You can also try to maintain the same speed with both sets of tires. I’ve done this. The tubulars always require at least 10 watts more to go the same speed.
Some good points there Jenn. Furthermore, if rr is (also) directly proportional to speed (thanks rmur) those 10watts you are giving up going up a 7-8% grade will significantly increase as your speed increases.
Interesting.
ot
This is a very interesting thread. I am a tufo user and have generally been satisfied, but I have no data to say that tufos are a fast tire. What I find amazing is that a tufo tubular would perform so much more poorly than a clincher, and it has nothing to do with the tires. I would be very interested to see some data on the rolling resistance of various tubulars
Consider this. Zipp 404 clinchers weigh a whopping 360 grams more than the tubular 404s. There will be a further weight delta once tires are mounted, since a tubular will weigh less than a clincher with a tube. Say 70 grams per wheel. Now a full pound of weight at the rim, will add a huge amount to the moment of inertia. Even if you put the glue on the wrong side of the tufo, I doubt it could slow you down enough to make a clincher faster.
Bottom line, I can believe tufo may be worse than other tubulars, but I think it basically defies the laws of physics when someone claims a clincher setup is faster, because in most cases there is a huge weight penalty to clinchers (yes adding 500 grams to your wheels is a huge penalty, like adding 10 pounds to the rest of your bike) compared to tubulars, although I think the zipps are an extreme example (Mavic cosmic carbones are nearly equally heavy in clincher and tubular; they must price these wheels by weight, because they are about the heaviest high end wheels available)
This is a very interesting thread. I am a tufo user and have generally been satisfied, but I have no data to say that tufos are a fast tire. What I find amazing is that a tufo tubular would perform so much more poorly than a clincher, and it has nothing to do with the tires. I would be very interested to see some data on the rolling resistance of various tubulars
Consider this. Zipp 404 clinchers weigh a whopping 360 grams more than the tubular 404s. There will be a further weight delta once tires are mounted, since a tubular will weigh less than a clincher with a tube. Say 70 grams per wheel. Now a full pound of weight at the rim, will add a huge amount to the moment of inertia. Even if you put the glue on the wrong side of the tufo, I doubt it could slow you down enough to make a clincher faster.
Bottom line, I can believe tufo may be worse than other tubulars, but I think it basically defies the laws of physics when someone claims a clincher setup is faster, because in most cases there is a huge weight penalty to clinchers (yes adding 500 grams to your wheels is a huge penalty, like adding 10 pounds to the rest of your bike) compared to tubulars, although I think the zipps are an extreme example (Mavic cosmic carbones are nearly equally heavy in clincher and tubular; they must price these wheels by weight, because they are about the heaviest high end wheels available)
Once again, somebody makes factual assertions that can, in fact be tested rather than merely regurgitated from some bike magazine article. And no, the extra weight of a clincher setup does not come close to offsetting a 10-15-20 watt difference in power requirements.
Just one piece of an example – moment of inertia only matters when you are accelerating – which I sure hope isn’t happening very often in a triathlon or TT. Second, just because we can say “moment of intertia is higher” doesn’t make it costly. We have to know *by how much, *and we have to know how much it actually affects the acceleration of the whole bike. As it turns out, it has a teeny tiny effect on the acceleration of the whole bike. The power cost to accelerate our massive bodies dwarfs the power to accelerate the wheels, more than drowning out the minor effect of wheel/tire mass differences. I’m not even going to bother with doing the math here. Google around, find the formulas and push a pencil around for a while. Calculate the partial derivative of “rim mass” versus total bike+rider acceleration rate. Pretty small figure, huh? Even smaller (vanishingly so) if you do it versus steady-state velocity. Now compare those numbers to the partial derivative of power or CdA versus acceleration and velocity. WOW! Those two things sure matter a lot!
And --* “adding 500 grams to your wheels is a huge penalty, like adding 10 pounds to the rest of your bike” --* you know, just because you read that stuff doesn’t make it true. It is something that can be measured, it has been measured, and it is *not true. *People just make stuff up, write it into magazine articles (like Bicycling) and somehow it is accepted as the Lord’s Truth. Cracks me up.
Some day, the circle will turn and folks will realize that light weight bike stuff has almost nothing to do with how fast you go. Only in a pure uphill situation will the weight of the bike and its components ever make a difference.
I don’t mean to single you out, Tri_yoda – I’m just going off on the mis-information industry out there that told you this stuff in the first place. Please excuse me on this – I mean no disrespect to you.
“Well, that’s like… your opinion.”
-El Duderino
As a teammate of mine is fond of saying, “That’s an nth order refinement to be worrying about.”. This is a fun academic thread, though.
Someone already did the math.
Wheel weight doesn’t matter unless you are doing an uphill only race and it’s a really long hill. The differences in performance are not measurable with current power meters. Maybe with a stopwatch.
How come those boy’s (Not all of them) doing the TDF use the tubbies ? You think they would know as much as you all. I guess the tire co. fooled them 
Has the king got clothing on ?
Dirt
I am having fun. Learn me somthing new.
Are we having a competition for the best anecdotal story or using data to backup arguments? You win the anecdotal story one, Happy?
Yes very happy! All of my kids (7kids) are in bed .
Ps I use tubbies because I like the smell of glue. I am in a 12 gear recovery program for glue sniffing.
Dirt The joy of cycling 
How come those boy’s (Not all of them) doing the TDF use the tubbies ? You think they would know as much as you all. I guess the tire co. fooled them Has the king got clothing on ?
Dirt
I am having fun. Learn me somthing new.
Oh yes, the old “top pros do it therefore it must be right” argument.
So we should all sit up and do a victory salute 15 meters before the finish (like Zabel and a bunch of others). We should all skip the aero equipment in 50Kmh time trials (like S. Chavanel and a few others). We should all ride 19c tires in rainy TTs (like team Phonak)…
Let’s face it: Euro pros are neither particularly educated nor particularly bright. If they do something, it’s as likely to be based on superstition, myth, and lore as anything else. They make plenty of colossally stupid decisions and are very slow to adopt new technology.
–jens
Just one piece of an example – moment of inertia only matters when you are accelerating – which I sure hope isn’t happening very often in a triathlon or TT. Second, just because we can say “moment of intertia is higher” doesn’t make it costly. We have to know *by how much, *and we have to know how much it actually affects the acceleration of the whole bike. As it turns out, it has a teeny tiny effect on the acceleration of the whole bike. The power cost to accelerate our massive bodies dwarfs the power to accelerate the wheels, more than drowning out the minor effect of wheel/tire mass differences. I’m not even going to bother with doing the math here. Google around, find the formulas and push a pencil around for a while. Calculate the partial derivative of “rim mass” versus total bike+rider acceleration rate. Pretty small figure, huh? Even smaller (vanishingly so) if you do it versus steady-state velocity. Now compare those numbers to the partial derivative of power or CdA versus acceleration and velocity. WOW! Those two things sure matter a lot!
And --* “adding 500 grams to your wheels is a huge penalty, like adding 10 pounds to the rest of your bike” --* you know, just because you read that stuff doesn’t make it true. It is something that can be measured, it has been measured, and it is *not true. *People just make stuff up, write it into magazine articles (like Bicycling) and somehow it is accepted as the Lord’s Truth. Cracks me up.
I suppose you consider a TT to be a lab experiment. Unless the course is perfectly flat with no wind you are always accelerating, because you are subject to constantly changing drag forces and the effects of gravity every time the grade changes. Intgrating these minor accelerations to overcome these dynamic forces over say 40K, does not yield an insignificant result, compared to rolling resistance, so yes weight does matter in this example. I don’t know why everyone always worries about a flat TT, I race very few course short of rolling.
I agree weight of wheels is insignificant compared to drag force and the weight of the rider, but read my post (In rolling resistance examples with tubulars and clinchers, rider weight and drag are held constant, the only two variables are wheel weight (I don’t beleive that a 30% difference in the weight of tubular vs. clincher wheels can be neglected when rolling resistance is the other variable) and rolling resistance. The resulting forces from these variables pail in comparison to drag, but may be relatively comparable in magnitude to each other. If tires had no rolling resistance the bike would not even roll, it would just slide, so some rolling resistance is required, obviously an excessively large amount might be noticeable. I don’t think the spectrum between some near zero value and what would be easily perceptable is very large.
I am not convinced that tires are responsible for 20 watts of power difference, since I don’t believe there will be a huge delta between tires in rolling resistance in a properly controlled test. If this is true, I find it hard to beleive tire companies would not be using this as a huge marketing tool. As I said, I find this hard to believe, but read my post “I would be interested in seeing the data”. The only one jumping to factual conclusions is you. I am waiting for the results of some tests that others have proposed.
Good thing you singled me out. The worst enemy of scientific progress is a differing opinion.
I agree that some/most euro pros do a lot based on tradition… however, teams like CSC and Postal/Discovery test the hell out of everything. Look at Lance’s F1 team with the Nike skinsuits and custom helmet. If they thought that clincher were faster in TT then Lance would be riding a clincher H3 and clincher HED disc. Now that does not have anything to do with the Tufo RR issue that this thread started on. The Tufo issue should be quantifiable without to much effort. Hell we are talking about a claimed 20 watts.
You’re right: the Tufo issue is easily quantifiable. Several others and I have done it (see the data I provided on the BTR link that Ashburn posted). Every one shows the Tufos being much, much slower. The only data I’ve seen comparing tubies and clinchers generally shows that tubies are much slower.
So, I challenge anyone who believes otherwise to run the test I suggested above and give us the results.
-jens
From what I’ve read here and a number of other sources, it sounds like the tire casing (particularly the thread count) is a significant factor in rolling resistance. From what I recall, alot of the Tufo tires have a relatively low thread count casing (somewhere in the 60 TPI (threads per inch) range). Vittoria and likely others use up to 290TPI in their better tubulars (and some clinchers). They also use latex tubes in the high end tubulars, unlike the butyl tubes in the Tufo’s. Both the high thread count casing and latex tube are supposed to decrease rolling resistance by allowing the tire to better conform to irregulaties of the road surface. I suspect that this could explain what difference there might be. I know that the higher thread count casings definitely add up to much better ride quality.
Vittoria even makes a TT specific tire called the Chrono CS. It also has the 290TPI casing and latex tube, but is lighter and has a pretty thin sidewall. All combined, it probably yields the lowest rolling resistance of any road tire they make. It just might not be the most durable. BTW, this TT specific tire does have a fine file tread.
Regarding tread pattern, I’ve been a fan of slick tires for a long time. I used to run Michelin Pro Race clinchers. If I’m running clinchers, I now use the Vittoria Open Corsa KS (slicks) for crits, and Vittoria Diamante Pros for road races (lighter and more durable). TTs are done on tubular Corsa KS tires, although I might try the Chrono CS on my disk.
For those who might want to do a budget test, they could do the following:
Vittoria has a pretty extensive line of clincher tires with TPI ratings from 26-290TPI. You could select tires at both ends of the spectrum, and one or two in the middle. This would allow easy tire changes on an identical test wheel. You could also test with latex or butyl tubes.
*** I used to use: Michelin Pro Race, Veloflex Pave, Hutchinson, & Tufo Tubulars in the past ***
(still have one remaining Tufo mounted, but will switch sometime in the near future)
I can’t reply to everything I have read here, so I’m just attaching to the last post.
not to get off topic but weight is definitely a significant factor in time trials. At 195 lbs I am acutely aware of this when comparing my power to smaller people for similar speeds. I will agree that the difference in weight between clincher and tubi is not much difference in a time trial though, in a crit maybe but only maybe.
no way would I believe 20W of difference. If it is, hurray because I ride S3’s and it would take a lot of effort to increase my ironman average 20W. 20W over the length of an ironman is going to be at least 10 minutes…I’m sure someone will run the numbers to see. If the difference were that much you would have no trouble discovering it.
I fail to see why smooth tread is not better under ALL circumstances…track or otherwise. Knobbies are for sand, channels are for rain (to prevent hydroplaning, which is not a problem for bikes).
The BTR link needs a password. Does anyone want to summarize it?
I am not suggesting that a slick tread has any bearing on rolling resistance when compared to the kind of tread patterns found on any traditional road tires. (I agree it probably causes no measurable difference). In fact, the interesting point that was lost when I tried to post originally was that the Vittoria Chrono (TT specific tire) actually has a very fine file tread.
My own personal preference for slick tread tires was based on three thoughts:
Treaded tires seemed to pick up more debris - some of this ends up on your legs, particularly if you have sunblock on.
This is just a theory of mine at the moment, but I’ve felt like having treaded tires would increase the risk of small glass, rocks, etc. getting caught in the grooves and increasing the likelyhood of a puncture.
More effective contact area with a slick tire, much like automotive racing slicks. This was never a consideration for TTs, but was for crits where you sometimes push the limits of traction.
All of that being said, I’m still considering going back to the file tread pattern on my Corsa tubulars on the race wheels with the thought that some tread might be helpful on some road conditions, and the debris issue is really a bigger deal on training rides.
From what I’ve read here and a number of other sources, it sounds like the tire casing (particularly the thread count) is a significant factor in rolling resistance. From what I recall, alot of the Tufo tires have a relatively low thread count casing (somewhere in the 60 TPI (threads per inch) range). Vittoria and likely others use up to 290TPI in their better tubulars (and some clinchers). They also use latex tubes in the high end tubulars, unlike the butyl tubes in the Tufo’s. Both the high thread count casing and latex tube are supposed to decrease rolling resistance by allowing the tire to better conform to irregulaties of the road surface. I suspect that this could explain what difference there might be. I know that the higher thread count casings definitely add up to much better ride quality.
Vittoria even makes a TT specific tire called the Chrono CS. It also has the 290TPI casing and latex tube, but is lighter and has a pretty thin sidewall. All combined, it probably yields the lowest rolling resistance of any road tire they make. It just might not be the most durable. BTW, this TT specific tire does have a fine file tread.
Just for the record, I was checking out the Tufo S3 Lite at the Nytro website, and here is the info they provided:
“Very pliable 305 TPI polyamide nylon permitting high pressures
Excellent adhesion on wet road. Very fine file tread, 244 TPI underneath the tread.”
Tufos are great tires. Are they the fastest in all conditions? I doubt it. Are there better ones out there? Maybe - I’d certainly like to try the Chrono. 20 watts of rolling resistance increase over clinchers? I don’t believe it. Many of schemes stated here for estimating the wattage difference do not take into account the increased tire weight and increased momentum that occurs with a heavier wheel setup, both of which could actually mimic a rolling resistance increase I believe (I’d have to think about this a bit more, so don’t hold me to that statement). Still don’t believe it anyway. I’m not even sure a cyclocross tire would be 20 watts different…
Straight from the Tufo website: S3 Lite <215 g Guaranteed specified weight. Our best selling road racing tire. Very unique properties in this tire weight category. High inflation pressure, minimal rolling resistance. Racing puncture proof ply protective rubber ply activated silica tread compound size 28" width 21 mm weight <215 g pressure 8–15 bar (115–220 p.s.i.) TPI count 120
http://www.tufo.com/index.php?lg=en&mn=1&id=53
You can’t always go by what the local shop posts for product spec. Nytro was off on both pressure and thread count.
That being said, I have nothing against Tufo’s. I’ve liked the following characteristics in them:
1 - The ability to use their sealant. I did this after flatting once. It was nice not to have to throw away or try to repair it. To this day, that tire is still in use.
2 - they were easy to get mounted very straight.
3 - at 215 grams, the S3 lite helped offset the bit of extra weight of the Renn disk over buying a Zipp.
What I’ve been told that counts against them in the aero department is the large ridge right in the middle of the sidewall. The Conti Comp that I’ve tried has fairly smooth sidewalls, the Vittoria Corsa has a smaller one (less than the Tufo), and I believe that the Chrono has little to none as well. This may be a minor point, but a consideration for those who are winning or losing by a few seconds.
Taped tufo elite vs. glue Corsa CX vs. clincher GP3000 comparison.
I just noticed this thread on Clincher/Tufo’s etc. Here are two tests I posted to the bicycletech forum
********** First Test 4/18/2005 ***********
Bike + rider 185lbs
front tire constant clincher GP3000 on cxp30 rim dura-ace hub
3" rollers
Tubular Tufo elite road 23c tubular taped to zipp 404/pt-sl hub
Pressure, avg watts, avg speed
Clincher pt-pro w/cxp33, conti GP3000
4) 115lbs 201 25.4
I can believe 1,2, and 3 but the difference with the clincher is huge!
There might be some calibration issues between the hubs. I suppose I could cross-check them with the computrainer.
Some things I noted:
I did the test increasing the pressure each time. A better control would be to go back down decreasing pressure and re-testing. I will test the tubular again to see if I can repeat the results. Once I can repeat them I will pull it off and glue it up for a second series of tests.
It was not too scientific but I am sure I did help conclude that a TT done on rollers with the tufo and tape will be slower than that done w/clinchers…
********** Second Test 5/2/2005 ***************
After using my freshly glued Corsa CX in last weekend’s races (90 mile RR and 50 min crit) I ran another roller rolling resistance test with surprising results.
Bike + rider 185lbs. All tests front tire constant clincher GP3000 on cxp30 rim dura-ace hub 3" rollers.
Corsa CX tubular glued to a Zipp 404 rim using Vittoria Mastik 1 3 thin coats on rim and 2 on tire. PT-SL hub.
Pressure, avg watts, avg speed
Re-run of previous Clincher pt-pro hub w/cxp33, conti GP3000
Pressure, avg watts, avg speed
** Looking at last night’s file vs. the previous test of the clincher I did not give the clincher as much time to warm up. The 24.2 is comparable to the clincher’s performance at the same point in time in the previous test. I will run again using a longer time to verify.
What needs to be run next is a test of the Tufo Elite with glue to isolate the the tire or the tape. Unfortunately I don’t have the motivation to remove my Corsa CX and glue the Elite.
In the crit last weekend a teammate rolled a Tufo using Tufo extreme tape on a carbon rim. The failure was in the middle - i.e. between the “glue” and the plastic strip not between the sticky stuff and the tire or rim. I would not use the tape in crits.
I was very reluctant to run the test fearing I would have this cloud hanging over tubular wheels if the speed were still down in the 21-22 mph range with the Corsa. I understand there are a lot of issues - RR is a small part of the total resistance the rider has to overcome, a 3" roller is quite a bit different than a flat surface, etc. But who wants to pay extra and go through all the hassle for increased RR? At least now I feel like the tubular if not better (it tested better) is as least the same as a clincher. Now that I have a front / rear Corsa CX I will compare both vs. a front / rear clincher. I might also try a latex tube in the clincher.
Kevin
OK, can someone summarize for me why the tape is the suspected culprit? I’ve seen increased rolling resistance attributed to small “wobbles” in a glued tire, but my taped tufos are friggen straight as arrows - you can’t detect any sort of wobble whatsoever. If it’s not the wobbles, what is it that is slowing things down?