The Mountain Bike Life

Finally got all my gear back from the brake study, now just waiting for the data from it. So that means I have my frame back with all my rear brakes again…..yeah. With the Avalanche on the stand I can start to loosely put on my gear and check clearances and fitment. I did get some 650b tires too. So let’s take a look at how it is all coming together.

The tires I got are Vee Rubber Mission 2.1 in the rear and WTB Wolverine Race 2.2 in the front. Best part is I managed to score them at Blue Sky Cycling for a good price. The 650b equipment is starting to become more available. As for the choice of tires, I like a little wider tire up front for a couple of reasons. When you hit some looser soil or sand the wider tire floats on it a bit better, with a narrow tire you can feel it sink in really quick. Then when cornering I like to have a bit more bite in the front and I like a little slide in the rear. Over the years I have found the 2.2F/2.1R combination the best for me. Much wider than 2.2 up front and I don’t like the rolling resistance. In the rear I want a lighter tire with even less rolling resistance. This makes for quick acceleration out of corners and up hills. Both these tires are right around 500 grams and are meant for dry conditions with some loose soil. Perfect for summer riding around here.

650b 2.2″ tire clearance on a Xfusion Enix fork.

Now that they are mounted up on the wheels let’s check fitment. The Xfusion fork has a lot of clearance for the 650b. Even with a wider 2.2 tire up front there are no problems at all. I have no worries with this setup and see why this makes sense from a manufacturing standpoint. Just make one fork and it can have 2 tire sizes on it. Now I have this fork shortened to 80mm for the older frame. If you intended to run it at 130mm you may want to make sure the tire doesn’t hit the frame on full compression. If it does there is a bump stop kit from Xfusion you can get to take off a little travel at the bottom of the stroke without having to shorten the travel.


Rear brake support clearance for a 650b 2.1″tire  on a GT Zaskar/Avalanche frame.

On to the frame, from everything I have read there should be plenty of clearance on a GT frame. Sure enough with the 2.1 I have plenty of clearance to the brake bracket. On the lower chain stay support it does get a bit tighter. I still have a good 10-12mm of clearance, but I wouldn’t want to go much bigger in tire size than this. I think a 2.2 would still fit, but it would be pushing it a little. Definitely wouldn’t want to try a 2.3 back there. Even if it did just clear any wheel problems or mud buildup would become a problem. So for me I have really happy with this.


Chain stay clearance for 650b 2.1″ tire on a GT  Zaskar/Avalanche frame.

The rest of putting this bike together is academic. I need to shorten the rear brake line and will need to figure out how to do that on these XT hydraulics. Get the bottom bracket and chain guides set. Last is get a new set of pedals. I am slowly going to migrate my bikes over to platforms since I really like them. Gives me something to shop for, or maybe I can get a couple of sets to review somewhere. Last but most importantly I need time. With the new little one I am switching back and forth with my wife on baby duty. It is cutting into my Laboratory time a bit, but worth it because I am spending time with my daughter. It should be on the trails in June and then I can compare that to the 29er.

26″ Wheel vs 27.5″ Wheel

Last note here…….As I was putting everything together for this bike I discovered I have an extra set of 26er wheels from Vuelta. They weigh within 10 grams of the 650b wheels. With the same rotor size on them I can literally swap this bike back and forth between a 26 and 27.5 wheel in seconds. I can try out a 76er combination and even see how that does. Should make for some interesting experiences. Next post up for me will be on my first ride on the 29er.

Hopefully I got some of you thinking and looking at your old 26er in a different way. Just when your wife asks why you just spent $300 on wheels and tires for your old bike tell her this. You were saving money by not buying an entirely new bike. Right? Then probably duck or step back quick.

The Mistress V2.0
The Roman Road to Sparta

1 Comment

LEAVE A COMMENT

FEEDBACK