How close in size (overall height) is a 27.5 plus tire, say a 2.8" on a 35mm rim, to a 29er: arguments sake lets say a 2.35" on a Stans Flow ex? I know there are many variables to consider, just looking for an approximation if they are close? Thanks!
27.5+ tire height
tatuowen
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Seems BB heights are all over the board with the different tire sizes and frame designs. It doesn't appear that a switch from 29 to 27.5+ equals a huge drop in BB height. Here are some figures I dug up from the manufacturers:
Specialized Stumpjumper 29 = 336mm
Specialized Stumpjumper 650b = 335mm
Specialized Stumpjumper 6fattie = 331mm
Cannondale Habit 27.5 = 334mm
Cannondale Bad Habit 27.5+ = 334mm
Cannondale Scalpel 29 = 332mm
Cannondale Jeckyll 27.5 = 364mm
Cannondale Trigger 27.5 = 351mm
Santa Cruz Hightower 29 = 337mm
Santa Cruz Hightower 27.5+ = 335mm
Trek Fuel EX 29 = 334mm
Trek Fuel EX 27.5 = 333mm
Specialized Stumpjumper 29 = 336mm
Specialized Stumpjumper 650b = 335mm
Specialized Stumpjumper 6fattie = 331mm
Cannondale Habit 27.5 = 334mm
Cannondale Bad Habit 27.5+ = 334mm
Cannondale Scalpel 29 = 332mm
Cannondale Jeckyll 27.5 = 364mm
Cannondale Trigger 27.5 = 351mm
Santa Cruz Hightower 29 = 337mm
Santa Cruz Hightower 27.5+ = 335mm
Trek Fuel EX 29 = 334mm
Trek Fuel EX 27.5 = 333mm
Depends if your putting a 150 lb person or 225 lb person on 15 psi.
G
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·not much in it to squak about.
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I think you misunderstood the OP. We are talking about converting an existing 29er, not BB height in general, which does vary a ton based on intended usage, crank length, suspension design/sag, etc. 10mm is a huge change in BB height that can potentially cause you big problems when riding.
-Walt
Understood. Was just putting out some numbers for reference.
Although in the case of the hightower that uses the same exact frame for 29 and 27.5+, the switch from 29 to 27.5+ only results in a 2mm drop in BB height. Obviously that's affected by the choice of tires used.
Although in the case of the hightower that uses the same exact frame for 29 and 27.5+, the switch from 29 to 27.5+ only results in a 2mm drop in BB height. Obviously that's affected by the choice of tires used.
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Same frame... sorta.
Santa Cruz Hightower review review - BikeRadar USA
"Flipping this chip in the shock and swapping the 140mm fork for a 150mm fork preserve the Hightowers geometry."
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One may assume that in order to get the equal height with 29er tyres on 27.5 + one needs almost real 27.5x3.5". Such a frame would be fully swappable between a 29er and 27.5+ I guess.
Is Santa Cruz Hightower is the closest?
Is Santa Cruz Hightower is the closest?
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^^x2
Once you start hitting 3.5" tires were into fat bike territory.
But again things very so much just on the tires your comparing.
Example: most of what I read was a 29" 2.3-2.3 tire and a 26x 4.7 tire are the same diameter give or take a couple mm.
But that's off. My bontrager 29" tires, 2.2 or 2.3 are about the same as my 3.8/4.0 Surly Nate's. My 4.7 tire on the front is quiet a bit taller.
So my difference converting to b+ will be different than the next person.
Seems to me that b+ is making 27.5 tires wider, but not that much taller than a normal tire.
Right now im trying to decide on wheels to build up for b+. But I welcome a tad lower bb height.
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Once you start hitting 3.5" tires were into fat bike territory.
But again things very so much just on the tires your comparing.
Example: most of what I read was a 29" 2.3-2.3 tire and a 26x 4.7 tire are the same diameter give or take a couple mm.
But that's off. My bontrager 29" tires, 2.2 or 2.3 are about the same as my 3.8/4.0 Surly Nate's. My 4.7 tire on the front is quiet a bit taller.
So my difference converting to b+ will be different than the next person.
Seems to me that b+ is making 27.5 tires wider, but not that much taller than a normal tire.
Right now im trying to decide on wheels to build up for b+. But I welcome a tad lower bb height.
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I'm not sure where you saw that 29x2.3 and 26x4.7 are the same height. Everything I've seen suggests 26x4.8 and 29x3 are about the same height. I've also read that 26x4.0, 27.5x3, and 29x2.2ish are about the same height. Those seem to be pretty accurate, except that the 27.5 needs to be bigger, like 3.25 to 3.5 to match up. This will of course vary depending on the exact tire and the rims as well.
Also, any time a tire gets wider it will also get taller, no way around that.
G
Guest
·indeed.
my findings as well
yup, hence the + size rim movement to accommodate.
mine will be i35 spank oozy 395+ trail for B+ wheelset. Curious to see how the ikon & rekon 2.8 measure.
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See how, graphically, they continue to insist that 29 = 27.5+, when in the "Outer diameter" note, there is a discrepancy of ~3/4" - which falls right into my prior posting that the 27.5+ axle is ~3/8" lower than the 29er. This is the reality of it. They are not the same size. They are not really interchangeable.
-F
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Actually a tire can get wider and not get taller. Tire diameter is not a function of anything except manufacturing specifications. A tire can be made to have the exact same inflated diameter whether it's 1" wide or 5" wide.
It's just what happens when they design tires. Bigger all around when they go wider in many cases.
Been reading a thread that mentioned 26" vs 27.5 fat tires. The 27.5 versions have less sidewall in an attempt to maintain overall diameter. And it's catching on it seems, according to those that have both are saying the "lower volume" 27.5 fat tires have several points of superiority due to the smaller diameter/sidewalls.
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Unless one uses 3,25-3,5"x27.5" and up from 3" is for me a plus size and those may be as tall as a typical 2,3x29" tyre. Any frame designed up to 27.5x 2,7"-2,9" makes little sense in terms of full 29er compatibility.
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anyone know if I went to a maxxis rekon (27.5 x 2.8) from the maxxis chronicle (27.5 x 3) how much my bottom bracket would drop? on 40 mm internal rims if that matters. my pony rustler is pretty low as it is, but the more aggressive treat on the rekon looks nice (and I assume the new plus high roller and minions would be same size as the rekon as well?)
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Maxxis Rekon 2.8 on a 34mm ID Derby rim has a overall diameter of 28 3/16" at 17psi. Tire has been installed on the front and ridden for a few weeks.
It has been an excellent match with a 2.4 Ardent (edit: 27.5x2.4) on the back of my Knolly Warden for summer riding. (just under 28" diameter)
It has been an excellent match with a 2.4 Ardent (edit: 27.5x2.4) on the back of my Knolly Warden for summer riding. (just under 28" diameter)
G
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·Here's the particulars on the plus wheelset I had built.
Spank Oozy 395+ trail rims (i35mm)
Schwalbe NN 2.8’s 67tpi KNOB-KNOB =68mm/ 2.7”
CASING = 67mm/2.64”
Dia = 28 3/8th
Spank Oozy 395+ trail rims (i35mm)
Schwalbe NN 2.8’s 67tpi KNOB-KNOB =68mm/ 2.7”
CASING = 67mm/2.64”
Dia = 28 3/8th
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