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Discussion Starter · #1 ·
Has anyone tried 27.5 wheels on a 29er frame? The geometry of my Scott Scale 940 is VERY similar to the Scale 740s geometry! Is it feasible to have a dual purpose bike just by swapping wheels?
 

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Bottom Brackett height for your 940 is listed as 12.2 inches, which is already kinda low. You would be lowering it at least an inch and a half to 10. 7 inches or less.
 

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Formerly of Kent
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How would it be dual purpose?

Just swapping wheels won't do anything other than lower your BB.


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Discussion Starter · #7 ·
Duel purpose like if I'm goin to a fast tight trail run 27.5 wheels and if I'm riding a technical trail with lots of obstacles or a bigger spread out trail run the 29er wheels! I was just looking at the demensions of the two frames I didn't think about how much height the BB would lose.
 

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Your wheelbase would be longer then the 27.5 model but barely shorter then the 29er, it would also steepen your head tube angle.
 

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You wouldn't lose that much BB height. If the overall diameter of the 27.5 is 1.5" less than the 29r, then your BB is dropping half of that, 3/4", because your wheel is connected at the center(think radius difference, not diameter). On some bikes that difference could cause pedal strikes in certain conditions, on others it might not be an issue.

Not saying the handling geometry wouldn't/couldn't change for the worse, but there are a lot of riders who have combined sizes front & rear, for the individual benefits of each. If you have a set of 27.5's available, wouldn't hurt anything to give it a try. I've done some offbeat projects(20" wheels on 26" bike, for instance) and have had plenty of people tell me how this & that was gonna happen, and how stupid it was. But, by and large, none had any actual experience with it and the project came out fine. Don't be afraid to try different stuff....
 

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LOL. Give it a whirl, but I think this illustrates the point of why a lot of 27.5" bikes are weak sauce. If you're going to have smaller wheels, shouldn't you get the accompanying shorter back end and/or wheelbase too?

In this case, you'll all of the bad things about a 29er, without what most people consider the good things.
 

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Discussion Starter · #12 ·
Unfortunately the only 27.5 wheels I have available won't work because their 15mm. I don't know how the geometry works I just thought that they were really close so it might be possible. I'm sure somebodies tried it. When I say I don't know how geometry works I just don't know wether a steaper head tube angle make a bike faster or wether shorter chain stays makes it respond quicker. I rode as a kid we just got on and pedaled like hell and jumped really high! Il definetly try it if I find some wheels that will work.
 

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Forgive him, he is newbie drinking the 650b kool-aid

OP, what does a 27.5 inch wheel do that a 29er does does not?
 

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The thing to do is experiment with a 29 front, 27.5 rear and vice versa. It isn't a two-fer, it's a foursome!
 

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Discussion Starter · #16 ·
Coming from a bmx and dirt jump background as a kid I like to ride fast bmx style trails with jumps. My 29er is awesome but I'm wondering if a 27.5 would work better for my riding style. I could alway ride someone else's but it's not gonna feel completely right because it's set up for them not me. If I could throw some 27.5 wheels on my bike that's setup for me I think it would have a better feel and give me better feedback. I don't really sit down and pedal. I stand up and pedal and carve around and jump stuff. Yeah my 29er is awesome but takes a lot of effort to pump through sections and carve through tight trails. Of course you can jump a 29er but is it really the best option? Would a 27.5 be better for hitting jumps? Just getting back into riding I'm just trying to explore my options. Especially with all the options out their these days why not try everything. I think if you ain't crashing you ain't goin fast enough so I'm just trying to get faster!
 

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Geometry is what makes or breaks a bike. Changing wheel sizes may give you some of the benefits of the donor size, and some positive changes to the handling, or you may end up with the disadvantages of smaller wheels and negative handling traits. It's a costly jump, but only you can decide if it's worth. Carving tight trails isn't going to be much different between the two arrangements, as that comes down to wheelbase / hta / fc.
Coming from a bmx and dirt jump background as a kid I like to ride fast bmx style trails with jumps. My 29er is awesome but I'm wondering if a 27.5 would work better for my riding style. I could alway ride someone else's but it's not gonna feel completely right because it's set up for them not me. If I could throw some 27.5 wheels on my bike that's setup for me I think it would have a better feel and give me better feedback. I don't really sit down and pedal. I stand up and pedal and carve around and jump stuff. Yeah my 29er is awesome but takes a lot of effort to pump through sections and carve through tight trails. Of course you can jump a 29er but is it really the best option? Would a 27.5 be better for hitting jumps? Just getting back into riding I'm just trying to explore my options. Especially with all the options out their these days why not try everything. I think if you ain't crashing you ain't goin fast enough so I'm just trying to get faster!
 

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Now mullets are back in fad, has anyone tried 27.5" front and back on modern long travel 29ers while keeping the same 29" fork? Someone did swap in 27.5 fork with wheels front and back on for slalom racing at Sea Otter, MY16 Evil Following. The bottom bracket height went from 13.3" to 12.5". Wheelbase went from 1162mm to 1150mm.

https://www.youtube.com/watch?v=z2S0zhnmITI
 
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