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2018-08-16 12:46 AM
in reply to: bnsafe

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Subject: RE: continental grand prix 2
Originally posted by bnsafe

although that might be in my head with no way to measure that. so all in all, i am extremely pleased.


The head is a very important tool so if changing the tires made you faster, it does not matter if it’s the tires or your head, you were faster. I’ll say it’s the tires as I have just bought myself a pair of these ro replace the ones that came with the bike and believing that I made an excellent choice which will make me faster WILL make me faster, so thanks ??

I changed them myself, my dad tought ne how to fix a flat when I was 10, a skill that has come handy a few times.



2018-09-14 6:13 PM
in reply to: Rollergirl


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Subject: RE: continental grand prix 2
update, well 6 weeks into the new tires my front one blew today. something went right throught the sidewall so had to trash a new tire. they were faster for sure, but now i am really concerned about my back one for my events coming up. went with a different one on the front
2018-09-14 9:46 PM
in reply to: #5247420

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Subject: RE: continental grand prix 2
That’s odd. How much do you weigh and what psi were you running? I haven’t blown one of those tires in the 5 years I’ve been running them or the original 4000S.
2018-09-14 9:56 PM
in reply to: #5249372

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Subject: RE: continental grand prix 2
Oh, I didn’t read your post correctly. Are you saying something punctured the sidewall? Those tires are pretty robust. I’m guessing that would have to be a pretty nasty pothole for that to happen. I would put another one on for the race or at least switch the back tire to the front since the 4000S II is probably going to be more aero than the other tire...the aeroness of the front is more important.
2018-09-15 8:15 AM
in reply to: JoelO


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Subject: RE: continental grand prix 2
something went thru the sidewall, but i was riding on a fairly smooth rode, no potholes. im gonna go ride with this tire i got now and see about speed then go from there. i cant find any local shops that carry 4000s so would have to prime one
2018-09-15 8:16 AM
in reply to: bnsafe


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Subject: RE: continental grand prix 2
oh, i am 6 3 190. so not real over weight, and was running around 115 psi


2018-09-15 11:56 AM
in reply to: bnsafe


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Subject: RE: continental grand prix 2
well i avg 0.5mph slower today. faster than the old tires i had, but not as fast as the gp2. also felt like i had to put alot more power into it. now what to do.
2018-09-16 9:57 AM
in reply to: bnsafe

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Subject: RE: continental grand prix 2

Originally posted by bnsafe oh, i am 6 3 190. so not real over weight, and was running around 115 psi
That may be too much PSI.  What wheels are you using, narrow or wide? What size tire, 23c, 25c?

2018-09-16 2:13 PM
in reply to: Donto


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Subject: RE: continental grand prix 2
25, it says 120 psi. i cant decide on rather to order another gp2 thru prime and put it on, or just ride with whats on it. i have more total rides this year, then i am going to cut back next year (ive trained for a century last year an HIM this year) to where it doesnt really matter cause im burned out. so prob just stick with whats on it and call it good. but man i liked the way th gp2 felt and speed.
2018-09-16 3:55 PM
in reply to: #5249373

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Subject: RE: continental grand prix 2
120 psi is the max recommended pressure. You're running too high using 25s. I would suggest running 100 front/105 rear or, at most, 105/110 front/rear.
2018-09-16 4:07 PM
in reply to: #5249417

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Subject: RE: continental grand prix 2
How many cycling miles have you logged this year? I'm a shade under 2100. I'm going to keep working at it to see if I can boost my ftp this fall/winter.

If you're feeling burnt out you might have more fun concentrating on short course racing...it's a lot of fun and doesn't require a huge training commitment (unless you're competing for a podium spot).


2018-09-16 5:30 PM
in reply to: JoelO


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Subject: RE: continental grand prix 2
i will cut back on the psi. thanks, and yes, it will be short course for awhile with minimal training.
2018-09-16 7:38 PM
in reply to: bnsafe


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Subject: RE: continental grand prix 2
they put a bontrager aw2 on the front. should i buy another gp2 for this race, get it put on but wont have time to ride more than 5 miles or so, or should i just leave whats on it there and go with it
2018-09-16 9:22 PM
in reply to: #5249418

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Subject: RE: continental grand prix 2
Personally, I wouldn’t hesitate in buying a new GP4000s II...I don’t like giving up free speed. Ride a few miles on the new tire and you’re good to go.
2018-09-16 10:03 PM
in reply to: JoelO


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Subject: RE: continental grand prix 2
i went to amazon to order one so i can get it here in time, but they sold out. i will look again tom. the bike shop in augusta has one but 70 bucks for a tire i can buy for 40 anywhere else, so i am stuck with this tire.
2018-09-19 2:59 PM
in reply to: bnsafe

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Subject: RE: continental grand prix 2

Originally posted by bnsafe i went to amazon to order one so i can get it here in time, but they sold out. i will look again tom. the bike shop in augusta has one but 70 bucks for a tire i can buy for 40 anywhere else, so i am stuck with this tire.
I hate how when you reply in a thread that you don't get an automatic subscribe to the thread, any way I digress. 

Too bad I didn't see this earlier I think I may still have an old spare still GP4k in the garage...Did you check with Nashbar or Performancebike?  Nashbar has them for $42.

Any yes you were way too high for PSI.  When I was at off season weight, 180 to 185 I rode 23's at 85 to 90 PSI on narrow rims.  A lot depends on the roads too.  If rough to chip seal you want lower end of PSI, this allows the tire to conform to the irregularities, otherwise this actually will slow you down.  If smooth pavement can go higher.  3 years ago a local sprint race that has a 7mile down and back on A1A along the FL coast was all repaved with smooth pavement and I raced at 100-105 PSI on my wide race wheels, talking about fast.  And I always used latex tubes too.  If I get back to a tribike it'll only be latex or tubeless if the tires are there.  Loving my gravel bike with tubeless and Stans sealant.



2018-09-19 6:16 PM
in reply to: Donto


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Subject: RE: continental grand prix 2
i didnt order any because couldnt get them here on time before i left. i may cough up the money to buy another one in ga if i can it put on. makes me a little nervous in case they pinch a tube or something, so i just dont know.
i wish i had known about the psi, it said 120 so thats what i did. live an learn. duh
2018-09-20 5:02 PM
in reply to: bnsafe

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Subject: RE: continental grand prix 2

120 is the maximum you can inflate to that they guarantee it won't explode.

2018-10-01 5:45 AM
in reply to: Donto

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Subject: RE: continental grand prix 2

I'm 6' and 186 lbs. On my TT bike I ride with the Continental 4000S at around 90 psi. This helps cushion my ride. See the attached link for tire rolling resistance rating. I will not vouch for its accuracy, but I will say I think these tires did seem to boost my speed.
https://www.bicyclerollingresistance.com/road-bike-reviews
2018-10-01 8:23 AM
in reply to: nickster

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Subject: RE: continental grand prix 2
Originally posted by nickster


I'm 6' and 186 lbs. On my TT bike I ride with the Continental 4000S at around 90 psi. This helps cushion my ride. See the attached link for tire rolling resistance rating. I will not vouch for its accuracy, but I will say I think these tires did seem to boost my speed.
https://www.bicyclerollingresistance.com/road-bike-reviews



Those tables are quite accurate. I've seen about 10 tires get tested with numbers very close.

You can go from rolling resistance to watts saved

If tire has a RR of .004 and another has .0035 the watts difference for a 165lb person (75kg) at 22.5mph (10ms/s) is
(.004-.0035) * 75 * 9.81 * 10 = 3.7 watts. This is between 2 pretty gppd tires

So difference between Gatorskins and 4000s with latex (80pis)
(.006-.0033) * 75 * 9.81 * 10 = 19.8watts . yes almost 20 watts

2018-10-01 7:12 PM
in reply to: marcag


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Subject: RE: continental grand prix 2
dunno bout all that math, but they are faster, lol. i will buy a new one before next year, and run lower psi. i looked around at ironman augusta and these tires were much much more prevelant than anything else i saw.


2018-10-01 9:53 PM
in reply to: #5249425

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Subject: RE: continental grand prix 2
Does reducing watts automatically equal faster though? Or does it simply mean you work less and go the same speed? I ask because I train on gatorskins and race on Corsa Open G+. Pretty big difference based on bicycle rolling resistance data. My speeds for the same routes are usually fairly similar though. The Corsa’s “feel faster” but I haven’t noticed any data to support that they are. I’ll take less watts though if it means my legs work less for the same speed.
2018-10-02 5:13 AM
in reply to: Parkland

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Subject: RE: continental grand prix 2
Originally posted by Parkland

Does reducing watts automatically equal faster though? Or does it simply mean you work less and go the same speed? I ask because I train on gatorskins and race on Corsa Open G+. Pretty big difference based on bicycle rolling resistance data. My speeds for the same routes are usually fairly similar though. The Corsa’s “feel faster” but I haven’t noticed any data to support that they are. I’ll take less watts though if it means my legs work less for the same speed.



yes, it means you can go faster on the same effort OR same speed on less effort.

2018-10-02 5:49 AM
in reply to: bnsafe

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Subject: RE: continental grand prix 2
Originally posted by bnsafe

dunno bout all that math, but they are faster, lol. i will buy a new one before next year, and run lower psi. i looked around at ironman augusta and these tires were much much more prevelant than anything else i saw.


Yes the match is not for everyone, but it's to show this ican be quite significant.

BTW, there are equally big savings people can find. For example, clothes are as big.
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