Anyone know the max tire width for Specialized Fuse 27.5+? Will 3.5s fit?
Thx
Thx
Specialized fuse max tire width?
Blue Sugar
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Anyone know the max tire width for Specialized Fuse 27.5+? Will 3.5s fit?
Thx
Thx
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944 Posts
I estimate that the max true width of a rear tire you could safely use on a Fuse is about 3.2".
The picture below shows a Ground Control 3.0 tire inflated to 15psi on a 38mm internal width rim. The tire measures 76mm wide (3.0") at the knobs There is approximately 6mm clearance on the drive side and 8mm on the non-drive side, the difference being due to the chainstay protector on the drive side. A true 3.2" wide tire would be 81mm wide which reduces the drive side clearance to 3.5mm which is cutting it pretty close!
![Image]()
Note that the lower chain also sits close to the tire in low gear. There is ~6mm clearance using a chainring with a 3mm inward offset. A non-offset chainring would give a bit more room, but the lower chain stay would remain a limiting factor.
The Rockshox fork on my Fuse Pro provides a bit more clearance: 8mm on each side of the Purgatory knobs (76mm, 3.0"), 92mm total, and over 20mm to the fork brace. You could get away with a 3.3" wide tire on the front, but a true 3.5" (89mm) tire would be asking for trouble.
The Stumpy 6Fattie has more rear tire clearance, 10mm on each side of a 3.0 Ground Control (75mm wide on a 29mm ID rim) so ~95mm overall. A 3.5" wide tire would have ~3mm on each side.
FYI, the chainstays on the new Santa Cruz Hightower 29/27.5+ are even more limiting. I mounted my rear Fuse wheel on one at a LBS and there was less than 3mm clearance on the drive side chainstay. Again, this was due to the chainguard - there was almost 6mm clearance on the non-drive side. This is one reason Santa Cruz has spec'd narrower 2.8" 27.5+ tires for the Hightower (they say a 2.8" tire gives "optimal performance"). I would not run a true 3.0 rear tire on the Hightower.
The picture below shows a Ground Control 3.0 tire inflated to 15psi on a 38mm internal width rim. The tire measures 76mm wide (3.0") at the knobs There is approximately 6mm clearance on the drive side and 8mm on the non-drive side, the difference being due to the chainstay protector on the drive side. A true 3.2" wide tire would be 81mm wide which reduces the drive side clearance to 3.5mm which is cutting it pretty close!
Note that the lower chain also sits close to the tire in low gear. There is ~6mm clearance using a chainring with a 3mm inward offset. A non-offset chainring would give a bit more room, but the lower chain stay would remain a limiting factor.
The Rockshox fork on my Fuse Pro provides a bit more clearance: 8mm on each side of the Purgatory knobs (76mm, 3.0"), 92mm total, and over 20mm to the fork brace. You could get away with a 3.3" wide tire on the front, but a true 3.5" (89mm) tire would be asking for trouble.
The Stumpy 6Fattie has more rear tire clearance, 10mm on each side of a 3.0 Ground Control (75mm wide on a 29mm ID rim) so ~95mm overall. A 3.5" wide tire would have ~3mm on each side.
FYI, the chainstays on the new Santa Cruz Hightower 29/27.5+ are even more limiting. I mounted my rear Fuse wheel on one at a LBS and there was less than 3mm clearance on the drive side chainstay. Again, this was due to the chainguard - there was almost 6mm clearance on the non-drive side. This is one reason Santa Cruz has spec'd narrower 2.8" 27.5+ tires for the Hightower (they say a 2.8" tire gives "optimal performance"). I would not run a true 3.0 rear tire on the Hightower.
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297 Posts
nice levity! very informative.
That is a 2020 frame.
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