Chimmy3

Hey everyone i was wondering if anyone could help me answer this definitively...

Is it possible to run 185/65-R15 using the stock steelie rims w/o any problems?

I keep getting different answers depending on who answers.
Tire rack for example says its not recommended, but I think I remember some people saying they've had no problems...(can't seem to locate those posts though)

I want to get 185/65s b/c there's more availability for the tire (selection wise), thicker sidewalls, and slightly more ground clearance (a necessity in my parts).

Oh and I'm not going thicker b/c I'm considering what to put on for winter tires.

FrankenScion

I beleive SciFly ran those tires on his box. You might PM him and ask.

smokeydog001

Here is a good url someone posted to a question I had. http://www.miata.net/garage/tirecalcold.html

Chimmy3

eh... I"m well aware of the side effects (to the speedometer) of running larger than normal diameter.. but according to other ppl's posts we're under or over (calibrated, depending how you count) to begin with. So this would even things out somewhat.

Thanks for the tip Frankenscion... I'll see if I can locate him.

TJ

Chimmy- I run 195-65-15 on the stock rim with no problems. I also am running a 185 70 14 on my winter set. They'll work fine. The stock rim will also accommodate a 205-50-15 with no problems

singleshot

I'm also runnin 195/65/15r for my winter tire combination, for the same reason you stated.. more selection.... No problems


singleshot

Dewmerz

Some information Tomas posted in another thread.

xA_Factor

A 185/65 is just outside the recommended +/- 3% difference vs. the stock rolling diameter. So, at an indicated 60mph, you'll actually be traveling closer to 62mph.

The effective taller gearing certainly won't help your low-end either.

It will work, it's just a bit tall.

Tomas

Not only does the bB come stock with only the 185/65R15, the xB repair manual shows both the 185/60R15 and 185/65R15 as the "stock" tire size...

The service manual for the xB speedometer shows it's standard calibration is 1.5 to 5.5% fast at 60MPH (3-8% fast at 100).

Going to the 185/65R15 tire is unlikely to make the speedo read "too slow" when the tire is new, and even more unlikely as the tire wears.

Is it show and tell time? Is it? Is it?

Oh goody!





Now, I want to do a quick check. Will everyone who normally reads their speedometer with less than 3 percent error from parallax, vibration, or other causes, while zipping down the highway at 60+MPH please raise their hands? Er, 1, uh, 2, uh, 3. OK. You can put them down. :D

xA_Factor

It's one thing to post useful information. It's another to be a smart-a$$ about it.

Tomas

Sorry if that seemed a bit smart-alecky...

Every bit of this information has been posted here before, xB_Factor, complete with the pictures, and in answer to the same questions. A little humor and leg-pulling should be allowed, especially for things that could have been searched for...

The humor was not aimed at you, 'Factor, but at all those who make assumptions about specific systems without checking the data for those systems first. I spent too many years as an engineering manager to put something in writing without checking it first (or to give three place accuracy to guesstimates). :D

I'm not trying to say your information is bad, just that the actual Toyota published repair manuals differ from the information you present. To back that up I again posted images from the actual Scion manuals. None of this is new.

As to calibration accuracy of the speedo regarding tire size changes, there is nearly as much variance in tires of the SAME size but from different manufacturers, or from the identical tires with and without tread wear, as there is from a plus or minus one size or a 5% aspect ratio change.

As to a 3% speedo error, I believe the width of the needle is about 3MPH (roughly 5 percent at legal speeds) - if your speedo is too fast, just use it's trailing edge as your data point or use the leading edge if it's too slow.

If a digital readout said one was going precisely 60.00 MPH one might assume it reflected the accuracy of the overall system. An analog display with high parallax, a lot of environmental vibration, very poor markings, and an indicator with a width of nearly 5% of the maximum legal reading, cannot be assumed to reflect accuracy to within a few hundredth's.

Now position that indicator, with only markings at every fifth whole number, spaced a small faction of an inch apart, at greater than arm's length, and it really can't be considered a highly accurate system. It is at best an educated guess.



An upgrade to a substantially better tire like the P185/65R15 BFG Traction T/A's drops around 80RPM at freeway speeds and makes the speedo "right on" with my xB auto...

Time to be nice again - I'm off vacation.

Hope everyone has a great new year.

xA_Factor

No harm, no foul. I appreciate the apology, Conveying one's exact mood/tone over the net can be difficult sometimes. I too, offer an apology for misinterpreting you.

BTW, I was not making a random assumption. The fact is, most wheel/tire suppliers recommend no more than a 3% variance in rolling diameter vs. stock. A 185/65 is just slightly outside that window....although just barely.

The Tire Rack, for example, lists the 185/60 as the OE size and therefore doesn't offically recommend a 185/65 since it's deviates about 3.1% from the stock rolling diameter of 23.7 inches.

In the end, I told him it will work. It's just a bit tall........using the 3% rule, that is.

djct_watt

I've been VERY happy running 195/60/15. . . it's only a 3mm gain in tire radius. I definitely notice the extra 10mm of width on the tread though. . .

. . . personally, I would recomment this tire over a 185/65/15, merely because of the width of the tire. However, I havn't really looked at the snow tire options for this size.

Tomas

There are obviously many options on tire size, even when sticking to just the stock 6JJX15 wheels.

I went to the slightly taller, same width tire for a number of reasons: Slightly better ride because of sidewall height, slightly better directional stability and rain performance from longer tread patch, no increase in rolling resistance or hydroplaning, and no decrease in snow performance from wider tires.

Beyond those reasons, which would apply to a tire identical to the OEM 60 series but in a 65 series, I also went to a substantially better tire for my purposes (normal driving on normal roads with very wet surfaces for a substantial percentage of the time - I do live in the Seattle area).

Since TireRack has already been mentioned, allow me to toss in a chart, courtesy of them, for the 65 series tires I was considering:



Again, for my specific purposes I rejected the wider tires... :D

djct_watt

And for good reasons. . . here in CA, the rain/snow isn't as bad.

telemike

Afer reading this, I may opt for 185/65R15's when it's time to get new tires

bB2NER

I plan on running 205/60/15's on the steelies after the GYs are worn.
What width are the steelies? I keep hearing different sizes. I hope they are 15X6 and not 15X5.5.

SkyonXa

xa-15x5.5
xb-15x6

bB2NER

Thanks, I thought they would be the same cause they have the same sized tires

BozzMan

i also plan on running 185/65/15 on my xA with TRD springs this winter. i hope they won't rub!