Going from 15" heavy wheels to light 14" wheels?
Discussion
So, I've had the '5 a week now, and I'm pretty happy with it. Whilst I like the look of the wheels that the car came with, I had a sneaking feeling that they would be rather heavy.
Eventually I found out they were Intra P-line alloys thanks to a PHer, and armed with that information, I was surprisingly able to track down the previous owner of these very alloys
So I asked him if they were heavy, and he confirmed that they were indeed rather heavy alloys, and I'm sure most MX5ers know that the car was designed with light wheels in mind.
I've spotted a set of daisy alloys, which I understand were one of the lightest OEM wheels around at the time of its production, and I'm guessing, probably still pretty light by todays standards.
What I want to know is, whether it will indeed make a noticeable difference to the drive. I've read mixed reports on this to be honest, some saying they've gone up to even quite large rims and not noticed much difference, but part of me feels sure that I should expect the following benefits:-
Anyone done a similar thing?
The car is a 1995 UK 1.8.
Eventually I found out they were Intra P-line alloys thanks to a PHer, and armed with that information, I was surprisingly able to track down the previous owner of these very alloys
So I asked him if they were heavy, and he confirmed that they were indeed rather heavy alloys, and I'm sure most MX5ers know that the car was designed with light wheels in mind.
I've spotted a set of daisy alloys, which I understand were one of the lightest OEM wheels around at the time of its production, and I'm guessing, probably still pretty light by todays standards.
What I want to know is, whether it will indeed make a noticeable difference to the drive. I've read mixed reports on this to be honest, some saying they've gone up to even quite large rims and not noticed much difference, but part of me feels sure that I should expect the following benefits:-
- Lighter steering (I don't have PAS)
- More compliant ride
- Better agility
- Better acceleration
- Possibly slightly less grip
Anyone done a similar thing?
The car is a 1995 UK 1.8.
On the plus side for 15" wheels, their tyre choice is better and cheaper too. Tyre weights can vary enormously (like their actual dimensions) and manufacturers arent usually keen to share them with us.
Id guess that light 15" wheels and carefully selected tyres would offer the best of both.
Id guess that light 15" wheels and carefully selected tyres would offer the best of both.
GC8 said:
On the plus side for 15" wheels, their tyre choice is better and cheaper too. Tyre weights can vary enormously (like their actual dimensions) and manufacturers arent usually keen to share them with us.
Id guess that light 15" wheels and carefully selected tyres would offer the best of both.
True.... but I have some nicely priced Daisies lined up for a good price, so it looks like I'll be going for the 14s anyway.Id guess that light 15" wheels and carefully selected tyres would offer the best of both.
The reason the daisies are cheap is probably because everyone gets rid of them for 15" wheels. There is a much better choice of tyres in 15" and they are cheaper too.
As for weight, well it's all a matter of opinion but my experience:
My old Mk1 was a Berkeley and they came with heavy 15" alloys. I replaced them with some lightweight 15" OZ Superlegerra and to be honest it made the ride worse. The tyres were swapped from the old to the new wheels so it was nothing to do with them. I think what was happening is that the 15" wheels made the tyres have to work harder so they absorbed a lot of the road harshness and smoothed it out. The turn-in was a bit sharper with the lighter alloys but it was marginal whereas the ride was a bigger difference.
Now on my Mk2.5 I have a set of light 15" Rota Circuit 10 and some heavy 17" OZ Superturissmo and while the Mk2 suspension hides the difference a bit the experience is similar. Despite having lower profile tyres the 17s give a more comfortable ride and it feels more stable at speed. The 15s feel sharper and more "alive" but the overall ride on the 17s is better. For that reason (and the fact 15" tyres are a lot cheaper than 17s) I use the 17s as road wheels and the 15s as track wheels.
As for weight, well it's all a matter of opinion but my experience:
My old Mk1 was a Berkeley and they came with heavy 15" alloys. I replaced them with some lightweight 15" OZ Superlegerra and to be honest it made the ride worse. The tyres were swapped from the old to the new wheels so it was nothing to do with them. I think what was happening is that the 15" wheels made the tyres have to work harder so they absorbed a lot of the road harshness and smoothed it out. The turn-in was a bit sharper with the lighter alloys but it was marginal whereas the ride was a bigger difference.
Now on my Mk2.5 I have a set of light 15" Rota Circuit 10 and some heavy 17" OZ Superturissmo and while the Mk2 suspension hides the difference a bit the experience is similar. Despite having lower profile tyres the 17s give a more comfortable ride and it feels more stable at speed. The 15s feel sharper and more "alive" but the overall ride on the 17s is better. For that reason (and the fact 15" tyres are a lot cheaper than 17s) I use the 17s as road wheels and the 15s as track wheels.
Note that my comparisons were with like-for-like tyres. On the Mk1 the tyres were swapped over and on the Mk2.5 I had F1 GSD3 on both wheels. You are unlikely to be able to do similar with 15" & 14" as most of the decent tyres that we generally use on 15s aren't available in the right size in 14".
OK, I've done the swap.
The daisies plus tyres were 4 KG lighter each than the 15s with tyres, so clearly they were a fairly heavy wheel for an MX5.
I hear what you're saying about comparing like with like in terms of tyres but subjectively, the car seems better all round. To me, it does ride better, it changes direction more keenly, and is more progressive when it breaks away, and is more feelsome through the steering (which is slightly lighter now for certain). The difference probably isn't enormous, but its definitely noticeable, and for the better IMO.
So I'm quite happy with the change. They also look better than I thought (sans centre caps).
The daisies plus tyres were 4 KG lighter each than the 15s with tyres, so clearly they were a fairly heavy wheel for an MX5.
I hear what you're saying about comparing like with like in terms of tyres but subjectively, the car seems better all round. To me, it does ride better, it changes direction more keenly, and is more progressive when it breaks away, and is more feelsome through the steering (which is slightly lighter now for certain). The difference probably isn't enormous, but its definitely noticeable, and for the better IMO.
So I'm quite happy with the change. They also look better than I thought (sans centre caps).
MX-5 Lazza said:
Get a life! 
ETA: That's nearly 260 a month!
I used to do a lot of posting in my old job, it's nothing like that much now! Well most of the time anyway! ETA: That's nearly 260 a month!
Sounds good OP, I'd love to see if I can get some lighter 15s on my car and see how they compare to the standard 16s. I just wish I knew which wheels I wanted!
TameRacingDriver said:
I would imagine, knowing mazda, that your 16s are probably fairly light anyway, and having just had a look in your garage, I'd say your car suits them anyway
Thanks! I have thought about keeping them and getting them refurbed and refinished in maybe a darker colour... I'm so indecisive!
The reason I think about 15s is the tyres are much cheaper than they are for 16s, which is a bonus!
LukeBird said:
Sounds good OP, I'd love to see if I can get some lighter 15s on my car and see how they compare to the standard 16s. I just wish I knew which wheels I wanted!
You are welcome to try my wheels out but you probably wouldn't learn much as they are currently fitted with Yoko A048 cut slicks with very stiff sidewalls so the ride quality will probably be worse compared to most other wheel/tyre combinations 
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