[slo_rider]

...If the wheel diameter decreases from 29 inches to 28.25 inches for a total loss of .75 inches (19 mm), then the expected drop in BB height would be half of that decrease in diameter (9.5mm), right? Meaning the expected BB height for the Stumpjumper would drop from 336 to 326.5. If that is accurate, does that seem manageable?

Does anyone have thoughts on what the lowest acceptable BB height would be for a 27.5+ conversion, in general, even though different styles and terrain will affect this?

29er rim is 622mm in diameter
27.5" rim is 584mm in diameter
difference between rim diameters is 38mm
difference between rim radii is half of 38mm, or 19mm

so, if you were to mount tires w the same heights as your current 29er tires, on the smaller 27.5" rim, then your BB height would drop by 19mm (ie, the difference in rim radii between the two wheel sizes)

if you are mounting 27.5+ tires that are presumably taller than your current 29er tires, then your new BB height would be less than this 19mm difference, and would be raised up by the taller 27.5+ tire.

the increased 27.5+ tire height compared to your current 29er rim and tire combo obviously depends on your 27.5+ tire and rim choice

 

[blidner]

11 9 simus

Fatlab 55mm rims
Vee 27.5 x 3.25

Can't wait to ride em

 

[makersmike]

Thanks phride and slo_rider for the helpful feedback on BB height. Seems like it may be worth considering raising the fork when doing a conversion if it helps with BB height (for example, from 140 to 150 on the FSR Stumpjumper).

As suggested, it might be better to just buy the FSR 6 Fattie, but I am hesitant until the wider rim with 38mm internal is available. I was able to test ride the Fattie, and although I had a few more pedal strikes, I am comfortable with the height, just uncertain about having an even lower BB.

I have considered converting my current camber evo, but my main concern is that it's 330 BB height is even lower than the regular FSR Stumpjumper. If I go that route, I'll get some photos posted.

 

[slo_rider]

Thanks phride and slo_rider for the helpful feedback on BB height. Seems like it may be worth considering raising the fork when doing a conversion if it helps with BB height (for example, from 140 to 150 on the FSR Stumpjumper)...

sure and glad you found it helpful.

yeah, a longer travel fork (or simply a fork with a longer axle to crown length) will raise your BB a bit. you can use this geo calculator to estimate changes if you know the a2c length of the longer travel fork. based on estimates from that calculator, a 10mm increase in fork a2c length will raise your BB by about 3-4mm and slacken the head angle by about 0.5 degree.

another thing to consider would be to use eccentric shock bushings (like these) to essentially lengthen the eye to eye distance between main frame shock mount and swingarm shock mount (still using the stock shock), which would raise the BB a few mm (as well as steepen both head and seat tube angles). the steepening effect would offset the slackening effect from a longer fork, and help preserve the bike's original geo--good if you liked the original geo, less good if you wanted a slacker HA from a longer fork:

 

[bikeny]

hmmm, let me give him another mail...

cost wise any alternatives to derby for 27.5+ 45mm? (yea non-carbon)

I'm not sure about aluminum, but most of the Chinese carbon rims can be had with 36h drilling.

 

[makersmike]

Thanks slo_rider, great information on options for adjusting geometry, if necessary!

 

[LI-MTB]

Dustyduke22 , quick question. I am planning on following your lead and building up a Yelli Screamy for 27.5+. Is the 2014 frame compatible?


Sent from the interwebz.

 

[makersmike]

Camber Evo setup, Ibis 741, WTB Trail Boss 3.0 and TB 2.8

Just got my 2014 Camber Evo set up yesterday with Trail Boss 3.0 front, and Trailblazer 2.8 rear, on Ibis 741 rims. Bottom bracket is about 10mm lower at 321, at 15 psi. Clearance is very good in the rear, and adequate upfront with about 3mm each side.

On a short 7 mile, 1000 ft climb ride. I was expecting the ride to be smooth and fun, and was not disappointed. What surprised me was how fast it was with the big tires, and I might end up faster on both climbs and descents than with my 29" wheels. I broke PRs on a mile long flowy singletrack as well as a short road climb back to my house. Looking forward to riding some more.

 

[NH Mtbiker]

11 9 simus

Fatlab 55mm rims
Vee 27.5 x 3.25

Can't wait to ride em

Nice setup. Look alot like my wheels, but have em at 150mm front and 197mm rear!

 

[blidner]

Nice taste in wheels NH

I only have a few rides on them but I am enjoying

 

[milly109]

I know this was already asked awhile ago, but has anyone tried to put a plus setup on a chromag surface, or root down? Im hoping to build up a root down over the winter.

I contacted Chromag and they said they don't recommend it as the rear wheel didn't have enough horizontal movement, but they were using a 52mm rim, so I'm curious if anyone has tried this?

 

[GTR-33]

On a short 7 mile, 1000 ft climb ride. I was expecting the ride to be smooth and fun, and was not disappointed. What surprised me was how fast it was with the big tires, and I might end up faster on both climbs and descents than with my 29" wheels.

I'm sure I'm fudging the numbers but IIRC Schwalbe tested the 27.5x2.8 at something like +6% rolling resistance over 29x2.35 but +25% more contact patch. Traction + confidence = speed.

 

[nitrousjunky]

I know this was already asked awhile ago, but has anyone tried to put a plus setup on a chromag surface, or root down? Im hoping to build up a root down over the winter.

I contacted Chromag and they said they don't recommend it as the rear wheel didn't have enough horizontal movement, but they were using a 52mm rim, so I'm curious if anyone has tried this?

I've been kinda curious there too. As long as there is tire clearance, it would be ideal IMHO. BB height would still be in a good range on one of those.

 

[Carbonegear]

Lynskey PRO29 1/2 a fatty fits fine

This bike rides like a champ. Totally new ball game- she is fast and nimble. The 2.8's are great- the sidewalls are a huge issue and hopefully the Nobby Nic's will solve that issue in the coming days. The drivetrain is flawless and it is a blast to ride- Short wheel base and stock 29 parts.

 

[LinkyPinky87]

Anyone tried the maxxas chronicle 27.5x3.00?

 

[bikeny]

Anyone tried the maxxas chronicle 27.5x3.00?

Lots of people have, might want to check out the 27.5+ tire thread.

 

[LyNx]

Tried the 29er version, was not too impressed with it to tell the truth and mine was a proto test tyre I was given alongside a CST BFT proto, so no monetary reason to feel obligated to like it - lots of self steer at good, low pressures, if you don't want that have to bump the pressure up past what I thought was ideal for actual trail use. BFT on the other hand is fantastic, lots less self steer at good pressures, rolls well and traction is just amazing, only downside, despite being announced, can't seem to see it on their web site or anywhere to buy retail.

Anyone tried the maxxas chronicle 27.5x3.00?

 

[LinkyPinky87]

Iv'e only seen the maxxis plus sized tyres on ebay. For Aus its "woolworths/bigW" click and collect (big supermarket chains)

Cheers for the heads up. Will keep looking and reading

 

[ticketchecker]

Hey Everyone!

What I would like to accomplish by this thread is a central place for guys and gals to post what rim and B+ tire options they are running on their standard 29er bikes.

I know there is a lot of pics and posts out there concerning B+ platform compatibility, so lets get it all in one place.

Please include pics of your setup.

I will start off.

I have successfully run the 650b Velocity Blunt 35 rims with TrailBlazer 2.8 tires on my Kona Process 111.

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And I am currently running the WTB Scraper i45 rim with the TrailBlazer 2.8 tires on my Canfield Yelli Screamy.

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This one with a Fox 36

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And most recently, my Santa Cruz Heckler set up B+

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And finally, the Canfield Brothers Riot

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Please post your setups! If you can include measurements and clearance pictures, it would be even better

How much room you got in that Heckler rear end? Thinking about doing this to a Bantam frame but the chainstay is listed at 4mm shorter

 

[dustyduke22]

How much room you got in that Heckler rear end? Thinking about doing this to a Bantam frame but the chainstay is listed at 4mm shorter

Tons of room. I could probably fit a 3 inch tire and be fine.