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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 08-25-11, 10:53 PM   #1
Ritterview
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Continental GP4000S Road Tyre - Twinpack

Probikekit has a 15% off sale on their usually good price on Continental GP4000s 25 mm tires, a twinpack for $93.37, or $46.69 per tire. No shipping, no sales tax. The suggested retail on these are $75.

I've become a big fan of the GP4000s since purchasing a pair (reflective sidewall), October 2010. Nice feel, supple, light and fast. And in nearly a year of riding, we haven't had a flat, and they haven't worn out.




Now, we don't generally have to ride on bad roads, and we are a sub <300 lb team that doesn't need a 28 mm tire. Otherwise, I don't see the advantage of a more rugged tire. Had we been on Gatorskins for the last year, we would have no fewer flats (zero), but would have had heavier, stiffer and greater rolling resistance tires. The GP4000's combination of performance and flat resistance is hard to beat, which likely explain why it is seen on a lot of RAAM tandem bikes.

But, this is just my opinion based on one year of riding on these. Anybody else think that their tandem tire is The Bomb?
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Old 08-26-11, 12:33 AM   #2
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I also like the 4000s. Got the reflectives, but don't like that feature. Too difficult and time consuming to find the label and put it over the valve hole when changing flats. I also dislike the new standard of putting the label on both sides of a tire. It's supposed to only be on one side, the skewer side. When everyone puts the labels on both sides, one can't even complain with one's dollars.

That is a good price. Bike24 has them for 29.90 Euros, which is 3 dollars less but there's shipping, but that's been the cheapest place.
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Old 08-26-11, 06:04 AM   #3
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Have them on our tandem too, great tire with excellent road feel. We are also a lighter 285lb team and find we don't need the size and weight of a 28mm. In 8months (knock on wood) no flats! We have the standard black side wall with black chilli compound. I would buy again when needed.
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Old 08-26-11, 06:33 AM   #4
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We (~330 lb team) have ridden Gatorskins for years in 28 mm, but recently decided to try out the Panaracer Paselas. Liking them a lot. Wish they had a bit more subtle sidewall color. Have a 32 mm on the rear at the moment (front doesn't clear a 32), running it at 110 lbs and liking the feel, though I'd be hesitant to make any specific claims. Really don't see the point of hard and narrow given all we seem to know about rolling resistance and pressure. Additional benefit of wide is when you want/need to do that stretch of dirt/gravel, as when we were in Vermont this summer.
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Old 08-26-11, 06:40 AM   #5
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So what kind of mileage are you talking about in 1 year or 8 months. I just changed out a Schwalbe Ultremo DD that was on the rear with around 2,000 miles on it, from the looks of it there is probably another 500-1,000 miles left. We are going to the Midwest Tandem Rally next week and I wanted a fresher tire on the rear. Moved the front to the rear and put a new Schwalbe Ultremo ZX on the front, both tires are 25mm.
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Old 08-26-11, 09:49 AM   #6
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PBK has a 10% off Promo code today, SUPER10, including sales items.

This brings the twinpack down to $84.03, or $42 per tire. With no sales tax, shipping, that is the lowest price you are likely to find in a while.

This code was only issued today because I ordered my GP4000 s's yesterday!
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Old 08-26-11, 11:30 AM   #7
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I would estimate about 1200 miles so far on them, and showing hardly any wear. Due to our light weight I run 100 psi front and 110 rear.

Quote:
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So what kind of mileage are you talking about in 1 year or 8 months. I just changed out a Schwalbe Ultremo DD that was on the rear with around 2,000 miles on it, from the looks of it there is probably another 500-1,000 miles left. We are going to the Midwest Tandem Rally next week and I wanted a fresher tire on the rear. Moved the front to the rear and put a new Schwalbe Ultremo ZX on the front, both tires are 25mm.
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Old 08-27-11, 05:57 AM   #8
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PBK has a 10% off Promo code today, SUPER10, including sales items.

This brings the twinpack down to $84.03, or $42 per tire. With no sales tax, shipping, that is the lowest price you are likely to find in a while.

This code was only issued today because I ordered my GP4000 s's yesterday!
GREAT DEAL it's the best price I've ever seen on these! thanks.
Even though I've got a good supply I couldn't resist so I bought another pair. With all the bikes we have they'll get used by next year.
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Old 08-27-11, 06:54 AM   #9
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[QUOTE=teamdonterri;13136626.... Due to our light weight I run 100 psi front and 110 rear.[/QUOTE]

We're not a light weight team (~350 lbs) and with 28mm tires (Conti GP 4 Seasons) we run 105 front/110 rear. Probably have 3000 miles at this pressure with no problems and the rear tire wire has definitely improved.
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Old 08-29-11, 10:08 AM   #10
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PBK sporadically has very good prices and tends to ship free to the US for smaller
lighter items. We scored Michelin Pro 2s in 25mm for $37 a few years ago and
about 3mo ago they had Conti Gatorskins in 25mm folded variant for $28 after the
10% discount. Not sure how they can do that, but I ordered 8.
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Old 08-29-11, 10:37 AM   #11
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I found them cheaper at Ribble.
They do charge for shipping but it is still less than PBK I think.
I have bought most of my parts from Ribble as they seem at have the lowest prices and best stock. PBK is many times out of stock.
I agree these are the best combo of performance and durability for a tandem.
I don't like them on my single bike though so I use Michelin Pro3 front and Krylion back.
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Old 08-29-11, 10:41 AM   #12
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I like the regular (non-S) GP4000 better. They last a little longer and are more flat resistant. I have been running the GP4000S and got 3 flats on the Hoodoo 500 this past weekend. Plus a flat the week before - 4 flats in like 2 weeks (2 front, 2 rear).

They are great tires, don't get me wrong, but time lost changing a flat is more than time lost by using the standard GP4000 v. GP4000S.
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Old 08-30-11, 05:24 PM   #13
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A lot of good tips on the Road Bike forum thread:

Where do you get your GP4000s?
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Old 08-30-11, 06:24 PM   #14
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Ritterview, can you tell me how many miles you are getting on the GP4000's
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Old 08-30-11, 06:57 PM   #15
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I like the regular (non-S) GP4000 better. They last a little longer and are more flat resistant. I have been running the GP4000S and got 3 flats on the Hoodoo 500 this past weekend. Plus a flat the week before - 4 flats in like 2 weeks (2 front, 2 rear).

They are great tires, don't get me wrong, but time lost changing a flat is more than time lost by using the standard GP4000 v. GP4000S.
Your results are the exact opposite what me and all of my riding buddies have experienced. The GP4000 in black chili is the exact same tire as the GP4000S except slightly different graphics so if you've experienced differences on all black tires then it's just a coincidence. The other color GP4000 tires are much inferior due to the fact that they use a different rubber compound that doesn't hold up as well nor ride the same. The colored GP4000 tires we've used suffered many more cuts and didn't last as long as the GP4000S. WE used these for several years on multiple bikes so our sample size was large. Plus the road feel of the black chili crubber compound is much improved from the colored versions. We're experiencing 500-1000 miles longer life with the GP4000S vs the colored GP4000 on single bikes.
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Old 08-31-11, 11:26 AM   #16
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Originally Posted by 2frmMI View Post
...Really don't see the point of hard and narrow given all we seem to know about rolling resistance and pressure. Additional benefit of wide is when you want/need to do that stretch of dirt/gravel, as when we were in Vermont this summer.
I don't see the benefit of hard and narrow on a tandem either. A 300lb team on 25mm tires would need 140psi to get the deformation as a 28mm tire at 120 psi. Heavier than that, and your off the chart.

Are you 25mm guys pumping your tires up to 140 psi, or you don't mind the higher rolling resistance of a 25mm tire at the same PSI as a 28mm tire (120psi). Just curious as to the thinking and actual inflation used there.

I assume you have seen this chart:

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Old 08-31-11, 11:33 AM   #17
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Ritterview, can you tell me how many miles you are getting on the GP4000's
Actually not. My tandem miles and half-bike miles are all conflated on my Garmin. I can check the stoker Node, but this may have been reset. GP4000's are an oft-discussed known quantity on the road bike forum, however, and the mileage on a tandem is likely not much different than a half-bike.
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Old 08-31-11, 11:40 AM   #18
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Are you 25mm guys pumping your tires up to 140 psi, or you don't mind the higher rolling resistance of a 25mm tire at the same PSI as a 28mm tire (120psi). Just curious as to the thinking and actual inflation used there.
Yeah, but there aren't any 28mm tires as sporty as a GP4000s, that I know of. So you get stuck with a higher-rolling-resistance tire like a Gatorskin or 4-seasons in 28.



I got a pair of the 25mm GP4000 non-S in black for about $65-70 a year or so ago. Love em! I run about 100 psi with a kid stoker. I have run with two adults, don't remember the psi but it wasn't over 120 - no problems.
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Old 08-31-11, 02:03 PM   #19
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Hi,

Thanks for posting the sale price and reviews, everyone.
I looked for these tires last month and could not find the 25's that we usually run or the 28. I have not used any continental tires in years after getting some gatorskins that developed a lump rather quickly.

I ordered 4 Schwalbe tires, 2 Ultremo DD and 2 Durano plus all 4 in 25 width.
I have never used Schwalbe before.

We are signed up for Cycle Oegon next month,the 11th thru the 18th and I prefer new tires for that week.
This will be our 6th time on the tandem.

I mounted the Durano plus just the other day but have yet to try them, probably this Saturday.
They are heavier and were a little hard to mount. Not so much as in fit but in stiffness due to being thicker even though they are a folding tire. They do not appear that wide on the wheel. They have a slight tread on the sides which may be helpful on wet roads.

I may pack the Ultermo DD set for the week long trip, just in case.

Last year I used the Vittoria cx 320 tpi in the 25 size. These were the nicest and fastest feeling tire ever used on our tandem, but they flatted easily and did not last long.

The year before the pro race 2 model, it seem to wear a little better and had a wide appearance for a 25.
I was sorry to see this model get phased out.

I just took off the Michelin pro optimum model (25c) for the front and rear. They are a nice riding tire and wear out at a normal tandem time frame or slightly sooner for us. The rear was getting a little square but could have gone longer. The front was fine and I moved it to my old winter bike for a front tire. These tires have a very thin upper side wall. I had one on my single bike that cut and pinched a few tubes before I realized the cause. In defense of the tire, I could have put the small nick in it transporting the bike or catching it on something in the garage, because I don't remember hitting anything that high up on the side wall.

I will try to post a Schwalbe review after some rides.

rob
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Old 08-31-11, 03:18 PM   #20
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Based on the chart above our ideal pressure is way off the chart. 240 captain + 120 stoker + 40 bike = 400
We are running 700 x 28 Continental GatorHardshells on our Cannondale. I fill them to the 116 max pressure.
500 miles since May 15 and no problems, city streets and pot holes, Chicago steel grating surfaced bridges, suburban roads and railroad crossings, crushed limestone paths.
No problems so far. Are we just lucky?
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Old 08-31-11, 03:51 PM   #21
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I don't see the benefit of hard and narrow on a tandem either. A 300lb team on 25mm tires would need 140psi to get the deformation as a 28mm tire at 120 psi. Heavier than that, and your off the chart.

Are you 25mm guys pumping your tires up to 140 psi, or you don't mind the higher rolling resistance of a 25mm tire at the same PSI as a 28mm tire (120psi). Just curious as to the thinking and actual inflation used there.

I assume you have seen this chart:
Yeah, there seems to be a movement towards wider tires and lower pressures, with the realization that thinner, high pressure tires do not have the advantage in rolling resistance that has seemed intuitive. Thus, in half-bike, 25 mm tires are gaining favor in comparison to 23 mm, and in tandems, 28 mm.

However, low-resistance racing tires are hardly available in 25 mm, let alone 28 mm. As mentioned above, the sportiest 28 mm tire is the Continental 4 Seasons, which will weigh 40 grams more per tire than a 25 mm GP4000s, lack the Black Chili, and have higher rolling resistance.

If 28 mm Conti 4-Seasons are advantageous on tandems, then you'd probably find examples on tandem racing venues, such as RAAM, time trials, etc. The photo's I've seen always seem to have 25 mm, despite what is extrapolated from Bicycling Magazine, June 1989.
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Old 08-31-11, 04:30 PM   #22
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I am using GP4000s 700x23 on the front and 700x25 on the rear.
I use about 125 psi and it works fine, in fact I prefer the 700x23 on front because it doesn't feel as clunky to me.
I discovered this by accident because I need to put a new tire on the front and the 700x23 was all I had at the time.
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Old 08-31-11, 05:01 PM   #23
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It looks like someone needs to tell Michelin that bike tires need to be wider. Here is a copy of the press release for the new Pro4 tire, http://www.michelin.com/corporate/co...IN-PRO4-EN.pdf

The widest tire they are offering in this series is 25mm.

I believe that i am going to stay with 700 X 25 tires.
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Old 08-31-11, 08:05 PM   #24
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If I hadn't already stocked up on Fortezza's earlier this year during a similar deal, I'd be snapping up a 1/2 dozen of these bad boyz:

http://www.biketiresdirect.com/produ...stein-fortezza

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Old 08-31-11, 08:23 PM   #25
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these bad boyz:
Yeah, well, if they had 28s maybe.
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