Outer Limits 4x4 Board

Just put a set of 33's on the hj60 on the weekend i now the speedo is out but does anyone know how much?
i'm guessign u can buy a new speedo gear or similar i havnt been enerjetic enough to get under and see yet....
any help would be gretly appreciated

whoneedsbitumen wrote:Just put a set of 33's on the hj60 on the weekend i now the speedo is out but does anyone know how much?
i'm guessign u can buy a new speedo gear or similar i havnt been enerjetic enough to get under and see yet....
any help would be gretly appreciated

I can't see it being enough to worry about (touchwood i hope u dont get a speeding fine now after i've said that) I think its around 5 clicks am i right?

based roughly on a calculation of 31" tyres standard

circ = pi * diametre

as a ratio of the orifonal circumference to the new circumference we have

pi * 33
--------
pi * 31

= 1.0645 (6.5% over drive)

I have the same (33's on a hj60), I just remember that at 100, im actually doing about 106.

Hey I wasn't too far off Shadow have you worried about fixing it, or do you just drive to suit?

i was told its roughly 10% but thats why im askign other's opinions..
eg speedo says 50 actual speed 55, speedo says 80 is 88 and 100 is 110 etc ?

Should be around 10% out.

Try this; http://www.marks4wd.com/speedo-correction.html

I have checked my speedo against my GPS in my 85 model 60 series. On 33's, the speedo is more or less pretty much spot on. On 35's its about 7% out. When running my 31's, the speedo is about 5% out in the opposite direction.

I think the speedo was calibrated for the 16 inch split rims originally, which are equivalent to roughly a 32 inch tyre.

joelthommo wrote:Hey I wasn't too far off Shadow have you worried about fixing it, or do you just drive to suit?

nup just drive to suit

id say what carts is saying is pretty spot on though, following my brother home in his BA falcon he had his cruis control set to 100k, and i was doing 100 on my speedo to stay with him. meaning either my speedo or his is out. I rekon it would be my 16 year old speedo as opposed to his 6 month old speedo

I typically sit about 5k under the speed limit and have never had a problem with speed cameras.

well i followed mate home from work today he was in 1 of the work BA utes and my speedo was about 2km/h out thru all speeds

whoneedsbitumen wrote:well i followed mate home from work today he was in 1 of the work BA utes and my speedo was about 2km/h out thru all speeds

so are you saying its pretty much spot on? cause that would make sense.

carts wrote:

whoneedsbitumen wrote:well i followed mate home from work today he was in 1 of the work BA utes and my speedo was about 2km/h out thru all speeds

so are you saying its pretty much spot on? cause that would make sense.

Yeah i could of said that but that would of been to easy

whoneedsbitumen wrote:

carts wrote:

whoneedsbitumen wrote:well i followed mate home from work today he was in 1 of the work BA utes and my speedo was about 2km/h out thru all speeds

so are you saying its pretty much spot on? cause that would make sense.

Yeah i could of said that but that would of been to easy

sorry...i didnt mean that to sound like i was having a go at you...i meant that if it is pretty much spot on, then it would make sense that the speedos were originally calibrated for 32.5 inch split rims, as opposed to 31's.

carts wrote:

whoneedsbitumen wrote:

carts wrote:

whoneedsbitumen wrote:well i followed mate home from work today he was in 1 of the work BA utes and my speedo was about 2km/h out thru all speeds

so are you saying its pretty much spot on? cause that would make sense.

Yeah i could of said that but that would of been to easy

sorry...i didnt mean that to sound like i was having a go at you...i meant that if it is pretty much spot on, then it would make sense that the speedos were originally calibrated for 32.5 inch split rims, as opposed to 31's.

thats ok my next question was going to be how big/height are the standard rims/tires ?
but you just answered that so thanks

Most 60's came from the factory with 31's...however, some povo packs came out with the 16 inch split rims.

60's came out with three tyre sizes

7.50 x 16
205 x 16
31 x 15

A lot of the 'povo pack' 60's had their tyres 'upgraded' to the trendier 31's.

I still have the owners manual for my 83 HJ60. It came standard with 205R16.

205R16 is a 32.4" tyre, which im pretty sure is the nominal diametre of my 33" Kumho AT's.

My 60 has on the tyre placard (end of drivers door near the latch mechanism if people dont know where they are) 7.5R16 (31") which is what it came with when my parents baught it. According to the tyre and rim association manual, a 7.50R16 measures close to 31.4" which is what makes my 33" tyres legal. (the nomninal diametre of my 33x12.5R15 Kuhmo AT's is something like 32.4")

I wish my tyre placard said 205R16, means I can legally go to a 33.4" tyre, which some 34" tyres would be.

A 205R16 spec also means you can legally (almost legally) run 12.5" wide tyres. You can increase tyre width by 50%, 150% of 205 is 307.5 = 12.3".

My tyres are technically illegal due to width, not diametre, since 7.50" 150% = 11.25". So my 33x12.5" tyres are over an inch too wide :(

Sixty's Guy, can you have a look at your tyre placard, and see what it says, if it says 205R16 im gonna go looking for one of these stickers at the wreckers

what did you do to the suspension to fit the 33s or are they on standard trucks?

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Shadow wrote:205R16 is a 32.4" tyre,

Sixty's Guy, can you have a look at your tyre placard, and see what it says, if it says 205R16 im gonna go looking for one of these stickers at the wreckers

Sorry Shadow. 205R16 is a 29" tyre. Bugger!

mine is standard

although i wouldnt do any fourbying with standard height prings
as with 12.5" tyres they scrub on the guards if i hit a descent bump in the road when the cars loaded.

definantly need 2-3" of suspension r body lift to functionally clear 33's

revrev wrote:what did you do to the suspension to fit the 33s or are they on standard trucks?

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I have 33x10.5x15 on a OME lift. I had them on before though with reset springs (1/2" front and 2" rear) and they didn't rub then, even when 4wdriving.

Sixty's Guy wrote:

Shadow wrote:205R16 is a 32.4" tyre,

Sixty's Guy, can you have a look at your tyre placard, and see what it says, if it says 205R16 im gonna go looking for one of these stickers at the wreckers

Sorry Shadow. 205R16 is a 29" tyre. Bugger!

you sure?

205 is 8.2" time 2 (2 sidewalls) + 16" is 32.4"

/me gets tyre and rim association manual

205R16LT is listed as a 747mm tyre using a traction tread (all terrain / mud terrain)

747mm is 29.88" :(

7.50R16LT is 812mm = 32.48"

i think i will stick with my 7.5R16LT sticker