Another Tire Question

[Justafordguy 10]

Has anyone had trouble with their car darting around on rough roads? I have 275/45/17 front tires and I wonder if they may be too wide? The car drives great on a good road but really wanders on a bad one. Any ideas?

[Justafordguy 10]

Has anyone had trouble with their car darting around on rough roads? I have 275/45/17 front tires and I wonder if they may be too wide? The car drives great on a good road but really wanders on a bad one. Any ideas?

[69again 10]

Mine does the same thing. Added the bump steer kit and realigned. Still does it. Is rack and pinion the only way to get ride of it?

 

ps I have 245x45x17's

Edited April 24, 2009 by 69again
added tire size

[69again 10]

Mine does the same thing. Added the bump steer kit and realigned. Still does it. Is rack and pinion the only way to get ride of it?

 

ps I have 245x45x17's

Edited April 24, 2009 by 69again
added tire size

[Justafordguy 10]

I had a rack on mine and it still did it. I recently installed an integrated power steering gearbox and it also made no difference. There is no play in the steering and the car drives very well on a good road. It only darts around on very rough road. The only thing I can think of is the wide tires are catching the ruts. I am at a loss at this point.

[Justafordguy 10]

I had a rack on mine and it still did it. I recently installed an integrated power steering gearbox and it also made no difference. There is no play in the steering and the car drives very well on a good road. It only darts around on very rough road. The only thing I can think of is the wide tires are catching the ruts. I am at a loss at this point.

[Justafordguy 10]

I just added weld-in subframe connectors and it may have helped a little but it still darts around more than any other car I have ever driven. Any ideas?

[grendi 16]

do you have a shelby drop?

if not that might be the solution.

.....and yes, your front tires are probably to wide.

[Justafordguy 10]

I did the shelby drop a while back but never got to drive the car. It made the front to low and the tires rubbed. Does it really help with the darting around?

 

Also what size tires would work best? I have 17x9 rims in the front.

[Pakrat 1,043]

I think 245 is the most rubber I would ever want up front, just for the sake of parking lot turning alone, it's right at home on an 8", not sure how well it fits a 9" though. How about the front sway bar, is that larger than stock yet? I would think that would help some but I do believe a lot of the issue is in those tires. Do you know anyone with the same lug pattern that can let you just try their wheels for a quick ride? Even if they were a stockish 225/75/14 it would at the very least either eliminate it as a suspect or point the finger at it more directly.

[69Heretic 10]

From what you are describing it sounds like Tramlining.

 

Here is a quote from tirerack on the issue:

 

"The term "tramlining" is being used to describe when directional control is disrupted by the vehicle's tendency to follow the longitudinal ruts and/or grooves in the road. It's name could be compared to the tram or trolley driver who does not steer because his vehicle follows the path established by the tracks."

 

Here is the link to the article and it has some things you can do to help correct the issue.

 

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=47

[Justafordguy 10]

I think 245 is the most rubber I would ever want up front, just for the sake of parking lot turning alone, it's right at home on an 8", not sure how well it fits a 9" though. How about the front sway bar, is that larger than stock yet? I would think that would help some but I do believe a lot of the issue is in those tires. Do you know anyone with the same lug pattern that can let you just try their wheels for a quick ride? Even if they were a stockish 225/75/14 it would at the very least either eliminate it as a suspect or point the finger at it more directly.

 

I do have a new larger front sway bar with urethane bushings and also a rear sway bar. It didn't seem to help this problem but did help body roll in a corner. I think you may be right about the tires. I'll have to beg someone to let me borrow some tires. I wonder how I can find out about the best size for the 9" rims?

[Justafordguy 10]

From what you are describing it sounds like Tramlining.

 

Here is a quote from tirerack on the issue:

 

"The term "tramlining" is being used to describe when directional control is disrupted by the vehicle's tendency to follow the longitudinal ruts and/or grooves in the road. It's name could be compared to the tram or trolley driver who does not steer because his vehicle follows the path established by the tracks."

 

Here is the link to the article and it has some things you can do to help correct the issue.

 

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=47

 

 

Wow, this really does sound like my problem. I think my wide low profile tires are what is killing my handling. All this time I thought the performance tires were supposed to help handling.

[69Heretic 10]

Wow, this really does sound like my problem. I think my wide low profile tires are what is killing my handling. All this time I thought the performance tires were supposed to help handling.

 

A lot of times when you upgrade one thing you find other componets need work! On my 69 stang I replaced all serviceable parts (bushings, new ball joints, ect) and it made a huge improvement in handling. Also with the drop your suspension geometry changes, so the car needs to have a custom alignment. I would print out these alignment specs and find a good shop. On a 1” Shelby drop that is street driven you want to run:

 

1/8" toe

0 to -.5 camber

+1.5 to +2.5 caster

[Justafordguy 10]

All parts are new and many upgraded. I have had two different shops align the car. I got these specs from Marlon Mitchell, Owner of Marlo's Frame & Alignment. He is an early Ford expert.

 

Camber

Left: 1/2 Degree Negative

Right: 1/2 Degree Negative

 

Caster

Left: 2 Degrees Positive

Right: 2 1/2 Degrees Positive

(note) caster may vary a little from side to side to get the car

to track straight, the caster numbers listed is the minimum

starting point

 

Toe-In

Overall: 1/8” Toe-In

 

 

Also unless I can find some different springs I can't run the Shelby drop because it lowered my car too much and my tires rubbed the fenders.

 

[Pakrat 1,043]

I do have a new larger front sway bar with urethane bushings and also a rear sway bar. It didn't seem to help this problem but did help body roll in a corner. I think you may be right about the tires. I'll have to beg someone to let me borrow some tires. I wonder how I can find out about the best size for the 9" rims?

 

I had posted links to a variety of online tire calculators a while back but I can't seem to find them right now. I did a little looking online though and it would seem a 245 tire is actually the recomended ideal width for a 9" rim and you can up as high as 295 but it bulges a little so your fine and could even go down as low as a 235 if you had too but that's about the limit.

[Jurisd 10]

 

Reading this I recall the same exact issue when I first drove my 1985 Corvette. The car was shod with 255/50/16s on front and back, and (as you can imagine for a Corvette) the sway bar was huge, bushings solid, and steering very tight. But, the car wandered all over, following the road ruts. One test you can try to confimr this is the issue is to compare by driving on pavement and concrete. The pavement will rut, whereas concrete (unless it is REALLY old) will not. I suspect you will notice little or no wandering on concrete.

 

On a positive note, the issue diminished as the tires wore down a bit. Or I got so used to it I no longer even noticed.

[grendi 16]

@pak

 

these two are very nice:

www.rims-n-tires.com/rt_specs.jsp

www.miata.net/garage/tirecalc.html

[Justafordguy 10]

 

Reading this I recall the same exact issue when I first drove my 1985 Corvette. The car was shod with 255/50/16s on front and back, and (as you can imagine for a Corvette) the sway bar was huge, bushings solid, and steering very tight. But, the car wandered all over, following the road ruts. One test you can try to confimr this is the issue is to compare by driving on pavement and concrete. The pavement will rut, whereas concrete (unless it is REALLY old) will not. I suspect you will notice little or no wandering on concrete.

 

On a positive note, the issue diminished as the tires wore down a bit. Or I got so used to it I no longer even noticed.

 

I really have no concrete roads around here to try but I have tried a few new pavement roads. It drives perfectly straight and handles great on a good road. I guess I'll try to get a set of 245 or 235 tires and see if it helps. I hate to waste these new 275's but I guess I could put them on ebay or save them for the back of my Fox mustang.

[Grabber70Mach 107]

Also unless I can find some different springs I can't run the Shelby drop because it lowered my car too much and my tires rubbed the fenders.

 

Might want to check into this:

 

http://www.stangfix.com/testforum/index.php?topic=1722.0

[Justafordguy 10]

That's an interesting idea. I wonder is the two modifications work well together as far as ride/handling goes?

 

I really think my current problem is tires but I may try this later.

[69again 10]

Justafordguy,

 

I have 245's on the front and 295's on the back of mine and it does it as well. Pretty scarry on the rough roads. Might want to borrow some tires before you make the purchase.

 

Dan

[Justafordguy 10]

Well guys I borrowed a old set of 225's from my brother off an SN95. I am totally shocked. I never thought that tires could make such a difference. My car drives totally straight even on the roughest roads. I drove it for about an hour and I still can't believe the difference. I can even drive with one hand now.

 

Now I just need to find some type of tire that will fit on my 17x9 wheels. I wonder if I could run a 225 on the 9" wheels?

[Angel 24]

9" wheels usually take a 255. ive got 225's on my 17x7 and the sidewalls are nice and straight with not bulging. might wanna get those wheels narrowed.

[Pakrat 1,043]

That first link that Grendi posted was one of the ones I was looking for and according to that they won't even let you put anything less than a 235 on a 9" rim and with good reason, at that width it is barely flush with the rim lip so if you can even find it looks like about a 235/50/17 is the narrowest you can go on that 9", I wouldn't expect much difference than the 225 you test piloted but I still think you would be better off with something like a 245/45 tire even if you sacrafice a little of that handling back.