Spare Tyre solutions

[OzzieRoss]

This.
I started shooting for a video on this weeks ago, but got distracted onto another project.

Despite being ~$100 more expensive, I think the 20" is a no-brainer.
It's a closer match to the rolling diameter of the OEM wheels, and as VB's photo shows, having a slightly smaller diameter means it fits into the wheel well with no trouble.
I haven't had the chance to jack up the car and do a test fit.
Was waiting on some rubber pads for my jacks.
Don't want to be marking the SVE jack pads (if I use the trolley jack at home) or the pinch welds (if I'm by the side of the road and using the supplied scissor jack).

Apologies for the tardy response... away, currently working in Saudi Arabia.

Unless I made a mistake, the 19” wheel is a closer match to the rolling diameter of the OEM wheels at the back (where it matters most) than the 20” wheel. See my post in this thread on 19th of Nov. I am not sure if the difference matters though.

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[Flamma3]

These are the calculations I came up with.

It depends which 19” option you are looking at.
However even if both DriveSava, I don’t think 0.2% on the rear makes any difference..

I went 20” because I wanted to be sure it would clear the brakes which are a little larger than on the s550.

I can also confirm the 20” fits into the boot no problem, without having to lube it up.



Rolling Diameters:

Factory OEM wheel
Font: 255/40R19 - 687mm
Rear: 275/40R19 - 703mm

DrivaSava
20"
155/60R20 - 694mm (1.1% Difference to factory front & 1.2% Difference to factory rear)

19"
155/70R19 - 700mm (1.86% Difference to factory front & 1% Difference to factory rear)


Other 19" options in the market
19"
135/70R19 - 672mm (2.3% Difference to factory front & 4.6% Difference to factory rear)

 

[OzzieRoss]

These are the calculations I came up with.

It depends which 19” option you are looking at.
However even if both DriveSava, I don’t think 0.2% on the rear makes any difference..

I went 20” because I wanted to be sure it would clear the brakes which are a little larger than on the s550.

I can also confirm the 20” fits into the boot no problem, without having to lube it up.



Rolling Diameters:

Factory OEM wheel
Font: 255/40R19 - 687mm
Rear: 275/40R19 - 703mm

DrivaSava
20"
155/60R20 - 694mm (1.1% Difference to factory front & 1.2% Difference to factory rear)

19"
155/70R19 - 700mm (1.86% Difference to factory front & 1% Difference to factory rear)


Other 19" options in the market
19"
135/70R19 - 672mm (2.3% Difference to factory front & 4.6% Difference to factory rear)

At the rear, where it matters most because these are the driven wheels, compared to OEM the difference for the 19” DriveSava is only 0.4% (3/7) while for the 20” DriveSava it is 1.3% (9/7). I don’t know if these differences are “significant”, but at the rear the 19” is the closest match.

Sure, I would also prefer the 20” spare in view of the brake fitting issue. That’s why I asked earlier if someone ordered the 19” for a Dark Horse (Australia specs) and found it fitted OK or not?

 

[Deano1978]

Am I missing something here? Is having a slightly smaller rolling dia on a spare tyre a big no no?

Being a city slicker, 90% of the time I'll be within 20km of a tyre place so prob don't need to be worried about speedo issues or any potential damage (or should I be worried?)

I get it for ppl in regional places where you might be a few hundred km from a service centre.

 

[bfets]

Am I missing something here? Is having a slightly smaller rolling dia on a spare tyre a big no no?

Being a city slicker, 90% of the time I'll be within 20km of a tyre place so prob don't need to be worried about speedo issues or any potential damage (or should I be worried?)

I get it for ppl in regional places where you might be a few hundred km from a service centre.

The biggest issue with having different diameter wheels on the same axis, is that its hard on the diff. So yeah you wouldn't want to be driving like that for too long and would want to limit the difference in diameter as much as you can.

 

[OzzieRoss]

My DriveSava spare wheel package from Pony Parts arrived yesterday. In the end I went with the 20" rim "to be sure to be sure" it would clear the brakes, in particular at the front. Today I tried the spare wheel at the front and the back, all good. Also the fit in the wheel well is as good as you might hope for. I attach a few pix. Note: in the picture with the spare wheel on the car (front), the car is still on the jack, hence it looks a bit odd. There's more clearance with the brakes than the OEM rims have, so I guess the 19" DriveSava would've done the job as well.

 

[ivonovi]

My DriveSava spare wheel package from Pony Parts arrived yesterday. In the end I went with the 20" rim "to be sure to be sure" it would clear the brakes, in particular at the front. Today I tried the spare wheel at the front and the back, all good. Also the fit in the wheel well is as good as you might hope for. I attach a few pix. Note: in the picture with the spare wheel on the car (front), the car is still on the jack, hence it looks a bit odd. There's more clearance with the brakes than the OEM rims have, so I guess the 19" DriveSava would've done the job as well.

thnx for the update and the photos mate. Does the cover/base fit snugly and flat to the rest of the floor or is there a slight gap, as in the wheel sticks out a bit from the well ?

 

[OzzieRoss]

thnx for the update and the photos mate. Does the cover/base fit snugly and flat to the rest of the floor or is there a slight gap, as in the wheel sticks out a bit from the well ?

It all fits snugly. The "installation manual" tells you to cut a circle with a radius of 50cm out of the insulation material underneath the spare wheel well cover, but I didn't do that and it still fits flat with the rest of the trunk floor. I wrapped the jack etc. in some rags to prevent them from rattling underneath the spare wheel, see photos. That's not quite how the instructions tell you to do it, but I like it that way and I can use the rags to kneel on or afterwards wipe my hands if I ever have to change the tires by the roadside

 

[Deano1978]

Given you're in WA I'll let the reference to "trunk" rather than "boot" slide

 

[OzzieRoss]

Given you're in WA I'll let the reference to "trunk" rather than "boot" slide

Well, it is an American car . . .

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