# Synapse Carbon Frame Issue



## mcwenzel (Jun 9, 2006)

*Synapse Carbon Frame Issue - With pics*

I have a 2015 Cannondale Synapse Carbon 3. Purchased new, never crashed.

Last week I was cleaning my bike, took off the rear tire to clean and put a new tire on and noticed what looked like a scratch. Then I looked closer and it looked like the something had happened to the carbon layering. Then I noticed it was on both sides of the chainstay.

Took it to local bike shop who sent it off to Cannondale for a possible warranty issue. Been more than a week now and have not heard anything back.

Anyone experience anything like this on their carbon Synapse?


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## tlg (May 11, 2011)

Looks like tire rub. What size tires are you running?


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## mcwenzel (Jun 9, 2006)

Michelin Pro 4 Service Course 25's on Hed Ardennes Black wheels. 

Bike came with 28's I think. It's designed for up to 28's.


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## Bob Ross (Apr 18, 2006)

The good news is, if it is some kind of carbon delaminating issue, Cannondale is pretty good about warranty replacement. Many years ago my wife discovered an odd looking "seam" in the toptube of her (then 1-year-old) Cannondale Synapse Carbon frame. Brought it back to the shop where we bought it, shop manager says "I'll show it to the Cannondale rep when he comes by next week. Rep comes by next week, takes one look, says "I'd be pretty upset if my new frame looked like that too." 

Three days later my wife had a brand new frame. And this was after she'd been riding the bike for a year!

Never did find out what that "seam" was all about.
*************

OP, the symmetry of those lines makes me think it's either an issue with the resin where the chainstays were plugged into the bottom bracket assembly ...OR, as tlg mentioned, tire rub. 

I've seen a _lot_ of carbon frames get a single line like that (on one side or the other) just from a tiny bit of glass or stone embedded in the tire tread scraping the frame for a few revolutions. But never seen a mirror-image pair on both sides like that before.


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## tlg (May 11, 2011)

Bob Ross said:


> I've seen a _lot_ of carbon frames get a single line like that (on one side or the other) just from a tiny bit of glass or stone embedded in the tire tread scraping the frame for a few revolutions. But never seen a mirror-image pair on both sides like that before.


It's not a single line. If you enlarge the pics, you can see a large line and multiple smaller lines. Along with shiny areas where the tire was "polishing" the paint.


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## mcwenzel (Jun 9, 2006)

*Pics of tire clearance*

Per the manual:

The actual measured size of a tire may be different than its sidewall marking. Each time you mount a new tire, take the time to inspect the actual clearance between the rotating tire and all parts of the frame. The U.S. Consumer Product Safety Commission (CPSC) requires at least 1/16" (1.6mm) tire clearance from any part of the bike. Allowing for lateral rim flex and a wheel or rim that is out-of-true will likely mean choosing a rear tire that provides even more clearance than the CPSC recommends.


My quick measurement is at least 2.5 mm clearance on each side.


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## ToiletSiphon (Jul 23, 2014)

It's tire rub, exact same thing happened to me but I found it before it went through the clearcoat. The little rubber pins on your tires are rubbing against the frame. If they are a bit dirty, it causes abrasion over time. Fixed it by cutting every rubber pin on any tire I mount on the back wheel. 

Envoyé de mon XT1563 en utilisant Tapatalk


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## mcwenzel (Jun 9, 2006)

Cannondale replaced the frame. Very happy with the service and with Cannondale standing behind their product. Confirmed clearance not an issue with my wheels with LBS.


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## Lombard (May 8, 2014)

mcwenzel said:


> Cannondale replaced the frame. Very happy with the service and with Cannondale standing behind their product. Confirmed clearance not an issue with my wheels with LBS.


Cannondale is excellent about honoring their warranties. I think they see that giving the customer the benefit of the doubt pays for them better than scrutinizing the damage. If it had been Trek, they would have told you to go scratch.

I have to wonder though if Cannondale paid your shop for the labor involved with transferring all your components over, or did your shop eat this?


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## mcwenzel (Jun 9, 2006)

Lombard said:


> Cannondale is excellent about honoring their warranties. I think they see that giving the customer the benefit of the doubt pays for them better than scrutinizing the damage. If it had been Trek, they would have told you to go scratch.
> 
> I have to wonder though if Cannondale paid your shop for the labor involved with transferring all your components over, or did your shop eat this?


I paid to have the components switched over. $150. Also paid $30 to the shop for doing the warranty paperwork.


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## Lombard (May 8, 2014)

mcwenzel said:


> I paid to have the components switched over. $150. Also paid $30 to the shop for doing the warranty paperwork.


Sounds fair enough considering that's what a shop generally charges for a major tune-up.


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