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Tire size question
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Greetings and happy new year, I've spent 3 days scouring the googles and my head is killing me, im finally breaking down and asking the pros here. I have a Argo18 117 tri bike. I have purchased some Reynolds AR58X carbon tubeless wheels. 19MM internal width 28mm external. I am going to run latex tubes in these wheels which will be ridden during races. I purchased Cont GP5000 25mm tires and I am wondering if I need to send them back and get 28mm or no? I did a prelim fit last night and aside from that tire refusing to mount lol I held off to ensure I dont need a 28mm tire before trying to slay the beast today. Ive seen many yes and nos and every site i go on seems to contradict the other site.

thank you for your time.
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Re: Tire size question [ToesonTheNose] [ In reply to ]
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Mounted tire width should be the same as the external rim width. The measurements given by manufacturers for tire width is not always what they actually measure when mounted.

Strava
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Re: Tire size question [ToesonTheNose] [ In reply to ]
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The problem and challenge you face is there is no standardization!

Even within a company, like Continental - their old 4000 line and their new 5000 line are sized completely differently! A 700 X 25 4000 is roughly the same as a 700 X 28 5000 etc . .

Then there is the matching of rim and tire. I get it that you want to optimize for aerodynamics - particularly on the front wheel. Makes perfect sense. I'll not argue against the numbers. But those matters, number little when you are standing on the side of the road, trying to do a quick tube change, and getting the tire back on is proving IMPOSSIBLE!


Steve Fleck @stevefleck | Blog
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Re: Tire size question [Fleck] [ In reply to ]
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So yes send them back and get 28mm or no ?
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Re: Tire size question [ToesonTheNose] [ In reply to ]
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The '25mm' GP5000 measure 28.4 on the 19mm internal rims I have here and 26.5 on 17mm internal rims, so I would not send these back for the 28mm version, or at least I wouldn't do it for the front wheel. I don't have any 28mm 5000's here to measure, but my guess would have them at 30-30.5mm install width on those rims which is fine for a rear, but too wide for the front.

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Re: Tire size question [joshatsilca] [ In reply to ]
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joshatsilca wrote:
The '25mm' GP5000 measure 28.4 on the 19mm internal rims I have here and 26.5 on 17mm internal rims, so I would not send these back for the 28mm version, or at least I wouldn't do it for the front wheel. I don't have any 28mm 5000's here to measure, but my guess would have them at 30-30.5mm install width on those rims which is fine for a rear, but too wide for the front.

Thank you so very much. Now to try and muscle these things on
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Re: Tire size question [ToesonTheNose] [ In reply to ]
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to an extent, tires will fill out in the internal rim width. So 25mm 4000s will look wider on wider rims, and narrower on narrow rims.
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Re: Tire size question [joshatsilca] [ In reply to ]
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joshatsilca wrote:
The '25mm' GP5000 measure 28.4 on the 19mm internal rims I have here and 26.5 on 17mm internal rims, so I would not send these back for the 28mm version, or at least I wouldn't do it for the front wheel. I don't have any 28mm 5000's here to measure, but my guess would have them at 30-30.5mm install width on those rims which is fine for a rear, but too wide for the front.

Josh I’m using your latex tubes and I have some orange seal here I plan on injecting before my race. You guys have a recommendation at Silca on how much to put in ?
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