I got my rims on, I had them on for all last night....now there's a real scary problem....the SLIP light in the tach starts flashing from time to time (not sure if it's when i hit bumps or not) and starts cutting power...This got to be real dangerous last night as I was on a few onramps doing about 50 and this thing slowed me down to about 30!!! i had to keep putting my hazards on the highway because i kept getting slowed down....do I have to reset the ECU or something now that I put my rims on? I had to take out this thing (pic) to put the front rims on, do you guys think this affected anything? PLEASE HELP

 

taking that off will not do anything. What size wheels and tires are you running?

 

19x8.5 (245/35) front

19x9.5 (275/30) rear

 

might be your problem? 30 profile?

 

your stock setup has a 26.7" diameter, your new setup has a 25.5" diameter

you're supposed to go with 35 profile so that the over diameter is within spec.

this site is helpful
http://www.miata.net/garage/tirecalc.html

 

this is what Dave at 350z mods reccommended....i was gonna ask someone on the forum about their sizes, but he told me he know because he only sells to 350z's and he would get the proper sizes...

p.s. Dave please reply if you see this post

 

i had notice the larger gap in the wheelwell immediately, but i figured he knows best...

 

might try a search too, i think several members had this problem before. i think droideka has the problem.

 

umm... You put your hazards on? why didnt you just turn off your traction control!? Thats the first thing I do when I get in the car. To really solve the problem though you are going to need a 35 profile tire in the rear. Since you effectively decreased the over all diameter in the rear with a 30 profile tire, the ecu thinks you are constantly spinning the rear tires.

 

I don't think it is the tire size only, it is the % difference in tire sizes between the front and back.

But, yeah the diameter of your rear wheel/tire is throwing it off.....

 

I think i know what happened at 350z Mods...I remember Dave had to ship them out late becuase he was saying something about tires being mounted w/ wrong offsetts or something...i wasn't really paying attention because all i heard in my heard was "your rims weren't shipped out last week" (or something like that)....maybe they put the wrong tires on my rears...i can't think of any other reason why a place that only specializes in 350z's would send out rims w/ tires mounted that's going to throw off the traction control...

 

that's also true:
https://my350z.com/forum/showthread....threadid=15835
(thanks Make Wazowski for the helpful links)

 

I use Euro Tire in New Jersey; their rule is "never exceed or get near an inch dif from the factory spec".

275 / 35 would put you at a 26.6 diameter -almost the factory number of 26.7.

Many of the tire sites explain "The plus concept", the retailer you purchased from should know this. They should be concerned for your ABS and traction control.

 

hey wzaccardi...is euro tire a good place to get my tires mounted and balanced on19" wheels?

i have the tires already but i need a place to mount

do they do alignments too?

please PM me with details

 

hey o..... change your tire size for 2 reasons...itll fix your problems...and the 30s arent a good idea with all the pot holes in jersey.....

-Sigma

 

i'm waiting on what Dave at 350z Mods (will call first thing Monday if I don't hear from him by tonight)...there was probably a mistake at his shop (like i mentioned above) and they put the wrong tires on...i just hope i the rims don't have to be shipped all the way back to Cali...someone told me i can get new tires mounted over here, and send the current 30's back w/out having to ship any rims...

 

You have an Enthusiast with stock 225/55/17s in front and 235/55/17s in rear.

The stock diameters (in mm) are -

Front:

225x.50 = 112.5 (sidewall size), 112.5x2 + 17x25.4 = 225 + 431.8 = 656.8 mm overall front tire/wheel diameter

Rear:

235x.50 = 117.5, 117.5x2 + 431.8 = 666.8 mm overall rear tire/wheel diameter

You now have -

Front:

245x.35 = 85.75 (sidewall size), 85.75x2 + 19x25.4 = 171.5 + 482.6 = 654.1 overall front tire/wheel diameter (2.7 mm smaller than stock)

Rear:

275x.30 = 82.5, 82.5x2 + 482.6 = 647.6 mm overall tire/wheel diameter (smaller than the front diameter! Its also 19.2 mm smaller than the stock rear diameter.)


The problem is that your rear tire/wheel diameter is now smaller than the front! The TCS is calibrated for the rear diameter to be slightly larger than the front. Combine that with shorter gearing from the smaller overall diameters all around and your TCS is going to go wacko.

I'd say that the guy who suggested those sizes didn't have a clue what he was talking about. To suggest a smaller diameter for the rears is nuts. He probably just gave you an arbitrary number for the hell of it. No offense, but I'd be kinda pissed!

Oh, and please check my figures. I do make plenty of mistakes sometimes. The 25.4 is standard conversion from inches to milimeters.

 

now i'm getting pissed...it's monday, i just tried calling, and no ones picking up.....i keep getting the machine or a busy signal.....wtf is goin on? on the machine it says something like 350zmods is closed from sept. 27-oct.6, but i can't tell because he's talking too fast..... ...on top of that i recentely discovered that it wasn't a mistake that i got the tire sizes, but they are actually recommending these sizes as someone posted in another thread....i assuming a lot of things right now, but won't say anything till Dave contacts me, or I can get a hold of him...if anyone talks to him, or knows him please alert him of this thread....driving w/out traction control in the rain is a ***** in this car!!! should i take the rims off?

 

some pics...rear wheel gap

 

rear tire...