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Discussion Starter · #1 ·
I'm riding a specialized roubaix with the rim brakes. I had the specialized stock 25s on there and the tires were getting wore out so I recently purchased the continental 4000 ii grand prix in 28. They ride like a dream but I was having trouble fitting them into the brake without deflating. I even loosened the brake with no luck. Nonetheless, this hasn't been a big deal because the ride was so much nicer....until yesterday I noticed a little bit of a buzzing sound. I stopped and inspected immediately and noticed the tire was rubbing on the bottom of the brake. I checked this when installing and it had very little clearance but clearance nonetheless. Long story short I have an older set of 28 gator skins on a spare bike that measures slightly less than the 4000s. I also have a set of 25 continental 4000 ii grand prix on my wife's bike (which she isn't riding right now). From a comfort standpoint am I better off trying the gator skins in 28 to see how they fit or am I better off riding the 4000s in 25? If unknown I'll just do the quick swap and try both options out but I figured I could save the effort if anyone has tried this before.

Very disappointing that the 28s in the 4000s aren't working out. They're so dang smooth.....I guess I'll have to wait until one day when I upgrade to the disc brake roubaix in the newer models...
 

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If you're looking for comfort the 4000s in 25 would be my choice. It depends on your weight but at 170 I would run them around 85-95lbs
 

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The Gatorskin's rolling resistance is significantly higher than the 4000S II, so I would only use the Gatorskin if puncture protection was of paramount importance. If comfort and efficiency are a higher priority, then get the GP4000S in a size that fits.

FWIW I seem to recall the GP4000S II tend to be bigger than the advertised: e.g. BCR measured the 25mm, inflated at 7 bar, at 27 width/25 height. How big the tire is on your bike, depends however on the rim's width and inflation pressure you will use.
 

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Seems odd u r having brake clearance issues, there must be some adjustments that could be made?

The only issues I had with the 4000s ii were tight frame clearances, but there's just enough space in my frames to be fine.

I think my 25s measured almost 27.



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Long story short I have an older set of 28 gator skins on a spare bike that measures slightly less than the 4000s. I also have a set of 25 continental 4000 ii grand prix on my wife's bike (which she isn't riding right now). From a comfort standpoint am I better off trying the gator skins in 28 to see how they fit or am I better off riding the 4000s in 25?
GP4000 in 25 will be far superior to gatorskins in any width. Gatorskins are heavy duty flat protection tires with reinforced sidewalls. They'll never be as comfortable as the Grand Prix.

FWIW I seem to recall the GP4000S II tend to be bigger than the advertised: e.g. BCR measured the 25mm, inflated at 7 bar, at 27 width/25 height. How big the tire is on your bike, depends however on the rim's width and inflation pressure you will use.
Correct. GP's generally measure 1-2mm wider than the listed size, depending on your rims.


Seems odd u r having brake clearance issues, there must be some adjustments that could be made?
They're rubbing the bottom of the brake. There's no adjustment for the height of the brake caliper.
The frame was probably made with the mounting pivot 1-2mm too low. Only options are smaller tires or possibly a different model brake caliper with more clearance.
 

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I thought comfort frames (especially the Roubaix) was supposed to accommodate giant sized tires?
I have no dog in this. But, OP never said how old his roubaix is. The Roubaix model has been out since around 2005ish. The "must use wide tires" thing has become fashionable in the last couple years. I would not assume an old roubaix was designed to fit the new wide tire trend.
 

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I have had and still do a series of Roubaix bikes over the years. The earlier ones do not fit the Conti 4KSii 28s (which measure 32mm on 17c rims!!!!), the later releases do but with no clearance to speak off.

Suggestion to the OP: If your Roubaix is of earlier release and mid-line or below, most probably came with Tektro brakes. If you replace the Tektro with Shimano you will increase the clearance to the tire, enough to fit a true 28mm tire.
 

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GP4000 in 25 will be far superior to gatorskins in any width. Gatorskins are heavy duty flat protection tires with reinforced sidewalls. They'll never be as comfortable as the Grand Prix.
A sidewall failure is the thing to go for and a tyre with propped up sidewalls is the invention of the devil.
 

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I'm riding a specialized roubaix with the rim brakes. I had the specialized stock 25s on there and the tires were getting wore out so I recently purchased the continental 4000 ii grand prix in 28. They ride like a dream but I was having trouble fitting them into the brake without deflating. I even loosened the brake with no luck. Nonetheless, this hasn't been a big deal because the ride was so much nicer....until yesterday I noticed a little bit of a buzzing sound. I stopped and inspected immediately and noticed the tire was rubbing on the bottom of the brake. I checked this when installing and it had very little clearance but clearance nonetheless. Long story short I have an older set of 28 gator skins on a spare bike that measures slightly less than the 4000s. I also have a set of 25 continental 4000 ii grand prix on my wife's bike (which she isn't riding right now). From a comfort standpoint am I better off trying the gator skins in 28 to see how they fit or am I better off riding the 4000s in 25? If unknown I'll just do the quick swap and try both options out but I figured I could save the effort if anyone has tried this before.

Very disappointing that the 28s in the 4000s aren't working out. They're so dang smooth.....I guess I'll have to wait until one day when I upgrade to the disc brake roubaix in the newer models...
A picture is worth a thousand words.

Can you post a pic please?
 

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Discussion Starter · #12 ·
I have had and still do a series of Roubaix bikes over the years. The earlier ones do not fit the Conti 4KSii 28s (which measure 32mm on 17c rims!!!!), the later releases do but with no clearance to speak off.

Suggestion to the OP: If your Roubaix is of earlier release and mid-line or below, most probably came with Tektro brakes. If you replace the Tektro with Shimano you will increase the clearance to the tire, enough to fit a true 28mm tire.

2015 roubaix sl4
 

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As DC Griz suggested, upgrade your brakes to Shimano 105 or Ultegra, and you should have enough clearance for that tire to clear safely.

You might have the shop techs check the fit to be sure, before you make the purchase. You'll get better braking as well as better tire clearance.
 

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Discussion Starter · #15 ·
As DC Griz suggested, upgrade your brakes to Shimano 105 or Ultegra, and you should have enough clearance for that tire to clear safely.

You might have the shop techs check the fit to be sure, before you make the purchase. You'll get better braking as well as better tire clearance.
I actually brought it to a LBS and the we placed the 105 brake on the bike and it had very little clearance. Needless to say I didn't buy them
 
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