Wednesday, May 30, 2012

Tarmac tire clearance

Mostly in the vein of playing around, and "why not?", combined with a stellar deal on some German tires, I decided to get some fat clinchers.   If you've ever wondered how much tire clearance a 2012 Tarmac SL3 actually has, and how big some of these tires actually are, he ya go.

All the following were brand new tires, mounted on Easton EA90SL clinchers with a 20mm external rim width (15mm internal).   I measured the width at several points around the tire with a set of calipers, the width varied between 0.10 and 0.30 mm, probably related to imperfect rubber, and the fact that I just unfolded them from their packaging.

Tire Advertised Width Measured Width
Specialized Turbo Comp 23 mm 23.8 mm
Continental GP 4000s 23 mm 23.8 mm
Continental GP 4000s 25 mm 25.4 mm
Schwalbe ZX 25 mm 24.3 mm
Schwalbe ZX 28 mm ~28 mm

My calipers maxed out at about 27 mm, so the 28mm is an estimate, but they appeared to be very close to the advertised 28mm.

I can't say I noticed any speed differences, just probably too small and too hard to tell, but the 28mm tire sure was fun.  Besides being comfortable, the biggest improvement seemed to be in fast twisty descents, with poor pavement.   With a 28mm in the rear, and a 25mm tire in the front, the bike just hugged the road better, and I felt much more confident at higher speeds.  Where the skinnier tires got skittish, the 28mm held firm.  It felt more like "carving" down the mountain.

As for tire clearance, there are still a couple of mm of room, the tightest place is around the chain stays, but that no issues there.  I only tried the 28mm in the back, not in the front.





Fat tires are fun, give them a try.

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