Continental's Grand Prix 4000 S II 28's (my tire pressure)
04-20-18, 01:33 PM
#1
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Continental's Grand Prix 4000 S II 28's (my tire pressure)
I put about 2,000 miles on my Vittoria Hyper RFX's last year and they needed replacing. They were essentially 32m road tires. I loved them, but alas Vittoria isn't making them anymore. I couldn't find a 32 that jumped out at me so I went for the Continentals. Those who say they are nearer to 32's than 28's are right.
Anyway... I know we clydes often have tire pressure questions so I thought I might provide my experience. I am 220lbs and I ran 105/97ibs r/f. I was very impressed. Ran as smooth or better than the Vittorias. I will be trying a bit less pressure on Monday and will keep you updated. Riding the mtb tomorrow.
Anyway... I know we clydes often have tire pressure questions so I thought I might provide my experience. I am 220lbs and I ran 105/97ibs r/f. I was very impressed. Ran as smooth or better than the Vittorias. I will be trying a bit less pressure on Monday and will keep you updated. Riding the mtb tomorrow.
04-20-18, 02:50 PM
#2
SuperGimp
I'm also 220 and I run my michelin pro4 tires (25mm) at 90F, 100R unless I'm going on an all-day ride, and then I"ll bump it up 10 psi. The max on the sidewall is 110. I haven't had a pinch flat in a million years (knock on wood). Obviously road quality and your riding style will impact the effectiveness of your tire pressure.
With tubeless 28mm I tried as low as 75 with no issues (and MAN WAS THAT COMFY!)
With tubeless 28mm I tried as low as 75 with no issues (and MAN WAS THAT COMFY!)
04-20-18, 03:07 PM
#3
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If I have full water bottles, my rack, Brooks saddle, etc, I am probably at the same weight, and I am running about 50psi front and 70 psi rear on what are nominally 28mm (the calipers measure them at 34mm on my rims). I've had them even lower, but they feel a wee bit squirmy.
04-20-18, 04:50 PM
#4
SuperGimp
Brooks saddle... yeah, that's the difference in weight. 
Even 75 psi starts to get a little squishy.
Even 75 psi starts to get a little squishy.
04-25-18, 01:13 PM
#5
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Dropped to 98/92 r/f
Didn't notice any additional rolling resistance, but they were definitely a bit more comfy. These really are some great tires (assuming they are durable)! Will lower another 5lbs tomorrow and report back.
04-26-18, 09:55 AM
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Schwalbe Marathon (Green). OEM for my Randonee, 700c x 32. After 5500 mi. they still look like new. My weight fluctuates north of 260.
I run them at 75 psi (front), 85 psi (rear). Max recommended pressure 95 psi.
Normally I feel it if pressure drops below 60 psi (danger for snakebite flats).
I run them at 75 psi (front), 85 psi (rear). Max recommended pressure 95 psi.
Normally I feel it if pressure drops below 60 psi (danger for snakebite flats).
04-26-18, 11:40 AM
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I have Conti GP4K S II 28's and I ride them at 80 psi front and back. I weigh 240-245. I think you can go lower than that.
04-26-18, 11:52 AM
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Wow, you all really ride some lower pressure. I'm sitting about 205-210lbs 'ish and I run my Conti GP at 100psi. I might try 90 to see how that feels.
04-27-18, 01:51 PM
#10
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Dropped to 90/82 R/F
I ran at this weight about 30 miles. With lower weight you definitely notice greater comfort. It seemed to feel a tad squishy--just a tad. I will probably do another 25-35 mile ride tomorrow and will update.
05-03-18, 10:42 AM
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At 220#, I’m running my 25c 4000s at around 105 front and 110 rear but to be honest, I only check them every third ride or so and they've often dropped to a hair below 100 and still roll fine.
For the record, I run 28s on my tandem and pump them to 120 and they feel rock hard. Total weight for the tandem is near 400#.
For the record, I run 28s on my tandem and pump them to 120 and they feel rock hard. Total weight for the tandem is near 400#.
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05-04-18, 02:31 PM
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Keep in mind that that chart shows the weight (axle load) per wheel.
I just got my hands on some GP4's and the first trip was 55 miles of steep mountains (GMR-39) with 60 front and 80 rear. Handled just fine.
Next weekend was 60 mi of flat at 50 front 65 rear. No problems and no "squishiness" Comfort level was almost equal to 42s at 40-55
I weigh around 220. With a 40%-60% distribution that's about 65 front 100 rear if you want theoretical minimum rolling resistance from the chart.
I just got my hands on some GP4's and the first trip was 55 miles of steep mountains (GMR-39) with 60 front and 80 rear. Handled just fine.
Next weekend was 60 mi of flat at 50 front 65 rear. No problems and no "squishiness" Comfort level was almost equal to 42s at 40-55
I weigh around 220. With a 40%-60% distribution that's about 65 front 100 rear if you want theoretical minimum rolling resistance from the chart.
05-16-18, 04:37 AM
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Yes, they are. And they should be durable. I have Conti 4000s on my bikes (I weigh 260 - I run 700cx25'sat 120 psi - I don't like squishy tires and I hate pinch flats) and have for a long time. Others have complained about sidewall issues, but my experience has been that they are about the best combination of durable, fast and grippy around. There are tires that are better at one or two of those factors, but none that I know of that are so good at all three.
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