Tire Pressure Recommendations?
10-26-20, 12:11 AM
#26
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Me and my heavyweight tour bike is 290+ lbs, only 5 lbs diff front/ back, just the bike. My SMP 35s are pumped to 70F/ 72R.
I let them sag 5 or 6 lbs for a few days.
I also have 38s x 584, that is about 225 lbs as ridden. They are 60F/ 62 R. Still rides pretty stiff.
I let them sag 5 or 6 lbs for a few days.
I also have 38s x 584, that is about 225 lbs as ridden. They are 60F/ 62 R. Still rides pretty stiff.
10-26-20, 05:53 AM
#27
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10-26-20, 07:01 AM
#28
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Here is a recommended table copied from Thorn. The max tire pressure is often determined by rim, not the tire. Wide tires can cause rims to split at the spoke line over time if overinflated.
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10-26-20, 09:02 AM
#29
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Sure, its a guide, but it aint accurate if its a 100lb rider with no panniers or a 220lb rider with 75lbs of stuff also....in fact, looking at it, for three of tire sizes that I use, the recomended pressures are pretty close to what I run when loaded up (but certainly not with just me on the bike---so maybe this is a "loaded touring bike chart"
Is it?
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10-26-20, 09:25 AM
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Thorn's strength is in loaded touring bikes, so I expect these recommendations are with loaded bikes in mind. However, many people are unaware that the maximum tire pressure stamped on the tire is not necessarily appropriate, because it may exceed the capabilities of their rim. This is especially true as tire width increases. Force on rim = Pressure x Area. For the same tire pressure, the increased Area of a wider tire can increase force to unacceptable levels for the rim, eventually causing rim to split. Rim manufactures usually do not post such numbers, so at least this table gives some guidelines.
10-26-20, 10:29 AM
#31
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Thorn's strength is in loaded touring bikes, so I expect these recommendations are with loaded bikes in mind. However, many people are unaware that the maximum tire pressure stamped on the tire is not necessarily appropriate, because it may exceed the capabilities of their rim. This is especially true as tire width increases. Force on rim = Pressure x Area. For the same tire pressure, the increased Area of a wider tire can increase force to unacceptable levels for the rim, eventually causing rim to split. Rim manufactures usually do not post such numbers, so at least this table gives some guidelines.
Some rims carry a rating, the photo is from my 16 year old A719 rim.
