Mountain Bike Reviews Forum banner
1 - 13 of 13 Posts

·
Banned
Joined
·
94 Posts
Discussion Starter · #1 ·
I have the stock md40s with 2.8 tires along with 175mm cranks. I apologise in advance if this is a dumb question but I'm new to the 27.5. I'm having wheels made that can take 2.2 tire. Will this tire change the hight of the bb to a point wear I should use a 170mm crank or will it not matter?
 

·
Wanna ride bikes?
Joined
·
9,839 Posts
I have the stock md40s with 2.8 tires along with 175mm cranks. I apologise in advance if this is a dumb question but I'm new to the 27.5. I'm having wheels made that can take 2.2 tire. Will this tire change the hight of the bb to a point wear I should use a 170mm crank or will it not matter?
The current bike comes with different wheels and tires. What year is your frame and which wheels/tires are spec'd?

What are your new wheels? specifically what rims and tires? 2.2 is pretty vague.

No strong conclusions can be made without specific details.
 

·
Registered
Joined
·
24,083 Posts
2.2" what, 29" or 650B? If you mean 29", then the BB will actually raise quite a bit as a 2.8" B+ tyre is about 1/2-3/4" shorter than a 29x2.2", if you mean 650B (no clue WTF you'd do this), then the BB will drop.
 

·
Banned
Joined
·
94 Posts
Discussion Starter · #4 ·
The current bike comes with different wheels and tires. What year is your frame and which wheels/tires are spec'd?

What are your new wheels? specifically what rims and tires? 2.2 is pretty vague.

No strong conclusions can be made without specific details.
I currently have 27.5 MD 40s that came on the bike with 2.8 tires. My new wheels are 27.5 spank oozy 350s and the tires I'm putting on them are Halo Twin Rail II 27.5" Tire - 27.5 x 2.2.
 

·
Wanna ride bikes?
Joined
·
9,839 Posts
I currently have 27.5 MD 40s that came on the bike with 2.8 tires. My new wheels are 27.5 spank oozy 350s and the tires I'm putting on them are Halo Twin Rail II 27.5" Tire - 27.5 x 2.2.
You're not going to like the way that works out. The BB will be too low. This frame is designed around 29" wheels or B+.

I'd see if you can return/exchange the wheels for some 29ers.
 

·
Registered
Joined
·
491 Posts
Here's some interesting info. The previous generation KM had 68mm of BB drop, and the new gen has 55mm. The difference in axle height between equal size tires in 29" vs 27.5" is 19mm. So, the new KM with 27.5" (not plus) tires will only have a BB 6mm lower than the old KM with 29" tires. Now, my old KM with 29" wheels was a pedal strike monster, and the new KM with 27.5" (not plus) would be worse... but not that much worse. YMMV, of course.
 

·
Registered
Joined
·
24,083 Posts
Your idea to run just regular 650B wheels and tyres (<2.5") is a bad idea, not only because it will lower your BB so you get loads of pedal strikes, but also if you're running a modern 1x setup, with those needed longer cage RDs, it'll be closer to the ground to get snagged on things or into the muck and mud, trust me.

OP, if you haven't already, you might want to go browse this humongous thread on the new Monkey, think you'll find all the info you could want in there.
https://forums.mtbr.com/surly/new-27-5-29-amp;quot;-karate-monkey-1018418.html
 

·
Banned
Joined
·
94 Posts
Discussion Starter · #13 ·
I appreciate all the help I was able to get a hold of the builder, he hadn't started building yet so I changed them for the 29 wheels. Really want to use some skinnier street tires so this way there won't be any issues.
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top