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Tire size front & back

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Tire size front & back

Old 03-01-20, 09:00 PM
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rower2cyclist
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Tire size front & back

I need some help with picking my next pair of tires. Currently, I run S-works Turbo Hell of the North (these are 28mm for the unfamiliar) on my Giant TCR stock SLR 1 wheelset. I am wondering if it makes sense to go different sizing for front and back. I read some use narrower in the front for aero gains. Is it worth taking that route or should I just keep them 28mm for both?
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Old 03-01-20, 09:08 PM
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I've been running 23/25, and 23/27, and happy with it.

Narrower front tire is close to the width of the rim, same pressure front & rear effectively gives higher pressure in the rear where needed,

and a bigger rear tire wears better.
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Old 03-01-20, 11:47 PM
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Aerodynamics is complicated. Tires that are sized appropriately for their rims will get you bigger aero gains than just using a smaller front. Either way at recreational speeds any aero gains from tires won't be as much as the difference in rolling resistance between good and bad ones.

If you need 28s for comfort or grip, keep using them. If you want your bike to ride harsher, switch to 25s or even 23s and blow then up to 120 psi.
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Old 03-01-20, 11:58 PM
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A 23 in the front will probably match the PR-2 for aerodynamics reasonably well, as that wheel is 23mm wide (ext) and most tubeless 23s will mount to 24 or 25 wide on that width wheel.

My wheels are 18.5mm internal (25mm external,) and the two different 23s I've tried have both mounted to spot-on 25mm wide.

I've noticed absolutely no difference in road feel going down in size on the front tire, but I also absolutely did not pick up some 23s to chase marginal gains-- 23s are a dying breed, and can often be had on clearance on the cheap.

I picked up a Maxxis Padrone and an IRC Roadlite for a combined $33.
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Old 03-02-20, 08:27 AM
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If your front tire isn't going to measure less than 23mm to optimize aero, might as well keep it at 28 for the grip/comfort.
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Old 03-02-20, 08:38 AM
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I think nobody in their right mind would tell you to go with the narrow rear.

If you donít have a deep-ish front wheel (like 40mm+) then there is very, very little point in going with the narrower tire up front. May as well reap the comfort, grip and wear benefits of a wider tire.

But if Iím being honest... this is so nitpicky. What really matters is whatís gonna make you get stoked to ride in this case. The rest is nearly negligible. So just do what makes you happy.
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Old 03-02-20, 10:05 AM
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Thanks everyone. I think I will stick to 28mm tires and will give GP5000s a try this time.
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Old 03-02-20, 10:17 AM
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Originally Posted by rower2cyclist View Post
Thanks everyone. I think I will stick to 28mm tires and will give GP5000s a try this time.
Great tires, love mine! On my fourth set, 25's and 28's, they've been fantastic.
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Old 03-02-20, 10:24 AM
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The latest aerodynamic research is fascinating, but remember that people managed to go fast on box-section rims back in the day...
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Old 03-02-20, 01:23 PM
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I like the same size front and rear for the grip and comfort. I run 25mm Michelin Pro4s front and back; they caliper out to 28mm on Dura Ace C24 wheels. I had 23mm Pro4s before and I I'm going as fast or faster on the 25mm ones and I have great comfort on the 25mm, too.
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Old 03-02-20, 03:41 PM
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Originally Posted by ThermionicScott View Post
The latest aerodynamic research is fascinating, but remember that people managed to go fast on box-section rims back in the day...
Not against other people with deep rims.
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Old 03-02-20, 03:49 PM
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Originally Posted by smashndash View Post
Not against other people with deep rims.
Probably why they're all on deep rims now.
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Old 03-02-20, 03:57 PM
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Originally Posted by ThermionicScott View Post
The latest aerodynamic research is fascinating, but remember that people managed to go fast on box-section rims back in the day...
Taking my stock wheelset, vs the 50mm wheelset I'm moving to, and looking at my recent road race, a couple of things stand out. The gains during average race speeds will probably be around 10w, not earth shattering, but not insignificant either (some would say negligible in a pack, but def helps when you're up front). But what really hit me was when I looked at the test results for 50kmh. My first thought was, that doesn't apply to me, I can't hold that speed for any amount of time. Then I realized that I was sprinting at that speed at the end of the race, and the difference then is about 30w.
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Old 03-02-20, 04:25 PM
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Originally Posted by Rides4Beer View Post
Taking my stock wheelset, vs the 50mm wheelset I'm moving to, and looking at my recent road race, a couple of things stand out. The gains during average race speeds will probably be around 10w, not earth shattering, but not insignificant either (some would say negligible in a pack, but def helps when you're up front). But what really hit me was when I looked at the test results for 50kmh. My first thought was, that doesn't apply to me, I can't hold that speed for any amount of time. Then I realized that I was sprinting at that speed at the end of the race, and the difference then is about 30w.
As a faster rider, I can tell you that those extra 30W are nothing to scoff at. If I could pay $2000 to gain 30W on my FTP (legally), I'd pay it in a heartbeat.
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Old 03-02-20, 04:59 PM
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Originally Posted by smashndash View Post
Not against other people with deep rims.
Deep rims didn't always exist. But you're determined to miss my point anyway, so I won't argue.
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Old 03-02-20, 05:12 PM
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If you're not rotating front to back how long are you willing to run on a front that is not going to wear out before it becomes a liability.
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