Aaron wants to build a sweet new Yeti 575 with a 650B front wheel. This brings up some issues. Let’s have a look, shall we?
Okay, I’m going to throw a monkey wrench into these three posts:
I’m going to put a 650B front wheel on a 575.
So far I’m leaning towards 2″ bars/50mm stem, but I need to determine whether or not I’m going to put on a 70mm stem.
The 650B front wheel is my only hangup.
Any suggestions? And please don’t suggest to not run a 650B front wheel. 🙂
P.S. I forgot to mention that with a 160mm fork the TT length increases and I’ll be running one of those 36 Fox Van Rs.
Well … OK … I won’t tell you not to run a 650B front wheel.
According to your site — bicyclesbyaaron.com — you build custom bikes. So you must know what you’re doing.
Just be aware of some things:
A 650B wheel is the midpoint between a 26-inch wheel and a 29-inch wheel. 650B wheels are about 27.5 inches in diameter. They supposedly provide the improved rolling of 29-inch wheels, with fewer of the drawbacks (immenseness, slower handling, frame/fork design constraints).
On rough trail, 29s roll about 6 percent easier than 26s. Let’s say 650Bs roll 3 percent easier. I’m not sure that’s worth the hassle.
First, is there room?
I have an older 36 FLOAT on my Enduro SL, and there is only about 5/8 inch clearance between a 2.3 Specialized Clutch and the fork arch. I don’t see you fitting a decent-sized tire on a 650B wheel in that fork. But: I have asked Fitz at FOX, and we’ll see what he says about the new models.
Given the same tire cross section, a 650B wheel will raise your front end 3/4 inches higher than a 26-inch wheel. So take 3/4 inch of your combined bar/stem rise.
Raising your front end 3/4 inch will significantly change your geometry.
On the Yeti site, the difference between a 140mm fork and a 160mm fork (.8 inches) is 1.6 degrees. The bigger wheel will slacken your geometry about 1.5 degrees. So, with a 160mm fork, an all-mountainish 66.9-degree head angle becomes a DH-ish 65.4 degrees.
Slackening your whole bike will lengthen your effective top tube by about 0.4 inch, or one centimeter. You can offset that by adding 10mm to your stem — but with a 65.4-degree head angle (and now a 68-degree seat tube angle) I wouldn’t be too worried about the seated climbing position. You’ve turned your 575 trail machine into a freeride beast.
Some very smart people designed the Yeti 575 and FOX 36. As a matter of fact, these guys work together to make the bikes handle a certain way. I’m inclined to trust them.
If you decide to go 650B punk rock, be sure you make the proper adjustments. And please tell us how it goes.