Cracked Pinarello Dogma F8 Fork

[smellymcfatfats]

I recently discovered a crack in the steerer tube on my Dogma F8, and was pretty bummed. I wanted to get some PF opinions on what to do next? I realize the bike is four generations old, so sourcing a replacement fork would be challenging I assume? Is carbon repair on a steerer tube worth it, and safe? Is the frameset toast, and should I just go shopping for a 58cm carbon race bike?

[saab2000]

Can you post a pic of the crack? Where on the fork is it?

[hernium]

I'm not sure if the length of the steerer tube would be enough for your frame, or if it even matches the color of your frame, but it would be a good shout to check out this one: https://www.cykom.com/products/pinar...ack-white-used

[verticaldoug]

I am close to the Pinarello Concept store people in London and am happy to ask the guys in the shop if you want.

I'll be over there this weekend so it's no problem.

D

[tellyho]

Curious: what led you to find the crack? (AKA how will I know if there might be a crack developing in my steerer?)

[zmalwo]

it really depends on the location. if it's not where the compression plug and stem clamp pushing against each other (the upper most part usually unless you run spacers on top of the stem which is a VERY bad practice for carbon steerers), you can stack as many layers of carbon as you want on the inner side of the steerer tube and use a bar that is a size smaller to firmly roll around the carbon sheets and compact them. The repair has to be done on the underside as doing repairs on the outer surface is tricky because 1. you can't compact it as good as when it was manufactured so the strength isn't there. 2. if you layer up too many layers of carbon to compensate for the differential in strength, you can't get the bottom bearing in. but this can be circumvented by installing the bearing first then do the repair and layer up as many layers of carbon as you want but you will not be able to take the bottom bearing out once the repair is done unless you sand down the repair site then re do the repair each time you change the bearing.

[Nomadmax]

Originally Posted by zmalwo

it really depends on the location. if it's not where the compression plug and stem clamp pushing against each other (the upper most part usually unless you run spacers on top of the stem which is a VERY bad practice for carbon steerers), you can stack as many layers of carbon as you want on the inner side of the steerer tube and use a bar that is a size smaller to firmly roll around the carbon sheets and compact them. The repair has to be done on the underside as doing repairs on the outer surface is tricky because 1. you can't compact it as good as when it was manufactured so the strength isn't there. 2. if you layer up too many layers of carbon to compensate for the differential in strength, you can't get the bottom bearing in. but this can be circumvented by installing the bearing first then do the repair and layer up as many layers of carbon as you want but you will not be able to take the bottom bearing out once the repair is done unless you sand down the repair site then re do the repair each time you change the bearing.

I may have read this wrong. Can you elaborate why having spacers above the stem on a carbon steerer is very bad?

[oldguy00]

Originally Posted by Nomadmax

I may have read this wrong. Can you elaborate why having spacers above the stem on a carbon steerer is very bad?

Not sure if this is what they meant, but one issue can be that if the section of steerer above the stem is long enough, the compression plug may not be reaching all the way down through the stem clamped section...

As for repairing the cracked fork, I'd send pics to Craig Calfee.

[Nomadmax]

Originally Posted by oldguy00

Not sure if this is what they meant, but one issue can be that if the section of steerer above the stem is long enough, the compression plug may not be reaching all the way down through the stem clamped section...

As for repairing the cracked fork, I'd send pics to Craig Calfee.

That's about the only thing I can think of but I don't know what I don't know. The only CF forks I have are on my Ti bikes and I use a 90mm compression plug. That bad boy goes thru my surplus steerer on top of the stem, past the stem and the top bearings in the head tube.

If there's a real reason, I'd be game to listen.