Larger Tyres Affect Speedo?

[burtbunch]

If I fit 265/75R16 Tyres to my GLS NH will it affect speedo reading? If so can it be remedied?

Are there any other problems with this upgrade? I plan on Cranking the front end up a little to level it out. Looksa like a dragster at the moment.

Thanks

Burty

[burtbunch]

Sorry The prospective new tyres are actually 285/75R16.

Is the 285 then tread width?

[Dexter]

Nope thats the diameter, most people here use the inch method. What are you currently running. Any change will effect the speedo, but the good news is you can get it adjusted, or just drive accordingly, I mean Pajero's arent really a powerhouse so you should have no probs staying under the limit.

[Micky-Lux]

285 is the tread width in mm.

I'm sure a thread like this would have been covered before though... It's a pretty common question.

[Austblue]

Micky is right 285 is your width but if they're 285/75 then I think they're 32" and yes your speedo will be out.

Go to the Jaycar website and search for the speedo corrector.

[j-top paj]

the original 265s are a 31" arent they? the 285s will be a 33"
when i went from original 32s to 33s it put my speedo spot on. id say with yours it will put it out a little bit but not that much. maybe just go fro a drive with a gps and see how much its out

[Pharb]

I think your NH would have originally been fitted with 255/70R15 which equate to just under 30" I think. 265/75R16s are about 32". 285/75R16 are about 33", probably a fairly big jump for your 3.0L with standard gearing.

The speedo sender drive gear can be replaced with one with a different no. of teeth from a different Mits model which will still match in alright with the driving gear on the output shaft of the transfer case.

My NJ was originally fitted with 235/75R15 tyres (about 30"). These were replaced with 235/85R16 (about 32"). I replaced the speedo driven gear with one from a GLS (265/70R16 and different diff ratio from the factory).
Speedo now reads with in 1km/h of actual at 100km/h with new BFG A/Ts and a little under when they are worn out.

There was a heap of info (including the tooth no. of various Mits models on the Pajero Club of Vic forum, but that may no longer be accessable with their new forum.

Peter H

[Pharb]

Just saw from another post your NH is a 2.5TDI.

My 2.8TDI is about 1/2 a gear lower up our local hills with the jump from 30" to 32" (with a corrected speedo)

I would be very worried the jump from 30" to 33" would loose at least a whole gear with the 2.5L.

Maybe try to hold off until your can try out a set or get some reliable feed back from some one who runs that size on that model.

Peter H

[burtbunch]

i currently have 265/70r15. is there extra strain on the engine? i have 2.5 TDI. the bloke at the local cooper dealer says there will be no effect on speedo if i fit the 265/75r15. he also said it would only go over legal limits by 7mm in dia. that's only 3.5mm more height than now!!!!

[Pharb]

So were you chasing 285/75R16s (833mm dia) or 265/75R15s (778mm dia) to replace your 265/70R15s (750mm dia)?

265/75R15 would be just a natural progression (to a light truck tyre) from the (probably passenger tyre type construction) 70 series tyre.

Peter H

[burtbunch]

Sorry, I got the numbers wrong at the start of this post. I have 265/70r15's. The tyres I was looking at were 285/75R15 not 16. I want a larger diameter tyre for more clearance to go along with the lift I am going to do at the front. 265/75r15's are only 28mm larger so I don't know how much larger/wider I can go before I create problems. Is the width a problem mechanically besides the rubbing at full lock?

Thanks

[j-top paj]

what spec NH is it? didnt some of the higher spec ones come with 31s?
if the factory spec tyres are 30s then it will put it out a bit further.
what does the tyre placard say?

[burtbunch]

It's a standard GLS I think. I am so confused with choice right now. Doing a big trip across the plenty highway and all around Alice Springs later this year. I grew up there so I know the country and I don't want tyre hassles. Tyre Placard says 235/75R15 & 265/70R15. I guess the latter is for GLS and the first is for GLX. Ithink that 31x10.5 inch is going to be the way to go. Maybe Yokahama's or the good ol' Desert Dueller's......Aaaaarghh!!

[j-top paj]

31x10.5s can be bought from almost anywhere. if your really concerned then stick with the 31s. but 33s arent really a problem either.
do you already have the 16" rims ?

[burtbunch]

Not getting new rims. Sticking with factory 15 in alloys. My originl post about 16's was incorrect. 33's don't pose problems without a proper lift?

[j-top paj]

is yours an auto or manual?

[burtbunch]

Manual.

[j-top paj]

do you know what box you got? the v5mt1 is the one with the bodylift i think.

[burtbunch]

v5mt1 is what th\e plate says. Don't think I have a body lift though. Underneath just looks like the rubber mounts.

[j-top paj]

can you measure it at all? i think its 30 or 35mm?

i have the body lift on mine and factory 32s so the 33s were almost a straight bolt on. if it has 31s then 33s should go on easy enough.

just lift it 2" and you will be fine. if money is tight then stick some GQ coils in the rear and crank the bars up front.
33 by 11.5 isnt really too hard as long as the offset is right

[Dexter]

just lift it 2" and you will be fine. if money is tight then stick some GQ coils in the rear and crank the bars up front.
33 by 11.5 isnt really too hard as long as the offset is right

The GQ coils and cranked front bars got 34.6's on my NL I had a little bit of scrubbing on the front at hard lock.

[burtbunch]

So Will need different rims to offset the width or something? Don't really want to do that. Like my factory alloys. There must be a limit while still using the standard wheels. I don't want massive hardcore truck look just a more competent tourer.

[Dexter]

Well before that I had 31x10.5R15s and they fitted fine with no mods at all, so I would think that a little lift and you would easily fit the 33s

[NJV6]

I had a 2.5 LWB briefly and I put my 33 x 10.5 x 15's on it and they fitted fine. 33 x 10.5 are not nearly as common a tyre though. It came with 265/70/15 or approx 30'. A common replacement was 31 x 10.5 x 15. It liked hills even less than normal with 33's (obviously).

Obviously if you go to a 285/75/16 you will need to change to 16 inch rims and unless you get the right offset they will rub at the back of the front wheel arch when turning. I have tried those (285's) on Toyota offset on mine and they rubbed, mine has the factory body lift.

As j-top paj said if you get the offset right they might fit.

Any 2.5TD or 3.0V6 doesn't have the factory body lift.

Hope this helps,
NJ

[j-top paj]

Any 2.5TD or 3.0V6 doesn't have the factory body lift.

i wouldnt say any, mine definately does

[psycronic]

I don't think the aussie delivered NH's had the factory body lift. The GLS 2.5TD would have come with 265/70R15s. I replaced mine with 31x10.5R15 cooper ST's, next time I will get a set of new rims and get the 265/75R16 as most camper trailers use this size.

The speedo is still out on my NH with the new tyres, reads 105 at 100 on road

[j-top paj]

mines a import also, forgot to mention

[burtbunch]

Weird, going by my GPS mine is 5 km too fast on 265/70R15 standar size tyres. What's your oopinion on the coopers psycronic? They are on my wish list but I may have to settle for something cheaper as I will ahve to pay to get the camber sorted after the front end lift as well as some new suspension bushes.

Cheers

Burty