Wheels/Tires

Miata Parts, Intakes, Superchargers, Headers, Exhausts, Shocks, Springs, Sway Bars, Brake Kits, Autocross and track mods.

Wheels/Tires

Postby Randale » Thu May 16, 2013 7:10 pm

About to pull the trigger on some new wheels and tires.

Will the combination below require any fender modification if I ultimately add a set of the Ohlins you have on the website?

Enkei PF01SS, 50mm, 5x114.3, 17x8, SILVER/Falken Azenis RT-615-K 225/45/17

Thanks,

Randale
Randale
 
Posts: 16
Joined: Fri Apr 19, 2013 5:49 pm

Re: Wheels/Tires

Postby Brian » Fri May 17, 2013 5:27 am

That will clear even if you lower 2 inches or more.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
Brian
Site Admin
 
Posts: 7897
Joined: Tue Feb 15, 2005 11:44 am
Location: San Diego CA

Re: Wheels/Tires

Postby Traum » Tue May 28, 2013 4:27 pm

Why go with 225/45/17 when you can go even wider at 235/40/17 without any issues? As a bonus, the 235/40/17 will not give you any speedometer discrepancies nor give you a taller effective gear ratio that robs you of a bit of torque.
What God has united, let men not divide.
Traum
 
Posts: 33
Joined: Mon Jul 28, 2008 8:06 pm
Location: Paradise, BC

Re: Wheels/Tires

Postby timw » Tue May 28, 2013 11:00 pm

Is wider always better? I thought for a momentum car diminishing returns rise pretty quickly with regards to wheel weight and rotational inertia, no? I am in the same boat, trying to decide on Rivals at 225/45 with the 3% speedo error or the 235/40 dunlops. Keeping it down at the 205/45 wheel/tire weight becomes a challenge (read $) with wheels given the heavier (and outward heavier) tires.
timw
 
Posts: 17
Joined: Sun May 26, 2013 10:51 am

Re: Wheels/Tires

Postby Va MX5 » Wed May 29, 2013 7:04 am

Folks,

I have the wheel / tire setup Traum was suggesting, which is 235/40/17. This combination required no fender modifications and I am very pleased with the results, in terms of improved Grip.

With that said, I can see the advantages of using the taller 45 series tires for high speed road courses in 6 speed cars, especially if there have been upgrades to power allowing the car to pull the revised final gearing. However, I do not have any complete major power improvement modifications in place, other then Brian's complete exhaust system upgrade. I would be interested in testing this setup to see the effects out on the track at some point. Guess, that one just got added to the "to do" list.

Regards to all.
Pat- Va MX5
2012 MX5 PRHT GT
Va MX5
 
Posts: 37
Joined: Wed Nov 28, 2012 11:36 am
Location: Sumerduck, Va

Re: Wheels/Tires

Postby Traum » Wed May 29, 2013 10:01 am

timw wrote:Is wider always better? I thought for a momentum car diminishing returns rise pretty quickly with regards to wheel weight and rotational inertia, no? I am in the same boat, trying to decide on Rivals at 225/45 with the 3% speedo error or the 235/40 dunlops. Keeping it down at the 205/45 wheel/tire weight becomes a challenge (read $) with wheels given the heavier (and outward heavier) tires.

From my own personal experience in street driving, autox, and lapping days using 3 different tire sizes on a stock powered NC (205/45/17, 215/45/17, 235/40/17), I would say that even the small jump in taller gearing from 205 to 215 was noticeable, but not really significant. With the 225/45 tire being even taller, I suspect the loss of torque is going to be more pronounced.

Further more, with 235/40, I definitely notice the extra weight in the tires (the 17x8 PF01 I use are the same weight as the OE 17x7 wheels), but at least the effective gearing ratio remains the same. So with a 225/45 tire, I suspect that you'd get hit with 2 penalties -- 1) taller effective gear, meaning less torque and slower acceleration, and 2) greater tire weight, which again means slower acceleration.

As far as lateral grip and stability between the 235/40 and 225/45 are concerned, the clear winner is going to be the 235/40.

Last but not least, from the 225/45 pictures that I've seen, I would say that the tire fills out the wheel well a little too much. The 235/40 has a more aggressive look that doesn't seem out of place.

This is why I prefer a 235/40/17 over 225/45/17 on the NC. Unfortunately, tire selection is a lot poorer with the 235/40/17, so you might want to take that into consideration as well.
What God has united, let men not divide.
Traum
 
Posts: 33
Joined: Mon Jul 28, 2008 8:06 pm
Location: Paradise, BC

Re: Wheels/Tires

Postby colt45 » Sun Dec 15, 2013 11:07 pm

What does the change from 55mm offset of the stock wheels to 50mm offset do to feel and feedback through the steering wheel?

John
Chatanooga
'06 Sport 6MT Ohlins 70N/50N
IBA/COG
colt45
 
Posts: 15
Joined: Fri Nov 18, 2011 5:53 am

Re: Wheels/Tires

Postby Traum » Mon Dec 16, 2013 1:56 am

colt45 wrote:What does the change from 55mm offset of the stock wheels to 50mm offset do to feel and feedback through the steering wheel?

John

I can't tell you what that isolated difference might feel like since I've never experimented with just that change alone. However, if the change from 215/45/17 on 55ET wheels to 235/40/17 on 50ET wheels is any indication, I suspect the car will feel slightly more stable laterally -- essentially you are widening the track at both the front and the back by 10mm, and basic suspension design principles dictates that you will get a slightly more stable car that is more resistant to lateral body motions (ie. body roll). I suspect the change will be noticeable, but not significant.
What God has united, let men not divide.
Traum
 
Posts: 33
Joined: Mon Jul 28, 2008 8:06 pm
Location: Paradise, BC


Return to Mazda Miata and Fiat 124

Who is online

Users browsing this forum: No registered users and 9 guests