From 285's to 33's

[Haskins1111]

I recently changed my tires from 285's to 33's, how do i tell what my correct speed is? Can i change something to correct my speedometer.

 

[alkaline747trio]

285s and 33s are almost identical in height so you shouldn't have an issue, you will be <1% off.

 

[Haskins1111]

Great thanks.

 

[notagp_afj55]

285's are exactly 32.8 inches in diameter, if they tyre
is a 285/75/16

 

[HntWhtTail]

If you were running 285's before, without changing anything, your spedo was already off, about 10mph slower at hwy speeds. shows 55 going 65.

 

[Socalfj62]

Check this thread out

https://forum.ih8mud.com/showthread.php?t=81430&highlight=285's

 

[Haskins1111]

Ok i made a mistake they were 235 not 285's, sorry.

 

[-Macca-]

235/75's or 235/85's?

 

[Pauciflora]

Haskins,

There is a company in Melbourne Mark's 4wd Adapters (internet: www.marks4wd.com email: marks4wd@ozemail.com.au) who produce among other things various speedo adapters for vehicles running larger diameter tyres. So for a bit of expert advice you could try emailing them.

I run 33" BFG muds on my 60 and my speedo is almost spot on. One option (the one I used) is beg, borrow or steal a GPS stick it on the dash and go for a spin.

Good Luck,

Ben

 

[Haskins1111]

Thanks i will try that pauciflora.

 

[NocalFJ60]

Did you change your gears or do you still have the stock gears which are 3.7?

https://forum.ih8mud.com/showthread.php?t=86253

 

[Haskins1111]

Same gears would like to do that next.

 

[SLOwag]

I have 33's (BFG AT that have 85% tread) and 4.11 gears. 65 = 67 as tested against the roadside flashing sign that radars how fast you're going....probably pretty close to actual.

 

[hondaguy6513]

A good way to check speedometer accuracy is "the flying mile" just measure the time from one mile marker to the next on a highway where you can do 60mph, then divide your distance by your time, and viola you know how fast you were actually going for that mile.

 

[WAVEPIMP]

another way is to just haul ass through a school zone early in the morning and I'm sure someone will let you know pretty quick how fast you where going. He may even let you see the digital read out from the backseat of his car.


This was just a joke and by no means do i expect people to fly through a school zone. I have children and would probobly be the first one to let you know to slow down.

 

[Haskins1111]

Thanks for the help i will try that on monday wavepimp!



J/K