Speedo Off?

So I've had my 14' SD for about a year now and still haven't got my speedometer checked out even though I know it's off. Keeping up with the traffic in the fast lane it reads between 85-90 so I'm thinking its between 10-15 mph off. Anyone else have the same issue? I asked the dealer about it and they said I was the first one to mention it to them

Search function is your friend on this site - the majority of issues have been discussed in depth already.

Here's a quick link to get you started, there's more around somewhere:

interesting, looks like they come from the factory at around +10%, that would explain it.

thanks!