Sunday, September 7, 2014

New Zipp Tangentes - Speed, Course, and SLSpeed - the Crr results

A bit over a week ago, Zipp announced at Eurobike the release of their entirely new tire line; specifically, the Tangente Speed and Course clincher models (in 23C and 25C versions for both) along with the Tangente SLSpeed Tubular models (a 24C and a whopping 27C version).  Below you'll find my roller testing results for these new tires. The Speed models are based on a 220tpi nylon casing and forgo an under the tread puncture belt, while the Course models use a 127tpi nylon casing and use puncture belt.  The SLSpeed tubular models use a similar tread that is glued to a 320tpi cotton tubular casing with a latex tube inside and they also feature a puncture belt.

The previous Tangente models from Zipp were apparently very good from an aero standpoint.  From a rolling resistance standpoint however, they were "less than stellar"...especially in this day of tire companies understanding the value of low Crr tires and their effect on performance and "comfort".  So, one of the main drivers of this new tire development was in lowering the Crr of their tire offerings.  On this point, I'd have to say that they've succeeded, in that Course models are basically tied with the current "industry standard" Continental GP4000S 23C from a Crr standpoint, with the Speed models being slightly faster. Their new tubular models, the Tangente SLSpeed, are also very low rolling resistance, with the 24C model basically tied with the benchmark Schwalbe IronMan Tubular, and the 27C (with the helping of its extra wide casing) taking over the current top spot for a "brand new" tire on the overall list of tires I've tested.

So, here's the nitty-gritty data for these tires, including data for the Schwalbe IM tubular, my "benchmark" GP4000S 23C tire, and the old model Tangente tubular.  All of the clincher data for this round was performed on a Zipp Super 9 clincher disc, with the tubulars all tested on Zipp 900 tubular discs for consistency. In rank order from lowest Crr to highest:

Zipp Tangente SLSpeed 27C Tubular = .0028,  26W for pair @ 40kph, width = 26.8mm
Zipp Tangente Speed 25C Clincher = .0030,  28W for pair @ 40kph, width = 24.8mm
Zipp Tangente SLSpeed 24C Tubular = .0032,  29W for pair @ 40kph, width = 23.5mm
Schwalbe IronMan Tubular 22C = .0032,  30W for pair @ 40kph, width = 21.7mm
Zipp Tangente Speed 23C Clincher = .0033,  31W for pair @ 40kph, width = 23.8mm
Continental GP4000S 23C = .0034,  32W for pair @ 40kph, width = 24.8mm
Zipp Tangente Course 25C Clincher = .0035,  32W for pair @ 40kph, width = 24.7mm
Zipp Tangente Course 23C Clincher = .0035,  33W for pair @ 40kph, width = 23.8mm
Old Zipp Tangente 23C Tubular = .0045,  41W for pair @ 40kph, width = 22.4mm

So...what are the takeaways here?  Well, I think it's fair to say that Zipp accomplished their goal of significantly improving the Crr of their tires, which can be easily seen by the comparison to the old Tangente tubular. Even the slowest of the new tires would save ~7W for a pair at 40kph, with the faster tires requiring more than 10W less at 40kph.  That's significant.  Also, in comparison to the GP4000S, the 25C Course model is basically tied with it, both in Crr and in actual tire width (at ~24.7mm) with the 23C Course model being only slightly slower (within the error margin of the testing).  The 23C version of the Speed models tested out slightly faster than the GP4000S (again within the margin of error) but measures a full 1mm narrower when mounted on the same rim.  That should help its aero properties. The 25C Speed model, however, is significantly lower Crr than the GP4000S saving a predicted 4W for a pair at 40kph, while measuring out at the identical width.

On the tubular front, the new 24C Tangente SLSpeed tire rolls just slightly better (within .0001 Crr) of the Schwalbe IronMan tubular, which is not surprising considering their similar construction (tread glued to a 320tpi cotton casing).  The 27C Tangente SLSpeed tire rolls VERY fast, but its extra wide 26.8mm mounted width is going to result in an aero hit.  I'd call that one a "rear use only"...but only as long as it can be shown that the width doesn't "give back" aerodynamically the gains that are made in Crr.

Well, that's the Crr results. What remains to be seen is how these tires perform aerodynamically.  But, as I've said before, and we've seen recently with tires like the Specialized Turbo Cotton, low Crr can "make up for a lot of aerodynamic sins".


  1. Tom, thanks for your work. Question: Any reason why you don't use the newer S II version of the Conti GP 4000 S as your benchmark? Thanks, Steve

    1. Hi Steve,
      There's a couple reasons. First, that's the SAME tire I've been using all along in my testing, so it makes for a good "control". Secondly, I've been told by sources at Conti that the only difference between the GP4000S I have and the GP4000S II is the addition of the colored ink on the sidewalls, and thus there should be no difference in Crr. I also just haven't gotten my hands on one yet ;-)

  2. based on the 220tpi construction and zipp's history with vittoria, I would have expected this tire to be pretty similar to the Pro Radiale; however, the pro radiale did very poorly on your RR test.

    I wonder what changed, and if vittoria will make similar changes to their diamante line of tires to make them perform better.

    1. The Radiale is actually quite different in that the bias angle of the plys is significantly steeper (i.e. more like a radial car tire), and that it seems like there is quite a thick layer of rubber on the sidewalls. That tire's compound also seems to feel quite soft. Only one of those 3 things would tend to make a tire low Crr (the ply direction) and that actually makes the steering less stable. I'm really not sure what Vittoria was trying to accomplish with that tire.

  3. Tom, great work as always! Things are really looking interesting for the cycling tire industry.
    Idea for the spreadsheet. How about adding a column after C to denote if a tire has puncture belt/protection or not. I think that would be good info for all the data.
    Oh, just noticed that you have the wrong data for "Old Zipp Tangente 23C Tubular = .0034", should be .0045 per the graph.

    1. Doh! Thanks for the catch. Updated. That's a good idea about the puncture belt, however sometimes that's not always known (for example, I couldn't figure out why the tubeless version of the Schwalbe IM clincher was faster than the straight clincher version w/latex tube until the rep at IB happened to mention the Schwalbe tubeless tires all omit the puncture belt), and they all aren't created equal either.

      I think I'll leave it to the reader to figure out what's what on that front and what level of "comfort" they have in running a particular tire.

  4. Tom, Love your work as always. Can you enlighten us at all about what "optimized for dry road conditions" really means? Or I guess I can just email Zipp. How bad will they be (tubulars in my case) in the wet for road racing? My uneducated guess is either the compound is not very soft or the tread pattern is designed for aerodynamics not water evacuation (looks like the pattern is backwards of most treads, which is better for aerodynamics, or so I read).

    1. I'm not sure myself what they mean by that.

    2. Late to respond to this, but from what I heard when I called zipp with exactly this question. Optimized for dry conditions means they desinged it with dry conditions in mind, Supposedly it offers better grip in all conditions than their previous tires did (tires which I was very happy with in varying conditions)

  5. Tom, I can't tell you how much I appreciate your independent testing. Thanks for making me faster!

  6. Hi Tom,
    Would you be interested in a new GP TT and a new GP 4000S II from me ? Free of charge of course, I want to try and do my own testing at home with your protocol but in the mean time I'm happy to send you these two tires to complete your chart if you are interested ?
    Pierre-Yves Facomprez - Look Cycle -

  7. Hi Tom
    Would be great if you could add the CRR of Conti Supersonic and Tubular Podium.

    And if the 26,8mm is really negative on aerodynamics if mounted on a 27mm Firecrest Profile

  8. Tom,

    Thanks so much for your posts and the time you take for testing and writing.

    I am going to put your test results to work via what I expect to be big improvements in a 12 or 24 hr ride. In particular, I had handcycled a 12 hr event with gatorskins (0.0058). By going to Cont. 4000S II on the next event, I expect quite an improvement. With handcycling at 16-17 mph, a cyclist will have far more of an improvement with a better rolling resistance tires as compared to a legged cyclist moving along at 25+ mph. I would not have thought that the Crr would be so different between tires without reading your blog.

    I have little choice in tires given that my wheels are 650C clinchers but the Cont. 4000S II tire is available in a 650C 23mm.

    Question: I have 3 wheels (delta design). Should I expect that the relative rolling resistance between tires holds for 3 wheels as it does for 2? I expect that the rolling resistance is less per tire (less weight going to each wheel) and probably less in total for all three wheels as compared to two wheels since less weight per tire would probably allow for less deformation of the tire?

  9. Tom,
    Thanks for the update on the new Zipp offerings!

    On the topic of other updated tires, I have heard from my LBS that Specialized has added some more puncture protection to the S-Works Turbo clinchers. I'm hoping it hasn't slowed them down too much.

    If you don't have some to test I'd be happy to send you a set!


  10. This comment has been removed by the author.