BB and rear spacing for plus size frame?

[VertigoCycles]

Hopefully Sean at Vertigo may chime in? I know he's built a bunch of these rigs with the 83x157mm TA set up.

I think what we're all seeing is that there are several ways to skin a cat and as long as what's done works, it works. As a builder, the bottom line is that you need to know your way around the various options and just choose one that'll work for you. If you like Boost and want to go for it, great. If you don't, choose another path...no big deal. It's your thing, so make it work for you.

Before I directly answer the question, it's important to give it context. I, like Kris, love short stays. The overwhelming majority of my customers come to me looking for a dirt bike with short stays and my way of doing things is with that in mind (this is way over-simplified so don't think stay length is the be-all end-all)

Boost - It's not for me and I can't claim to understand why the big MFGs chose to put their weight behind it rather than using something that already existed (83mm shell and 150/157 back end) You get a couple of mm's out of it and that's it. With the current trend moving toward single ring setups, a perfect chain line can be had by putting a ring in the big ring position and using a 150/157 axle spacing. I've been doing it that way for six or seven years. The existence of Race Face's new cranks with their 3mm offset ring, makes this easier and gives lower gearing options.

29ers - I build out the chainstay inside width at the tire knobs with 75mm of clearance. That's room for a big ass tire and mud clearance and then some. You can't run an honest 3" tire, but I've had some customers put on 2.7's in dry conditions with no complaints and others who have put on 27.5+ wheels that work great. These frames aren't intended to work with plus tires and I use a 73mm shell, ring on the outside and a 150 or 157thru axle spacing. If you consider the centerline of the bike and work out where the constraints are...the inside edge of the stay is at 38mm, the inside edge of the ring is at 56mm which leaves 18mm in which to squeeze a swaged 22.22mm tube (assuming the ring and tire are overlapping or close to it). I can safely squish my tubes down to 16-16.5mm, leaving me with 1.5mm of clearance to the chainring (in reality, it's more)

I have to go pick up my kid from school, but that's the logic on every frame. Know the constraints, know your limits with bending and forming and then figure out what's going to get you where you need to be.

[joth jacobson]

(In response to Kris' recommendations)

Yep, I've got both 135 and 142 axles and have built using both. But moving up to 148 or 150/157 would require sending more money to Anvil (which ain't a bad thing - very helpful and supportive), hence the inquiry...

[VertigoCycles]

(In response to Kris' recommendations)

Yep, I've got both 135 and 142 axles and have built using both. But moving up to 148 or 150/157 would require sending more money to Anvil (which ain't a bad thing - very helpful and supportive), hence the inquiry...

Joth,

Make a top down drawing. It'll answer all your questions.

[fortyfour]

<SNIP> And modified...

Make a drawing.

^THIS^. This is just about as important as it gets. Having a plan in the form of a drawing with all necessary parts either in hand or having parts drawings to reference is really important. You don't know what you're doing until you have a drawing of WHAT you're attempting to build.