R6T7

I have a 2005 coupe that I've driven over 47,000 miles and have been delighted with the way that car tracks on the highway at pretty much any speed. I recently took delivery of a 427 convertible, and while I really like that car in many ways, I find that it does not track very well, especially on road surfaces that are somewhat uneven. It is night and day different from the way the 2005 handles. I have had it back to the dealer for front end alignment, which helped a little, but I'm still not satisfied. I know the wheels and tires are different sizes, but the basic suspension geometry should be very similar. I know the power assist is different, but I wouldn't expect that to affect straight line handling/tracking.

Have any of you 427 owners experienced this situation compared to other C6's?

Bob

Ozzy12

From my experience, the rear tire on the 427 provides a substantially wider footprint, and because of the different offset of the wheels; it basically puts the tires right on top of the ridge in the road. This is where a trucks dual tires meet and form a gap in their contact pattern, and the road surface becomes elevated over time there (not really elevated as much as immediately on either side of it, it's worn down further). It creates a different feeling where the car is trying to track on top of that ridge and keeps going left and right of it. I have experienced this same phenomenon with lifted trucks with 15" wide tires, and also in Class 8 trucks with a single 445 rear tire instead of traditional duals. It really isn't a Corvette problem as much as it is a road maintenance one.

Gearhead Jim

No 427 here, just a 2006 Z51 and now 2009 Z51.

The wider tires do tend to "tramline" more. Also, the GM alignment specs are a mile wide; the alignment can be pretty crummy but still "within spec".

I'd do a search for the Pfadt alignment specs here and have the car done to the Street specs, and use just a touch of toe-IN both front and rear. Different alignment machines use + or - for toe, just be sure you get a little toe-IN and not ANY toe-OUT.
Of course, be sure the lug nuts are tight!

Vette Lag

The 427 has incredibly wide tires. They tramline quite a bit. I tried the competitive driving mode, and at the same time, sport mode. This will show you the difference. I think it is something you have to live with.

Seadawg

I have basically the same tires on my GS, and it was very sensitive to road surfaces with the factory alignment. I would search the C6 forums for "PFADT alignment", and read up, it should help you out.

Blindfingers

Yep, mine does it too and I agree it is the wider tire widths.

Yellow 2000

I noticed the same thing when I upgraded my C5 to a C6 Z06. I also think it's due to the wider tires.

pmartjr

It is indeed the wide tires. I upgraded my '95 Acura NSX to wider tires and wheels and got the same result. My 427 is a "wanderer" for sure! I had my front end aligned also and saw no relief from this characteristic. It is the price we pay for the massive grip we get when cornering at over 1 G.

terradriller

Same situation here, I have a 427 vert and an 06 vert. The 06 is much easier to handle on the roads with any ridges at all,the 427 tracks all over the place. I did have the Pfadt steet alignment done and it helped quite a bit..

I did recently have the 427 to the dealer due to uneven ride height. The car was off 1/2" from the drivers side to the passengers side front and rear.The dealer adjusted the height of the car and realigned it to GM spec's. The car handles much better than before, but still tramlines on some pavements.

I too believe it is the steam roller tires that are on the car. Otherwise I love that beast..

427

R6T7

Thanks for all the feedback - I plan to re-check the alignment using the Pfadt specs, and dial in as much caster as I can get which should help a little.

Just don't want to be daydreaming while driving that car!!