Bottom brackets, Road/Mountain
06-03-23 | 06:16 PM
#1
Thread Starter
Senior Member
Joined: Aug 2007
Posts: 1,761
Likes: 1,546
From: Ouest Seattle
Bikes: Mercian King of Mercia, Surly Long Haul Trucker,81 Fuji Gran Tour SE, 83 Fuji S12S LTD, Voyageur 11.8 chrome, , Voyageur 11.8
Bottom brackets, Road/Mountain
I have a Sugino triple I want to use for a build. I see Sugino suggests 110 BB vs 113 BB for road vs mountain. Why the difference on the two? Inner chainring clearance?
06-03-23 | 07:11 PM
#4
Really Old Senior Member
Joined: Feb 2007
Posts: 14,685
Likes: 1,921
From: Mid Willamette Valley, Orygun
Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3
Don't be too obsessive about CL.
It presumes you use all cogs & rings an equal amount and gives the best "average" CL.
That may work for robots.
I tend to use the middle ring & outer cogs the most.
I use the next longer BB to give me a best average CL for the gears I use the most.
It presumes you use all cogs & rings an equal amount and gives the best "average" CL.
That may work for robots.
I tend to use the middle ring & outer cogs the most.
I use the next longer BB to give me a best average CL for the gears I use the most.
06-03-23 | 09:08 PM
#5
Senior Member
Joined: Apr 2011
Posts: 12,791
Likes: 4,890
06-04-23 | 06:35 AM
#6
Old fart
Joined: Nov 2004
Posts: 26,411
Likes: 5,350
From: Appleton WI
Bikes: Several, mostly not name brands.
Off-road frames often have curved chainstays to accommodate wider tires, and need the crank arms positioned further out to clear the stays.
06-04-23 | 09:32 AM
#7
Mad bike riding scientist
Joined: Nov 2004
Posts: 29,210
Likes: 6,286
From: Denver, CO
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
It depends on the crank design. While mountain bike frames are wider, some mountain bike cranks use narrower spindles than road bike because the arms curve inward towards the frame more than road cranks do. For the Sugino cranks in question, the recommendations are correct but they might not be for other cranks.
__________________
Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
06-04-23 | 11:40 AM
#8
Senior Member
Joined: Apr 2011
Posts: 12,791
Likes: 4,890
Yabut…
It depends on the crank design. While mountain bike frames are wider, some mountain bike cranks use narrower spindles than road bike because the arms curve inward towards the frame more than road cranks do. For the Sugino cranks in question, the recommendations are correct but they might not be for other cranks.
It depends on the crank design. While mountain bike frames are wider, some mountain bike cranks use narrower spindles than road bike because the arms curve inward towards the frame more than road cranks do. For the Sugino cranks in question, the recommendations are correct but they might not be for other cranks.
06-04-23 | 11:47 AM
#9
Senior Member
Joined: Jul 2015
Posts: 7,498
Likes: 3,301
From: NW Oregon
Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike
Yabut…
It depends on the crank design. While mountain bike frames are wider, some mountain bike cranks use narrower spindles than road bike because the arms curve inward towards the frame more than road cranks do. For the Sugino cranks in question, the recommendations are correct but they might not be for other cranks.
It depends on the crank design. While mountain bike frames are wider, some mountain bike cranks use narrower spindles than road bike because the arms curve inward towards the frame more than road cranks do. For the Sugino cranks in question, the recommendations are correct but they might not be for other cranks.
care to present an example of these mysterious reverse curving MTB cranks, Cyco? the ones i've seen/installed/stock all "curve" outward, then go parallel to the main frame line before reaching the pedal threads.... not one "curves" in.. not one. except a badly bent 105 crankset that already went to the scrap heap.... someone parked a Buick on top of that bike...
Last edited by maddog34; 06-04-23 at 11:56 AM.
06-04-23 | 11:55 AM
#10
Mad bike riding scientist
Joined: Nov 2004
Posts: 29,210
Likes: 6,286
From: Denver, CO
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
Because there is no such thing as a “designated spindle” when it comes to internal bearing bottom brackets.
__________________
Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
06-04-23 | 12:10 PM
#11
Senior Member
Joined: Apr 2011
Posts: 12,791
Likes: 4,890
