My model of MX-5 is: MK2 1999 SE in British Racing Green 1.8
I’m based near: Cheltenham
I’m looking for technical help or recommendations on: Changing my stock 5 spoke 14" wheels to 15s.
I’ve recently completed a suspension rebuild on my MK2. The car was on the original suspension on 155K miles so as you would expect it was completely shot.
This includes Miester R Sportive Coilovers, new bushes, control arms, ball joints, drop links etc. In addition it’s also had a BOFI spec 'Fast Road alignment, which has made a noticeable improvement to how it corners.
Anyway the car is running on the stock 14" 5 spoke alloys on 185/60/14 tyres.
As many of you know the tyre choice in this size is somewhat limited. I also don’t really like how they look, however I don’t think ‘Big’ alloys look good on the NB either.
15" seems to be about the sweet spot IMO.
I’m looking to get 15" wheels which would use 195/50/15 tyres, which are still fairly cheap and come in a fairly wide range of options. (Also looking to get them in Bronze/Gold as the BRG and Bronze combo looks great).
They might be as simple as the 15" OEM Enkei’s which you can get pretty cheap, and look quite smart, especially after a proper refurb.
My actual question is: Is there any handling or performance advantage to moving up to 15 wheels, over 14s. The tyre is going to be slightly wider and the tyre wall shorter so a bit stiffer. But does that equate to a noticeable difference in road holding and cornering?
50% of me wants it so I can get them in bronze and the aesthetics, but I’m hoping it will open up better tyres choices, and therefore better performance.
In theory the lower profile tyre should have stiffer sidewalls which ought to equate to sharper turn in, change of direction and better steering feel. Braking and traction may also be marginally improved given a larger contact patch.
In practice alot will depend on any number of variables. Modern technology and tyre designs plus the difference between tyres of manufacturers may mean the actual differences are negligble on the road.
If you find a wheel that weighs less the lower unsprung weight should help the suspension do it’s job more effectively.
Again, that could also depend on how much the tyre weighs.
For a road car the most likely and substantial benefit could simply be aesthetics.
When you get it done it would great to hear of your actual experience.
I was told that fitting a front strut brace to my NB wouldn’t make any difference but it feels better to me.
Not sure what size the tyres were, but somebody with more knowledge than me will probably advise.
What I can say is the car drove well and roadholding and cornering were great. Not driven a Mk2 on 14" wheels so unable to compare.
There were several Mk2 (and Mk2.5) variants fitted with 15" wheels so I wouldn’t think there would be an issue providing the correct spec tyres are fitted.
Hi, my first '5 was a 98 NB jap import on stock 14". I put Michelin Energy Savers on and the steering was light and easy.
I then got a set of 15" of the same type and put Michelin Pilot Sports on. Steering was heavier but noticeably sharper. Acceleration wise, the bigger, heavier wheels did make it feel more sluggish. I did go back the 14s for a bit which confirmed the comparative lightness but also more understeer - narrower and older/lower performance tyres.
I keep the pilot sports on as they grip for days. I covet Enkei RPF1s or Advanti Storm S1 forged 15" to reduce the weight.
I did keep a record of fuel economy 14 vs 15 and the 14s were definitely better on juice. 5-10% typically.
None what so ever really , basically you will gain more rubber and less ally , they will fill the arch just the same as the 15",rotation is the same, so throws nothing out like the speedo etc, so will feel lighter ( that will be in the head , they are the same) and more cushioning from the extra air bags in the rims.
Tyre and rim choices are far far better for 15" less so for 14", rim choices at 14" are not as great on looks and tend to be a bit bland , so the 15" win for that reason simply because there are some very good tyres for the 15" and very nice selection of rims to pick from,because there is no getting away from the personal touch of rims ( width and look) and shoes( for how you drive her), like the Uniroyal riansports which are spot on for these road roadsters at very good prices not to kill pockets , plus 15" they will look far better in the arch .
M-m
The 15s have a smaller tyre profile, 50mm, compared with 60mm on the 14s. This would tend to give a slightly firmer ride. You will lose a little comfort but cornering will be more precise with what is effectively a harder wheel. Actual circumference is the same, so any fuel savings or performance changes will be down to tyres. MK1/MK2 cars do seem to be very flexible in that respect, unlike the MK3; very sensitive to tyre choice and suspension setup/geometry.
Many MK1 and MK2 cars fitted with 14s as standard but most would agree that the 15 is probably more suited to car and most drivers. Enkei 15 is a good wheel if you can find a set that hold air; some nice 5 spokes fitted to the MK2.5 as standard available cheap. Nothing more depressing than tyres that leak air and need pumping up every week or so, so make sure they are refurbished and fit for purpose before fitting.
Ask yourself a question.
Would Mazda put 15" wheels on the Sport Spec and higher spec Special Editions if they didn’t perform as well as 14"?
The size is the same - same diameter and circumference.
With original spec wheels the weight will be the same or lighter - more alloy less rubber
Don’t know if it helps the discussion but my 93 Mk1 was fitted with 16" alloys when I bought it. Obviously not standard Mazda. But the previous owner thought they looked good! They did! But the handling wasn’t the best and there was always slight vibration at high speed. Numerous attempts at rebalancing didn’t solve it. Eventually bit the bullet and bought a set of 15" alloys with larger ratio tyres to give the same radius. The difference in performance was significant and the unsprung weight of the new wheels and tyres was minus 2.5 kg per wheel. My advice would be don’t overdo the size for the sake of appearance.
Tyre availability is the main advantage. They look better by modern tastes but the car wasn’t designed for them. Check weights before you change, as some of the Sheerness-fitted wheels were stupendously heavy. And do tell your insurers; they will usually want more premium for larger wheels. They rarely care about smaller ones.
mk1 eunos. interesting issue changed to new 6x15 competition revolution minilites from the std daisy 14’s some 18 months ago and today my teck guy calls me and says when i fit your new japanese front pads, all std mk1brakes ,the wheel spokes are catching, jamming on the caliper…catching by about a mm, so i have ordered a couple of 3mm spacers, the wheels were supposed to be a few made for a mx5 race series Using std small brakes somewhere abroad and thats why i bought them , light strong and supposedly 20mm ET… now i havent seen the issue it was just a quick call… and the teck guy is a very experienced operator and not easily waylaid… report later… w
