Clincher or tubulars for time trials?
- Thread starter Maverick
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I think the majority of TT bikes i've seen have Tubs on them, like e_guevara said probably due to lightness. People that still ride Tubs say they feel a lot different but i can't comment on it having never ridden a decent Tub. They can be expensive to repair and it is difficult to do it your self, not impossible but difficult. Just my 2 pence worth.Maverick said:
Maverick said:
since you're having to ask this question, I would guess you don't have much experience with time trials or tubular tires. that said, the perceived difference between the two, tubulars or clinchers, won't make any real difference.
the question I have for you is...do you already have experience with tubulars? if not, go with clinchers. good tubulars are expensive, and can be a real pain to mount (stretch, apply glue, apply glue, apply glue, mount). again, go with clinchers.
rv said:
You're right, I'm not very experienced, having only raced one (last) season.
In the 4-5 time trials I did I rode on tubulars, and in the road races I used clinchers.
I never had to deal with mounting and gluing, because I raced on borrowed wheels.
And I'm sure you're right, neither of the two alternatives can be much faster than the other, but traditionally tubulars are more often used in time trials. Tufos seems easier to mount than other tubulars though.
Weight wouldn't concern me for TT efforts, unless there is climbing involved. Rolling resistance, and the drag cross-section would be more important.Maverick said:
Here's a link to data taken by IRC which measures rolling resistance of tires loaded to 50 kg and running on a smooth steel roller at various pressures. It indicates that their Avocet clinchers have a lower rolling resistance that tubulars.
http://www.sheldonbrown.com/brandt/rolling-resistance-tubular.html
Whether tire weight is a consideration depends on the course. If it's a country road out and back, then it won't matter. If there's a lot of cornering, lighter tires are going to accelerate faster. Either way, it's only going to add up to a second or two over 20km. A good smooth clincher is probably the best way to go.RC2 said:Yeah weight isn't much of a consideration for TT. TT bikes are typically heavier as a trade-off for being more aero. Get the most aero tire!
Seriously I wouldn't waste energy on a sew up.
Yeah that's why I said "typical". If we're talking about a run up L'alpe de huez shaving weight is pretty important and tub's may be worth the effort.
But I'm a weekend racer and don't make my money from winning races, and would have a real hard time justifying the amount of effort spent wrangling and gluing a tubular... not to mention worrying about it flying off my rim b/c I don't have a pro-level tech doing a quality glue job for me.
But I'm a weekend racer and don't make my money from winning races, and would have a real hard time justifying the amount of effort spent wrangling and gluing a tubular... not to mention worrying about it flying off my rim b/c I don't have a pro-level tech doing a quality glue job for me.
I'm using tubulars for several years now and I'm very surprised to see, that someone can advise clinchers as "easier" option. Gluing tubular is in my oponion many times easyer than trying to put clincher on a rim. As an weekend racer (I'm also one) You need not pay so much attention to gluing it perfectly. As the biggest disadvantage of tubular for me is fact, that I did not anytime manage to repair any tubular tire.
Blasp said:
Maybe effort was the wrong word, time requirement was what I was getting at... You pull a clincher bead on the rim, insert tube, pull on next bead, inflate w/floor pump, and it's out the door in 2-3 minutes. Tubular: stretch out the green tire, apply cement (I'll assume your using one that doesn't require mixing, another extra step) first coat, let dry, apply another coat, align & pull on tubular, pump, and allow to dry overnight, and out the door in how much time? Get on bike and worry that you used too little cement, allowed it to pool, and are going to eat a curb in a tight turn. Surely with practice that rundown gets 'easy' and maybe I'm being wrongly paranoid about a blow-off crash, but I sure find the clinchers easy to deal with...
http://www.sheldonbrown.com/brandt/rolling-resistance-tubular.html[/QUOTE]
I think that study has a pretty major problem. Larger diameter tires have less rolling resistance than smaller diameter, and you'll see that the majority of the tires tested are of the 25 and 28 mm width. You'll notice tires of similar brands (specialized and avocet) have higher rolling resistance with the skinnier tires across the board. The tubulars are likely 21 or 23 mm, so part of the difference is due to that. The Michelin Hi-Lites do test extremely well, but they test well in comparison to both tubulars and other clinchers. So I wouldn't put too much weight into that study.
http://www.torelli.com/home.html?http://www.torelli.com/tech/tires.shtml&1
Go to the very bottom of this page for info on why wider tires have less rolling resistance.
The main weight savings you'll see from running tubular tires is from the weight of the rim rather than the weight of the tires. A tubular zipp rim weighs 150 grams less than the comparable clincher rim. All told you can save around 400 grams/wheelset with tubular rims.
I don't think that's a very big savings or of much importance for a time trial. Campy shamal wheels are some of the best around for TTs, and they weigh almost 2000 grams for the set.
I would say if you enjoy working on your bike, like I do, then get a set of tubulars. I don't have any trouble gluing them on and don't mind spending a few minutes over the course of a couple days to do it. If you would rather not deal with it, go clincher.
I think that study has a pretty major problem. Larger diameter tires have less rolling resistance than smaller diameter, and you'll see that the majority of the tires tested are of the 25 and 28 mm width. You'll notice tires of similar brands (specialized and avocet) have higher rolling resistance with the skinnier tires across the board. The tubulars are likely 21 or 23 mm, so part of the difference is due to that. The Michelin Hi-Lites do test extremely well, but they test well in comparison to both tubulars and other clinchers. So I wouldn't put too much weight into that study.
http://www.torelli.com/home.html?http://www.torelli.com/tech/tires.shtml&1
Go to the very bottom of this page for info on why wider tires have less rolling resistance.
The main weight savings you'll see from running tubular tires is from the weight of the rim rather than the weight of the tires. A tubular zipp rim weighs 150 grams less than the comparable clincher rim. All told you can save around 400 grams/wheelset with tubular rims.
I don't think that's a very big savings or of much importance for a time trial. Campy shamal wheels are some of the best around for TTs, and they weigh almost 2000 grams for the set.
I would say if you enjoy working on your bike, like I do, then get a set of tubulars. I don't have any trouble gluing them on and don't mind spending a few minutes over the course of a couple days to do it. If you would rather not deal with it, go clincher.
With today's modern tyres, I'd be going for clinchers every time - just a lot less fuss and a bit cheaper.
Try something like the Vittoria Open Corsa CX - in 20 / 23mm section its an ideal tyre for time trials.....
Cheers
bicyclerubber.com
All the rubber your bikes need !
Try something like the Vittoria Open Corsa CX - in 20 / 23mm section its an ideal tyre for time trials.....
Cheers
bicyclerubber.com
All the rubber your bikes need !
Good point about the widths; glad someone looked at the data. Certainly this data isn't the end-all. It is suspect in my mind since it comes from a clincher manufacturer...no surprise their brand comes out best. Also seems like it must be at least 5 years old. As I know nothing about tubulars, don't know if IRC picked low-resistance tubulars for comparison either.
Thanks for the interesting torelli link. I like the discussions of tubular vs clincher and correct tire pressures.
Thanks for the interesting torelli link. I like the discussions of tubular vs clincher and correct tire pressures.
There's no such thing as a kilogram 'force'. The proper metric unit of pressure is the Pascal, which is a Newton per square meter. A Newton being a kilogram meter per second^2. Assuming the author really meant N/cm^2, the numbers are still off by an order of magnitude. The scale on that plot most likely corresponds to bars.ct2 said:
More importantly, the author made no direct mention of how results of the spinning wheel test were corrected for rotational mass.
Also, as dhk mentioned their sample of tires was pretty small relative to the range of tires available.
Yes, and I was surprised to find that Renn makes clincher discs, and that's why I have one......easier to change out. The difference in the weight of their 575 rim is only about 100 or so grams between the tubular vs. clincher, if we compare the same model...the clincher is slightly heavier. Also, not all tires companies are the same. If you look at Vittoria, their Corsa EVO tubulars weigh more than their Open Corsa EVO clinchers (about 60 gm each heavier). Of course, you must take into account the glue on the tubular and the tube in the clincher.leegregory said:
I take it that the pressure scale is bar (14.5 psi), but this certainly does indicate a sloppy approach to the graph. Also agree that without knowing the test procedures and measurement methods, things like rotational mass and aero drag could play a part.artmichalek said:
Also question the value of measurements taken against a smooth steel drum and using these to represent a flat road surface with real textures. If the steel drum only produces a small % of rolling resistance compared to real roads, then seems to me taking measurements and extrapolating results by scaling up the Crr would produce bogus results. http://www.analyticcycling.com/ForcesTires_Page.html
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