Looking At Getting 19's

[Kimberley Scott]

Look at me I have twenties

Mate I cannot see how bigger rims will give you more ground clearance, as the rolling diameter should be roughly the same as would the radius and the (what the line that goes all the way through?).

Scotty

[Fat-Tony]

Look at me I have twenties

Mate I cannot see how bigger rims will give you more ground clearance, as the rolling diameter should be roughly the same as would the radius and the (what the line that goes all the way through?).

Scotty

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Lesson 1

my rear tyres are a 245/35/20

the overall diameter (OD) of them is 680mm

the OD of stock 235/45/17 is 616mm

that then gives the a 64mm difference in the OD of the stock tyre compared to the 20's. Divide that by 2 to give you the difference from the wheel centre and that gives you a raise in ground clearance by 32mm.

Enough said

[myXR6turbo]

Look at me I have twenties

Mate I cannot see how bigger rims will give you more ground clearance, as the rolling diameter should be roughly the same as would the radius and the (what the line that goes all the way through?).

Scotty

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I just need that little bit more clearance as just the exhaust tips scrape a little bit at the moment. The 19's will give you more ground clearance than 18's.

I can not fix the driveway. If I could I would. My driveway is way to step and the sub box and sometimes full tank of fuel dont help a lot.

"I have found some 19 x 9.5 (& 8.5 for front) rims that no one on this forum has (I'm yet to determine why), they look f'ing spectacular, come in both black and silver.... but are $3300 with tyres. I'm dying to get my hands on a set of these, so we'll see how we go."

What are those rims if you dont mind me asking?

[Kimberley Scott]

Allright I am happy to accept I am wrong. How does such a large difference then go with gearing and more importantly correct speedo calibration?

Scotty

[Fat-Tony]

Allright I am happy to accept I am wrong. How does such a large difference then go with gearing and more importantly correct speedo calibration?

Scotty

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Well I have noticed that the car is a touch slower, due to the extra weight of the wheels and yes slightly do to the gearing change. As for speedo calibration I had the forutanate opportunity to check it againts a speed check display on the freeway on the way back from getting the wheels fitted and its dead accurate. I can only presume that is because speedos are set a little out favouring reading a higher speed than you are actually doing.

[Kimberley Scott]

Lumpy Iam way to pissed to do the maths , but Pie R squared something, will help Fat find out how far his speedo is out.

Scotty

[myXR6turbo]

Allright I am happy to accept I am wrong. How does such a large difference then go with gearing and more importantly correct speedo calibration?

Scotty

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Well I have noticed that the car is a touch slower, due to the extra weight of the wheels and yes slightly do to the gearing change. As for speedo calibration I had the forutanate opportunity to check it againts a speed check display on the freeway on the way back from getting the wheels fitted and its dead accurate. I can only presume that is because speedos are set a little out favouring reading a higher speed than you are actually doing.

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The factory speedo most of the times shows more than what speed you are really doing.

[Fat-Tony]

Ahhh that's what I just said

[Kimberley Scott]

Understand that, only have to use a GPS to work out how happy the factory speedo is. but such a large radius increase, would amount to a substantial circumferance differnce, which would change the speedo dramatically.

Given that alot of people on this site have said that 20 in rims are not good for dragging as traction is an issue, and Mcwrist/Fat boy has said they have improved traction. This would indicate a difference in gearing.

Making me think it is hurting.

Food for thought.

Scotty

[Fat-Tony]

Understand that, only have to use a GPS to work out how happy the factory speedo is. but such a large radius increase, would amount to a substantial circumferance differnce, which would change the speedo dramatically.

Given that alot of people on this site have said that 20 in rims are not good for dragging as traction is an issue, and Mcwrist/Fat boy has said they have improved traction. This would indicate a difference in gearing.

Making me think it is hurting.

Food for thought.

Scotty

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Ok as I come from a 4 wheeler background also I can tell you that when I increased a wheel diameter size from 28 inch to 31 inch tyres on a jeep it gave a 5 % inaccuracy in the speedo, now there isnt that much in the ford so and assuming the factory speedo is out about 3% percent I dont think its going to cause that much of an issue. As far as traction goes, I stil have problems but on the same token I spent money on decent rear rubber to, which im sure has a lot to do with it