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Continental Grand Prix vs. GP4000 profile
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My road bike is a Giant Propel. My rear brake cable that goes across my tire scrapes on the tire when I close/use the brake. The cable is frayed and it wears a flat spot on my tire... I've stopped using the rear brake. I'd use it if I had to... I digress, I was looking at the "regular" Grand Prix tire and was wondering if it had the same profile as the GP4000. I know the GP4000 are a bit taller than most 23 tires. Otherwise it (regular Grand Prix) looks like it might be a good tire for my road bike and getting through the winter, riding rollers and the occasional spin outdoors when it's warm enough.

If its roughly the same profile, I might just spend the extra couple of $'s since I know and like the GP4000s outside of my rear brake issue. :\
Last edited by: xeon: Nov 20, 15 6:32
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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Why is your rear brake cable going across the tire? I have never seen a case like that. Any pics?
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Re: Continental Grand Prix vs. GP4000 profile [RichardL] [ In reply to ]
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RichardL wrote:
Why is your rear brake cable going across the tire? I have never seen a case like that. Any pics?

Giant propels have a brake that is a bit like a v brake on a mountain bike, only the cable is closer to the tyre to reduce cable pull making it work with road levers.

I'm surprised they don't work with 23c tyres though.....
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Re: Continental Grand Prix vs. GP4000 profile [RichardL] [ In reply to ]
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It looks like this... it's a Giant proprietary brake design thing AFAIK, sort of a mountain bike type of design...




Not a huge fan of these brakes, love the bike but the brakes are disappointing. These are factory replacements as the originals were impossible to adjust. These are better but have clearance issues... these are 23mm tires. Worn a flat spot on the tire and they still scrape the brake cable. Anyway these are 4000s and the rear touches the brake cable when I close them.

I may pull the trigger on the Grand Prix's although one review says something about a taller sidewall than the 4000 S II tires.. taller is bad for this bike.
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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This is buffoonery.

maybe wider rims would reduce the tire profile - either way this has to go. Horrible.
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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Can't see the pic. I have two friends that ride Propels with 4000S2s. No problems. But I think the profile is the same as the 4000. Can you repost the pic?
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Re: Continental Grand Prix vs. GP4000 profile [FatandSlow] [ In reply to ]
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Maybe this will work for you... mine hits big time. This is a 4000S (not IIs) on a Ksyrium SLS I ordered the Grand Prix's, we will see. :/
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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4000S is closer to 24mm than 23mm fwim. I suspect a wider rim would reduce the issue and that the bike/frame was designed with that in mind somewhat. Michelins on the opposite end seem ot run a little undersized.


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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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This is the brakes on some of the older Propels. See your LBS about having them upgraded to the newer version which has the proper amount of clearance.
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Re: Continental Grand Prix vs. GP4000 profile [DeanV] [ In reply to ]
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Wow, that is just ridiculous. It fraying the cable. This is simply dangerous. Surely any bike should safely run 23c tyres, they aren't particular big by any means.
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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Which gen of the brakes are you using? I am on the MY 2015 Propel with the Speedcontrol SL-TI (not the carbon) brakes. I have more clearance problems in the front that the rear. However, I run the 25mm GP 4Seasons on 23mm wide rims f/r with no problems. I have also run Schwalbe ONE 25's in the rear with no issue. 23mm of both the GP4000S and the One's f/r with no problems.

If you are having the clearance problem consistently one place to look is at the Fouriers aftermarket brakes, which will allegedly increase clearance and allow you to keep using the tires you want to use.

http://www.fouriers-bike.com/...3&cid=10&f=2
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Re: Continental Grand Prix vs. GP4000 profile [JesseN] [ In reply to ]
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I am looking at buying a new propel but the brakes and stories like the OP's are what is holding me back. How are the stock brakes for switching between wide and narrow rims? Do you find them finicky at all once they are setup or do they stay in place pretty well with no rubbing? Also any comparison to a regular Shimano DA /Ult setup for stopping power?
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Re: Continental Grand Prix vs. GP4000 profile [Jmath] [ In reply to ]
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The brakes have been a non-issue for me. There were tons of complaints after the first version, and the '2.0' really nailed it. I might wish for a little better tire clearance, and it doesn't seem like it'd be a huge burden to Giant to shift the bosses 2mm on the frame to account for it. The wheel/tire combinations that have problems seem very individual to the bike.

As far as setup goes, they are a 'V' style brake and that will inherently be more maintenance intensive vs. a standard caliper. I had to tweak the set screws a lot at first, but they eventually settled in and require almost no adjustment now. A lot of this comes from keeping your bike and brakes clean. Get crap in the housing and or noodle, you'll be done for. Cable routing for the brakes is less than ideal aero-wise. Took me a little while to get over the look.

Stopping power and modulation is really excellent IMO. I don't have to think about it.

Brakes aside, the Propel is a really, really, really excellent bike, insanely stiff, excellent handler with the beefy 'overdrive' front end. The Giant OEM parts are aces. The bike is generally pretty well thought out. I have the mechanical Ultegra. In retrospect I would have ponied up for the Di2 as it will make some of the wrenching headaches go away. If you go mechanical, you absolutely must built using Shimano polymer coated shift cables. Do not skimp on these. Normal cables will shift like crap.
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Re: Continental Grand Prix vs. GP4000 profile [DeanV] [ In reply to ]
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I think these are the upgraded version my bike shop installed after I bought the bike, maybe not? All I know is that my rear brake stinks, otherwise I love this bike!

Closing and using my rear brake currently goes like this.. at about half pull the cable contacts the wheel and bites in deeper as you grab it all the way. This in turn causes the left side brake part to not open fully after you release and it doesn't spring back away from the wheel. Not good.

Yes I know about the Fourier brake, but IMO having to buy a brake just so my 23 tire doesn't scrub the brake cable is a bit much IMO. It may be the route I go.

Adjusting it for a wider tire is easy, the caliper has two places for the cable... one for thinner wheels and one for wider wheels. Squeeze the caliper release it and put it in the wider slot... reverse for thinner wheels. Super easy!

I'm thinking I'd like to engage Giant on this one, this rear brake is just "off".
Last edited by: xeon: Nov 22, 15 15:56
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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Looking at my bike there are varying clearances front and rear. It wouldn't surprise me if there are some issues in consistency in placing the bosses on the frame. That is to say, some frames may have more clearance than others, and you may have gotten a bad one.
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Re: Continental Grand Prix vs. GP4000 profile [JesseN] [ In reply to ]
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JesseN wrote:
Looking at my bike there are varying clearances front and rear. It wouldn't surprise me if there are some issues in consistency in placing the bosses on the frame. That is to say, some frames may have more clearance than others, and you may have gotten a bad one.
I was having the same thought. I've looked at pics and there's all sorts of clearance on other bikes, no fraying brake cables or flat spots on top of tires. Now to figure out how to get in touch with Giant.
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Re: Continental Grand Prix vs. GP4000 profile [xeon] [ In reply to ]
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To follow up on my own thread, Giant has informed me there is a Gen 3 brake that fixes all of the Gen 1 and 2 (I guess that's what I have now) issues. I relayed this to my bike shop and they are going to get the latest Rev of my brakes... hopefully that solves my brake saga on an otherwise awesome bike.

Props to Giant for improving and sending out parts to remedy this sort of thing. Will follow up after I get Rev. 3 installed.
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