New GP5000 S TR coming soon
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Might just be the 454 then.
edit: "The big change on this latest model of 404 wheels is the move to a wider, straight-side (meaning “hookless”) rim bed that’s optimized for 700x25mm tubeless tires. Unless you’re a bigger rider, by which Zipp means anyone over ~190lbs (~86kg), at which point they think you’ll be faster with a 28mm tire…either on the rear only, or both front and rear as the scale tips higher."
https://bikerumor.com/2021/06/23/rev...ctual-weights/
A 25mm tire on a 23mm rim (what I run) is freaking massive. I run 45-50psi in mine. A 28 on a 23mm rim is definitely overkill on smooth roads. At least for small guys like me
Last edited by smashndash; 10-04-21 at 04:40 PM.
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Zipp says what is optimized for 25mm?
Per 303S description on sram's site: "The key innovation is in the 303 S Series’ rim design. Its 45mm rim depth is the same as its predecessor, the 302 Disc brake. But its rim width is 2mm wider, at 27mm, and its tire bed is a full 7mm wider, at 23mm. That rim platform is designed to be the fastest with a 28mm tire."
I didn't see any ad copy on the 404 page that has any similar language.
I believe the issue is ETRTO. An inflated 25mm tire on a wide rim would probably be about ideal (105% rule) inflated width from aero perspective on a 27mm width external rim. However, ETRTO is going to hamstring manufacturers by indicating that for a 23c rim, the minimum width tire you're "allowed" to run is a 28mm. For a hookless rim, to bring the internal width down to 21mm minimum (says ETRTO), but keeping the 27mm external, they'd need a thicker bead wall.
Per 303S description on sram's site: "The key innovation is in the 303 S Series’ rim design. Its 45mm rim depth is the same as its predecessor, the 302 Disc brake. But its rim width is 2mm wider, at 27mm, and its tire bed is a full 7mm wider, at 23mm. That rim platform is designed to be the fastest with a 28mm tire."
I didn't see any ad copy on the 404 page that has any similar language.
I believe the issue is ETRTO. An inflated 25mm tire on a wide rim would probably be about ideal (105% rule) inflated width from aero perspective on a 27mm width external rim. However, ETRTO is going to hamstring manufacturers by indicating that for a 23c rim, the minimum width tire you're "allowed" to run is a 28mm. For a hookless rim, to bring the internal width down to 21mm minimum (says ETRTO), but keeping the 27mm external, they'd need a thicker bead wall.
https://bikerumor.com/2021/06/22/new...a-lot-lighter/
https://www.bikeradar.com/news/zipp-404-wheel-range/
Are you saying ETRTO doesn't allow 25mm to be used on a 23mm internal rim width? There seem to be lots of reviews out there of Zipp's 23mm internal rims mentioning or using 25mm tires.
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"optimized for 28" does not inherently mean "slower with 25". It simply means they use a 28mm tire as a reference when tuning the shape. Narrower tires tend to dominate wider ones in aero tests. Ie anything that is optimal for 28s will be even better (or at least extremely similar) for 25s.
Still, I'd be surprised to learn that 25s are faster than 28s on anything they're saying is "optimized" around 28s. 25s might be more aero, but might also have more rolling resistance and/or more vibration.
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Yes, also worth noting that when Zipp says "optimized" they're talking about more than just aerodynamics. They use the term "total system efficiency" which takes into account vibration and rolling resistance.
Still, I'd be surprised to learn that 25s are faster than 28s on anything they're saying is "optimized" around 28s. 25s might be more aero, but might also have more rolling resistance and/or more vibration.
Still, I'd be surprised to learn that 25s are faster than 28s on anything they're saying is "optimized" around 28s. 25s might be more aero, but might also have more rolling resistance and/or more vibration.
Ofc things might be slightly different IRL. But Zipp's marketing says they tested narrower tires at the same pressure and thus same contact patch size, which is nonsense.
IMO the only reason zipp is pushing wider tires is that they know tire manufacturers can't make TL tires that won't blow at the requisite higher pressures for narrow sizes on their cheaper hookless rims.
btw I'm not saying there is no benefit to large tires. The ability to run SUPER soft pressures and a larger, more square contact patch are all great things. But I don't think speed is a benefit of wider tires.
Last edited by smashndash; 10-04-21 at 05:38 PM.
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Yeah, I guess I didn't look at Zipp's website regarding the 404/454 and 25mm tire sizes, but media reviews have stated they're optimized for 25mm:
https://bikerumor.com/2021/06/22/new...a-lot-lighter/
https://www.bikeradar.com/news/zipp-404-wheel-range/
Are you saying ETRTO doesn't allow 25mm to be used on a 23mm internal rim width? There seem to be lots of reviews out there of Zipp's 23mm internal rims mentioning or using 25mm tires.
https://bikerumor.com/2021/06/22/new...a-lot-lighter/
https://www.bikeradar.com/news/zipp-404-wheel-range/
Are you saying ETRTO doesn't allow 25mm to be used on a 23mm internal rim width? There seem to be lots of reviews out there of Zipp's 23mm internal rims mentioning or using 25mm tires.
As for what is officially "allowed", and getting a real read on what is ok, there's various differing info out there. eg.
Veloflex indicates an 18mm max internal width to run a 25mm tire hookless: https://www.veloflex.it/en/blog/post...-rims-coupling
Vittoria is similar: https://www.vittoria.com/ww/en/stori...rto-bike-tires
I typically refer to some charts that Mavic used to have up, but have taken down -- it marries both width compatibility with tire pressure, which makes sense. This would tell you that 21mm is the widest TSS(hookless) rim you can use for 25mm tires, but max of ~72psi.
eg
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Yeah, supposedly not ok per ETRTO -- but this is nothing new. People have ignored ETRTO for a long time.
As for what is officially "allowed", and getting a real read on what is ok, there's various differing info out there. eg.
Veloflex indicates an 18mm max internal width to run a 25mm tire hookless: https://www.veloflex.it/en/blog/post...-rims-coupling
Vittoria is similar: https://www.vittoria.com/ww/en/stori...rto-bike-tires
I typically refer to some charts that Mavic used to have up, but have taken down -- it marries both width compatibility with tire pressure, which makes sense. This would tell you that 21mm is the widest TSS(hookless) rim you can use for 25mm tires, but max of ~72psi.
eg
As for what is officially "allowed", and getting a real read on what is ok, there's various differing info out there. eg.
Veloflex indicates an 18mm max internal width to run a 25mm tire hookless: https://www.veloflex.it/en/blog/post...-rims-coupling
Vittoria is similar: https://www.vittoria.com/ww/en/stori...rto-bike-tires
I typically refer to some charts that Mavic used to have up, but have taken down -- it marries both width compatibility with tire pressure, which makes sense. This would tell you that 21mm is the widest TSS(hookless) rim you can use for 25mm tires, but max of ~72psi.
eg
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Then again, ETRTO doesn't make sense to me on air pressure maximums. As I understand it, they say 72psi is the max for hookless regardless of road tire width. This seems to go against the basic premise that narrower tires can be inflated moreso than wider tires since there's less volume. Not sure why the rules change for hookless.
Last edited by Sy Reene; 10-05-21 at 05:58 AM.
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Yup, but more practically, who cares? Most people that buy these wheels or similar are doing so with the intent of running modern 28s or larger. Arguing about a hypothetical fringe use case is an exercise in futility (and very much a BF wintertime activity - we're not there, yet).
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Then perhaps they've just tested themselves and come away with determination that it's ok, though now they're just shying away from overtly contradicting ETRTO on their own site? For similar hookless dimensions but perhaps (?) a bit more safety margin with 25s, the enve 45s would perhaps make more sense. I think for many you'd also be fighting air pressure concerns trying to run 25s. Zipp's own tire pressure calculator errors-out for a 150lb rider with 20lb bike, meaning you also likely start choosing to inflate more than ETRTO also advises.
Then again, ETRTO doesn't make sense to me on air pressure maximums. As I understand it, they say 72psi is the max for hookless regardless of road tire width. This seems to go against the basic premise that narrower tires can be inflated moreso than wider tires since there's less volume. Not sure why the rules change for hookless.
Then again, ETRTO doesn't make sense to me on air pressure maximums. As I understand it, they say 72psi is the max for hookless regardless of road tire width. This seems to go against the basic premise that narrower tires can be inflated moreso than wider tires since there's less volume. Not sure why the rules change for hookless.
"The big change on this latest model of 404 wheels is the move to a wider, straight-side (meaning “hookless”) rim bed that’s optimized for 700x25mm tubeless tires. Unless you’re a bigger rider, by which Zipp means anyone over ~190lbs (~86kg), at which point they think you’ll be faster with a 28mm tire…either on the rear only, or both front and rear as the scale tips higher. (Check their tire pressure/size chart in the launch coverage)."
https://bikerumor.com/2021/06/23/rev...ctual-weights/
Speaking of aerodynamics, it’s worth noting that Zipp says the new 454 NSW and 404 Firecrest are both optimized for a 25 mm (printed width) tires, and if you abide by the “105% rule“, you won’t want to go any wider than 26 mm.
https://cyclingtips.com/2021/06/zipp...t-aero-wheels/
Zipp also specifically tested the 404 and 454 with a 25mm tire when developing their pressure recommendations, which are intended to provide the fastest possible setup:
“The tire pressures were set by the AXS tire pressure app,” said Zipp product manager Nathan Schickel. “Each wheel’s pressure was set according to the individual specs for the rider, wheel, and tire. Previous model 404 Firecrest and 454 NSW wheels are 19 mm internal hooked [and the rim-brake 454 NSW was 17 mm — Ed.] and the new wheels are 23 mm internal hookless. All wheels ran the Zipp RT25 tire. The older wheels were run at 77 psi front and 82 psi rear. The new wheels were run at 65 psi front and 69 psi rear, again the appropriate tire pressures for the given tire/rim system.”
https://axs.sram.com/guides/tire/pressure
This shows 150lb rider on 20lb bike, with 23mm i.d. rims, 25mm tires, standard casings, road use = 63.4psi F/67.4psi R.
For a 180lb rider it shows 68.4psi F/ 72.7psi R.
A "thin" tire casing seems to require more psi. I'm assuming the GP5000 would be considered a "standard" tire casing? Not really sure on that.
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Yup, but more practically, who cares? Most people that buy these wheels or similar are doing so with the intent of running modern 28s or larger. Arguing about a hypothetical fringe use case is an exercise in futility (and very much a BF wintertime activity - we're not there, yet).
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Oh -sorry if my posts come across as argumentative - not my intent. You're correct that in practice I am not likely to ever run anything narrower than 28mm on my own 23mm i.d. hookless rims, so it's a non-factor for me. I mostly just want to try to understand the limitations and technology involved.
The easiest explanation is this: ETRTO recommendations have always been conservative. Go back a few years and look at recommendations for tire/rim combos for regular clinchers and you'll see that it was pretty routine for users to operate outside of the recommended parameters, 'specially once players like HED started widening rims. But yeah, practically speaking, it's less likely that users would want to use combos outside of what's currently recommended. If I wanted to run 25s on my 303S (I don't), and the calculated necessary pressures looked okay, I wouldn't be too ascared about it, though.
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We might be looking at different pressure calculators.
https://axs.sram.com/guides/tire/pressure
This shows 150lb rider on 20lb bike, with 23mm i.d. rims, 25mm tires, standard casings, road use = 63.4psi F/67.4psi R.
For a 180lb rider it shows 68.4psi F/ 72.7psi R.
A "thin" tire casing seems to require more psi. I'm assuming the GP5000 would be considered a "standard" tire casing? Not really sure on that.
Yeah, it's kinda kludgy the whole tire pressure thing. Like I said, I really don't understand what's magical about 72psi. If you want to be a 'modern' bike rider, you'll want to adopt both the latest aero and width advice. If a 28mm tire, your rim has to be 30mm external.
Looking at their tire chart, IMO it looks like they just took the 72psi, stuck it in the bottom left cell as a value, and then had to come up with a way for there to be a logical progression from there -- and it doesn't match up with their calculator.
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The tires under it in the pecking order might get cheaper also. Sweet!
Last edited by seypat; 10-06-21 at 12:23 PM.
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Has anyone seen these for sale anywhere yet?
I was at a local shop yesterday and they hadn't gotten any yet and had no idea when they would. I don't see them available anywhere online.
I was at a local shop yesterday and they hadn't gotten any yet and had no idea when they would. I don't see them available anywhere online.
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edit: https://www.bikeforums.net/road-cycl...l#post22266085
Last edited by WhyFi; 10-14-21 at 09:49 AM.
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I just got a new Conti GP 5000TR to replace a bum HardCase Light on my Domane. The instructions specifically stated not to use on a hookless rim. Maybe they were an older model ? 700x32. Man they were tight AF to get on my wheel (carbon Bontrager Aeolus pro 3V). Lots of cussing and I even threw it to the floor in frustration but managed to stretch it on without tools just a little soapy water. Talk about forearm pump !!! Thinking maybe hitting the tire (if I buy one for the front) with a low temp heat gun and stretching it by standing on the tire and pulling a little? Is that a no-no ?
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I just got a new Conti GP 5000TR to replace a bum HardCase Light on my Domane. The instructions specifically stated not to use on a hookless rim. Maybe they were an older model ? 700x32. Man they were tight AF to get on my wheel (carbon Bontrager Aeolus pro 3V). Lots of cussing and I even threw it to the floor in frustration but managed to stretch it on without tools just a little soapy water. Talk about forearm pump !!! Thinking maybe hitting the tire (if I buy one for the front) with a low temp heat gun and stretching it by standing on the tire and pulling a little? Is that a no-no ?
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Can confirm the TL's are ridiculously tight on some rims.
Reports are that the S TR goes on a lot easier. This guy installs one on a Zipp 303S without levers. It goes on really easy, though he does have to use a boost tank to seat it:
WhyFi I can't tell from this video if the tire stays seated on deflation or not. It looks like he doesn't let all the air out at the end, so hard to tell.
Reports are that the S TR goes on a lot easier. This guy installs one on a Zipp 303S without levers. It goes on really easy, though he does have to use a boost tank to seat it:
WhyFi I can't tell from this video if the tire stays seated on deflation or not. It looks like he doesn't let all the air out at the end, so hard to tell.
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WhyFi I can't tell from this video if the tire stays seated on deflation or not. It looks like he doesn't let all the air out at the end, so hard to tell.
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Yep another confirmation here! I'd been mounting GP4000S tyres with ease to all my rims for years. Got a set of GP5000's and man oh man where they a bugger to get on!
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Very little chance that you got a GP5KS TR - you almost certainly got a GP5K TL. The S TR is very new and is designed to be hookless compatible. The TL has been around for a couple of years and is *not* to be used hookless. The TL also has a reputation for being tight bastards, too.
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https://www.bicyclerollingresistance...prix-5000-s-tr
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure. So the tire is probably slightly faster. Maybe like 1 watt.
Jarno also mentions that the casing is stiffer. afaik the old gp5k wasn't exactly known to be supple (relative to other race tires) so this might not be great news.
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure. So the tire is probably slightly faster. Maybe like 1 watt.
Jarno also mentions that the casing is stiffer. afaik the old gp5k wasn't exactly known to be supple (relative to other race tires) so this might not be great news.
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https://www.bicyclerollingresistance...prix-5000-s-tr
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure. So the tire is probably slightly faster. Maybe like 1 watt.
Jarno also mentions that the casing is stiffer. afaik the old gp5k wasn't exactly known to be supple (relative to other race tires) so this might not be great news.
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure. So the tire is probably slightly faster. Maybe like 1 watt.
Jarno also mentions that the casing is stiffer. afaik the old gp5k wasn't exactly known to be supple (relative to other race tires) so this might not be great news.
Yeah, I'll be interested to hear riding impressions.
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https://www.bicyclerollingresistance...prix-5000-s-tr
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure.
Interesting. BRR measured the same-ish rolling resistance for a given pressure, but the tire has also gotten ~1.5mm smaller, which means you'd have to run it at a slightly higher pressure.