13” wheels + FW bodywork

[Weekend Warrior]

I put my new 13 “ wheels on and I have to say how impressed I was ,the  car feels more nimble and precise and a different drive . I know most use them for the track and when I’ve read posts on how good they were ,I had always thought that the difference would be minuscule and that they were used to save a second or too a lap .

I’m pleased to say I’m wrong and I’m glad I swapped, however there is a downside ,if you have a FW bonnet  it no longer stays open on its own and this means access is even more limited .

I could copy the Cat and run without one saying it fell off .What are the consequences if caught ? 
Or as I like a v8 bonnet ,can you swap a FW bonnet for a V8 bonnet and fit a nose come ?

[CraigHew]

Does your speedo still read true?

 

[Weekend Warrior]

  I Don’t know ,how can you tell ?

I do know It doesn’t make it feel any slower 😁

[CraigHew]

Ive got zero experience but I think going from 15 to 13 inch will result in a speedo under- read.

 

Perhaps 15% (rough mental calc of the difference between 13 and 15)

 

That's fine till you nudge the speedo up to the current road limit and pass a camera..

.

[Weekend Warrior]

23 minutes ago, CraigHew said:

Ive got zero experience but I think going from 15 to 13 inch will result in a speedo under- read.

 

Perhaps 15% (rough mental calc of the difference between 13 and 15)

 

That's fine till you nudge the speedo up to the current road limit and pass a camera..

.

 
It’s not A 2” difference as such because the sidewall on the 13 “ tyre is bigger .My bonnet only just stayed open before the wheel change but the reduced radius just stops it from doing so ,the difference in the wheels is only 15 mm .

Its just dawned on me that I’m probably over thinking this ,could I not just  Adjust  The front shocks to get my 15 mm back ? 
‘As you can tell I’m a bought not built owner 😂

[CraigHew]

If it's just the 15 mm ride height that's causing the body problem then yes, raising the front shocks could eliminate that.

But then you're altering the rake of the car between front and rear.....

[Weekend Warrior]

4 minutes ago, CraigHew said:

If it's just the 15 mm ride height that's causing the body problem then yes, raising the front shocks could eliminate that.

But then you're altering the rake of the car between front and rear.....

So if I do back the same does that keep everything balanced ?

[CraigHew]

SYes.

 

The most quoted ride heights are 140 front, 160 rear (mm) .

 

Must admit, my S2000 is 160 / 180 because of grounding out the gearbox chassis hoop.

 

So long as there is a rake difference of around 20mm then the balance should be OK. Have you had a geo setup done?

[Burgerbob]

52 minutes ago, CraigHew said:

Ive got zero experience but I think going from 15 to 13 inch will result in a speedo under- read.

 

Perhaps 15% (rough mental calc of the difference between 13 and 15)

 

That's fine till you nudge the speedo up to the current road limit and pass a camera..

.

https://tiresize.com/comparison/

 

Put the two tyre sizes in this comparison and it'll tell you the different dimensions and impact on speedo readings

[Weekend Warrior]

I’ve had the car 3 years now using 15” wheels and all has been well ,the previous owner had it set up .

I’ve been searching the net and from  what I can gather if I go for a 70 profile tyre instead of the 60 I’m using now I’ll get my 15 mm back .The 15” wheel had a 50 profile tyre on it and if you put a 70 profile tyre on a 13” wheel you get similar diameters _

[CraigHew]

Well maybe.

 

Measure the current ride heights as use that as a baseline.

 

Then whatever you change, be it tyre depth, wheel diameter or wearing two pairs of underpants, you have a reference point to refer to...

[Kingster]

1 hour ago, CraigHew said:

but I think going from 15 to 13 inch will result in a speedo under- read.

Depends on what you go from and to...

 

Im going 15” 195x50 to 13” 205x60 and the difference is minuscule. 

[LoneWolf]

On 19/01/2020 at 18:39, Weekend Warrior said:

I put my new 13 “ wheels on and I have to say how impressed I was ,the  car feels more nimble and precise and a different drive . I know most use them for the track and when I’ve read posts on how good they were ,I had always thought that the difference would be minuscule and that they were used to save a second or too a lap .

I’m pleased to say I’m wrong and I’m glad I swapped

Wow this decisely put a stop to my intention to buy some new shiny 15" rims. As you said I've heard 13" are better on Westfields but didn't think that much, especially on the road

From which to which rims have you made the change if I can ask?

Thanks

[Dave Eastwood (Gadgetman) - Club Chairman]

before you do anything always make sure the tyres that yon want to predominantly run are available in the wheel size you'd like to go for.

 

As good as 13" are, there are many tyres just not available.

[Weekend Warrior]

2 hours ago, LoneWolf said:

Wow this decisely put a stop to my intention to buy some new shiny 15" rims. As you said I've heard 13" are better on Westfields but didn't think that much, especially on the road

From which to which rims have you made the change if I can ask?

Thanks

I’ve gone from 15 to 13 . team dynamic 1.2 
If you decide not to go down a size and want a set of 15 I’ve a nice great condition  set with   good toyo R1r tyres  205 /50/15 including a new boxed rim as a spare !