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'15 Cervelo S5 25mm tire rub - Zipp?
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Hi all,

I just got a new pair of Zipp 303 clinchers for my 2015 Cervelo S5 and bought a 25mm GP4000II for the rear. Now, I had read that the '15 version of the S5 was designed to fit a 25mm tire but I am getting *the slightest* amount of run on the non-drive chainstay, pretty much only under power but enough to make me want to change the tire. Bought the wheel from a reputable dealer who had just rebuilt the hub and trued the wheel after the hub recall so I know that is not the issue.

Anyone else have this issue? Oh well, back to 23's...

Thanks!
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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Even a good wheel builder may need to make adjustments from time-to-time. Take it back to the dealer and let them know of your issues. They should be able to make slight adjustments to wheel tension to reduce this from happening.

I just went though something similar myself (on the drive side). I have two of the same sets of wheels, and one seemed to be produce this tire rubbing on the drive-side (under power / climbing). I have a spoke tension meter and noticed that (In the rubbing wheel) my spoke tension was higher on the drive side than in the wheel with no rubbing issues. I solved my own problem by backing off the spoke tension on the drive side.
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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Yes, I've seen this also. Rubs under load. You're not alone with this problem.

The repair was a replacement with an updated S5 frame.
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [Slunnie] [ In reply to ]
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I have a 2015 S5, I use a 2015 Zipp 808 rear with 25mm contis and I have never had such a problem.
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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There are likely a couple of issues going on here. Your wheel could be slightly dished to the drive side, or your frame could be slightly out of alignment. Either way, you can solve it with a quarter turn dishing to the non-drive side. The other issue is that a 25mm tire is generally not 25mm. Your 303's will have bead seat width of 17.5mm so the tire will measure 27-27.5mm wide on that wheel, whereas a 404 or 808 have a 16mm bead width so the tire will measure more like 26mm wide on those wheels. Dropping air pressure will also help. from 100-115psi will see that tire grow by nearly 0.4mm which could be the difference between rubbing and not.

We wrote a blog article on this issue that may help explain further: HERE

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Re: '15 Cervelo S5 25mm tire rub - Zipp? [joshatsilca] [ In reply to ]
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Hello joshatsilca and All,

What wheel do the colors on your purloined chart represent?

Thanks for the info ..............

Cheers, Neal

+1 mph Faster
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [Slunnie] [ In reply to ]
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Slunnie wrote:
Yes, I've seen this also. Rubs under load. You're not alone with this problem.

The repair was a replacement with an updated S5 frame.

There is no updated S5... the current S5 has been the same 2015-16.

The 2013-14 had narrower chainstays...
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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I got chainstay rub on my 2015 S5 with both a Flo 30 and a Hed Jet 6+, and Conti GP4000S 25mm.

The posted tire width alone won't tell you whether you will rub, it's the tire-rim combination that matters.

Graham Barron Design: Custom west coast house design http://www.grahambarron.com/
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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Check the springs on your QR to also make sure they are in the proper direction and QR is fully in the drop outs.

Or take the bike and wheel back to the wheelbuilder and ask for them to adjust the dish. They can make some small adjustments and make it fit properly.
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [Ghost234] [ In reply to ]
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update: trued the wheel myself and backed off the QR pressure - the combo seems to have fixed the problem.

however, in truing the wheel, i think i altered the spoke tension slightly - any significant danger in riding around on a wheel where the spokes are a bit uneven in tension? or should i shell out the $$ for LBS to check it?
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Re: '15 Cervelo S5 25mm tire rub - Zipp? [johnj121591] [ In reply to ]
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Sorry to bump up an old post, but I'm able to run 25mm Vittoria Corsa G+ on Zipp 404 FC. I have a 2012 S5 Team size 51.
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