Login required to started new threads

Login required to post replies

Tires for Hed 3
Quote | Reply
I have a old style Cervelo P3 carbon. I just bought a set of Hed 3 rims. The original narrow ones. I know this has been discussed endlessly but I have searched all the threads I could find but I have never heard a answer to this question.

I know that these rims are best used with a 20c tire. My question is does anyone have a good idea of what my time loss over 40k would be using GP 4000s tires opposed to Supersonics? I know the Supersonic is probably the best tire for this rim but just how much is lost with the 4000s?

Thanks in advance for any information.
Last edited by: SRT-4: Mar 17, 17 18:04
Quote Reply
Re: Tires for Hed 3 [SRT-4] [ In reply to ]
Quote | Reply
~9 watts

http://bikeblather.blogspot.com/
Quote Reply
Re: Tires for Hed 3 [Karl.n] [ In reply to ]
Quote | Reply
What about the "magical aero qualities" of the GP4000 does it get any of this back or is the Supersonic just as good?
Quote Reply
Re: Tires for Hed 3 [SRT-4] [ In reply to ]
Quote | Reply
SRT-4 wrote:
What about the "magical aero qualities" of the GP4000 does it get any of this back or is the Supersonic just as good?


Below is the combined aero+Crr that shows the H3 with 3 different tires, including the 20mm Supersonic, vs. some other tire/wheel combinations.

You can see the Supersonic is the right tire among those 3 for the H3, and a good combination overall.

However not as good as the 23mm Supersonic on a Flo 90. And that's the *old* Flo 90, so the newer ones should be faster.





Quote Reply
Re: Tires for Hed 3 [trail] [ In reply to ]
Quote | Reply
trail wrote:
SRT-4 wrote:
What about the "magical aero qualities" of the GP4000 does it get any of this back or is the Supersonic just as good?



Below is the combined aero+Crr that shows the H3 with 3 different tires, including the 20mm Supersonic, vs. some other tire/wheel combinations.

You can see the Supersonic is the right tire among those 3 for the H3, and a good combination overall.

However not as good as the 23mm Supersonic on a Flo 90. And that's the *old* Flo 90, so the newer ones should be faster.





you raise some excellent points. one should also note that the above graphic does not take into account rotational drag. in other words, when you include 'watts to spin', one could find the the H3 combination is faster than any of the others in that chart. depending on how big you believe that value is, it would certainly outperform all others at 0-5 degrees, and maybe more.

this is notable for a rider making a selection -- particularly if they are a faster rider and/or race shorter events (higher speed).
Quote Reply
Re: Tires for Hed 3 [trail] [ In reply to ]
Quote | Reply
trail wrote:
SRT-4 wrote:
What about the "magical aero qualities" of the GP4000 does it get any of this back or is the Supersonic just as good?


Below is the combined aero+Crr that shows the H3 with 3 different tires, including the 20mm Supersonic, vs. some other tire/wheel combinations.

You can see the Supersonic is the right tire among those 3 for the H3, and a good combination overall.

However not as good as the 23mm Supersonic on a Flo 90. And that's the *old* Flo 90, so the newer ones should be faster.






What conditions get you negative yaw? Or is that just the difference between a wind from the left vs right?
Quote Reply
Re: Tires for Hed 3 [mvenneta] [ In reply to ]
Quote | Reply
mvenneta wrote:


What conditions get you negative yaw? Or is that just the difference between a wind from the left vs right?

Yeah, that's left and right of center.
Quote Reply
Re: Tires for Hed 3 [trail] [ In reply to ]
Quote | Reply
Aren't wheels symetrical? Why would they not have same drag on both sides?
Quote Reply
Re: Tires for Hed 3 [trail] [ In reply to ]
Quote | Reply
trail wrote:



That's an interesting plot - I hadn't seen it before... I guess it's time to break out the old saw of: "best to test with the actual products one is considering on your own dime or time"... 'cuz those numbers don't really jive with my experience testing the same tires on the H3 on the road/rollers/tunnel.

=================
Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
Quote Reply
Re: Tires for Hed 3 [BikeTechReview] [ In reply to ]
Quote | Reply
BikeTechReview wrote:
trail wrote:





That's an interesting plot - I hadn't seen it before... I guess it's time to break out the old saw of: "best to test with the actual products one is considering on your own dime or time"... 'cuz those numbers don't really jive with my experience testing the same tires on the H3 on the road/rollers/tunnel.


Keep in mind that the graph is *combined* Crr and aero. If you haven't seen it before I'd recommend looking up the "Wind Tunnel Playtime" series on Tom A's blog for full context.
Quote Reply
Re: Tires for Hed 3 [trail] [ In reply to ]
Quote | Reply
trail wrote:
BikeTechReview wrote:
trail wrote:





That's an interesting plot - I hadn't seen it before... I guess it's time to break out the old saw of: "best to test with the actual products one is considering on your own dime or time"... 'cuz those numbers don't really jive with my experience testing the same tires on the H3 on the road/rollers/tunnel.



Keep in mind that the graph is *combined* Crr and aero. If you haven't seen it before I'd recommend looking up the "Wind Tunnel Playtime" series on Tom A's blog for full context.

I gathered that it was combined from the plot. I guess it's still "best to test with the actual products one is considering on your own dime or time".

=================
Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
Quote Reply
Re: Tires for Hed 3 [BikeTechReview] [ In reply to ]
Quote | Reply
BikeTechReview wrote:
trail wrote:



That's an interesting plot - I hadn't seen it before... I guess it's time to break out the old saw of: "best to test with the actual products one is considering on your own dime or time"... 'cuz those numbers don't really jive with my experience testing the same tires on the H3 on the road/rollers/tunnel.

What year did you test all these same tires on the H3 in the tunnel and on rollers? Most of the tires on this plot are fairly new to the market, or in the case of the SS, appear to have received production changes that improved how well they rolled. The Bontrager may be the only tire on the plot that isn't new to the market or updated in recent years.
Quote Reply
Re: Tires for Hed 3 [SummitAK] [ In reply to ]
Quote | Reply
SummitAK wrote:
BikeTechReview wrote:
trail wrote:





That's an interesting plot - I hadn't seen it before... I guess it's time to break out the old saw of: "best to test with the actual products one is considering on your own dime or time"... 'cuz those numbers don't really jive with my experience testing the same tires on the H3 on the road/rollers/tunnel.


What year did you test all these same tires on the H3 in the tunnel and on rollers? Most of the tires on this plot are fairly new to the market, or in the case of the SS, appear to have received production changes that improved how well they rolled. The Bontrager may be the only tire on the plot that isn't new to the market or updated in recent years.

he mentioned experience with the H3 & associated tires; those tires haven't changed in years.
Quote Reply
Re: Tires for Hed 3 [mvenneta] [ In reply to ]
Quote | Reply
mvenneta wrote:
Aren't wheels symetrical? Why would they not have same drag on both sides?

Good eye. Presumably these were front wheels tested on their own. In most cases the data looks quite close (i.e. you could think of +5 and -5, +10 and -10, for example, as matched pairs) -- but not in every case.

Seems odd! I must be missing something.

My only thought was a QR with a lever, but I'd think they'd have used bolt-on skewers for this.

Hm.
Quote Reply
Re: Tires for Hed 3 [tetonrider] [ In reply to ]
Quote | Reply
if you, or he, aren't talking about the tires on Tom's chart I don't see your point. If you are talking about the tires on that chart, the faster rolling supersonic was of newer vintage and the chart was actually updated to reflect the rolling resistance improvement.
Last edited by: SummitAK: Mar 18, 17 21:59
Quote Reply
Re: Tires for Hed 3 [SummitAK] [ In reply to ]
Quote | Reply
One thing to consider is that the h3 is the only wheel to be just as aero as a back wheel. Metal spoked wheels like flo and Zipp have different spoke patterns and spoke counts on the rear, which most likely cost a few watts compared to the front.
Quote Reply
Re: Tires for Hed 3 [SummitAK] [ In reply to ]
Quote | Reply
SummitAK wrote:
if you, or he, aren't talking about the tires on Tom's chart I don't see your point. If you are talking about the tires on that chart, the faster rolling supersonic was of newer vintage and the chart was actually updated to reflect the rolling resistance improvement.

I tested in 2009. On 4.5" aluminum rollers I observed Crr's at ~0.002 for the good ones.

=================
Kraig Willett
http://www.biketechreview.com - check out our reduced report pricing
=================
Quote Reply
Re: Tires for Hed 3 [tetonrider] [ In reply to ]
Quote | Reply
tetonrider wrote:
mvenneta wrote:
Aren't wheels symetrical? Why would they not have same drag on both sides?


Good eye. Presumably these were front wheels tested on their own. In most cases the data looks quite close (i.e. you could think of +5 and -5, +10 and -10, for example, as matched pairs) -- but not in every case.

Seems odd! I must be missing something.

My only thought was a QR with a lever, but I'd think they'd have used bolt-on skewers for this.

Hm.

What you're "missing" is that in real life, everything isn't EXACTLY symmetric ;-) Wheels, tires, fixtures, etc....



http://bikeblather.blogspot.com/
Quote Reply