Determining compatible tire sizes
09-25-09 | 02:22 PM
#1
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Determining compatible tire sizes
Hi, I'm trying to find out the maximum tire size i can use. I have Alex PRD-15 rims and can't find specs on them. they came with 700cx25 tires. Looking on Sheldon Brown's page, it seems that most rims that will take a 25 can take a 28 as well, which is the size I want. can anyone confirm / deny? Also, what is the most accurate way to measure clearances? The bike is a Fuji Newest 3.0 54cm, if that helps any. Thanks.
09-25-09 | 02:32 PM
#2
Thrifty Bill
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Most accurate way is to spend about $10 and get a digital micrometer. On your other question, few of us would argue with Sheldon.
09-25-09 | 02:50 PM
#3
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From: A Coffin Called Earth. or Toronto, ON
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digital or analogue caliper.
if you measure on the outside of the rim, which is inaccurate, you subtract by 5.5mm, which gives you a rough size on inner rim width.
so say you get 20mm outside width rim, then you have an ETRO 622x15mm rim.
15mm rims can go from 23mm to 38mm
if you measure on the outside of the rim, which is inaccurate, you subtract by 5.5mm, which gives you a rough size on inner rim width.
so say you get 20mm outside width rim, then you have an ETRO 622x15mm rim.
15mm rims can go from 23mm to 38mm
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09-25-09 | 03:09 PM
#5
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I haven't run into a rim on a lightweight that can't take a 28. S.Brown's page indicates that and he adds the bit about individuals going beyond...
A digital caliper shouldn't be nec., not that critical. Tire help desks will know off the bat and should agree. It's a popular bike, the wheels are commonly found
A digital caliper shouldn't be nec., not that critical. Tire help desks will know off the bat and should agree. It's a popular bike, the wheels are commonly found
09-25-09 | 08:54 PM
#6
Bianchi Goddess
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WHAT? calipers to check tires? OMG are we that critical? you are only talking 3 millimeters difference. I would say you have a 99.99999% chance that they will fit. my first real bike came with 700x20 tires and I have run 700x 38 cross tires on it.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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09-25-09 | 10:04 PM
#7
Insane Bicycle Mechanic
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OP: I usually eyeball tire clearance. It's best to leave at least a couple millimeters since trapped debris can get jammed between the tire and fork. This is either annoying or dangerous, depending on the nature of the debris.
Remember that tire sizes are not always honest. You might be able to fit one manufacturer's 700x28C but not another's.
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09-25-09 | 11:50 PM
#8
cab horn
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Jesus ****ing christ people. 25 to 28 doesn't require a caliper. Jesus ****ing christ. It'll work if 25 isn't tight on the frame/brakes already clearance wise. Rim is not a problem.
09-26-09 | 03:20 AM
#9
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09-26-09 | 04:33 PM
#10
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From: San Antonio, TX
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Thanks everyone. Looking closely at the rim, in tiny print, is the marking "622x16" and the frame looks like it'll fit fine. Hope everyone's having a good weekend.
