Hello all of you wise Mustangers I have been searching for an answer to this question but haven’t been able to find an answer.
I like the look of a Mustang HT in general but especially if it has wider rear tires that fill up the wheel wells. At the moment I run the 1968 period correct 14” Styled Steel GT wheel. But even though I like them because they give the original “Ford Style” look - they seriously lack something in the wide tire department which keeps bugging me.
This has made me think about aftermarket wheels – preferably a staggered look with 7” in the front and 8” in the back. E.g. Cragar Eliminator 500G or Rocket Fuel Gray.
Following I have been wondering what a “staggered” wheel and tires package will do to the cars handling characteristics. Will it understeer more, or will it oversteer more, or will it stay the same?
it will have more understeer. its easier to setup a mustang with the same size tires all the way around. "however" the 69-70 boss 302 roadrace mustangs had wider tires in the rear but those cars also had lots of suspension tuning and used a locker to bring the back end around in the turns.
it really depends on how you set the suspension up. with a little tuning you can mitigate any grip differences front to rear due to a difference in tire sizes.
Only causes a problem with steering on hard cornering. On the dragstrip it's beneficial. That said, I need to replace my rear springs to settle the rear down (I have a 1.5* rake, ie too much IMHO for corner carving).
Nothing wrong at all with a staggered setup for a street car.
The one negative would be rotating tires. No more front to back. If you have directional tires, that means demounting and remount to rotate your tires, from side to side every 5000 miles
You absolutely can NOT run staggered tires! It will destroy your handling.
Just ignore people like this wiseguy.
OK, really. Like stated already, a little bit more understeer thats pretty straightforward to mitigate if it bothers you. I like a bit of understeer in a driver street car, to a point anyway.
You absolutely can NOT run staggered tires! It will destroy your handling.
Just ignore people like this wiseguy.
OK, really. Like stated already, a little bit more understeer thats pretty straightforward to mitigate if it bothers you. I like a bit of understeer in a driver street car, to a point anyway.
thats a rear engine car that handles different from a front engine car. that car also has suspension so far superior to a mustang theres no comparison. and that cars suspension only moves about 1.5" at most. those tires are also racing tires and can have different compounds for the front and rear. get out on a roadrace track and push the mustang to its limit and thats when you find out that it will corner faster with the widest tires of the same size all the way around. on my last 65 i had 275/40/17 on the front and 315/35/17 on the rear. i was told by the roadrace guys it was going to push and it did. i had to loosen the rear to get it to corner good. it would have cornered faster with 315/35/17 on the front and i would not have had to loosen the rear. it your are just putt puttun around on the street it doesnt matter what you have unless you want to corner very fast.
I agree mostly with what Super said, although you can have a "neutral" car that does not require a ton of other modifications to balance with closer variations in width between the two tires, more 255 front and 275 rear, as opposed to the problems that he had with 275/315 combo which is too much contact patch difference to easily balance. No matter what you have, the suspension "system" needs to be tuned to fully optimize it, with most of that tuning coming from shocks, springs, and sway bars.
Suspension design and geometry has a whole lot to say about handling, contact patch is an influencer in the equation IMO. That said, you want as much contact patch as you can get while not unbalancing the car under all suspension conditions.
The link Steven gave is pretty in depth, and a good resource.
All good points, basically you have to decide what type of driving you plan. If street/track, the easiest setup to balance is four identical tires. With the weight bias on the front, asking smaller tires to work well with big rear tires is a tall order. Big tires on the rear is fine if that's where the engine is. An extreme example would be a Pro Street. A friend of mine once drove his to work, thought all the roads were dry. Hit a wet patch in the shade on a straight, level road, and the car swapped ends. He wasn't even accelerating, just cruising up the road. When I was in school, having little stock tires on the front and L60-15's on the rear was the hot setup. But it wouldn't corner as well as a stock 6 cylinder car.
I have had 2 BMWs with staggered wheel sizes; they looked and handled awesome. Maybe a completely different story on an old Ford suspension set up though.
Spring rate, camber curve, roll center, shock dampening, Ackerman angle, weight distribution.....all these are an integral part of handling, along with tire contact patch.
"thats a rear engine car that handles different from a front engine car" Ya think?
All sarcasm aside now, you shouldn't have any issues with your proposed ideas just like how 69machi and 289fan are happy with their setups they mentioned earlier in the thread. By the way Bebob, thank you for sharing your car specs with us. Those who pay attention to that can conclude that actual racing probably isn't on your agenda anytime soon, nor are hugely wide tires.
Thank you all, once again VMF has proved to be the right solution to question mark. @GypsyR: You are correct - I will probabaly never race the Mustang - but a trackk day once in a while is not out of the question.
I am very happy with my Mustang and I have accepted that the stock handling is not “sportscar pedigree”. But I still search to make it handle better – I will continue to buy parts from Opentracker to make the car just a little better than when it was produced almost 50 years ago. After all a Boss302 was considered a capable handling machine back in the day and I guess my 68 HT can be made to handle the same.
I understand your answers this way…. I can run a staggered wheel package but the handling (road/cornering) will not benefit from it (maybe even be worse). The same tire size front and rear will be easier to balance and make as good as possible.
What size 15” tire is the best for at 68 model on all 4 corners?
I think they decided understeer was more likely. FWIW, on my 68 coupe I am running 225's up front and 265's on the rear. 15" wheel, I think 60 and 50 series to get the height right.
My car handles acceptably but not great. To compare it to 90's cars, it does cloverleafs and single turns FASTER than my 98 MarkVIII or 97 Aurora. I have what I guess is a bumpsteer problem (non dropped front end I believe) and no power steering. This makes me feel like if I ever lost it in a turn recovering would be difficult. Mercifully this hasn't happened to me yet. On the real tight 2 lane blacktop it doesn't feel as agile as my 90's cars. Dunno if it is the heavy 351w in front or the before mentioned steering.
Real suspension and steering mods are a few years off. I'll report back then.
Sorry, I personally can't recommend a uniform tire size because I like the biggest tires that will fit my cars and that means staggering. Going with uniform sizes surely isn't a bad way to go and is more sensible.
Don't directly compare the handling of a vintage pony car to anything but stuff like other vintage pony cars and very similar vehicles. It just isn't a fair or sensible comparison otherwise.
If I may suggest, look into upgrading the front brakes (at least) to some kind of disks first. Also continue to buy Opentracker parts (excellent choice). THEN shop for wheels and tires. You'd hate to do some modifications later and find that you can run wider tires or need a different wheel offset or something. If this car is something you are driving regularly then do whatever. You have to make compromises to work around doing that and I can't blame anyone for wanting to drive their car. Just expect that your wheel/tire options and needs might change later as work progresses.
Perhaps start a whole new thread asking what tire sizes people recommend? Wouldn't hurt.
I agree with Gypsy. Maximizing tire width almost always means staggered sizes, you don't need steering clearance on the rear axle. Another plus is that it aids traction, which is always an issue. It will not harm your handling, any increased understeer can easily be dialed out with spring rate adjustments or swaybar size(s). Enough stagger may warrant the addition of a small rear bar. Adjustable bars are fantastic for fine tuning balance, just be aware that what feels good a 35 MPH might be scary loose in a high speed corner.
BTW, many cars without rear weight bias use staggered tires, like the Corvette that has near 50/50 distribution.
@GypsyR, I get your point and I agree with you. I think Mustangs from 1964 to 1970 are lovely cars and I enjoy driving my own car a lot. The sound of the engine and the sight over the long hood is something special. It gives me driving pleasure in an unexpected way.
But being from Europe we are very much used to small compact cars. They certainly don't have the V8 power but some of them make up for that with light weight. My first fun car was one like the picture below. It is a Peugeot 106 Rallye - it was solely designed to compete in the small rallye championship (similar to the Boss302 in Trans Am racing) 1400 pounds and 100 HP at 7200 rpm and a very stiff suspension made a fun driving machine 20 years ago. It was very noisy and the engine didn't do anything below 3500 rpm but then it woke up and charged towards the redline. Topspeed was 118 mph - thats fast in such a small car.
I guess I thought that I would eventually sell the Mustang and buy a lighter racier car - maybe like a Lotus Super 7.
But by now both me and my wife think the Mustang is part of the family - and I really don't think I will sell it.
I will continue to build the Mustang and improve on it - making the difficult compromises along the way:grin2:
I have run 275 50s in the front and 295 50s in the rear of most all my rides untill BFG decided to stop making 275s. Had 8 x 15s front and 10 x 15s rear. Handling has been outstanding from my mustang to my grand marquis. A bigger issue with staggering even same size is wheel offset. In general wider track in the rear promotes under steer, wider in front promotes over steer. Keeping the track the same more towards neutral handling even if front tires are wider than rear.
Your 68 will look great with larger rear wheels and tires, and the understeer effect will be unnoticeable in street driving, and even a few laps on occasional track days. It is a big step up to 'racing', and that would easily be rectified with a set of track wheels. True racing is going to require sticky slick tires (plus many other modifications) and if that is not in your future with this Mustang, then don't worry any more about it.
A performance alignment, and some good (stickier) front tires will take up any understeer issues that arise from the relatively small increase at the rear tire. I think the alignment will be something you can feel as an improvement in handling. The bigger rears, meh, not much
1 degree negative camber
3-5 degree castor (3 with manual steering and 5 with power steering)
1/32" to 1/16" toe in
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Vintage Mustang Forums
4M posts
89.2K members
Since 2001
A forum community dedicated to vintage Ford Mustang owners and enthusiasts. Come join the discussion about restoration, modifications, NOS parts, troubleshooting, VIN codes, and more!