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wheels - internal width?

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wheels - internal width?

Old 04-23-21, 08:52 AM
  #26  
msu2001la
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Originally Posted by scottfsmith View Post

A 28c tire also could be problematic on a 25mm internal rim, both in terms of seating and in terms of potential rim damage due to the edges not being protected by tire.
Originally Posted by Camilo View Post
A 25 internal width, probably minimum tire size of 30-32, and maximum ~50?
FWIW, Zipp's latest wheel (353NSW) is a 25mm internal rim that they say is aero optimized for 28mm tires.
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Old 04-23-21, 01:01 PM
  #27  
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Originally Posted by msu2001la View Post
FWIW, Zipp's latest wheel (353NSW) is a 25mm internal rim that they say is aero optimized for 28mm tires.
Very interesting, thanks. I read another source that say their similarly wide rims are optimized for >2". And the charts I've found lately are all over the place. I'm going to fit a 35 on a 25 iw rim but can't find a definitive guide. Based on what you wrote and another source I quoted above, I'm going to give it a shot. But many of the charts I've looked at say the rim should be several mm narrower than that, some day it's ok.
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Old 04-23-21, 03:11 PM
  #28  
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That Zipp is an outlier, all the 25mm internal rims I have seen are for gravel sized tires. You want to go with what the manufacturer states because they have optimized the rim for particular tire sizes, and outside the range the tires might not even seat properly on the rim.
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Old 04-23-21, 04:43 PM
  #29  
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Originally Posted by scottfsmith View Post
That Zipp is an outlier, all the 25mm internal rims I have seen are for gravel sized tires. You want to go with what the manufacturer states because they have optimized the rim for particular tire sizes, and outside the range the tires might not even seat properly on the rim.
Hardly an outlier. The Bontrager 3V, ENVE AR, LB WR, 3T discus and probably others I'm missing are 25mm rims that allow 28mm tires. The ETRTO approves it.

https://engineerstalk.mavic.com/en/th...ght-rim-width/
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Old 04-23-21, 05:08 PM
  #30  
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Maybe I wasn't clear, I meant outlier for what they were optimized for, not what they allow. The ENVE AR is the only one I know which like the Zipp 353NSW is optimized for 28mm not something bigger. The rest allow 28mm but it is at the edge of the allowed tire size so was not aero optimized for it. Or so is my impression. I recently got some LB WR's and my impression is they were optimized (not just rated) for bigger sized tires and I have not tried 28s on them. Of course I would be happy to hear otherwise as it would make the rims more flexible for me.
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Old 04-23-21, 05:33 PM
  #31  
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Originally Posted by scottfsmith View Post
Maybe I wasn't clear, I meant outlier for what they were optimized for, not what they allow. The ENVE AR is the only one I know which like the Zipp 353NSW is optimized for 28mm not something bigger. The rest allow 28mm but it is at the edge of the allowed tire size so was not aero optimized for it. Or so is my impression. I recently got some LB WR's and my impression is they were optimized (not just rated) for bigger sized tires and I have not tried 28s on them. Of course I would be happy to hear otherwise as it would make the rims more flexible for me.
You're gonna have to define "optimized" for me. Are you claiming that any of these wheels would be slower with 28s than with bigger tires? If you care about aero, you go with the narrowest tire that works for your application.

I'm sure some wheels are more focused on wider or narrower tires so that might factor into your decision of whether to buy a particular rim, though. Like I wouldn't necessarily want to buy a wide rim that's designed for gravel tires if I'm looking for a road rim. You're right that the LBs say "the WR50 features a deep Gravel Optimized Aero profile that cuts through crosswinds and decreases lateral resistance" but I wouldn't put too much stock into that. Nothing about that profile is different from every other aero wheel on the market.

I believe they said the same thing about the AR56 and that was one of the fastest wheels on Hambini's test. I bought the AR56 and use them with 25mm tires and they are extremely fast and stable. Regardless of whether you put stock in Hambini's test, it is a small piece of evidence to suggest that these wheels are fast with narrow tires.

Last edited by smashndash; 04-23-21 at 05:37 PM.
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Old 04-23-21, 06:16 PM
  #32  
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Originally Posted by smashndash View Post
You're gonna have to define "optimized" for me.
When rim manufacturers make an aero rim they put it in a wind tunnel (or a simulation) with certain size tires on it. They can't make the rim work best on all tire sizes, the physics of airflow just doesn't work that way. So the goal is to make it work well on some range but best on a sweet spot, the optimized size.

The only thing widely quoted is the vague 105% rule: the rim max width should be 105% of the tire mounted width. So my LB WR50's (32.5mm at widest) should be optimal with a 31mm tire by that. 28c tires will mount to around 31mm on a 25mm internal rim so by that rule they are optimized for 28c tires. But, it could be that the designers did something else in the profile to make it do relatively better with larger tires and relatively worse with 28c's.. there is a lot more to rim shapes than the maximum width.
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Old 06-04-21, 06:35 PM
  #33  
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Any of you guys use prowheelbuilder.com recently? As a result of this thread I ordered a set of wheels from them on 4/26/21 and they gave an initial estimate of 5/24/21 as the build date. In the 2 weeks since then I have emailed them 3 times and left a voice mail but still haven't heard back anything about a new estimated build date. They seem to have good reviews here but it's frustrating being 50% past the estimated time with them not responding. At what point should I call visa to dispute the charges?
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Old 06-05-21, 03:02 AM
  #34  
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Originally Posted by tedder987 View Post
I am looking around for new wheels to put on my 2017 Roubaix Comp. Unfortunately I can't swing anything expensive (i.e. carbon, or over $700) so getting the 'ideal' wheel isn't really an option. Since I am on the bigger side (95kg/210lbs) and run wide tires (GP5000 28 front, 32 rear) I was thinking about grabbing gravel wheels on the assumption that they will e stronger and might better support the wide rubber. But I am not sure how wide is too wide.

My stock (DT swiss R470) were 18 internal and 22 external. Since I am on such wide rubber, I definitely want to go to ~21 internal at least but a lot of the gravel wheels now seem to be 25 wide internal. Not sure if this would make my 32 blow up too big to fit on the bike (which is rated for 32mm tires but there is still a fair bit of space there with the 32mm GP5000 on my stock skinny wheels).

So who has experience with wide gravel wheels on a road bike, or knows of a site with measurements for tires on various rims they can point me to?

p.s. almost bought some Reynolds AR41 (41 deep, 21 internal, 30 external) which looked near ideal from the pro's closet but moved too slow
According to the ETRTO guidelines a 18mm internal rim is perfectly fine for 28 and 32mm rubber.

If you want a stronger wheel, get a "gravel wheel" that is rated at least ASTM 2.

"wide rims" is largely evidence free marketing hype. Same as "Hook less ´technology´ " (lol). Nothing wrong with what you got.
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Old 06-05-21, 04:08 AM
  #35  
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Originally Posted by smashndash View Post
Hardly an outlier. The Bontrager 3V, ENVE AR, LB WR, 3T discus and probably others I'm missing are 25mm rims that allow 28mm tires. The ETRTO approves it.

THE RIGHT TYRE WIDTH ON THE RIGHT RIM WIDTH - Engineerstalk : Engineerstalk
Not sure what ETRTO chart you are looking at. ETRTO recommends a max 19mm internal rim for a 28mm tyre. Some tyre manufacturers additionally allow their tyres to be mounted on wider rims, but the bulk of information out there points to 19mm as the max recommended.
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Old 06-05-21, 05:58 AM
  #36  
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Originally Posted by Racing Dan View Post
Not sure what ETRTO chart you are looking at. ETRTO recommends a max 19mm internal rim for a 28mm tyre. Some tyre manufacturers additionally allow their tyres to be mounted on wider rims, but the bulk of information out there points to 19mm as the max recommended.
Referring I assume to this chart in that article, based on the newer ETRTO guidelines (which also adds tire pressure as a 3rd factor in decisioning)

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Old 06-05-21, 06:40 AM
  #37  
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Guess you are right. It is an inflation chat tho, but I guess it can be inferred that mounting a 28mm tyre to a 25mm internal rim is now "allowed". It wasn't before. In my opinion its hardly the same as saying its the preferred combination either. The same issues with "too wide" rims still applies and is also mentioned in the article. - That is the tyre getting a flat (wrong) profile.

"Equally, if the tyre is too narrow relative to the rim width, it will get a flat shape that is bad for rolling efficiency and ride feel. "

and increased risk of the tyre blowing off of the rim as indirectly evidenced by the decreasing max inflation pressure as the rim widens (see the chart), and as mentioned in the text.

"Some tests performed by several tyre manufacturers, including Mavic, have shown that a narrow tyre on a wide rim has a higher chance of severely coming off the rim."

With that in mind I cant imagine the widest possible rim is the best solution, even if marketing likes me to think so and it apparently it is now included in the ETRTO standard.
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Old 06-05-21, 07:15 AM
  #38  
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My current Pirelli tyres (Cinturato Velo 32c) specifically state a maximum internal rim width of 20 mm. Other tyres may vary depending on their design. But going as wide as 25 mm on the rim will limit your tyre choices. FWIW my Giant SLR1 carbon rims are only 17 mm internal width and they come with 28 or 32 mm tyres as standard from new. It's probably not the ultimate aero combination, but who cares on an endurance bike? If I was buying new rims, I think I would look for around 20 mm internal width and not worry about it.
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Old 06-14-21, 06:06 PM
  #39  
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I will have some more direct experience shortly. The wheels I ordered from prowheelbuilder ended up getting cancelled due to problems sourcing the parts (thanks covid). So I ordered a set of Roval Terra C (the cheap ones) with 25mm internal, 30mm external (and 33 deep) to be my new hoops. Should be here for the weekend but unfortunately I am away the next 2 weekends so no big rides planned immediately. There were a few reviews where they were run with 28mm tires (e.g. https://cyclingtips.com/2019/10/2020...gravel-wheels/) and thats as narrow as I will ever run so ... I will give a review here in a month or so
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Old 06-16-21, 09:52 PM
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Old 06-20-21, 06:56 PM
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Too late for that. Just rode the Rovals for my first quick ride (23 miles, 1240 ft vertical). Definitely like them, they are about 350g lighter than what they replaced, might (?) be slightly aero, and are running tubeless. As for the tires on them,

Front GP5000 TL 28c ----> 30.9 mm (at 75 psi)
Rear GP 5000 TL 32c ----> 33.0 mm (at 70 psi)

Lots of space still available in the Spz Roubaix frame. For comparison, on the old rims (18mm internal), the 28c GP5000 was 29.2 and the 32c GP5000 was 31.8. This is at the same pressures but for old tires with ~3500 miles on the front and 2000 on the rear.
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