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GP5k vs GPTT
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Time for some new race tires. I usually run a pair GPTT (23) on an 858/Super9 combo with Vittoria latex. They are race day only wheels/tires, never had a flat but I do replace a tire any time I see a cut, etc, so they don't get that many miles on them. The TT's don't seem to make it far before showing some sort of damage. Figured with all the praises and data on the GP5k I would give it a shot on the front for the aero advantage and a little extra flat protection, since the data seems to show that up front you aren't giving up much over a GPTT. I read that the 5k is narrow but I when mounted up a 5k 23 on the 858 and it just seems maybe a little too narrow? The wheel (at the brake track) is slightly wider than the max width of the tire at 95PSI. As you can see from a straight on view the leading edge of the brake track is exposed (more than the photos show... terrible photos :-/.) Not sure if I should try a 25 (guessing too wide) or go back to the GPTT up front. Or maybe this is exactly how you want set up? Yes, overthinking things:).. but I am bored.






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Team Zoot
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Re: GP5k vs GPTT [gregtay] [ In reply to ]
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Have you given it time to stretch? My GP tires often grow a little after initial mounting.
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Re: GP5k vs GPTT [rijndael] [ In reply to ]
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they sat overnight without change. If they did strech a little it wouldn't be enough. I very curious how a GP5k 23 would look on an 808 as I think it would be even more of a difference in width. The 858 is a decently narrow rim.

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Team Zoot
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Re: GP5k vs GPTT [gregtay] [ In reply to ]
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Isn’t that what you want with the rule of 105%? Where the width of rim is wider than tire? I guess that doesn’t mean brake track necessarily but same idea. I know most wheel widest point isn’t the brake track. Guess I never looked straight in to notice. I do measure all my tire widths and compare to rim width to check for 105 compliance.
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Re: GP5k vs GPTT [gregtay] [ In reply to ]
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The profile of a tire isn't really an optimal leading edge for an airfoil so I would guess the air is trying separate from the tire above the rim area. Having the rim be wider with that small edge is probably better than having a wider tire.
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Re: GP5k vs GPTT [grumpier.mike] [ In reply to ]
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Yep, tire slightly narrower than the brake track is best for aero... usually.
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