Pondering Tire Sizes???

[Funmart6]

I just have a couple/few tire questions.

1) What is the widest tire that will fit on the stock chrome SHO wheel?
2) What is the widest tire that can be run on our cars without causing any issues with rubbing anything?
3) If you were to change the wheel to a 17 inch, what would be the best size to run, height and width?

 

[ThatShoGuy]

I just have a couple/few tire questions.

1) What is the widest tire that will fit on the stock chrome SHO wheel?
2) What is the widest tire that can be run on our cars without causing any issues with rubbing anything?
3) If you were to change the wheel to a 17 inch, what would be the best size to run, height and width?

im running 245/50/r16 on my stocker wheels i have since i bought new tires for this car and have had 2 different sets of the same size on the car. since i have owned it.

i have seen rub marks on the passenger front side shock but just very light.
and now that i have lowered the car(by sliding the struts in the spindles) i notice a little rub sound in the rear when backing out the drive way but thats it. which i dont think thats the tires but still unsure.

all in all i think they are the widest you could fit. i like them alot rides nice imo!


heres a pic if it helps you any

 

[stephen newberg]

I just have a couple/few tire questions.

1) What is the widest tire that will fit on the stock chrome SHO wheel?
2) What is the widest tire that can be run on our cars without causing any issues with rubbing anything?
3) If you were to change the wheel to a 17 inch, what would be the best size to run, height and width?

1. 245 is the maximum width I have seen that the manufacturer will suggest putting on the original rim width for the Gen III SHO and even that is rare. Last one I saw would be the 900 series group from Bridgestone, and I do not know if they still suggest it as in range for the newest of 900s or not.

2. 245/45 is probably it. Because of the angle of the struts, getting wider without touching is very hard. Note that the previous poster was touching with 245/50. Lowering the sidewall that additional 5mm gets you away from that.

3. I would think 235 on a 17 inch would be your best bet. Remember that you are doing a compromise between swung weight and contact patch, with swung weight being the big determinant for acceleration while contact patch has a lot to do with handling (both in general terms).

pax, smn

 

[ThatShoGuy]

not that it rubs bad just enough so i can see it on that strut. and on the rear idk i think its more of those odd angles that make it rub.

 

[stephen newberg]

Its good that the rub is minor, but I admit I would be concerned about any rubbing at all. If you get 245s again, I suggest you might want to bring the sidewall down to 45. Additionally, this will give you the advantage of having about the same circumference as the original 225/55s, so there will be less speedometer error.

pax, smn

 

[1bad98SHO]

when i bought my SHO it had 245/50's on the front. It was stupid and looked plain ********. I went back with the stock 225/55's and it looks much better.

 

[SHOspazz92]

im running 245/50/r16 on my stocker wheels i have since i bought new tires for this car and have had 2 different sets of the same size on the car. since i have owned it.

i have seen rub marks on the passenger front side shock but just very light.
and now that i have lowered the car(by sliding the struts in the spindles) i notice a little rub sound in the rear when backing out the drive way but thats it. which i dont think thats the tires but still unsure.

all in all i think they are the widest you could fit. i like them alot rides nice imo!


heres a pic if it helps you any
http://www.sccoa.com/forums/attachment.php?attachmentid=38368&d=1247321245 [/QUOTE]

I can't see how that Tires grips any better then a 225. You not getting a Full contact patch with a Tire that wide on a wheel that small. Not to mention, It looks terrible in my opinion.

225 For a 7'' wheel is Perfect, 245 for a 8'' wheels is also Right where you want to be as you are going to be able to utilize the whole tire for a much larger contact patch as opposed to the sidewalls bulging out like that to form to the wheel giving you no bigger of a contact patch and essentially wasting the tire.

-Sam

 

[stephen newberg]

I admit to never having cared about looks at all, myself, but back when My Gen III was new and I tried 245/45/16s from Bridgestone that did in fact suggest a 6.5"-8" rim, there was noticeable handling improvement from the RSAs that had been on the car. Of course, some or all of that could have been from just getting away from the RSAs, which were really not very good tires. But the point should be the sidewall. If the sidewall can remain relatively vertical on the rim, then the increased size of the contact patch will remain in use and depending on other factors (how sticky the rubber is, how well the rest of the suspension keeps the patch on the pavement, etc.), handling will improve.

So, the sidewall is really critical the critical factor in this, and it is based on that factor that the manufacturer will suggest a rim width range. So long as you stay in that range, you will likely do OK and often will increase the handling capabilities of the vehicle. And sidewalls are always getting better as tire makers look to improve their product, so over time, you can end up doing more with less. Looks, well, those are a personal thing. Some people seem to really like it when the tires look very fat. I do not really care enough about that sort of thing for it to matter to me.

pax, smn

 

[1bad98SHO]

a 245 on the stock SHO rim puts the sidewall waay out there. I see no way that it can be beneficial to have the sidewall where the tire looks like its flat all the time. The sidewall is no where near vertical and there is no way the tire can do what its supposed to do no matter how stiff the sidewall is.

Look at the above picture of the SHO posted with 245's. That tires looks like its about to roll right off the side of the rim. No way that sidewall will perform the way its supposed too.

 

[RonPorter]

I can't see how that Tires grips any better then a 225. You not getting a Full contact patch with a Tire that wide on a wheel that small. Not to mention, It looks terrible in my opinion.

225 For a 7'' wheel is Perfect, 245 for a 8'' wheels is also Right where you want to be as you are going to be able to utilize the whole tire for a much larger contact patch as opposed to the sidewalls bulging out like that to form to the wheel giving you no bigger of a contact patch and essentially wasting the tire.

-Sam

For myself, I've found that a 215 tire is perfect on a 7.5" rim, and 225s are perfect on an 8" rim. I run 215s on 7.5s on the LGT. For track use, I can stay with street pressure cold, with no rollover issues. On my last tire set (RS2s), they had nice even wear for all of the 8K miles before they were done. Awhile back I had 225s on the stock slicers on my '94. It was horrible at the track. I had to run 45-50 cold psi to keep the front tires from rolling over.

 

[stephen newberg]

a 245 on the stock SHO rim puts the sidewall waay out there. I see no way that it can be beneficial to have the sidewall where the tire looks like its flat all the time. The sidewall is no where near vertical and there is no way the tire can do what its supposed to do no matter how stiff the sidewall is.

Look at the above picture of the SHO posted with 245's. That tires looks like its about to roll right off the side of the rim. No way that sidewall will perform the way its supposed too.

In general, I agree with you, but it is going to vary with the tire. That is why tire manufacturers put a suggested rim width range on their products. As noted before, sidewall construction is everything when talking about this particular aspect.

Personally, like Ron, I tend toward stock or below stock width on the OEM rims. For summer tires I use the stock width of 225 while for winter tires I use 215. But I am also paying extra $$$s to buy good tires, rather than trying to get away with minimum costs. My tendency when using 17" rims is to use 235 summer tires. Again, that is with really good tires with very solid sidewalls.

Basically, there is no 'perfect' answer. It varies with the suggested rim range and the tire itself (plus, obviously, what you are after for results).

pax, smn

 

[ThatShoGuy]

i guess its our own opinion on looks but i think it looks great! i really like the look when i see a sho with stock tires i think it looks wimpy compared to mine. i dont know my just has this look and every one that see's it in person things the same and we cant seem to point it out. even when it was stock

i never really intend to drive this car really hard. imo i think it looks and drives great compared to stock. but maybe i didnt have stocks size when i bought the car i don't remenber sizes.

i guess this is all opinion so to each there own i guess. ether way just wanted to throw out there i get a little rubs(just very minor) i think the car looks pretty good. and omost the whole tread is on the ground unless im missing somthing

 

[stephen newberg]

Looks are so totally personal a thing that there is no way to disagree, IMO. But I would remain somewhat concerned about the rub. Can you tell from the tire where it is touching on the tire itself? If it is hitting the outer edge of the tread at the corner, that is of less concern than if it is hitting anywhere along the side. But if the touch is anywhere in that side area, I would think you are in a risky situation, even if the rub is minor, and you might want to go back to the people you bought the tires from, point out the problem, and have them correct it for you by shifting to a different size or a different tire.

pax, smn

 

[ThatShoGuy]

well thanks for the advise but it is a 1 in 100000000 rub and i think its just mostly the plastic fender things... like i did state tho it does show light rub on the one strut but dont look like its an all the time thing like maybe when i turn the wheel all the way or somthing. its been like that for years and no other issues. first set was bfgoodrich this set is kumho estac both seem very nice

 

[RonPorter]

i guess its our own opinion on looks but i think it looks great! i really like the look when i see a sho with stock tires i think it looks wimpy compared to mine. i dont know my just has this look and every one that see's it in person things the same and we cant seem to point it out. even when it was stock

i never really intend to drive this car really hard. imo i think it looks and drives great compared to stock. but maybe i didnt have stocks size when i bought the car i don't remenber sizes.

i guess this is all opinion so to each there own i guess. ether way just wanted to throw out there i get a little rubs(just very minor) i think the car looks pretty good. and omost the whole tread is on the ground unless im missing somthing

Having the whole tread on the ground isn't the only issue. First off, you aren't adding, relatively speaking, that much tread. Just over an inch going from 215 to 245.

The sidewalls are designed to work when they are vertical. When you pull them in with narrow rims, they lose a lot of their designed rigidity. Plus they also don't give as much support to the outer edge of the tread, so the perceived wider tread has less effectiveness.

If you want the wider-tire look, the obvious best way is with a wider rim with the proper offset.

 

[drivinhard]

The sidewalls are designed to work when they are vertical. When you pull them in with narrow rims, they lose a lot of their designed rigidity.

Yep.

General rule of thumb, try to match the tread width to the rim width, you can +/- this a hair. And look at the actual tire specs, not just what is on the sidewall. All "2xx" tires are not the same.

A properly sized tire on a given size rim will work better, and have better performance, than the same size rim with somebody stretching a wider tire on it.

Rim width is far more important than "tire" width.

 

[stephen newberg]

Agree completely with both of you.

pax, smn

 

[RonPorter]

Yep.

General rule of thumb, try to match the tread width to the rim width, you can +/- this a hair. And look at the actual tire specs, not just what is on the sidewall. All "2xx" tires are not the same.

A properly sized tire on a given size rim will work better, and have better performance, than the same size rim with somebody stretching a wider tire on it.

Rim width is far more important than "tire" width.

Good point, Mark.

The stated width (say 225) is NOT the tread width, it is the section width. And even that will vary tire-to-tire. Plus, the section width is also dependent on the rim width. Put it on a narrower rim, and you will lose section width.

FWIW, the Tire Rack Specs page is an excellent source of info. Zero in on the recommended rim widths. The spec width is the width used to determine the tires specs. Vary from that, and the specs change. Sticking with the spec rim width for a given tire is the optimal solution.

FWIW(2), at the SHO Convention track events, I've been running 215/45/17 tires on my LGT since Putnam in '05. Invariably, the only folks in front of me in the Advanced group are folks like Kirk and Sergio running track tires. Granted, I tend to run sticky summer tires like RS2s and now Azenis 615s, but they work well with the proper rim.

 

[Funmart6]

Looks like the best thing is to stick with the OEM size.
Thanks for the replies.

 

[stephen newberg]

Nothing wrong with that. After all, that is what the rims were designed to go with.

pax, smn