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Mazdaspeed Archive => Suspension => Topic started by: Orange Power on February 03, 2006, 10:09:49 PM



Title: 215/45/17 on stock wheels?
Post by: Orange Power on February 03, 2006, 10:09:49 PM
I am considering switching to 45 series tires on stock tires for these reasons:
1. little softer ride
2. little more “over-drive” (3500rpm: 205/45:70mph, 205/45:72.4mph, 215/45:73.5mph)
3. speedo correction (speedo is over-states actual speed, taller tires compensate)
4. help prevent bent rims
5. fills up the fender wells (a little, w/o lowering)

Looking at Kumho MX or BFG Gforce Sport tires in these sizes:
205/45/17
215/45/17

Any thoughts, comments or experience ?
Is 215/45/17 too big (too tall/wide) ?
Which tire is better?





Title: Re: 215/45/17 on stock wheels?
Post by: Sb00 on February 04, 2006, 04:05:57 AM
i'm running the 215/45/17 Kumho MX's

good tires :) definatly can't go wrong with em!


Title: Re: 215/45/17 on stock wheels?
Post by: DreamNshadow on February 04, 2006, 09:31:37 AM
So our MSM's are actually going slower when reading 80mph than another miata reading 80mph?  Doesn't this also make the odo go faster?

I am considering switching to 45 series tires on stock tires for these reasons:
1. little softer ride
2. little more “over-drive” (3500rpm: 205/45:70mph, 205/45:72.4mph, 215/45:73.5mph)
3. speedo correction (speedo is over-states actual speed, taller tires compensate)
4. help prevent bent rims
5. fills up the fender wells (a little, w/o lowering)

Looking at Kumho MX or BFG Gforce Sport tires in these sizes:
205/45/17
215/45/17

Any thoughts, comments or experience ?
Is 215/45/17 too big (too tall/wide) ?
Which tire is better?






Title: Re: 215/45/17 on stock wheels?
Post by: unknownhost on February 04, 2006, 10:21:21 AM
just somthing to mull over...

i might be mistaken but, 235/40 17s should give you about the same ride height but leave you with about an inch more width=traction?

wondering why so many folks going with the less wide 45 series tires, seen several posts about this lately is all. is there a real advantage to them?

/edit for giggles i just checked the weight on the 215/45 17s (for the kumhos anyways) and they list at 21lbs, so that would be a weight saver in regards to the 235/40 17s listing at 23lbs for the same brand, but still adding over the stock list weight of 19lbs per tire for the same brand.

still think that extra inch of rubbers worth it though.  ^-^


Title: Re: 215/45/17 on stock wheels?
Post by: Orange Power on February 04, 2006, 10:44:08 PM
I suspect that 235s (and probably 225s) are too wide for a stock MSM rim.


Title: Re: 215/45/17 on stock wheels?
Post by: unknownhost on February 04, 2006, 11:17:06 PM
not at all. i myself am using 235/40 17d as are several other MSM owners.  :beer:


they looked huge at first but they fit very easily.

in fact... heres Krissybares pics of her 235/40s from the photo gallery.
http://mazda-speed.com/forum2/index.php?topic=3282.0


Title: Re: 215/45/17 on stock wheels?
Post by: wineboyatx on February 04, 2006, 11:52:03 PM
I have 215/40/17s on mine and was wondering about the speedo correction until I was tagged by a roadside radar sign that said I was going 81mph when my indicated speedo said 81!  Another thing I noticed was that my mpg got worse as the speedo and odometer slowed down.  I actually get almost a mile per gallon less now.
Boo.
Oh, I have Bridgestone Potenza RE050A's on mine and although they give a slightly better ride feel and they are extremely progressive at the limit, my treadwear rating is 140!  That's horrible.


Title: Re: 215/45/17 on stock wheels?
Post by: Orange Power on February 05, 2006, 08:36:06 PM
not at all. i myself am using 235/40 17d as are several other MSM owners.  :beer:

They may fit the fender wells/lips, but do they fit a 7" stock rim?  Do they bulge?
Does this size increase the rolling height and protect the wheels from bending?


Title: Re: 215/45/17 on stock wheels?
Post by: unknownhost on February 05, 2006, 09:03:59 PM
Orange P.,  yep. im using stock rims and so is KrissyBare in the link above, check'er out shes got that thing looking sweet.  :mrgreen:

they stand a half inch taller than the stock 205/40s and the bulge is very slight, nothing like the way most tires do over 15" rims as far as the tire widening more than the rim does as it gets further away from the point of rim/tire contact/seal.


should really look at krissys pic though as that says it all hehe. ive been half-assed reworking my car domain page and have some shots of my own going up whenever i gettem there but...actually heck lemme go do a slop-job fix and make them viewable. be warned my tires are dirty though   :laugh:
Krissy got it looking puurty.   :smitten:

/edit - heres a closer up shot of the 235/40s on the stock 17s. beware they're filthy  :oops: i hate my job and how it treats my car.  :'(
http://www.cardomain.com/ride/2185532/7 


Title: Re: 215/45/17 on stock wheels?
Post by: speedj on February 06, 2006, 10:53:55 PM
I think that a 225-45-17 goodyear eagle f1 gs-d3 is a very good choice for what you want to do.  It's much stickier than any of the above mentioned tires. It fits the current rim width. It's bead will protect the rim from marring and it'll knock off 250 rpm's going 80 in sixth gear.

Myself, I've ordered a 235-45 for the rear and a 225-45 for the front.  The 235 could really use a .5" wider rim, but it'll knock off 300 rpm @ 80/ 6th gear.  I've go coilovers I can work back the ride height and adjustable eibach bars so I can massage the front to rear cornering balalnce back to neutral.


Title: Re: 215/45/17 on stock wheels?
Post by: Orange Power on February 07, 2006, 07:57:24 PM
I've read a thread that 215/45/17 tires on stock rims will hit the insider front fender.
The 225/45/17 should hit even more and harder.
Is that true?

                   sidewall    radius
205/40/17       3.2"       11.7"
215/45/17       3.8        12.3
225/45/17       4.0        12.5
225/40/17       3.5        12.0
235/40/17       3.7        12.2


These numbers indicate that a 235/40 is about the same height as 215/45.
But does the extra width on the front cause the tires to hit inside fender or lip?
What 235/40/17 tire is rated to fit a 7" rim?

TireRack recommends only these upgrades for stock rims:
205/45/17
215/40/17




Title: Re: 215/45/17 on stock wheels?
Post by: Jae on February 09, 2006, 06:27:01 AM
My Hankook's are 215-45/17 and they rub in the front on hard corners and dips, esp with a passenger.  I would recommend a 40 or 35 series tire with a shorter sidewall.


Title: Re: 215/45/17 on stock wheels?
Post by: Roast Beef on February 09, 2006, 03:27:35 PM
My Hankook's are 215-45/17 and they rub in the front on hard corners and dips, esp with a passenger.  I would recommend a 40 or 35 series tire with a shorter sidewall.

How do you like those tires?  I've been thinking about getting the same ones in 235/40/17.


Title: Re: 215/45/17 on stock wheels?
Post by: Jae on February 12, 2006, 02:46:43 AM
The Hankooks are great!  Highly recommended for twistie driving.  Much better than the stock Toyos, and priced pretty nice too.  I did notice they got a bit slippery on a hot track last summer (100+ degrees ambiant!), but that was expected with street tires.  For everyday drivers, I would buy another set.  40 series profile though to keep from rubbing.


Title: Re: 215/45/17 on stock wheels?
Post by: Orange Power on February 12, 2006, 08:11:02 PM
Responses are all over the map.
Some 215/45/17 don't rub, some do.
Some say 225/45/17 are fine, others say no way (they rub easily).
Some say 235/40/17 are too wide for stock rim, others disagree.
Some say 225/40/17 will fit and not rub.

Is the tire brand making the difference?
If so, what is good tire to prevent rubbing for these sizes?



Title: Re: 215/45/17 on stock wheels?
Post by: Roast Beef on February 14, 2006, 06:48:45 PM
Responses are all over the map.
Some 215/45/17 don't rub, some do.
Some say 225/45/17 are fine, others say no way (they rub easily).
Some say 235/40/17 are too wide for stock rim, others disagree.
Some say 225/40/17 will fit and not rub.

Is the tire brand making the difference?
If so, what is good tire to prevent rubbing for these sizes?



The brand does make a difference.

I would think that if some 215/45s rub then 225/45s would have significant rubbing problems. 

I'll probably end up with 215/40's, since 235s seem to require an 8" wide wheel and the MSM wheels are only 7" wide.


Title: Re: 215/45/17 on stock wheels?
Post by: Keeper of the FAQs on June 21, 2006, 02:25:25 PM
Responses are all over the map.
Some 215/45/17 don't rub, some do.
Some say 225/45/17 are fine, others say no way (they rub easily).
Some say 235/40/17 are too wide for stock rim, others disagree.
Some say 225/40/17 will fit and not rub.

Is the tire brand making the difference?
If so, what is good tire to prevent rubbing for these sizes?



The real question you should be asking is: have the folks telling you something doesnt work actually done it? When several people tell you 'Im doing X and it works fine' and then a couple of people say 'thats wrong, there is no way that could work'... I know who I would believe.

This goes for pretty much any mod on the car. A lot of us got told, in no uncertain terms that the things we had already done to our cars would
1) Never work
2) Wouldnt make a diffrence
3) were totally dumb and there was a better way to do it.

A good rule of thumb: If someone hasn't actually tried a change, and cant provide a solid answer besides 'no', have a lot of doubt. ESP when you have other folks raising thier hands saying 'oh yea, that works fine, I did it on my car, no problem'


Title: Re: 215/45/17 on stock wheels?
Post by: Derek on July 05, 2006, 02:28:16 PM
Anybody use this?
http://www.miata.net/garage/tirecalc.html
It's a tire size calculator (that I've been using for years) that'll let you know how your speedo is going to change.

I was thinkin' a 215/40/17 would provide just a little more grip and a little bigger sidewall that will protect your wheels a little more but wont get your speedo off.

Hope that's useful.  sssmilely


Title: Re: 215/45/17 on stock wheels?
Post by: SilverMiataRacer on July 06, 2006, 08:26:43 PM
TThe only problem with any tire calculator is they assume the tire sizes are standard.  Sometimes a manufacturers specs aren't standard.  The best way to use the tire calc to get real results is to look up the tire you have and get it's specs from a place like Tire Rack and make sure the size you enter gives you that spec.  Then do the same thing for the tire your picking.  I've found as much as a 1/2" difference from reality.


Title: Re: 215/45/17 on stock wheels?
Post by: Derek on July 06, 2006, 08:41:33 PM
1/2" ? Wow, that's significant.
Is that a between manufacturer comparison, or a (same manufacturer, same tire) comparison?


Title: Re: 215/45/17 on stock wheels?
Post by: SilverMiataRacer on July 06, 2006, 09:53:47 PM
Between what the tire calc said a tire of that size should be in Dia. and what the manufacturers spec for their tire was.