C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Front end drift/float @ speeds above 50mph

Thread Tools
 
Search this Thread
 
Old 07-11-2018, 07:55 AM
  #1  
KevinL46
Heel & Toe
Thread Starter
 
KevinL46's Avatar
 
Member Since: Jun 2018
Location: the Internet
Posts: 24
Received 7 Likes on 5 Posts
Default Front end drift/float @ speeds above 50mph

Hi all. I'm a long time lurker who finally made the jump to being a member. I'm the 3rd owner of a 102k actual miles, L46/M21 '69 convertible with a set of G60 Goodyear PolyGlas tires. I've owned the car for several months now and love it, it's such a blast to drive. Everything works but the one issue I have is that the car can be a little squirrelly as you approach highway speeds. It drives pretty straight with only the slightest pull to the right (so slight it's almost not noticeable and I even hesitate to mention it). However, as I get up to speeds of 50mph and greater it seems to have a drift or float in the front end or at least I think its coming from the front end. What I mean by drift/float is that without hitting a bump, groove in the pavement or whatever, @70mph I'll suddenly find myself going from the center of my lane to 6" into the lane next to me, without any input to the steering wheel from me. This could be either the lane to the left or the right. It's like something is loose in the front end allowing the wheels to go one direction and the suddenly the slop or looseness allows the wheels to shift orientation ever so slightly the other direction (I hope that long rambling explanation makes sense). I thought for sure that it must have a bad bushing(s), tie rod end, ball joint or something. Since I couldn't locate anything, I took it to the front end shop and had them take a look. They took it for a drive and said they experienced exactly what I described but they found everything up front was tight as a drum and said all the bushings looked better than what they see in most 5 year old cars. The only recommendations the front end guys had was to ditch the PolyGlas tires (which was already on my to do list) and talk to someone who knew C3 cars and see if they had any suggestions. So that leads me to here, reaching out to this community for any input on what you think the root cause might be or where I should start looking next to find what's causing the problem.

Thanks in advance for sharing your knowledge - Kevin
Old 07-11-2018, 08:14 AM
  #2  
dochorsepower
Drifting
 
dochorsepower's Avatar
 
Member Since: Sep 2010
Location: Laguna Niguel California
Posts: 1,412
Received 49 Likes on 42 Posts

Default

Well, welcome to the forum. First of all Those tires have not been made in this century, they're dangerous.. Next, you should have the condition of front suspension bushings and steering checked by a C-3 Corvette specialist - NOT the auto shop down the street.
The following users liked this post:
KevinL46 (07-11-2018)
Old 07-11-2018, 08:34 AM
  #3  
gbvette62
Race Director
 
gbvette62's Avatar
 
Member Since: Oct 2000
Location: Shamong, NJ
Posts: 11,104
Received 2,022 Likes on 1,312 Posts

Default

Without a doubt, get rid of the Polyglas GT's. If you plan on driving the car, a good set of modern radials, like BF Goodrich TA's, is the way to go. The original tires on the car were F70 x 15 bias ply's, and the modern equivalent to the F70's is P215/70R15. There are reproductions of the original F70 bias ply tires available, but they're really best for show cars and "trailer queens", and not for cars that are driven regularly.

Once you've replaced the tires, I would find a shop familiar with the Corvette suspension, and have a good, 4 wheel alignment done. Making sure the Corvette's independent rear suspension is properly aligned, is as important as the condition and alignment of the front end.

Let us know where you are in Florida, as there are a number of Corvette shops in Florida, and a number of members here live in Florida, so I'm sure someone can recommend a good shop to take your Corvette too.

Welcome to the Forum!
The following users liked this post:
KevinL46 (07-11-2018)
Old 07-11-2018, 01:15 PM
  #4  
KevinL46
Heel & Toe
Thread Starter
 
KevinL46's Avatar
 
Member Since: Jun 2018
Location: the Internet
Posts: 24
Received 7 Likes on 5 Posts
Default

Originally Posted by gbvette62
Without a doubt, get rid of the Polyglas GT's. If you plan on driving the car, a good set of modern radials, like BF Goodrich TA's, is the way to go. The original tires on the car were F70 x 15 bias ply's, and the modern equivalent to the F70's is P215/70R15. There are reproductions of the original F70 bias ply tires available, but they're really best for show cars and "trailer queens", and not for cars that are driven regularly.

Once you've replaced the tires, I would find a shop familiar with the Corvette suspension, and have a good, 4 wheel alignment done. Making sure the Corvette's independent rear suspension is properly aligned, is as important as the condition and alignment of the front end.

Let us know where you are in Florida, as there are a number of Corvette shops in Florida, and a number of members here live in Florida, so I'm sure someone can recommend a good shop to take your Corvette too.

Welcome to the Forum!
Thanks GBVETTE62. I'm in the Northeast Florida/Jacksonville area. Any reputable Corvette shop recommendations in the area would be appreciated.
Old 07-11-2018, 10:47 PM
  #5  
doorgunner
Nam Labrat

Support Corvetteforum!
 
doorgunner's Avatar
 
Member Since: Sep 2013
Location: New Orleans Loo-z-anna
Posts: 33,893
Received 4,173 Likes on 2,735 Posts

Default

Unofficial quick-check pictures below...…………………….



BEFORE DIY temporary camber adjustment






AFTER DIY camber adjustment...notice there is NO gap between tire and level now.
The following users liked this post:
KevinL46 (07-12-2018)
Old 07-11-2018, 11:26 PM
  #6  
Metalhead140
Drifting
 
Metalhead140's Avatar
 
Member Since: Aug 2015
Location: NSW, Australia
Posts: 1,939
Received 472 Likes on 344 Posts
C3 of Year Finalist (track prepared) 2019
Default

Also, worn rear end suspension bits can also cause wandering at speed that feels like it's the front end - voice of experience here. Check out the rear as well.
The following 2 users liked this post by Metalhead140:
KevinL46 (07-12-2018), Sunracer (07-24-2018)
Old 07-12-2018, 06:44 AM
  #7  
KevinL46
Heel & Toe
Thread Starter
 
KevinL46's Avatar
 
Member Since: Jun 2018
Location: the Internet
Posts: 24
Received 7 Likes on 5 Posts
Default

Pictures are always good for me, Thanks Doorgunner
Old 07-12-2018, 06:46 AM
  #8  
KevinL46
Heel & Toe
Thread Starter
 
KevinL46's Avatar
 
Member Since: Jun 2018
Location: the Internet
Posts: 24
Received 7 Likes on 5 Posts
Default

Originally Posted by Metalhead140
Also, worn rear end suspension bits can also cause wandering at speed that feels like it's the front end - voice of experience here. Check out the rear as well.
Good advice I had not considered, Thanks
Old 07-12-2018, 04:41 PM
  #9  
GTR1999
Tech Contributor
 
GTR1999's Avatar
 
Member Since: Aug 1999
Location: Connecticut, USA
Posts: 14,053
Received 2,602 Likes on 1,333 Posts

Default

Do you have play in the steering going straight? If you have to move the steering wheel a few inches you are not steering the car you are aiming it, I agree a complete front suspension check is in order. The car should not wander under 120mph
Old 07-22-2018, 09:16 PM
  #10  
KevinL46
Heel & Toe
Thread Starter
 
KevinL46's Avatar
 
Member Since: Jun 2018
Location: the Internet
Posts: 24
Received 7 Likes on 5 Posts
Default

Originally Posted by gbvette62
Without a doubt, get rid of the Polyglas GT's. If you plan on driving the car, a good set of modern radials, like BF Goodrich TA's, is the way to go.
Just to follow up on my original post, Replacing the Polyglas GTs did the trick! I put a set of modern Goodyear p225/70R15s on it and now it rides like it's on rails. Previously, I'll admit it was a bit of a hairy ride when you got above 55 but with the new shoes I got it out on the interstate and did "a wee bit" over over the posted 70mph speed limit, purely for testing purposes , and it couldn't have handled better.
Old 07-22-2018, 09:29 PM
  #11  
OMF
Melting Slicks
 
OMF's Avatar
 
Member Since: Jul 2006
Location: Salmon Arm, BC
Posts: 2,024
Received 343 Likes on 250 Posts

Default

Originally Posted by KevinL46
"a wee bit" over over the posted 70mph speed limit, purely for testing purposes
That's just "normal Corvette testing" ......you won't get in trouble on here for that, everyone's a bit of a test pilot
Old 07-30-2018, 08:52 PM
  #12  
davidchristopher
Racer
 
davidchristopher's Avatar
 
Member Since: Mar 2009
Location: Brant County Ontario
Posts: 276
Received 31 Likes on 24 Posts

Default

Hell, if I could, I'd be doing daily tests. Like... leave a work meeting early because I need to run the unit tests on the corvette daily...
Old 09-19-2018, 02:05 PM
  #13  
Flighthog
Heel & Toe
 
Flighthog's Avatar
 
Member Since: Oct 2006
Location: Maryland
Posts: 21
Likes: 0
Received 0 Likes on 0 Posts

Default

Had a similar issue definetly check rear trailing arm bushings. Mine where so hard they shattered when moving the arm while on lift.

Get notified of new replies

To Front end drift/float @ speeds above 50mph




Quick Reply: Front end drift/float @ speeds above 50mph



All times are GMT -4. The time now is 12:03 PM.