mx5cartalk.com

Sorry if its been asked before

I have the opportunity to get some r888 types of a mate that's sponsored rather cheaply

I was planning on throwing them on the std nb8b 16x7s

Looking at the sizes on the goto site, anything that comes close would be 195-50-r16 or a 225-45-r16. Would the 195s work on the std rims?

On the 'Sizes & Specifications' tab here you can check out Toyo's recommendations for wheel width on any of the tyres... 195 should be no worries on your stockies

great link slug_dub, there's a great pdf for spec miata setup under "Setup & Care"

NB8B wheels are 16x6.5''

I would say the 225s are potentially too wide The 195s will fit fine and iirc 888's are slightly wider than the tyre width would indicate so they're probably pretty close to a 205/50 anyway.

Regie wrote:Sorry if its been asked before

I have the opportunity to get some r888 types of a mate that's sponsored rather cheaply

I was planning on throwing them on the std nb8b 16x7s

Looking at the sizes on the goto site, anything that comes close would be 195-50-r16 or a 225-45-r16. Would the 195s work on the std rims?

I've got 225/45s on my 15x9 6ULs... they're snug, but not stretched... I can't see them on a 6.5" wheel without being b-a-g-g-g-y... dawg..

sweet looks like it will be the 195's

thats peoples

205's look slightly bulgy/baggy on a 6.5" rim as well, I ran 205/50/15 on 6.5" advanti racing rims for a long time. I'll see if I can find some pictures when I get back from work.

I learned this weekend that over-tyreing a car actually slows you down.

I know, I know... How could that be?

This info was given to me on Sunday, from someone with many years racing experience and who currently races a Mazda with Mazda backing.

MX5s are too light to adequately press a 225 into the road enough to get them working properly.

Yes they work, but the downsides are:
Not actually gripping MORE than a 195
More rolling resistance
More aquaplaning
More temperamental suspension setup
Costing more


Upsides:
225s look hella-Tough. =)

I don't think you should be too quick to accept that information as gospel never to run wider tyres. The contact patch shape is better suited to lateral grip Vs longitudinal grip on a wide tyre. In an underpowered car this lets me corner faster while losing some grip accelerating in a straight line and braking. Other than a race start I'm accelerating out of a corner at an angle so most of the time that lateral grip gives me more advantage. I can overheat 225's as it isn't that much more tyre and when driving at ten tenths on even a luke warm day I can bead up and overtemp even hard compound's in the wider tread within 1 lap. I find on a really cold dry day it can take upto 5 laps to start overheating the tyres. My best ever session was the regularity last year where I got 4 laps with maximum grip, partial first lap they were cold and starting to go off and slide in the 6th.

Yes they're more expensive per tyre but I've found I get more trackdays per set which evens that out. I don't mind needing a warm-up lap if on the 225's I can have 2 good laps on a hot day whereas I only get 1 on the smaller tyre. Different setups work for different people so don't dismiss it unless you've actually tried it.

MX5s are too light to adequately press a 225 into the road enough to get them working properly.

Just think of this, if weight is the only determining factor on how wide your tyres should be. Why don't formula #1 cars run thin tyres? Tyre size is way more complicated than that.

Not actually gripping MORE than a 195 - True but as stated above contact patch shape changes. Also the wider the tyre the softer the compound you can run so you can increase your total grip in that way with wide tyres. Just look at things like time attacks/super lap. The fastest laps were done on a hot day with soft compound tyres. They may only do 1 fast lap before the tyres are coming apart and overheating but it's faster.
More rolling resistance - Also increases the aero drag but cools the tyre down more.
More temperamental suspension setup - I'll leave this alone as it's pretty vague but just say that changing anything suspension related which increases stiffness also arguably makes it temperamental.

This is from my experience of running about 4 sets of 205 wide semi-slicks of varying compounds compared to 5 sets of 225 wide semi slicks on a 1070kg Mx5 (1155kg with me in it). I've done a fair bit of 3-5 lap sprints, 6-10 lap races and 2*130+ lap enduro's now. The original poster is also talking about running Toyo R888's which are known to be on the hard side but try a V700 or Medium D03 in 205/50/15 and tell me you can't get them to overheat easily.

Regie,
R888's are fine for the track.
On the road they're not too flash.
They humm like crazy, and because they don't get hot enough on the road they have minimal grip in the wet.
I've managed to move from one lane into the other on Forest Rd on the corner near Blairs in the wet without turning the wheel at just above legal speeds.

Oh and 225 works fine on 8" rims..just ask CB.

Sailor wrote:Regie,
R888's are fine for the track.
On the road they're not too flash.
They humm like crazy, and because they don't get hot enough on the road they have minimal grip in the wet.
I've managed to move from one lane into the other on Forest Rd on the corner near Blairs in the wet without turning the wheel at just above legal speeds.

Oh and 225 works fine on 8" rims..just ask CB.

thats cool these will be track only tyres anyways..oh and porlly drive to the track on them, they will be cheap enough to do that