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Old 11-06-07, 07:00 AM   #1
tgzzzz
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fat v. skinny tires

From http://www.schwalbetires.com/balloon_bikes:

"Anyone who believes wide tires mean harder riding is mistaken. With the same air pressure as a narrow tire, a wide tire will roll much more easily. “The wider the tire, the lower the rolling resistance. Because a wide tire has a shorter footprint in the driving direction, the tire bounces less and the flattening of the footprint on the road is smaller”, explained Frank Bohle. Result: The tire deforms less, remains “rounder” and rolls more easily."

I'm troubled by: "with the same air pressure as a narrow tire ..." I thought the idea was low pressure tires would flex more taking up shock. Would you run Big Apples with 90-100# of air? If so, why aren't racers doing it?

There is a lot of conversation on this topic throughout the forum but now I noticed a senior guy on here is running Big Apples on his heavily-modded Swift. Other experienced riders are still going the narrower/higher pressure route. I have a DT 8H with a narrower tire on the front than the back which I had taken to be a good thing, i.e. less weight. And I have front suspension to make up the comfort difference. Now I'm wondering if the 2.0 Big Apples really have less rolling resistance, why not put them on and replace the heavier suspension fork, maybe ending up with easier riding and less weight?
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Old 11-06-07, 08:13 AM   #2
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Could be that racers dont want 2" tires for aerodynamic reasons, but beyond that, I am not going to answer your question, just throw a couple other wrinkles into the mix:

I have a Big Apple in front, where I want the extra cushion and because I want to lift the front of the bike up a little. I have the smallest tire I could find, a Primo Comet 1.35, in back where I have suspension anyway, and I wanted to get the back of the bike as low as possible.

If you replace your suspension fork with a rigid one, make absolutely sure you don't change the geometry of the frame very much. A regular rigid fork is shorter, so the headset of the bike will sit closer to the ground, effectively changing the frame angles -- very possibly with a detrimental effect.
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Old 11-06-07, 08:26 AM   #3
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As RHM said aerodynamic drag is the big factor. Rolling resistance is relatively insignificant compared to aerodynamic drag at higher speeds. So what they say about rolling resistance is true, but aerodynamic drag is a much bigger deal if you ride fast.

That said while touring with panniers and stuff strapped all over the bike the aerodynamic drag of the tires is probably insignificant compared to the panniers.

If you are poking along at 10 MPH neither aerodynamic drag or rolling resistance is probably a big deal.
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Old 11-06-07, 08:43 AM   #4
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At the same air pressure the number of square inches of tire touching the ground stays the same. The shape of the footprint changes from an oval shape on skinny tires to a more rounded shape on bigger tires. My friend and I did a bunch of testing of this when he was racing tandems in RAAM. It was when he switched from 700c rims to mtb rims to get a lighter wheel. There was no difference in ride or cornering but a 36 spoke 26 inch wheel had the strength of a 48 spoke 700c wheel and was a lot lighter. Roger
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Old 11-09-07, 09:49 PM   #5
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Quote:
Originally Posted by tgzzzz View Post
There is a lot of conversation on this topic throughout the forum but now I noticed a senior guy on here is running Big Apples on his heavily-modded Swift. Other experienced riders are still going the narrower/higher pressure route. I have a DT 8H with a narrower tire on the front than the back which I had taken to be a good thing, i.e. less weight. And I have front suspension to make up the comfort difference. Now I'm wondering if the 2.0 Big Apples really have less rolling resistance, why not put them on and replace the heavier suspension fork, maybe ending up with easier riding and less weight?
I put Conti GPs on my Swift because I was out to build it lightweight. Big Apples are heavy, relatively speaking.
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Old 11-10-07, 06:07 AM   #6
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Originally Posted by staehpj1 View Post
If you are poking along at 10 MPH neither aerodynamic drag or rolling resistance is probably a big deal.
Ha! This is certainly true. I ride a little faster than that but I don't cruise over 20 MPH like many of you. And the thought of 30-40 downhill is kinda ... uh ...terrifying. I'm past that green twig fracture age.

Honestly, I'm not experienced enough to find any fault with my stock Kenda Kwests other than they're not cool Big Apples. I'm not used to thinking in terms of grams but I see now that the BAs are relatively heavy.
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Old 11-10-07, 11:00 AM   #7
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I'm not used to thinking in terms of grams but I see now that the BAs are relatively heavy.
Don't get sucked into obsession about weight I think it's rather overrated, even for longer rides at a fast pace. Don't get me wrong, I'm sure a 40lb bike is less fun than a 20lb bike on a hilly ride..

But let's say a typical folding bike weighs 25-30lbs. And a typical rider weighs 175 lbs. So the total weight is 200-205lbs. Even though the Big Apples are heavy tires, the difference between their weight and a set of Stelvios is a very small proportion of the total weight. To my mind, frankly not worth worrying about if comfort means anything at all to you!

There's no such thing as a "performance" bike, some people seem to forget that all bikes come without an engine.. (No, my shopping bike isn't as fast as your racer - but you know what I mean??)
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Old 11-10-07, 12:15 PM   #8
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FWIW, I suspect that Schwalbe is occasionally full of it. Market-speak, that is.

I happen to have both Marathon Slicks and Marathon Racers. The Slicks are 100psi, 20 x 1.25, accelerate well and maintain high speeds, but aren't particularly comfortable. The Racers are 85psi, 20 x 1.5, are more comfortable but are slower than 65psi Kenda Kwests. Oh, and Schwalbe claims the Racers are as fast as the Slicks. Wrong....

I haven't used the Big Apples yet but I seriously doubt that when you're going faster than 15mph, they'd be anywhere near as fast as the Slicks. Even Schwalbe doesn't make that claim.
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Old 11-11-07, 03:58 PM   #9
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Oh, and Schwalbe claims the Racers are as fast as the Slicks. Wrong....
I never saw the claim but I agree that the Stelvios are a faster tire for road riding.

Racers are excellent "everyday" tires. I leave them on for training rides and many club rides too. I can't compare then to the Kenda Kwest, but they are relatively quick and light for their width. And we like them for traveling and touring since they have a folding bead.

I have only used the Big Apples on the Mini. They are excellent everyday tires as well.
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Old 11-11-07, 04:57 PM   #10
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Originally Posted by tgzzzz View Post
From http://www.schwalbetires.com/balloon_bikes:

"Anyone who believes wide tires mean harder riding is mistaken. With the same air pressure as a narrow tire, a wide tire will roll much more easily. “The wider the tire, the lower the rolling resistance. Because a wide tire has a shorter footprint in the driving direction, the tire bounces less and the flattening of the footprint on the road is smaller”, explained Frank Bohle. Result: The tire deforms less, remains “rounder” and rolls more easily."

I'm troubled by: "with the same air pressure as a narrow tire ..." I thought the idea was low pressure tires would flex more taking up shock. Would you run Big Apples with 90-100# of air? If so, why aren't racers doing it?

Now I'm wondering if the 2.0 Big Apples really have less rolling resistance, why not put them on and replace the heavier suspension fork, maybe ending up with easier riding and less weight?
Schwalbe has something very special and for the first time, you can get comfort and adequate performance with fat tires. It used to be to do the same required high pressure tires with expensive suspension systems like the Birdy. Not anymore.

While, using Big Apples will never give you the same performance of a Moulton, it's adequate for most utility cycling. I tested wide Kendra tires on the Strida and it felt just as comfortable as the Brompton costing twice as much. If the Strida had gears, it would have had the same overall speed as a Brompton with faster accleration due to the rigid frame.
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Old 11-11-07, 05:41 PM   #11
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I never saw the claim but I agree that the Stelvios are a faster tire for road riding.
http://www.schwalbetires.com/bike_tires/road_tires

Check out the little graphs next to the tire type. The Slicks have 5 out of 6 bars, the Racers 6 out of 6. Maybe for other tire sizes it's faster, but definitely not for 406.


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Originally Posted by invisiblehand
Racers are excellent "everyday" tires....
I dunno, I found that for 406 they suck. Same with the "regular" Marathons actually....


Quote:
Originally Posted by Dahon.Steve
Schwalbe has something very special and for the first time, you can get comfort and adequate performance with fat tires....
"Adequate," I guess. I suspect they may just be a little faster than you'd expect from a super-wide tire. But if you conclude from the Schwalbe Website Marketspeak that a Big Apple is as fast as a narrow racing tire, then someone is, hmm, how to put this politely... "miscalculating."
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Old 11-12-07, 07:31 AM   #12
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Racers are excellent "everyday" tires. I leave them on for training rides and many club rides too.
Well ... in ERTO 40-406, the Racers are able to support a decent range of tire pressures (50-85), have a slight inverted tread which performs well on roads and paths such as the C&O Canal, relatively light for their width, and seem to have a good durability. The only puncture this year was from a goat head in Albuquerque. At the moment, I am right around 3000 miles on the same set of tires and it looks like they will take me through the winter. They are relatively expensive. Admittedly, this is simply an anecdotal example. What made your experience negative?

EDIT: Note that I switched tires with my wife sometime later in the year. My assessment of their durability is flawed.
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Old 11-12-07, 07:38 AM   #13
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Originally Posted by Bacciagalupe View Post
http://www.schwalbetires.com/bike_tires/road_tires

Check out the little graphs next to the tire type. The Slicks have 5 out of 6 bars, the Racers 6 out of 6. Maybe for other tire sizes it's faster, but definitely not for 406.
But those slicks are not Stelvios ... are they? The tread doesn't match what I have.

If I look under racing, I find Stelvios. Moreover, it isn't clear to me how to interpret the bars. Are they designed to be absolute measures or relative measures within a category?
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