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cranky
Joined: 20 May 2004
Posts: 146
7/2/13 11:22 PM |
Are 700x20c tires gone from the US?
So, I leave cycling for ten years and when I come back, I can't find a 700x20c tire at any of the LBS's. Can't find any on line, at least not at a US-based retailer.
Would someone please explain to this cranky ol' Rip van Winkle what the deal is? Thanks.
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ErikS
Joined: 19 May 2005
Posts: 8337
Location: Slowing boiling over in the steamy south, Global Warming is real7/3/13 4:21 AM |
They are proven slower than 23mm and now 25mm tires. They ride poorly too.
So they are rarely seen anymore.
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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5101
Location: Nashua, NH7/3/13 5:22 AM |
Exactly
Wider tires have lower rolling resistance, provide better grip, are less prone to pinch flats and can be run at lower pressures that make them much more comfortable (they can really take the sting out of today's stiffer frames). To paraphrase a tired cliche, 25mm is the new 20mm. Essentially, everything we thought we knew about tire width vs. performance in the '80's and '90's was wrong.
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA7/3/13 5:31 AM |
Pretty much any frame and fork will accept 700-23 and most will clear 700-25 tires so there is no reason to use 700-20 tires these days. Above that, you probably run into clearance issues with most road frames and forks.
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Stanley83
Joined: 21 Jan 2004
Posts: 238
Location: The 'ville, Mass.7/3/13 5:44 AM |
The shop i work at still has some in the basement.
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greglepore
Joined: 10 Jan 2004
Posts: 1724
Location: SE Pa, USA7/3/13 5:48 AM |
quote:
Above that, you probably run into clearance issues with most road frames and forks.
Yes, assuming the op is riding his old bike. Most current f/f are accounting for the trend, however. My cheap carbon frame/fork cleared 28's easily, the only issue being getting the calipers to open enough for easy wheel changes.
The other trend cranky should be aware of is the move to wider wheels-23 mm wide wheels with a 17mm or greater rim bed are becoming common, if not the standard. This allows for a more relaxed tire profile, enhancing the benefits of a wider tire. I'm really knocked over by how a 25mm high tpi tire on a 23mm rim performs, it corners much more tubie like (that is the turn in is more linear, less of the tipping in feeling) and the ride is very nice. Not 100% of a good tubular, but so close that I doubt I could tell blindfolded.
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA7/3/13 8:23 AM |
My two Easton carbon forks and Litespeed frames, all dating from 2006, look like they will clear 25c tires but with little slack and absolutely nothing wider.
I do have Tektro brake levers (with Retroshift mounts and dt shifters) that have a qr in the levers and Shimano brakes so I have two qr's per wheel. Open WIDE!
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Sparky
Joined: 08 Dec 2003
Posts: 19080
Location: PDX7/3/13 9:47 AM |
My Blade has a 20 front and a 23 rear on HED narrow clincher rims. Conti
I put on A23 w/25C GP4Ks wheels and the difference in ride was unreal. Out of the bikes I have rode with the A23/25C GP4Ks the biggest noticeable difference.
They are the early Gran Prix tires FWIW.
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April
Joined: 13 Dec 2003
Posts: 6593
Location: Westchester/NYC7/3/13 9:58 AM |
If the OP is asking about 20mm tires, I doubt he's interested in going 28.
I run 25 now but had run 23 before. I'd say the 23 feels lighter on acceleration simply because there's less tire and less air to spin around. Granted, that's totally negated while cruising, when the slightly "flywheel" is carrying speed better.
I always thought the reason for today's wider tires is because they can take higher pressure, which works out on reducing rolling resistance?
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Sparky
Joined: 08 Dec 2003
Posts: 19080
Location: PDX7/3/13 10:09 AM |
While we are on the subject or tire width and rims etc.
Heads up $:
WTB Dual Duty XC 29er Rim @ Bluesky on total!! blowout. 24mm wide and have machined brake tracks.
Not so light for a road wheel @ 540 grams.
But at that price for a commuter/training or 29er wheelset, for-ged-a-bouda....
buy one for 19.95 and get one free.
Also tri-flo 2 OZ for 1.98, which I recommend for general bike use. Especially for STi lube after flushing. 8.00 at the LBS. I lube the last DR whip/housing every few rides and keep the bike shifting crisp and quick. Not great for chains, flys off.
http://www.blueskycycling.com/product3827_61_-WTB-Dual-Duty-XC-29er-Rims-**Buy-1%2C-Get-1-Free**.htm
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JohnC
Joined: 10 Jan 2004
Posts: 1939
Location: Glastonbury, Ct7/3/13 10:56 AM |
quote:
I always thought the reason for today's wider tires is because they can take higher pressure, which works out on reducing rolling resistance?
The reason usually given for wider tires is that the larger volume allows you to run LOWER pressure for a given rider/bike weight while still avoiding pinch flats. The lower pressure provides greater comfort, and more secure cornering, which generally means higher speeds in practice. On very smooth surfaces (velodromes, e.g.) higher pressure means lower rolling resistance, but in the real pavement world that theoretical advantage is lost by the bouncing and chattering.
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Matthew Currie
Joined: 11 Jan 2004
Posts: 802
Location: Vermont7/3/13 6:24 PM |
I know all the arguments, but back when I had a nasty old rough riding Cannondale I liked those 20's. I inflated them hard as rocks and enjoyed feeling every pebble. Practicality be damned. I liked those tiny thin hard little tires.
When I finally replaced the Cannondale and got a newer bike that came with 23's, I went with those, and I probably did go faster. Not as fast as that damn Chrysler, though.
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KerryIrons
Joined: 12 Jan 2004
Posts: 3236
Location: Midland, MI7/3/13 6:40 PM |
Hard going
quote:
I liked those tiny thin hard little tires.
Could we interest you in some solid rubber tires?
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mag7
Joined: 11 Jan 2004
Posts: 888
Location: Lake James, NC7/3/13 7:52 PM |
Suggested new at"tire"
Just took delivery of Vittoria's newly released 700x24 Open Corsa SR 320 tpi which match up nicely to 24mm Velocity wheels. More supple ride vs re"tired" Conti GP4s.
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greglepore
Joined: 10 Jan 2004
Posts: 1724
Location: SE Pa, USA7/3/13 7:54 PM |
Harder still
On an alu Cannondale, nonetheless. Holy chipseal, Batman...
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Sparky
Joined: 08 Dec 2003
Posts: 19080
Location: PDX7/3/13 8:27 PM |
"More supple ride vs re"tired" Conti GP4s."
Been paying 38.00 for the GP4s last 2 sets, how much are the Vitts?
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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5101
Location: Nashua, NH7/4/13 6:07 AM |
You can get the GP4000S for around $40...
...if you buy them from dealers in the UK. It's a supple tire (don't let the black sidewalls fool you) and very grippy.
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dan emery
Joined: 11 Jan 2004
Posts: 6890
Location: Maine7/4/13 7:25 AM |
Hard tires
On an auto forum I check the question of bike tires came up and one guy recommended using 1.5" tires pumped up to 120 psi. I suggested that might be a little, um, stiff, and the guy told me I was nuts, he had ridden them and they were great (he hadn't ridden in years because he was too busy, but he remembered they were great). I said lots of things seem great if you haven't tried anything better, but I don't think he was impressed.
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Pat Clancy
Joined: 13 Jan 2004
Posts: 1353
Location: Manchester, CT7/4/13 7:56 AM |
Aerodynamics
I recently read that part of the push to wider rims had to do with a smoother transition from the tire to the rim. Improves the aerodynamics, apparently more than making up for the small increase in frontal area. Not that I would feel it at my low average speed.
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greglepore
Joined: 10 Jan 2004
Posts: 1724
Location: SE Pa, USA7/4/13 7:58 AM |
The sr's are still pricy, 60/per on ebay in pairs, the cx's around 45-50.
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ErikS
Joined: 19 May 2005
Posts: 8337
Location: Slowing boiling over in the steamy south, Global Warming is real7/4/13 9:24 AM |
Amazon has been my online source lately
There are lots of bike stores there now and you can pic up stub like lever hoods and tires etc for a good price.
Remember, I have no LBS so online is my source for bike gear. The community won't support a shop. The demographics aren't right.
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Sparky
Joined: 08 Dec 2003
Posts: 19080
Location: PDX7/4/13 12:24 PM |
TPI VS ride quality.
Obviously high TPI tires have the TPI per layer added up.
So I guess my question is what is the opinion as far as TPi adding to ride quality. I would assume too many layers is going to make for a stiffer tire. And less ease in conformity to road surface = harder ride...
To what degree point I guess I am wondering...
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA7/4/13 2:20 PM |
quote:
Obviously high TPI tires have the TPI per layer added up.
Some do and some don't. The "honorable" advertisers list the tpi for each layer of casing, e.g. 150 tpi for each layer. The less honorable ones list the total for the two or more layers, e.g. 60 tpi for each of two layers layers is advertised as 120 tpi.
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KerryIrons
Joined: 12 Jan 2004
Posts: 3236
Location: Midland, MI7/4/13 6:31 PM |
Get layered
quote:
I would assume too many layers is going to make for a stiffer tire.
True in principle but in practice pretty much all the tires have the same casing fold pattern so the only time you have "extra" layers is when they put a puncture resistant belt in the mix.
Otherwise all you have to do is figure out how they are doing their TPI count and make the comparison on an apples to apples basis. And even there more threads is not the sole factor because you can have stiff thread that is small diameter and therefore closely packed for a high count but it won't necessarily be more compliant than a lower TPI tire. Rubber durometer and overall tire thickness come into play as well.
Buying tires based on TPI as the only comparison pointwill not lead down the path to full enlightenment.
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