29 Vs 27.5+?

When it comes to running the same frame with either of the above options there seems to be a difference of opinion as to which is the best in the real word, so I thought I'd get some differing opinions here too ;) I'm mainly thinking Chromag Primer / Surface / Rootdown BA as potential options. I recently rode a Surface (29) and a Primer (27+) around a car park which admittedly doesn't mean too much and surprisingly the 29 felt like a slacker bike despite the Primer actually being slacker. The Surface did have a super short stem and 800mm bars Vs the 50mm stem and 780mm on the Primer. Maybe I needed a gnarlier car park?

I've got a Rootdown BA I'm running both 29 & 27.5+ wheels. The 29 I've got a Bontrager SE5 on the front and a Minion dhr on the rear, both 2.35's. My 27.5+ I run 2.8's dhf/dhr. I definitely  find the 29's quicker and more agile than the plus. If im doing a lot tech climbing and pedaling, I'll run my 29's. For gravel climbing, then decending with little pedaling ill go 27.5+. I prefer the 29's overall.

without a reference how would you know which is faster?

I tried juniors 27.5 and to be honest it didnt feel any different from my 26 but afterwards he said "when you got on my bike you were keeping up while on your bike it was easy to ride away from you"

I bought  29 so I  let my GF ride it after she fell over and had a bo bo,  it became harder to ride away from her and she didnt stall and fall over on the trail ...she is sold on 29

I chatted a bit with a buddy , he asked a mechanic with a lot of time testing between the 29" and the 27.5"+ models of the same bike . In the end as he's a serious racer he choose the 29" as it was consistently faster on the same trail . He did also mention the 27.5+ bike is way more fun as a all around bike and is more play full on the trail .

I just went from 26" to 29" and I have noticed a big difference all around running less travel and all . Very happy with my choice .

I've got the Rootdown BA as well. I started off at front and rear 27.5+. Rode that for a few months and while I enjoyed it, I found the lower overall bb annoying on the techy climb trails that I ride. I really really enjoyed the extra traction and bit of cush in the + rear tire though.

I've since swapped over to a 29 front wheel with 2.35 tire. I'm not missing anything about the + setup on the front. I've got more bb clearance, better precision due to a more supportive tire, and not notice any difference in front wheel traction. Only downside for me now is I feel the bike is too slack mainly while climbing again. But pointed down is absolutely amazing.

I've sent you a pm trump

Thanks peeps. Good point about BB height. My current bike is at 13" which is 'nice' but I wouldn't want it too much lower and the Rootdown PA for example is 12.6 with 29er tires (not sure what size but unless they are 1.9" Smoke Lites it wouldn't make a huge difference!). As much as I like the look and idea or Plus tires, it seems like the logical choice for a Squamish All Terrain Gnarpoon might be 2.5" 29er tires.

yeah 2.5" 29'ers

and remember going  29"  only raises the BB half the difference between 27.5 and 29  ... so .7"

I did an in-depth review of my experiences on 29 vs 27.5+ and the Rootdown BA: https://nsmb.com/forum/forum/gear-4/topic/forum-testing-suntour-auron-34-rc2-pcs-129442/?post=2411021#post-2411021

^Thanks for that. Pedal strikes annoy the hell out of me so 29 seems to be the way to go.

Anyone here tried 650b+ on a non-BA  Rootdown?  I'm guessing about 2.8" max (fine with me) but possibly way too low a bottom bracket.

^I've done that too prior to picking up my BA. 29mm internal rim, 2.8 WTB Trailblazer. Had probably 1/4" clearance at either chainstay, not ideal if wheel goes a bit out of true or if the mud is real sticky, but good enough to play around with and appreciate the improved traction and compliance. Keep in mind the Trailblazer is definitely more conservative in the knob department.

Excellent, thanks. 

I'd probably choose a pretty mellow tire (like a plus size Slaughter if that's a thing) as I'm attracted by using the volume for traction without the drag of big knobs. 

Was pedal strike an issue for you?  Looks like you had fairly chunky pedals and long crank arms.