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tire sizes
#1
I need to replace the tires on my Specialized commuter bike- currently using 700x32; am I locked into tires of only this size? If not, what is the range of sizes I can choose from and still have them fit my rims?
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#2
(12-30-2021, 10:18 AM)pwrplay99 Wrote:  I need to replace the tires on my Specialized commuter bike- currently using 700x32; am I locked into tires of only this size? If not, what is the range of sizes I can choose from and still have them fit my rims?

Aside from frame and fork (caliper brakes and fenders if applicable) clearance you should only go about 1.5 to 2 times the inner rim width generally speaking (I have gone narrower than 1.5 inner rim width with high pressure tires [+120psi]; ran 18mm tires on a 13mm rim at 140psi). It may depend on the actual tire design, rim, and/or what type of riding and terrain. You should be able to contact both the rim and tire manufacturers to get their best recommendations as to the minimum and maximum size limits. The size you are "locked into" is the 700 (622 ETRTO) (diameter), but not the width.
Take care,
Jesper

"I am become Death, the destroyer of bicycles." NJS
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#3
Potentially yes.

I just had an issue with the wheels that came with my GT Transeo. I had attempted to install 25c tires, but the rim doesn't accept them and there was issues with even inflation of the tire and innertube integrity.

I looked into a guide for the rim width and it said that my wheels were "compatible" with 30c at the lowest, but optimal performance begins at 32c. I would guess based on what you're saying that your rims are the same.

Measure your internal width and check a visual guide to know for sure.

I decided myself that even though I could get a 30c tire, that I would get a 32c instead for the optimal performance. I don't like having issues when I'm riding. I'm going to be trying out the Pirelli P7 Sport.
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#4
(12-30-2021, 09:40 PM)ReapThaWhirlwind Wrote:  Potentially yes.

I just had an issue with the wheels that came with my GT Transeo. I had attempted to install 25c tires, but the rim doesn't accept them and there were issues with inflation of the tire and innertube integrity.

I looked into a guide for the rim width and it said that my wheels were "compatible" with 30c at the lowest, but optimal performance begins at 32c. I would guess based on what you're saying that your rims are the same.

Measure your internal width and check a visual guide to know for sure.

I decided myself that even though I could get a 30c tire, that I would get a 32c instead for the optimal performance. I don't like having issues when I'm riding. I'm going to be trying out the Pirelli P7 Sport.

I am curious as to what your inner rim width was. Do you know?

As in most cases, the manufacturer's spec's (tires and rims) should be followed to ensure safety and performance, but they generally have built a little +/- leeway into their tolerances. Again, type of use can even make manufacturer's spec's inappropriate if using in extreme conditions. There is also an ongoing problem (though not as bad as 30-40 years ago and earlier) with tires (mostly), and rims (rarely) not actually meeting the required standardized defined dimensions. Fortunately, this usually only occurs on cheaper equipment. I have had issues with tires not fitting a quality rim even though they were of the "proper" size. Nothing is guaranteed 100%.
Take care,
Jesper

"I am become Death, the destroyer of bicycles." NJS
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#5
It's about 20mm, which I just checked again, and it says I could use 28c (compatible) but 30c is where [optimal performance] starts.

But I don't feel comfortable with 28c really (just a 3mm difference) after what happened at 25c.

I used WTB's chart.

https://www.wtb.com/pages/tire-rim-fit-chart#
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#6
(01-02-2022, 01:13 AM)ReapThaWhirlwind Wrote:  It's about 20mm, which I just checked again, and it says I could use 28c (compatible) but 30c is where [optimal performance] starts.

But I don't feel comfortable with 28c really (just a 3mm difference) after what happened at 25c.

I used WTB's chart.

https://www.wtb.com/pages/tire-rim-fit-chart#

I would certainly agree with the 30mm tire for 20mm rim. It follows the 1.5 x width general rule. 28mm would be the minimal width at best; 25mm way too small in any case. I'm usually running 13mm to 15mm rims with 23/25mm (120psi+) to 28mm (100-110psi) tires.
Take care,
Jesper

"I am become Death, the destroyer of bicycles." NJS
  Reply


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