tag:blogger.com,1999:blog-6080071290235905056.post6096554933842597194..comments2024-02-27T18:30:46.362-08:00Comments on Blather 'bout Bikes: Win Tunnel Playtime - Part 1Tom Anhalthttp://www.blogger.com/profile/08175472546482777614noreply@blogger.comBlogger18125tag:blogger.com,1999:blog-6080071290235905056.post-17165852365582020402017-10-08T07:17:11.108-07:002017-10-08T07:17:11.108-07:00This is a phenomenal source of information. Thanks...This is a phenomenal source of information. Thanks so much. I heard of this on the excellent Time Trial Podcast.Anonymoushttps://www.blogger.com/profile/04287730535477719018noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-34063177878797756692017-08-01T23:06:21.568-07:002017-08-01T23:06:21.568-07:00Your blog is very useful, I am truly to this blog ...Your blog is very useful, I am truly to this blog which is specially for bikes, I really appreciate your blog.<br /><br /><a href="https://zackees.com/" rel="nofollow">biker</a>Petersonshttps://www.blogger.com/profile/09889148403145412096noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-24608249925509098402016-09-01T16:34:28.762-07:002016-09-01T16:34:28.762-07:00Hi Robert. The entire round platform you see in th...Hi Robert. The entire round platform you see in the picture at the top is a load cell to measure the aero drag forces. The wheel rotation is driven by a motor through a drum so that the wheel speed matches the wind speed. The "struts" are made from aero-section bar and are of a shape that stalls at a very high angle of attack, and are spaced widely apart. That is done to minimize interactions with the test articles. I hope that helps.Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-27045127138853046622016-09-01T14:59:27.444-07:002016-09-01T14:59:27.444-07:00Hi Tom, great post! I was hoping to find out some ...Hi Tom, great post! I was hoping to find out some details about the specialized facility where you performed drag measurements. Are they obtained using a force transducer? Also, was the wheel rotation driven by a motor or just allowed to rotate freely, and were the arms which hold the wheel in place designed with an aerodynamic profile to limit interference with drag measurements? Thanks, I'm designing a wheel test stand for use in measuring drag on racing wheels in a wind tunnel right now so any additional insight into this setup would be great.Anonymoushttps://www.blogger.com/profile/01780901926274773893noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-16720564607287373902015-11-04T06:14:07.304-08:002015-11-04T06:14:07.304-08:00Tom: Any insight if the S-Works Turbo Tubular Allr...Tom: Any insight if the S-Works Turbo Tubular Allround2 will roll as well as the Turbo Cottons? I'm looking for a tubie to replace my Schwalbe Ironman (butyl) on my Stinger disc. Flat protection and compound seem to be the same but the casing is different as per Spec's site. LAIhttps://www.blogger.com/profile/11870813170619451897noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-30432220046129046472015-11-01T16:47:01.381-08:002015-11-01T16:47:01.381-08:00Hi Steve,
I'm glad you're enjoying the dat...Hi Steve,<br />I'm glad you're enjoying the data. Yeah...there's a lot of "interactions" going on not only with tire model but also mounted width. That's one of those things that people seem to forget with the new wider rim models...the mounted width is going to be MUCH wider than the stated size, and that CAN have aero drag effects.<br /><br />It's funny...but Chris Yu pointed out to me that nowhere on the new 22C S-Works turbo tire does is say "22" except for what's molded into the sidewall. The label itself says something like "24mm wide when mounted on a Roval CLX64 wheel"...and he insisted on that labeling due to people thinking the tire would be too narrow for use on a wheel.<br /><br />There's going to be a follow on blog post with some excellent data that Cam Piper took a week after my visit. Aero data from all sizes of S-Works Turbo and Turbo Cotton on the CLX64 wheel :-)Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-11978572762705093112015-10-29T08:18:15.674-07:002015-10-29T08:18:15.674-07:00Tom, really glad to see you getting some time in t...Tom, really glad to see you getting some time in the wind tunnel to get some aero data to complement your great work on rolling resistance. Be interested to see what conclusions you reach when you combine the contributions of each. <br /><br />My readers are always asking if they can put wider tires (typically 25C) on their rims to improve comfort and rolling resistance. I always tell them you need to keep the pressure the same or not too much lower in the wider tire in order to improve rolling resistance but you'll probably offset those RR gains with aero losses, especially if the mounted/inflated tire width greatly (>1mm or so) exceeds the rim width, which it will be for a 25C tire with most any rim that isn't 26 or 27mm wide at the outer edge of the brake track. I ran several scenarios on rims and tires of different widths to show the amount of overlap and it can get quite large (see scenarios 1-6 here: http://intheknowcycling.com/2015/05/28/best-road-bike-tires/#Design).<br /><br />Of course, the relative benefits of better tire aerodynamics and reduced rolling resistance depends on whether you are riding in the wind most of the time like a TT/Triathon or solo road cyclist (increases importance of aerodynamics) or you are drafting others in road race or doing group riding (increase importance of rolling resistance).<br /><br />I wonder if your aero testing begins to quantify some of the effect of the width difference between the tire and rim at the outside edge of the brake track in aero performance? While only the tests on the Zipp rim test the same model tire at two different widths, there are considerable tire-rim width deltas with some of the different tires you ran on each rim. Using rim width measurements from Greg Kopecky, formerly at slowtwitch and wheel co data for the old Zipp and new Spesh wheels along with your mounted/inflated widths, I charted the tire-rim width deltas for the combinations you tested. It looks as follows:<br />-Zipp 101, SWT 22 Delta = -0.2mm (tire narrower than rim), SWT 24 Delta = +1.0mm (tire wider than rim<br />-Jet 6+, SWT 22 -0.5, TC 24 +1.7<br />-CLX 64, SWT 22 (old tire) -0.9, SWT 22 (new tire) -0.3<br />-FLO 90 SWT 22 -0.7, CSS 23 +0.4, CA22 -0.1<br />-H3 CSS 20 +0.8, VFR 20 +1.9, BATT19 ) +0.1<br /><br />Any thoughts on how much of the aero performance difference is due to tire model choice vs tire-rim width deltas?<br /><br />Best,<br />Steve Steve@intheknowcycling.comhttps://www.blogger.com/profile/16189668733741295992noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-73300412745119384002015-10-26T12:54:32.850-07:002015-10-26T12:54:32.850-07:00Top stuff! Will be interesting how the new 2016 ty...Top stuff! Will be interesting how the new 2016 tyres with roll rr claims (eg. Zippy, vittoria graphene etc ) fair in the futureAnonymoushttps://www.blogger.com/profile/11009866047839946623noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-73557764691430828932015-10-19T14:02:25.624-07:002015-10-19T14:02:25.624-07:00Eagerly awaiting part two. I am really curious to ...Eagerly awaiting part two. I am really curious to see the numbers with Crr and aero data combined for the Specialized tires. <br /><br />There was also some talk that Spec changed to a lower TPI casing on the "regular" S-Works turbo tires (from 220 to 120tpi maybe?) and that would lead to the S-Works Cottons to be even faster-er in comparison.KJhttps://www.blogger.com/profile/04402125607607595308noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-4599323703094851722015-10-13T22:54:19.744-07:002015-10-13T22:54:19.744-07:00Sounds about right...Sounds about right...Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-44833929426143322522015-10-13T22:43:03.335-07:002015-10-13T22:43:03.335-07:00If I'm reading that right, the aerodynamic per...If I'm reading that right, the aerodynamic performance difference at 10 degree yaw across the range of wheel/tyre combos tested is approx 1 second per km, with adjustments for Crr variation to be layered on top.Alex Simmonshttps://www.blogger.com/profile/00698332397074026424noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-47833376292766088762015-10-10T09:44:05.082-07:002015-10-10T09:44:05.082-07:00Tom, I really can't thank you enough for this ...Tom, I really can't thank you enough for this information, and for sharing it. This is spectacular. Since you didn't test the GP400s2, can you surmise anything based on previous testing efforts and coast-down tests?whareaglehttps://www.blogger.com/profile/15824055294445501713noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-80380994875786428272015-10-06T09:34:26.901-07:002015-10-06T09:34:26.901-07:00Oops...I mis-wrote above. Runs 57-63 were in the m...Oops...I mis-wrote above. Runs 57-63 were in the morning, not the afternoon. But, it shows that between those morning runs and the afternoon runs the agreement was tight. The first runs with the new tire (22-28) perhaps show some sort of "out of the box new tire" effect? Like I said...more questions than answers most times ;-)Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-65182538202037772822015-10-06T09:30:24.725-07:002015-10-06T09:30:24.725-07:00Yes. Runs 85 on where after an ~1.5-2 hour break f...Yes. Runs 85 on where after an ~1.5-2 hour break for a ride and lunch, which is why the last run of the morning (Flo90 w/SWT 22)was repeated when we started back up again.Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-8274148362342595432015-10-06T00:13:01.487-07:002015-10-06T00:13:01.487-07:00So are runs from 85 on a later session? Keen to se...So are runs from 85 on a later session? Keen to see the other data you've mentioned :-)<br />At my mass and on the surfaces I race it is disappointing that I always have to go for CRR taking priority (as do most riders if they've paid attention to us...) and sacrificing aero. Rationality just isn't as cool as having the most aero set up/<br />cyclenutnzhttps://www.blogger.com/profile/04266241560236873574noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-64934354922042642572015-10-05T17:35:52.695-07:002015-10-05T17:35:52.695-07:00Thanks Tom. Great work!Thanks Tom. Great work!Gary Tingleyhttps://www.blogger.com/profile/04332175697701273159noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-91084251477910444552015-10-05T14:11:06.150-07:002015-10-05T14:11:06.150-07:00That was the first run with the control combo in t...That was the first run with the control combo in the afternoon, and it's within .001 of the other, later afternoon run...so those 2 are consistent. The "control" values plotted above are the average of all 3 runs.<br /><br />About all I can think of is that there may be some un-modeled environmental variation in the data acquisition? That ended up being quite a hot day in Morgan Hill...I went on the lunch ride with Chris and Cam and I'm pretty sure we went through some spots that were in the triple-digits (Fahrenheit).<br /><br />I knew you, for one, would appreciate the spreadsheet :-)Tom Anhalthttps://www.blogger.com/profile/08175472546482777614noreply@blogger.comtag:blogger.com,1999:blog-6080071290235905056.post-31148320655887696412015-10-05T13:53:09.294-07:002015-10-05T13:53:09.294-07:00What happened with the CLX64 test in runs 57-63? M...What happened with the CLX64 test in runs 57-63? Much lower values than the other runs for that combo? In fact, of 3 runs with new tyre it looks like a lot of variation? <br />Thanks for making spreadsheet available so I can play with data.cyclenutnzhttps://www.blogger.com/profile/04266241560236873574noreply@blogger.com