner on a geared frame so a little more economical $$wise to change out than your WI freewheels or switch chain if not much adjustment on your frame.
 

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Discussion Starter · #8 ·
Good deal, gonna go with the same gear for now but have the option to jump to the 19 if needed (WI Dos freewheel)
hopefully this weekend I will be able to find out, im thinking I may need to though since I was running 26x2.0 with 34x17 and will be running 27.5x2.2 and the same34x17.. ill see if my old knees can holdup!

As always with these generic inquiries, you'll get a lot of varied responses. Typically for starters it's 1 tooth jump up on cog for 650's, 2t for 29er's. It really does depend on terrain and riding abilities. If not a lot of ups/grunts and more rolling on your reg rides then leave it in your current 2:1 gearing setup like you've mentioned. You may adjust to it with the big(er) wheels right away.

My current 650 SS setup is 34/19 running the 2.2 WTB Wolverines and BeeLines which are not huge per say but quite abit bigger than the 2.1 CrossMarks I had on before. Although they add a tad more roll once up to speed on the flats/rollers etc, I'm finding a tad more effort on climbing which I like and my rides tend to have a good amount of lately. Could be the change in tires or just me getting old too tho.... Thinking about going to 34/20 or maybe 32/19. I'm running an SS kit with individual cogs on a geared hub and tensioner on a geared frame so a little more economical $$wise to change out than your WI freewheels or switch chain if not much adjustment on your frame.
 

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NedwannaB
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Good deal, gonna go with the same gear for now but have the option to jump to the 19 if needed (WI Dos freewheel)
hopefully this weekend I will be able to find out, im thinking I may need to though since I was running 26x2.0 with 34x17 and will be running 27.5x2.2 and the same34x17.. ill see if my old knees can holdup!
57 y.o. knees here. :) I know your pain! :mad:

Brief surf thru your flickers, is it that GT ss you're converting?
 

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Discussion Starter · #10 ·
I hope I can say that I still riding when I reach that age.. by then my knees may be shot!!

no the GT is back to it's original build when I used to race it about 15 years ago.. but that was my first SS build then I swapped the frame to a Bianchi Grizzly.
now all off that has been moved over to the Soma B-Side. GT1.1.jpg bianchi.jpg 5.JPG

GT, as it stands now.. Bianchi only pic I could find on this pc and the Soma hoping to ride it soon..


57 y.o. knees here. :) I know your pain! :mad:

Brief surf thru your flickers, is it that GT ss you're converting?
 

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NedwannaB
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well the 34x17 with 2.20 was a bit much atleast for now.. lol, I swapped over to the 34x19 and it feels about the same as the 34x17 with 2.0 on the 26r..

I am deff liking the 27.5 wheels though and the bike feels as quick as the 26r was.
Similar here. Just bumped up a tooth to a 34/20 on mine (from 34/18 previously on a 26r). Only one 10 mi/2k ' ride. Like it but still on fence. It may be perfect with 2.1 CrossMarx on.
 

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NedwannaB
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good deal, JMac.. I wish someone local would have had 2.0 or 2.1's.. but after riding them a couple days I think I may like the fatter tires, was a little strange at first but seem to have plenty of hold cornering.
I dont seem to have to finesse the bike so much.
Another SS ride (longer) in the books with adjusted tire pressure and the new gearing change. Like you I'm thinking to keep the 2.2's on for a little more cush and grip. Leaving the CrossMarx on the fs.
 

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Discussion Starter · #15 ·
Another SS ride (longer) in the books with adjusted tire pressure and the new gearing change. Like you I'm thinking to keep the 2.2's on for a little more cush and grip. Leaving the CrossMarx on the fs.
good deal.. yeah that is another thing the 2.2's are good for, more cush! running lower pressure than I have ran in the past and it's kinda nice..

whats your SS setup?
 

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Discussion Starter · #17 ·
Mostly carry over parts except xt brakes. :thumbsup:[/QUOTE]

Nice, looks good.. probably a bit lighter than my setup! Im thinking of swapping to one of the carbon rigid forks and want to upgrade to XT brakes.. there was a deal from Ribble but missed out.. so gotta wait until I find another deal on them.
 

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I ran a 32/18 on my 26" riding in steep terrain (7-13% grade). I got a 27.5 and I run a 32/20. It works good for me in steeper terrain but not so good in flat terrain.
 
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