Tuesday, December 04, 2007

650B Truth?

650B tire size? Let's see now, mountain biking wheels come in the oldish standby size that supports 26-inch diameter tires (the so-called standard), then along came the 29er stuff (29-inch diameter tires), and now there is a new (actually quite an old standard) size that is 27.5-inches that has long been dubbed 650B (not to be confused with 650C).

Hmmm...this new-old 650B idea really peaked my interest since I have been seriously looking into the concept of building or buying a full-suspension 69er (that's a large 29er front wheel and a small 26" rear wheel on the same bike). Why?...I have tried several 29er full-sussy bikes and just never felt at home one. On the other extreme I found I have a preference for 26" full-sussy bikes, but I also found that I dislike the small front wheel (it's much more prone to endo action and I really hate going over the handle bars). So the whole bigger wheel in front and smaller wheel in back on a full-sussy bike made sense to me and I wanted to find out if it would be the ultimate super-butt squish ride for me.

So I was drooling all over Trek's new top Fuel 69er (actually I still am - yes I want one) when Kirk Pacenti alone had a real 650B mtb tire made - that man has some serious faith in the 650B tire size to pony up the $$$ to have one mass produced (yes it takes money to make a tire mold). After many obsessive "research" hours spent looking over the whole 650B thing I decided I was going to build a FS bike of my choosing and drooling that was like the Trek 69er, but built with a 650B tire up front vs. the overly large 29er tire up front.

My Ellsworth Truth is the bike I chose - you may recall that in earlier posts I said the bike was a rough draft...well that rough draft has come much nearer to completion with a Pacenti Neo-Moto 650Bx2.3 tire mounted to a Velocity Blunt 650B front wheel laced to a DT Swiss 240 disc hub (HOT!!!) that I just built up. I also enhanced the rear wheel with a Bontrager Jones ACX tubeless tire mounted onto Stans Notubes ZTR 355 rim laced to a DT Swiss 240 disc hub. More enhancements are still planned so I have the say the bike is still in draft form.

The ride with the 650B front wheel is better than I had hoped...more testing (time trials, long hauls, and pure sufferage) as weather permits, but so far all I can do wonder in awe...Is this a bike I will actually keep longer than a few months? Any bets?

6 comments:

Jon Jones said...

Great pic. Your truth is much the same as my Ram 4.0 that I was wanting to 69. your post at mtbr and another showing a 650b fitting into a fox f100 has ahcnged my mind. I will now do a 67.5er

Super B said...

Very Sweet bike Super E.
So you have a tubeless in the rear and a tube in the front? I am planning on doing a 27.5 in the front of my full suspender, but I go through tubes in about 5 minites where I live in pinch flat city, N.M. Any ideas?

ERic said...

Super B - I'm going to try a 650B tubeless setup using a Stans Flow rimstrip in the Velocity rim...I'm not sure it will work but for me it's worth the effort since thorns are abundant here.

Super B said...

I'm waiting for Stan's ZTR 355 rim he is coming out with in the spring. This setup should be more foolproof. I'm not a fan of tires without a UST bead though, but it will have to do until...

Hope you are enjoying the ride. Again, it is a very sweet setup. Nice to have an option of a bigger wheel up front. 29 is too large for a bike that was not designed around it, and there are not many full suspension 69ers to choose from. I love my Rush although Ellsworth would be my second choice.

GreenLightGo said...

good looking so far.

I've got an '07 32 TALAS R on my 5" dual suspension bike - tempting to do this as I do like the feel of my 29er HT as well. The Fox fork action is so nice...

Any travel issues you have to deal with (like limiting)?

I run 819s so I'd look to convert a Velocity - any of the existing rim strips work, or would the 26" tube cut open have to suffice?

I run Stans Flows on my 29er, they'd be great in 650B size as well.

Spodnik said...

Thanks for the beta - looks like a nice set up - inspired me to try it out...post some results later in the season