Should I get OEM size tires?

Post by **PoorManQ45** » Tue Jun 07, 2005 1:29 pm

My current tires are 2in smaller then OEM.

I like the look of it being 2in lower, but the load rating on the tires is too low.

I'm wondering what you guys think. Should I get larger tires and sacrifice the higher ride, or find the same size tires(maybe wider) with the proper load rating?

The reason I'm bring this up is that some(maybe alot) of you pay ~$400 for eibach lowering springs to lower it by ~2in, and you pay ~$1000k+ for 4.08 rearend(not saying mine equates to that, but it's larger them OEM with these tires).

Thoughts?

OR should I choose option C and keep the current size tires AND get lowering springd for a total of 4in lower then OEM?

Post by **rsiwicki** » Tue Jun 07, 2005 1:46 pm

with even your suggestion of running those small of tires, I think I like your Q as a driveway ornament versus a rolling 4,000lbs accident

Post by **szh** » Tue Jun 07, 2005 2:58 pm

PMQ, aren't you reading the recent posts and responses on tires and load indexes?

You know what my response is going to be!

Z

Post by **SmithSR** » Tue Jun 07, 2005 3:51 pm

OK so if your tire is fully 2" shorter than OEM size, your tire is 1" shorter in either direction from the wheel hub.Your suspension/body is 1" lower but wheel gap actually Increases from OEM... car still looks jacked up... accomplishments to date: none... no comparo with eibachAdd in a smaller than OEM tire that is severely overloaded, and we have recipe for failure at high speeds resulting in lawsuit. People are being sued daily and all tire companies are covering their ***es to avoid having the finger pointed at them.Makes me wonder what shop would have mounted such small tires to your car.Never admit, especially in print, that you know your tire is below minimum load index for your car. If you admit to knowing this then the tire company can get out of paying you or somebody you crash into and kill the millions their family could sue(and win) for.BTW can you tell us the tire size, specs, and name & location of the shop doing the negligent tire work.

Post by **Jeff Williams** » Tue Jun 07, 2005 4:28 pm

YES!

Or, get 235/60/15's, like Dennis has. His Q drives great.

Post by **elwesso** » Tue Jun 07, 2005 4:34 pm

Jeff Williams wrote:YES!

Or, get 235/60/15's, like Dennis has. His Q drives great.

Agreed.. I have 235-60-15 on my factory wheels and they were wonderful!

Post by **maxnix** » Tue Jun 07, 2005 6:10 pm

Here's a third on the XGTH 235/60-15. The perfect size for stock wheels, and a 98 load rating to boot. Speed raing only H.

For normal non-top speed runs, they are great. Just stay under 130 mph.

Post by **Q45tech** » Wed Jun 08, 2005 1:13 am

Speed rating applies to only brand new tires, NEVER ASSUME that a USED 8,000 mile tire is safe at the indicated speed rating even for a few minutes.

To me a USED------ H rated Michelin is not safe at even 130 mph BUT extremely SAFE at 100 MPH till the tread wears totally out and the metal cords begin to show.

Getting away from speed, a smaller diameter tire heats up faster and thus braking distance suffer a great deal. The Converse is true 26>27" and a higher load index [extra 100 pounds ABOVE OEM] increases longevity........almost always at least repaying the extra cost in longer wear mileage.

FORD RWD POLICE CARS are a good comparison model for a Q..........lots to be learned from their experiences. Brakes, tires.

Post by **szh** » Wed Jun 08, 2005 7:31 am

There are plenty of good tires that will fit an OEM 15" Infinit wheel. Here is a listing in 215/65-15, 225/60-15 and 235/60-15. Some of these are Standard Touring, All-Season, etc., but still way better and safer than a tire that is 2" too small.

Price ranges from $46 (for the Fusion HRi 215/65 and 225/60) to $141 (for the Pirelli P600 235/60). I am sure that you would find something that will fit your budget and performance needs.

215/65-15Bridgestone Potenza G009Dunlop SP Sport 5000 SymmetricalDunlop SP Sport A2Dunlop SP Sport A2 PlusFirestone Affiniti LH-30Firestone Touring LHFuzion HR iGoodyear Eagle GT+4Goodyear Eagle GT-HRKumho ECSTA HP4 716Michelin Pilot XGT H4Michelin Pilot XGT V4Pirelli P4000Pirelli P6 Four SeasonsPirelli P6000 Sport Veloce 95HPirelli P6000 Sport Veloce 95VSumitomo SRIXON4Yokohama Avid H4SYokohama AVS dB S2

225/60-15BF Goodrich g-Force SportBridgestone Traction T/A HBridgestone Traction T/A VBridgestone Potenza G009Bridgestone Turanza LS-HContinental ContiExtremeContactContinental ContiTouringContact CH95Dunlop SP Sport 5000 SymmetricalDunlop SP Sport A2 PlusFirestone Firehawk SZ50EPFuzion HR iGoodyear Eagle GT-HRKumho ECSTA HP4 716Kumho ECSTA KH11Michelin Pilot Exalto A/SMichelin Pilot XGT H4Michelin Pilot XGT V4Michelin Energy MXV4Michelin Energy MXV4 PlusPirelli P6 Four Seasons 96HPirelli P6 Four Seasons 96VPirelli P6000 Sport VeloceYokohama AVS dB S2

235/60-15Michelin Pilot XGT H4Pirelli P600

Regards,

Z
Modified by szhosain at 11:53 AM 6/8/2005

Post by **Q45tech** » Wed Jun 08, 2005 9:09 am

"plenty of good tires " that is the key UNFORTUNATELY NONE are of the Quality nor RESERVE of the oem tire provided on the 90-93Q. Even the current Michelin Pilot XGTV4 was a much lesser quasi all season tire with a V rating

The orginal Michelin SPORT XGT- V was their top of the line for the EARLY 90's..............in many ways similar to the current Michelin Pilot Sport but it wore out even faster having a 15,000 mile useful life [if rain was factored in they needed replacing every 10,000 miles].

The real question is ----------- does a 95 load index stamped on the side wall mean that ALL so labeled are the same now and then or of equal quality.

Many people believe the US Government tests tires that is not true!

They write the specification minimums and let the manufacturers test and report...........WITH WIDE LATITUDE and dubious accuracy..........special hand made by experts samples may be used having little resemblence to future factory real world production but extrapolated for the next 6 years and representative of what is really being sold [doubtful].

There is no after the fact checking........NONE!

My point is a 95 Michelin may perform like a 98-100 rated lesser tire at 20,000 miles on each.........that is by Michelin Corporate Design and they spend the $3.00 in extra material cost/strength to make it happen.

This is what happens when one tries to use a lesser brand with a 95 rating on a Q45.......the fronts wear out fast and the tire gets internally destroyed [balance, conicity, feathering a host of other problems] while looking ok on the outside

Post by **PoorManQ45** » Wed Jun 08, 2005 10:09 am

Ok, first, I'm not running OEM wheels. I've got 16 x 7.5 or x 8in.

Also, I didn't say that the load rating is below OEM. I said that it is too low for my liking.

Also, I know the wheel gap is still large. I'm just wondering, should I stick with this size AND lower it then? Giving me a total of 4in drop with less wheel gap. Anyone on here have there Q lowered more then 2in? How's it look?

THanks for the help.

Post by **louiegz** » Wed Jun 08, 2005 10:18 am

I always thought that one main reason to lower the car is to get rid of wheel gap. If you increase the gap, I don’t think it will look right. Use 255/50/16. That’s what I use. Falken 512 about $74 a tire at Discount Tire. 99 load rating.

Post by **PoorManQ45** » Wed Jun 08, 2005 10:26 am

I'll check into those.

I didn't realize that using smaller tires actually increases the wheel gap. I thought it'd just stay the same. Does that mean that there is more travel in the suspension?

SR_Smith wrote:BTW can you tell us the tire size, specs, and name & location of the shop doing the negligent tire work.

225/45/16 Aquatread. DOn't know what brand that is. Don't remember the shop.

Post by **louiegz** » Wed Jun 08, 2005 10:35 am

You can also do 225/55/16 with a load rating of 95. Easier to find more brands in that size.

Post by **louiegz** » Wed Jun 08, 2005 10:37 am

PoorManQ45 wrote:Does that mean that there is more travel in the suspension?

No

Post by **szh** » Wed Jun 08, 2005 11:19 am

Q45tech wrote:"plenty of good tires " that is the key UNFORTUNATELY NONE are of the Quality nor RESERVE of the oem tire provided on the 90-93Q.

Sorry, Dennis, I did not mean to imply that these are all recommended tires that compared to the original OEM design.

What I meant was that they are "good", relatively speaking, when compared to one that is 2" too small(!) or with load index values that are below(!) what should be the minimum on a Q45!

Z
Modified by szhosain at 2:34 PM 6/8/2005

Post by **szh** » Wed Jun 08, 2005 11:23 am

PoorManQ45 wrote:Ok, first, I'm not running OEM wheels. I've got 16 x 7.5 or x 8in.

Also, I didn't say that the load rating is below OEM. I said that it is too low for my liking.

You need to re-define "too low for my liking" and "didn't say ... below OEM" in your vocabulary! As you mention in a later post, you are running 225/45-16, and all the 225/45-16's listed at Tire Rack range from a load index of 89 to 93 (one tire at that value.) By my definition, these are all below OEM and dangerously too low.

Z
Modified by szhosain at 2:36 PM 6/8/2005

Post by **szh** » Wed Jun 08, 2005 11:28 am

PoorManQ45 wrote:Does that mean that there is more travel in the suspension?

Nope.

PoorManQ45 wrote:225/45/16 Aquatread. DOn't know what brand that is. Don't remember the shop.

That is an old Goodyear brand. The Aquatred 3 is an old model that may have been ahead of its time when it first came out, but is outclassed by most new tire formulations (for wet handling) today.

I do not believe that the load index on this tire meets OEM specs. Please look at the tire (after the size value of 225/45-16) and if it says something like 90 or less, then you might as well leave your car up on blocks ... the static weight of a Q45 with gas and people might overload the tire at a normal tire pressure (let alone the 36psi where it is usually measured at.)

Z

EDIT: More recent info: The Goodyear Aquatred 3 has been discontinued for some time now. Your tires may be old enough to warrant replacement, I would say. Check your rim width (you said you did not know if it was 7.5" or 8.0") and get something appropriate for that size. If you need help, send me e-mail and I will make some recommendations - those that are safe, not those that "lower the car 2" without any rational reason.
Modified by szhosain at 7:02 PM 6/8/2005

Post by **JedCoop** » Wed Jun 08, 2005 4:05 pm

Q45tech wrote:The orginal Michelin SPORT XGT- V was their top of the line for the EARLY 90's..............in many ways similar to the current Michelin Pilot Sport but it wore out even faster having a 15,000 mile useful life [if rain was factored in they needed replacing every 10,000 miles].

My first Q had XGT-Vs on it when I bought it. They were awful in the rain and wore fast. But they were round and smooth.

When I ran Kumho's, they were pretty dead by the end of their tread life. I hadn't thought about it, but a high load rating should go with better longevity of internal structure/balancing of the tire. Would it really higher load rating mean less feathering too? I thought that feathering has more to do with alignment and tread pattern.

Post by **maxnix** » Wed Jun 08, 2005 4:08 pm

And tread stability, thus carcass strength.

Post by **JedCoop** » Wed Jun 08, 2005 4:17 pm

SR_Smith wrote:...Your suspension/body is 1" lower but wheel gap actually Increases from OEM... car still looks jacked up... accomplishments to date: none... no comparo with eibach

The main reasons I would lower a car:

1) to reduce weight shift to outer wheels on turns and roll dynamics2) to reduce high speed aero drag and aero lift

Main reason for stiffer springs:1) To reduce Body Roll dynamics (but not weight distribution)

And to lower a car shorter springs are needed, therefore they must be stiffer, too.

Main reasons to use alloy wheels:1) to improve the ratio of sprung versus unsprung wieght - improves ride and traction on uneven surfaces - which means pretty much every road in the US.

And you try and do this keeping suspension camber neutral - another goal - for both traction and tire wear.

Did I mention good looks ??? Looks only follow function.

[I think low-rider trucks are silly, too.]

Post by **maxnix** » Wed Jun 08, 2005 5:49 pm

JedCoop wrote:
[I think low-rider trucks are silly, too.]

This post reserved for future picture for Jed.

Post by **DR.Q** » Wed Jun 08, 2005 10:29 pm

PoorManQ45 wrote:Ok, first, I'm not running OEM wheels. I've got 16 x 7.5 or x 8in.

Also, I didn't say that the load rating is below OEM. I said that it is too low for my liking.

Also, I know the wheel gap is still large. I'm just wondering, should I stick with this size AND lower it then? Giving me a total of 4in drop with less wheel gap. Anyone on here have there Q lowered more then 2in? How's it look?

THanks for the help.

Just to reiterate what was already well stated by SR SMITH: If your tires are 2" less in diameter, then they are 1" less in radius, the distance between the center of your hub and the ground. So since your car is only sitting 1" lower and Eibachs only lower the car 1", the most total drop you could hope for would be 2" with your current tires and the Eibachs. But do yourself a favor and get the correct size/load tires on there and then buy the Eibachs. Check here for photos of my Eibach'ed Q.

http://cgi.ebay.com/ebaymotors...%3AIT

Or better yet, buy my wheels/tires and Tokicos/Eibachs.

Post by **PoorManQ45** » Thu Jun 09, 2005 2:32 am

Dr. Q: Could you take a side picture of your Q while holding the camera at about the level of the middle of the door. THe angle tyou took the other pictures at it is kind of hard to see how much wheel gap there is

Post by **pito11213** » Thu Jun 09, 2005 3:16 am

Well I had 245/55/16 on my Q and it drove fine except on uneven pavement when you got a little pull. But on flat surface the handling was beautiful. By the way the tires were Kumhos Ecsta.

Post by **szh** » Thu Jun 09, 2005 3:20 am

pito11213 wrote:Well I had 245/55/16 on my Q and it drove fine except on uneven pavement when you got a little pull. But on flat surface the handling was beautiful. By the way the tires were Kumhos Ecsta.

Which Kumho ECSTA specifically? As I recall, most Kumho tires begin with that ECSTA name!

Z

Post by **pito11213** » Thu Jun 09, 2005 4:03 am

I believe it was The supra line or something like that.

Post by **Q45tech** » Thu Jun 09, 2005 4:05 am

Lowering does reduce the weight shift/transfer BUT NOT ENOUGH TO MATTER.....................as the formula is CG/Track Width x sprung weight X G force:

With a front CG of 22"/60" =0.366666 a lowered 21"/60=0.35 and and sprung weight of ~~900 [guesstimate] the difference in weight transfer at 1.0G is 15 pounds about 1.6%. BUT Q front tires cannot support 1.0 G.

The ratio of the actual weight transfer to the tires max load reserve is the best indicator of what the possible G loading could be [A FACT LOST ON MANY].

Consider a static front load of [4300 x 0.54...../ 2 =1161 pounds and a max load of 1521 [95V] leaves 1521-1161= 360 pounds of handling/braking reserve..........unfortunately most don't run 44 psi so the reserve is decreased some and as you approach the limit the graph become non linear so 90% of max load is pretty much it.........that's1369 pounds.

1369:1521-1369=208 not 360 as could be transfer at 1 G.........this 150 pound short fall is why the Q cannot usually exceed 0.8 G [front tire are the limiting tires].

Going to 98 or 100 load index with appropriate tread softness and correcting camber to optimize the footprint at a higher load WILL increase the G forces possible as long as you maintain the sprung weight.

Lowering the CG then using heavier tires and wheels is SELF CANCELLING!

IF one goes from say 215/65 to 235/60/15 on the same wheels with tthe same tire you usually gain about half the increase in load index number.

About 3-4.5%, significantly more than lowering 1" will accomplish, do both and the net might be 4.5-5.5%.......if you correct the increase in camber cause by the lowering.

The side benefit is the 8-9% higher load index yields about 8-15% longer life which unfortunately doesn't wash with the 30% higher price of the 235/60/15 vs 215/65/15 [Michelin Pilot H4]........but it helps some to defray the cost increase.

Post by **pito11213** » Thu Jun 09, 2005 4:08 am

http://www.tirerack.com/tires/...1=yes

I believe this is the tire I had.

Post by **szh** » Thu Jun 09, 2005 7:30 am

Q45tech wrote:Going to 98 or 100 load index with appropriate tread softness and correcting camber to optimize the footprint at a higher load WILL increase the G forces possible as long as you maintain the sprung weight.

On my M45, I have not changed the springs (or changed anything else for that matter,) but decided to get 245/45-18 Goodyear Eagle F1 GS-D3, because a few months ago, they released a new load index model in this size: 100W (the old model was 96Y.)

So far, the results are very good! Yesterday, it rained here in the South Bay Area (unusual ... I rushed to a local dealer rather than wait for an order from Tire Rack - my tread was down below 2/32 on the rear tires, and I do not like to get that low.)

The handling was like I expected (based on experience on my wife's Acura.) These tires are as good as the Firestone Firehawk SZ50EP in wet, albeit much noisier on the highway (the SZ50EP remains the high standard in this regard.) Stiffer sidewall than the SZ50EP, so a slightly harsher ride in the Eagle. Plenty sticky enough in dry conditions and very good steering response.

Like on my wife's Acura, I expect that I will need to re-balance often (I do it on her car every 3000 miles or so), but that is a small issue now - the tire place I went to has assured me of free balances "for the life of the tire." Even if I am not happy with a balance they do and come back in a few miles!

Z
Modified by szhosain at 1:26 PM 6/9/2005

Should I get OEM size tires?

Should I get OEM size tires?

Re: Should I get OEM size tires? (PoorManQ45)

Re: Should I get OEM size tires? (PoorManQ45)

Re: Should I get OEM size tires? (Jeff Williams)

Re: Should I get OEM size tires? (elwesso)

Re: Should I get OEM size tires? (maxnix)

Re: Should I get OEM size tires? (PoorManQ45)

Re: Should I get OEM size tires? (szhosain)

Re: (PoorManQ45)

Re: (PoorManQ45)

Re: (PoorManQ45)

Re: Should I get OEM size tires? (Q45tech)

Re: (PoorManQ45)

Re: (PoorManQ45)

Re: Should I get OEM size tires? (Q45tech)

Re: Should I get OEM size tires? (JedCoop)

Re: (SR_Smith)

Re: (JedCoop)

Re: (PoorManQ45)

Re: (pito11213)

Re: (szhosain)

Re: (Q45tech)

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