A Special Favour

[Autopia]

Hi all,

I would like to ask a special favour of an R36 owner living in Melbourne.

I'm thinking about putting 19's on an R36 wagon but I'd like to know if someone in Melbourne has put 19's on their R36 and would be willing to take me for a short drive so I can assess the ride quality.
It would be HUGELY appreciated. I don't want to put the wheels on only to find that the ride quality is overly harsh and difficult to live with on a daily basis.

Cheers
Sean

[schoona]

if you are staying at standard ride height (Ie. not getting lowered) I don't see why you can maintain a tyre size that allows comfort. By running larger tyres this should also correct your speedo (I know golfs/polo's are out).

Ie run a chunky tyre for your comfort, but you will still have 19s for looks.

[Macka]

Hi all,

I would like to ask a special favour of an R36 owner living in Melbourne.

I'm thinking about putting 19's on an R36 wagon but I'd like to know if someone in Melbourne has put 19's on their R36 and would be willing to take me for a short drive so I can assess the ride quality.
It would be HUGELY appreciated. I don't want to put the wheels on only to find that the ride quality is overly harsh and difficult to live with on a daily basis.

Cheers
Sean

I live near Geelong and would be more than happy to let you drive mine to assess. I would actually be very interested myself as l only drove 60km's when l picked it up and then put the 19" rims on so l can't really say what the difference was as l didn't drive it for long enough with 18's.

The ride should be a little harsher though as l run 245x35x19 tyres whereas the original l think are 235x40x18. The "35" is a % of the tyre width. Therefore whilst it has the same rolling circumfrence the actual height of the tyre is lower. Therefore from my experience this will also result in the ride being a bit harsher. However l came out of a current Subaru Liberty GT Spec B with the bilstien suspension and l can tell you that this is like driving on air compared to the Subie.

[Autopia]

if you are staying at standard ride height (Ie. not getting lowered) I don't see why you can maintain a tyre size that allows comfort. By running larger tyres this should also correct your speedo (I know golfs/polo's are out).

Ie run a chunky tyre for your comfort, but you will still have 19s for looks.

Hey schoona,
If you run a chunky tyre as you put it, you increase the rolling diameter of your wheels and your speedo will be way out. That's why you have to reduce the profile of your tyre as you increase your wheel size. The rolling diamter should be kept as close as possible to original to maintain speedo accuracy.

[Autopia]

I live near Geelong and would be more than happy to let you drive mine to assess. I would actually be very interested myself as l only drove 60km's when l picked it up and then put the 19" rims on so l can't really say what the difference was as l didn't drive it for long enough with 18's.

The ride should be a little harsher though as l run 245x35x19 tyres whereas the original l think are 235x40x18. The "35" is a % of the tyre width. Therefore whilst it has the same rolling circumfrence the actual height of the tyre is lower. Therefore from my experience this will also result in the ride being a bit harsher. However l came out of a current Subaru Liberty GT Spec B with the bilstien suspension and l can tell you that this is like driving on air compared to the Subie.

Thanks a heap Macka. I'll PM you.

[Lance B]

Hi all,

I would like to ask a special favour of an R36 owner living in Melbourne.

I'm thinking about putting 19's on an R36 wagon but I'd like to know if someone in Melbourne has put 19's on their R36 and would be willing to take me for a short drive so I can assess the ride quality.
It would be HUGELY appreciated. I don't want to put the wheels on only to find that the ride quality is overly harsh and difficult to live with on a daily basis.

Cheers
Sean

As Macka pointed out, the correct tyre size, to keep the same rolling diameter would be the 245/35 x 19 as this gives a diameter of of 645.1mm. The original 18" rims run 235/40 x 18 which is a diameter of 645.2mm, so they are essentially the same diameter and therefore the same circumference.

You could go to 235/40 x 19 which would give you a diameter of 670.6mm which is 3.9% increrase in diameter and therefore circumference. This is not a bad thing as it will mean that your speedo will be more accurate, as they generally read 5% slow, and you will not lose any benefit in ride quality as you will be using the same aspect ratio tyre of 40%, which is what basically gives you the ride quality.

The beauty of the 235mm width tyre over the 245mm width tyre is that they will not "bag out" like the 245mm width tyre and therefore fit the rim better although the wider tyre does have the advantage of being able to help protect the rim from gutter scrapes and the like.

Make sure you get the correct speed and load rating for your tyres which is located on the door pillar, I think.

Just check with the tyre shop and see if they believe that this would be ok as I am sure it will be.

[Mischa]

who cares about the speedo, what about your effective final drive ratio going out of what with the wrong tyre size!?

[Lance B]

who cares about the speedo, what about your effective final drive ratio going out of what with the wrong tyre size!?

What does the final drive ratio have to do with anything?

The main criteria is for good handling, good ride quality and an accurate speedo.

[Mischa]

What does the final drive ratio have to do with anything?

The main criteria is for good handling, good ride quality and an accurate speedo.

if you put oversized tyres on, you'll make all your gears longer and acceleration slower.

[schoona]

Mischa's point is equally valid.
Maybe it was a polo (yes other end of the scale ) thread were I explained better.

I knew speedos were out to a point, hence the increase in diameter would make you more accurate".

I have gone from a 205/50/16 to a 215/35/18 and although the reduced acceleration effect is mainly down to the wheels, I know that the change also effects the final drive.

Bottom line, an inch really is nothing to worry about. throw them on. You may find the tyres you have are icredibly stiff in the sidewall. If this is the case, get a softer one to fix the problem.

[Lance B]

if you put oversized tyres on, you'll make all your gears longer and acceleration slower.

The difference in acceleration would be minimal at best. In fact, I doubt you would even feel the difference at all.

[Autopia]

You could go to 235/40 x 19 which would give you a diameter of 670.6mm which is 3.9% increrase in diameter and therefore circumference. This is not a bad thing as it will mean that your speedo will be more accurate, as they generally read 5% slow, and you will not lose any benefit in ride quality as you will be using the same aspect ratio tyre of 40%, which is what basically gives you the ride quality.

I like this idea. You get the larger wheels yet maintain the ride quality of the 18's but you also fill more of the wheel arch which will improve the appearance.

Looks like a win win win. I am a little concerned with Mishas comment though re the acceleration etc. Never actually thought about that possibility. Maybe an inch won't be too much of an issue.
I'll drive Macka's car and see what the 245/35/19's are like.

[olcoop]

I guess your 0 - 100 time might be a bit slower, but 100 would be 100, where as now it would be more like 95!

[James1001]

Macca have you had any problems with tyres rubbing the inside of the guards whilst having 2 people in the rear seats? i have also put 19" rims with 245x35x19 tyres, but i found that there is a bit of rub with the extra weight in the back seat

[Macka]

Macca have you had any problems with tyres rubbing the inside of the guards whilst having 2 people in the rear seats? i have also put 19" rims with 245x35x19 tyres, but i found that there is a bit of rub with the extra weight in the back seat

No l haven't to date but my kids are the only ones in the back seat and they are 9,7 & 6 so they don't weigh that much. I will have to try it out. It would also depend on the offset on the rim that you have. The RS4 rims had the exact same offset as the standard rims. Not sure what yours are but that may be the issue.