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I was talking with a friend the other day and learned that he has a Zipp 404 wheel with a Bontrager RXL Pro tubular installed using Tufo tape (extreme for higher temperatures not the standard tape). Opportunity knocked and he agreed to lend his wheel for a Crr test. Always guessed that the tape was slow but curious to see how bad it might be but not curious enough to try it on my test wheel after reading of problems with getting rid of the stuff. In fact one BTR member offerred to send a couple of VF Carbon tires and tape but I didn't take him up on the deal. Of course these are the same model tires but not the same tire. Both had ~ 100 miles. The Tufo taped tire had a Crr = 0.00260 compared to Crr = 0.00239 with Mastik 1 Glue (3 coats rim - 2 coats tire). Not as bad as I thought it might be but still a slightly slower set up although arguably an easier and more convenient way to mount a tubular tire ?? Some of the tape was exposed and it was somewhat soft and deformable by finger nail - not hard like dried glue. Possibly this slight compliance might be stealing some power ??

Note the correction above - the Tufo tape used was the extreme tape not the standard as I had first thought.

so Al, doesn't that mean the Tufo tape tested faster than a 'regular' glue job? I remember the Bonty's testing a little slower (.027?) using your old glue protocol.

One thing I'll say is that the Tufo tape doesn't seem to harden with time (I've seen it still gummy after several years).

Al,
Your crr chart and data are always helpful for me.

Do you know Miyata/3M "TTP-1" tubular glueing tapes which are common in Japanese cyclists? They are made of bonded-fiber fabric and strong adhesive. They are in fact "spongy" compared to TUFO's (but i only have a yellow, standard one).

http://www.amazon.co.jp/gp/switch-langu ... anguage=en


I've tested TTP-1 with my ~100km used Crono Evo CS on ZIPP w/PT @120psi in a hill climb. It had a Crr=0.00365. P2L w/PT @120psi showed Crr=0.00340 in the same test. According to your chart, Crono (w/ Proper Glueing) and P2L had a Crr=0.00233 and 0.00254, respectively. So in "AFM's Crr scale", My Crono w/ TTP-1 had a Crr = 0.00365*(0.00254/0.00340) = 0.00273.

Therefore,
(Crono + TTP-1)/(Crono + ProperGlueing)=0.00273/0.00233=117%

From Al's number:
(RXLPro + TUFO)/(RXLPro + ProperGlueing)=0.00260/0.00239=109%

Clearly, TUFOs are better at least in terms of Crr.... it seems that spongy bonded-fiber fabric layer absorbs quite a bit power. Though this spongy layer helps robust adhesion between uneven surfaces (Indeed, their adhesibility is stronger than TUFOs).

Jack Watts wrote:


Yes, that's true. Early on I was going for as thin and hard a glue layer as possible not realizing the importance a good glue bond over as close to 100% of the area as possible and was using Continental glue. Also the "old protocol" was used to expedite testing and not damage tires as well but again not realizing that it also resulted in higher Crr. Then of course switched to "lots of" Mastik 1 after testing CT's wheel. Conti I think would be fine as is your experience but I've never gone back to investigate. Maybe the tape is another data point showing the importance of "complete" area bonding but also showing that a compliant material soaks up some energy. But a lot of hand waving from 2 data points .

Having said all that it makes me think that I should have tested the Tufo tape earlier on .

horikenji wrote:


Thanks for your inputs and testing. Further indication that a compliant bonding material will suck up some watts. IIRC soft glues may have been used in the data shown on Analytic Cycling which lead many to concluding that thin and hard glue layers were desirable for tubulars ?? I'm not sure exactly how your tests were done - probably climbing at constant speed ??

It was climbing at "as-constant-as-possible" power. Crr was determined from avg. power and avg. speed over the test course assuming constant CdA.

As reduction of body weight by sweating was a source of error, i drank some sports drink between each runs. But i didn't carry any drink during test runs.

I think it was not desirable method, but the resulting Crr values were reasonably consistent over a few test runs.

Using Al Morrison's data, 0.00260 for Tufo tape versus 0.00239 for Mastik, an extra 8.8% rolling resistance. That's a cost of 2.06 J/kg/km. For example when climbing a 7% grade with total mass = 70 kg that's the equivalent of an extra 200 grams carried up the hill.

Yesterday I did the Mt Diablo Hillclimb (we climbed only half the hill in the time trial) which gained 590 meters in 10.0 km. I used Mastik. If I averaged 270 watts, and I weighed 55.9 kg, my bike was 5.5 kg and my equipment was maybe 1.5 kg = 62.9 kg, then that's 1295 J / 270 watts = approximately 4.8 seconds it would have cost me.

It would be interesting t o see what fraction of the riders that would have cost a place in the overall standings. I'm guessing around 25%.

4.7 seconds in a time trial is a big price to pay for maybe 10 minutes of time spent applying glue. in contrast, at my threshold of $3.50/gram saved (which eliminates most carbon bars and stems, for example, as well as virtually all "SL" frame upgrades) it is an effective cost of around $630 (using 62.9 kg).

djconnel wrote:



Good stuff, Dan. It's always nice to see these things put into a diferent context that folks' can more easily relate to. You should be in marketing! )

kraig wrote:


I thought the forum rule was we had to be nice to each other?

JV wrote:



I dig marketing guys, computer scientists, engineers, and...even lawyers! )