Convertible top speed with top up?

[dmd]

This is probably just academic, but after watching an unnamed British car show reviewing an Aston Martin, it was mentioned that it had a 99mph speed limit with the top up. It got me wondering if there's a similar speed limit on our convertibles as well. I've been to 145 on a racetrack with the top down, but now I'm curious if the wind would've ripped it apart if I'd tried it with the top up. The only limits I can find discussed in the owner's manual relate to failures in the tires, suspension or traction control systems. Is it essentially certified to the stock C5 top speed of 175mph?

[Tuna]

Good question. I've never seen a max recommended speed for the convertible with the top up. If the top blows off at speed, it would ruin your day.

I have seen 145 plus in my C5 convertible with the top up and it stayed right there. I also been over 130 with my C6 convertible without any issues. I prefer to go really fast in my coupe as it a lot more aerodynamic for that sort of thing.

[dmd]

Thanks Tuna. My suspicion is that the top's articulation may have much to do with its high-speed stability, and the C5/C6 have scissor-like designs that may not have the same speed limitations as the Aston.

Yes, certainly the coupes are more aerodynamic, but as I recall the C5 convertible is still more aerodynamic than the C4 coupe was! As I said this is largely academic, I may never attempt anything like that again. But I'd still like to know.

If anyone who reads this happens to get the opportunity to speak to an engineer at an event over the summer, and cares long enough to remember this, could you ask what sort of high speed tunnel testing they do on the 'verts?

Other anecdotal speed test stories are still welcome.

[timfitz63]

Well, for what the observations are worth to the discussion:

• I've had mine to ~107 mph running a quarter-mile on the drag strip. Top never flapped or otherwise gave any indication that it would come "unhinged."
• The convertible top (when up) gives the vehicle an aerodynamic shape similar to the FRC; I suspect the convertible would have similar drag coefficient numbers to the FRC as well.
• Personally, it seems to me that the car accelerates better with the top up than with it down, but that's just my uncalibrated butt dynometer speaking... But in my mind, I can see where that might actually be the case: with the top down, there's more turbulent flow around the windscreen/cockpit, and therefore more drag -- although putting the side windows up with the top down seems (to me) to be much closer to top up...

[TooFast]

I believe, if I recall correctly, the convertible top speed is reduced to 167 mph. This is due to the reduced aerodynamics of the convertible.

[6 Shooter]

[TooFast]

Only been to 130 with mine

[Tuna]

Maybe GM did a pretty good job building a convertible top that is good to the limits of the car. I hope so as I've never really gave the top a second thought when I've hammered either of my convertibles.

[catbert]

155 in a 98 ragtop - no problem.

[powderski13]

173 in my 02 vert with no problems