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maximum tire size


95CutlassVert

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I have a '95 Cutlass convertible and was wonering what is the largest size tires I can go with before they rub. It has the 16" 5 spokes and I love the wheels, but wouldn't mind better handling and a more aggressive look 8)

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i think some people on here have 245's. mine came with stock 5spokes like yours and 215's , i had just put on 225's and for some reason the right front tire just barely scrubs the back side of the fender when i make a sharp turn, doesn't do it the other way and the left front tire doesn't do it at all so maybe my wheel well lining is a little off or loose. the 3.4 cuttys came stock with 225's I don't think their dimensions and stuff are any different than the 3100's with the 215's. TGP's came with 245's, still think GP's come stock with 225. I personally would only go up to a 225, looks good, great grip and within reason. You have 215's i presume since having the 5spokes huh.

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Guest TurboSedan

my 225/60-16's don't rub at all anywhere even with the car lowered. altho, i have the 16x8 crosslace GTP style wheels with a 25 mm offset.

 

i'm planning on buying 225/55's next.

joshua

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The STOCK TIRE OD is 26.1" Therefore to avoid screwing up your speedometer, find a tire as close as you can to 26.1 OD.. As far as width, I don't think anything wider than 9" is going to fit without excessive rubbing on the inner fenderwells during sharp cornering. Consult the tire manfacturer physical dimensions for a better fit then relying on the P-numbering system. Since different tire brands can be the same P-numbers but different in physical size :!:

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Dang.. Even the calulator is OFF by .5 "!!!!! The calulator shows 225/60R16 has being 26.6 :?:

 

Where did I come up with 26.1? Simple.. Goodyear was the standard factory tire maker for the 89 SE....P215/65R16 Same for the '97 up 225-60R16 tires on the newer GP's ... Guess what, BOTH sizes have identical OD's!!! 26.1" The Factory speedmeters were calibrated based on the Goodyear tire OD of 26.1" Therefore If you want the most accurate speedometer readings... Go with 26.1!

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...Goodyear was the standard factory tire maker for the 89 SE....P215/65R16 Same for the '97 up 225-60R16 tires on the newer GP's ... Guess what, BOTH sizes have identical OD's!!! 26.1"

Do you mean 215/65R15? By math, the 225/60R16 and 215/65R15 come out to be 26.6" and 26.0", but yes the actual dimension depends on the tire. Compare 2 different tires of the same size and one may even look wider.

 

My '89 came with 195/70R15, which is not made anymore. By math it's diameter comes out to be 25.75". I have some yet to be installed 225/55R16's on 16"X7" GP 5 spokers. Those have a 25.74" diameter, so they should be real close.

 

I always wondered if 235/55R16 tires would fit (26.18" diameter). I believe that was a stock size on some F-Body cars. They'd look pretty meaty on a W-Body. I wonder if they'd bulge out too much a 6.5" wide rim.

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The Factory speedmeters were calibrated based on the Goodyear tire OD of 26.1" Therefore If you want the most accurate speedometer readings... Go with 26.1!

 

I did not know that. So, there weren't different calibrations for different size wheels (like in the old days with different combinations of plastic speedo gears)? Are all the modern GM FWD cars like this?

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Guest TurboSedan
Consult the tire manfacturer physical dimensions for a better fit then relying on the P-numbering system. Since different tire brands can be the same P-numbers but different in physical size

 

so obviously not all 225/60-16 tires are created equal. the calc might not be wrong. besides, the guy wanted to know what the largest tire size he could use before rubbing, while offering better handling and a more aggressive look. that's not really possible with a 26.1" tire IMO, unless you get 17's.

 

i doubt a 225/55-16 would really throw things too out of whack anyway. i really doubt that all speedo calibrations are based on 26.1" tires. a TGP 245/50-16 is not the same OD as a 225/60-16.

joshua

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I wouldn't go much wider than a 225 or 235. The 245's that come stock on the TGP's will rub if you turn really sharp. I have been looking to go wider on my STE (215 isn't wide enough for me), and I was actually looking at 245 & 255's, but I think I will probably end up going with 235's because of rubbing issues. Maybe not though.

 

Shawn

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You also have to consider the width of your rims when talking about tire width. For example, mine are 15x6 so 225 is about the max I should put on 6" wide rims. TGP's with 245's I believe had 7 or 8" wide wheels.

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The TGP rims are 8", and supposedly the TSTE rims are 6.5", but I measured mine on the tire balancer at school and it read 7" so I am not sure. I doubt the tire machine would be off, but why would every source I read say the TSTE's have 6.5" rims if they are really 7. But anyways, yes, rim size definately needs to be taken into account.

 

Shawn

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Guest TurboSedan

another very important factor is offset. the 16x8 TGP crosslace wheel has a 25mm offset, which puts the wheel farther out compared to other stock W-body wheels.

joshua

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another very important factor is offset. the 16x8 TGP crosslace wheel has a 25mm offset, which puts the wheel farther out compared to other stock W-body wheels.

joshua

 

YES, OFFSET IS VERY IMPORTANT... A lower offset will "push" the wheels further to the outside of the car. Giving a "wider" rim more room in the wheel wheels. Putting a 8" wide wheel that has a higher offset such as +40mm is going to cause problems.

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I have a common question for everyone. Bolt pattern....will the 114.3 bolt pattern give you trouble considering ours have the 115? Offset is a problem for us due to the calipers.

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I just put a set of 225/75/R16's on my 1990 Lumina Euro just now, and have not had any trouble so far. I had purchased a set of very nice factory alloy wheels and Goodyear GS-A tires from a 1991 Lumina at a junkyard last week, and today I pulled out the my large hydraulic jack and went to work changing both axles.

 

Before I did, though, I took the car for a drive on a long curvy road about 10 miles from here and payed carefull attention to how the car handled with the 215/60/R16's that it had on it when I purchased it. Then I did the same thing on the same road with the new set.

 

I could tell a big difference in ride, and the handling had improved a good bit. I took several corners with hard oversteer, and with the old set the tires would break traction and squeal a little. With the new tires, quiet as a mouse. It did make a difference.

 

So Luminas are go for 225/75's, and I would imagine all W's should be able to handle them.

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Guest TurboSedan

So Luminas are go for 225/75's, and I would imagine all W's should be able to handle them.

 

75 series definately won't help anything but ride quality. i really can't imagine it would handle better than the equivalent 60 series. does it look funny with that size?

joshua

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I just put a set of 225/75/R16's on my 1990 Lumina Euro just now, and have not had any trouble so far....So Luminas are go for 225/75's, and I would imagine all W's should be able to handle them.

Wow! you put truck tires on it & they fit? That size has a diameter somewhere around 29.5".

 

I have a common question for everyone. Bolt pattern....will the 114.3 bolt pattern give you trouble considering ours have the 115? Offset is a problem for us due to the calipers.

I've heard many people say that about the offset. Wouldn't caliper clearance have more to do with the contours of the back of the wheel? If part of the center section is going to hit the caliper, why does it matter how far the rim is offset? Granted if you add a large enough spacer (thereby adding negative offset), the caliper won't hit the rim, but that's not what I mean. I believe that you can have 2 different wheels with the same offset and have 2 different caliper clearances.

 

As for the 114.3 vs 115, read my reply: http://www.w-body.com/forum/viewtopic.php?t=11967

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Guest TurboSedan

i wouldn't think that wheel offset has much to do with caliper clearance. tire clearance with the fenders, yes, but probably not caliper clearance. wouldn't the diameter of the wheel be more of an issue in terms of caliper clearance?

joshua

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So Luminas are go for 225/75's, and I would imagine all W's should be able to handle them.

 

75 series definately won't help anything but ride quality. i really can't imagine it would handle better than the equivalent 60 series. does it look funny with that size?

joshua

 

As stated above, I could tell a ride quality difference and a bit of handling difference. I drove them both on the same road so that I would be able to gauge the difference.

 

It does not look all that strange. It looks kind of like you are trying to put alot of rubber on the road to stop the tires from spinning. As to if I'm going to leave them on, I don't know yet.

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Blue GP:

 

If I put "truck tires" on my Lumina, then the fellow who had owned the Lumina in the junkyard must have had them on his also. I had to jack up the car and take them off myself. They obviously worked for him. The only difference I could tell was they really fill up the wheelwells.

 

My primary reason for purchasing them was that the wheels are in alot better shape than the ones that are on mine now. I purchase a good bit of parts from him, so he usually gives me good deals. With a price of four wheels and tires for $50.00 I would not complain if they had semi tires on them.

 

I put them on and drove it and happen to see a forum member asking the maximum tire size, and I thougt I would share what I knew. Ultimately everyone must decide what tires fit their particular needs best.

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I put them on and drove it and happen to see a forum member asking the maximum tire size, and I thougt I would share what I knew.

You're absolutely right. I didn't mean to offend; I just didn't think that tall of a tire would fit.

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  • 7 months later...

Sorry about bringing another thread back from the grave, but it's not in vain.

 

That size has a diameter somewhere around 29.5".

 

Are you still running this tire size? I'm looking at putting an AT tread on one of the cars, and if I could put 30" tires on it that would be great, ground clearance wise and traction wise. Suppose there's room for an extra .25"? When it comes down to it I'm putting on whatever size tires I can find for free, but a definite size limit would be handy.

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