oscarlee1981

just got one set of 19 inches wheels. the stock size is 285/30/19 for the rear wheel. if i use 285/35/19. will that be any side effect. i know there might be speedo off. thx for help..

alx

it is taller overall and will change the front/rear turn ratio. this might screw up the abs and asc setup...

okbarnett

I dont thik youll ever know any difference

B R

Look up the tire specs for that particular tire, well actually both your fronts & rears. OD will vary between brands & models. As long as you have no more variance than 1" OD between the F & R you should be fine.

EXECMALIBU

I have 295/35/19 on the rears and 265/30/19 on the front with no problems...

The 5mm (30 vs 35) in height is less then the tire wear from new to worn out... The 5mm is in reality only 2.5mm from the center of the spindle to the ground... Tire manufacturers have more then 5mm difference even in the same companies different tires. Longer tread life tires will be taller (deeper tread) when new then ultra hi-po tires of the exact same size.

danlnyc

should be no problem

threeMBs

What??? on SL?

295/35-19 is a 27.1" diameter tire
265/30-19 is a 25.2" diameter tire
Difference is 1 and 9/10" (almost 2 ") or 48.26mm not 5mm as stated above. Sidewall of your rear tire is over 24mm (almost an inch) taller then your front, not 2.5mm as you stated. The second number in tire's size is not in mm (first number is), its an aspect ration or percentage of the first number.

SL is a front engine car not designed to run with greater diameter tire at the rear. Rear and mid engine cars use this set up.

To the OP: if you want to run 285/35-19 tire at the rear, it is fine as long as you run 245/40-19 at the front. Same diameter as many people running 20" on SL - 245/35-20 & 285/30-20.

EXECMALIBU

Read the post first!!

5 mm size difference for his rear tires is what he asked about will 285/35/19 be OK as opposed to 285/30/19... I wrote that I use slightly oversized tires front 265 vs 255 and rears 295 vs 285 with no problems....

threeMBs

I read what the OP wrote.

I also read what you wrote:

"
I run 295/35/19 which are wider/taller with no problems....
I have 295/35/19 on the rears and 265/30/19 on the front with no problems...

The 5mm (30 vs 35) in height is less then the tire wear from new to worn out... The 5mm is in reality only 2.5mm from the center of the spindle to the ground... Tire manufacturers have more then 5mm difference even in the same companies different tires. Longer tread life tires will be taller (deeper tread) when new then ultra hi-po tires of the exact same size.
"

1. OP question vs. your answer:
285/30-19 vs. 285/35-19 is not 5mm - its 25.4mm (1").
FYI: 285/30 vs. 295/30 is 8mm and 285/35 vs. 295/35 is 8mm too.
Width is not in question here - hight is.

2. Tires sizes that you stated you're runnnig:
265/30-19 is a full inch less in diameter that stock's 26"
295/35-19 is full inch more in diameter than stock's 26"
difference is full 2" front to rear.

From what you wrote, it means you have no idea what you're talking about or made a costly typing error.

For people who do not know how to calculate tire dimeter and then convert from mm into inchs, this is the formula:

width of tire in mm (first number) * aspect ration (second number) / 2540 (to convert to inches) = sidewall hight, since there are 2 sidewalls (hope everyone understands this) need to multiply by 2 then add wheels diameter.

In your example, that you say you're running on SL:

front (265 * 30 / 2540 *2 ) + 19 = 25.23" (much less than stock's 26")
rear (295 * 35 / 2540 *2) + 19 = 27.13" (much more than stock's 26")

Now what I think you meant to write, was that you're running:

front: 265/35-19 instead of 255/35-19 (that is 10mm wider and 1/5" higher than stock, but is absolutely fine)
rear: 295/30-19 instead od 285/30-19 (that is also 10mm wider and only 1/9" higher than stock, but is absolutely fine too).

I'm 100% sure that's what you're running, not what your wrote.

When people ask question, especially for tire sizes, puting a wrong aspect ration by mistake can lead to them making a wrong and $$$ costly decision. That's my only point.

To the original poster:

On the SL as on most if not all MBs, you must keep front and rear tires diameters the same or as close as possible, that is why I wrote that if you want to use 285/35-19 (a full inch higher tire that stock's 285/30-19) at the rear, you must also increase front's diameter by close to 1" too, hence 245/40-19 (fyi: 255/40-19 will rub).

oren217

so what your saying is something like these would never work:

(30mm in front, 35mm in rear)

http://cgi.ebay.com/ebaymotors/19-BE...Q5fAccessories

threeMBs

Hello here.

We were discussing tires width/hights, not wheels offsets. Talking about apples vs. oranges.

Gene Gorman

This web link is very helpfull in picking tire sizes. http://www.miata.net/garage/tirecalc.html

Hope this helps.

DoctorV8

EXECMALIBU:

What threeMB's is saying is that your statement about 35 vs 30 series tires is totally wrong.

The aspect ratio is NOT measured in millimeters, but rather a a percentage of width. So the sidewall height is 30 or 35 PERCENT of 285mm, which is either 99.75mm (35 series) or 85.5mm (30 series).....and that is for ONE sidewall. You have to double that, since there are two sidewalls including in calculating overall tire height.

SO the difference in diameter is 99.75mm-85.5mm X2, which is 28.5mm, NOT 5mm as you posted.

Hope that clarifies things.

oscarlee1981

Thanks for all your reply. I already get 285/30/19 and put to my wheels as what manual says. but learn lots of valuable information here.

oscarlee1981

this website seems very helpful. i have saved it to my favorites...

pww3

I know it is an old thread but oh my God, EXECMALIBU sorry but you are the biggest idiot I have ever met on the internet LOL

RoundTheBenz

You use your second post to insult a member who's been on here for almost 10 years? So he was wrong, big deal! Remind me not to try to answer any of your questions...

Sometimes people really amaze me.

aussieSL55

Hi, sorry to ask the questions again - but as has been mentioned - these are DAMN expensive - especially here down under (nudging $3k)

Here in Australia - we only had the 18 inch wheels on the SL55. The later SL63 had the 19's.

My car has the SL63 19's with the standard 255/35R19 fronts and the 285/30R19's rears. One of the rears is dead now. I would like to go ONE size wider. It seems I am having some problems with getting the power down to those rear tires :-)

So ideally - 265/35R19's front and 295/30R19 rears. The miata conversion site and 1010 tires site both indicate the speed difference is no problem.

I think one person on this forum has indicated this works.

Has anyone tried this exact set-up - and have you had any issues?

THANKS IN ADVANCE!

55slamg

I'd be concerned to run any wider than the 255 35 19's on the front. These tires run real close to the control arm on the inside. I trashed 2 tires so far. But it was my own fault for not checking the air pressure before taking it out after being in storage.

aussieSL55

Thanks 55SLAMG. Yes i noted the control arm - its about 10mm clear - so I figured 5mm either side should work. But your information suggest maybe not.

With tire pressure - I run 40 PSI. What have the problems you had and what PSI please?

55slamg

I'm running Bridgestone potenza at 36 psi. Learned my lesson in regards to tire pressures. I run nitrogen now and check the pressures regularly. Problem is when you blow a tire, your waiting a couple days for a tire shop to order in. Pricey too. Bought the last set of tires online from Tirerack.com. They were half the price of the local tire shop.

aussieSL55

Thanks for the fast reply.

36 makes good sense. My wife E55 Wagon was notorious for picking up anything because the pressures were too high (the rears). I think my SL55 has done the same.

I am still unsure about the 265/35R19. Some people reckon its worked. When you did try this tyre - did it rub immediately or only after you had higher (or lower) pressure?

On price - these will cost us $3,000. We get jammed on everything (ok - maybe not sun tan lotion!)

55slamg

Loss of pressure was my issue. Pulled it out of garage for a ride after being stored for the winter. Never checked the pressures after sitting for 5 months. Couldn't hear anything rubbing, but when I opened it up to 160 kph the front right let go. After removing wheel and inspecting the tire I found a wear mark on the inside sidewall which I figured was from the control arm. The arm can trash a tire real good.

Tirerack.com utilizes UPS for shipping. The prices are decent and were worth paying the duty on importing from USA to Canada. Might want to check with them on shipping to Aussieland.

aussieSL55

OUCH! The profile of these is so low - that its really easy to do. The guys with 20's must be really focussed on this.

Yes the control arm is a question. The guys at my retailer say it should fit - and they'll provide a lifetime replacement if it buggers up.

But I'll ask them to absolutely check once its on the car - if its less than 5mm - then we'll change back to 255/35R19.

Thanks a lot for the feedback and help.

Oh - and 160km/h - no way you did that on the roads. Of course you did that on the track:-). I had a SL63 out 2 years ago at an AMG drive day - 270km/h and I thought I was in heaven! Seems a crime that these babies can't have there day in the sun!

55slamg

I live in an area wear we have some pretty nice straight rural roads. Doesn't take much to get up to 160 kph once you punch it down. Yes, the guys that run 20's have to be real careful. I've read some of their posts and the issues they experienced. Forgot to mention that I also run a set of 13mm spacers on the rear.