Larger tyres for 120 prado

[DARREN Lurker Find all posts View Profile Close DARREN]

Hello all,

I wish to fit the larger 265/70/17 tyres to my new prado.(cooper stt possibly) Does anybody know if this tyre size will fit on the 120 prado whilst at standard height ? i will proberly get a lift eventually but i think the larger tyre size would be my first mod and the lift would come later.
i also guess this would throw out the speedo by a few kilometeres per hour but im sure this could be fixed.
anybody have any thoughts...??


8)

[pcm_120 Member Find all posts View Profile Close pcm_120]

Hi Darren.

I am running 265/70/17 Cooper ATR’s and according to my GPS, I’m travelling 6-7% faster than speedo.

There are a few messages about calibrating the 120 speedo on http://autos.groups.yahoo.com/group/120scool/ “From memory” no one has managed (Yet). It appears that Toyota have used a combination of signals and the speedo is controlled by the ECU.

Jump on to the link above and do a few searches.

Paul.

[lc120_man Advanced Member Find all posts View Profile Close lc120_man]

There is potential legal/complience problem with larger tyre size but they will fit without any mods...

As far a speedo goes, while you can't calibrate toyota speedo you can
use GPS or Scangauge on 2005 model petrol prado to check your speed...

[DARREN Lurker Find all posts View Profile Close DARREN]

Thanks fellas ..... exactly what i was after... 8)

There is potential legal/complience problem with larger tyre size

Yes correct ,
I think the main thing here is to make sure you have told your insurance company of the mod..... and make sure they are happy with it.

8)

[Stockgtr Lurker Find all posts View Profile Close Stockgtr]

265/70/17 STT

Hi Darren.

I am running the STT's in 265/70/17 on steel rims. They are awesome, a little noisy but great off road. The suspension is standard and I have had no rubbing anywhere.(even off road)
The only complaint I have is that the car brakes and accelerates a lot worse and fuel consumption is up from 13.4 to 14.5lt per 100km.
They are REALLY heavy, but I'd rather go off road with these than the stockies and then have to pay $830 per rim if I damage the alloys.
Hope this helps.

Nick

[DARREN Lurker Find all posts View Profile Close DARREN]

Re: 265/70/17 STT

I am running the STT's in 265/70/17. The suspension is standard and I have had no rubbing anywhere.(even off road)

This is what i wanted to hear..... thanks nick......

I might be up for a few of these.... i think.... :lol: :lol:




:lol:

[Frank R Lurker Find all posts View Profile Close Frank R]

Am also running 265/70/17 Cooper STTs on steel wheels which I put on when I want to go bush. Got the dealer to lift the car on the hoist with tyres in place and checked clearances all round, no problems. The tyres are 38mm larger in overall diameter which gives you an addtional 19mm clearance at the axle. Speedo reading is out by 6kph as verified by a radar gun I borrowed from work. i.e 100kph on the speedo and your actually doing 106kph. And as far as the tyres go I think thy're fantastic, brilliant in mud and in hard rock surfaces and gravel conditions, couldn't fault them. Noisy on the road but hey the are muddies. If you do get steel wheels get 17"x8" as the 7" wide wheels will not fit as they are actually base on a modified 16" wheel well.

[DaveO Junior Member Find all posts View Profile Close DaveO]

Hi Darren.

I am running 265/70/17 Cooper ATR’s and according to my GPS, I’m travelling 6-7% faster than speedo.

There are a few messages about calibrating the 120 speedo on http://autos.groups.yahoo.com/group/120scool/ “From memory” no one has managed (Yet). It appears that Toyota have used a combination of signals and the speedo is controlled by the ECU.

Jump on to the link above and do a few searches.

Paul.

There are products around to address the issue of changed tyres sizes impacting the speedo accuracy & consequential auto-trans shift points.

I'm trialling one now.

[DaveO Junior Member Find all posts View Profile Close DaveO]

There is potential legal/complience problem with larger tyre size but they will fit without any mods...

As far a speedo goes, while you can't calibrate toyota speedo you can
use GPS or Scangauge on 2005 model petrol prado to check your speed...

Speedo is electronically calibrated (based on original diff ratio & tyre size). A result all of the speed related things will be incorrect (including what you can get from the ECU).

I'm trialling a unit to adjust the speed to the correct figures on my car. 4 wire fitment & allows original & larger tyre size selection.

[lc120_man Advanced Member Find all posts View Profile Close lc120_man]

Re: 265/70/17 STT

Hi Darren.

I am running the STT's in 265/70/17 on steel rims. They are awesome, a little noisy but great off road. The suspension is standard and I have had no rubbing anywhere.(even off road)

Nick

I run 265/75/R16 MTR's as a second set and they are (overall diameter) is about the same size as 265/70/R17 STT's

http://www.miata.net/garage/tirecalc.html

They rub on the front guard flares on max or near max wheel lock on my car (without bullbar). If you fit bullbar you won't have this issue...

[lc120_man Advanced Member Find all posts View Profile Close lc120_man]

Speedo is electronically calibrated (based on original diff ratio & tyre size). A result all of the speed related things will be incorrect (including what you can get from the ECU).

I'm trialling a unit to adjust the speed to the correct figures on my car. 4 wire fitment & allows original & larger tyre size selection.

Yes, ECU will still give the same speed as shown on the speedo, but
you can use Scangauge to adjust that value up or down by percentage... So if the speed shows 60 and you are actually going about
6% faster, they you can adjust the scangauge value for speedo by 6%... The downside is that unit only works with newer model prados (from 2005). I haven't tried it on 90 series yet...

[prado4x4 Member Find all posts View Profile Close prado4x4]

A device to adjust the spedo on a 90 series isn't really needed. The speedo seems to read under anyway. Putting on larger tyres (265/75R16) actually brings the speedo to a correct accuracy (as measured on a few cars with GPS's etc).

[DaveO Junior Member Find all posts View Profile Close DaveO]

A device to adjust the spedo on a 90 series isn't really needed. The speedo seems to read under anyway. Putting on larger tyres (265/75R16) actually brings the speedo to a correct accuracy (as measured on a few cars with GPS's etc).

Interesting - cause I have a proto-type speedo adjuster in test rigjht now!

Well, my speedo reads 6% slow without the speedo-matic - enough to done for speeding, by 6km or more, if you use the speedo reading as gospel.

Perhaps you have different tyre dia or diff ratio.

Bigger tyres (like 285/75/16 or Simex JT /JT2 in 280/80/16) will definitely be even further off. Since I've run out of points twice (for silly things like a few k's over each time) I'm trying to be even more careful now.

[prado4x4 Member Find all posts View Profile Close prado4x4]

DaveO - Interesting findings.

Here's what I found with three vehicles over here.
- Mine with 265/70R16 Grandtreks, going to 265/75 R16 BFG AT
- Friend of a friend with 265/70R16 grandtreks
- Brother-in Laws work vehicle 265/75R16 BFG AT's.
All 3.4 v6 GXL's - Should have the same diff ratio.

The standard 265/70R16 grandtrek tyres gave a low speedo reading. (ie: speedo saying 100, actually doing 95-96km/hr). Putting on 265/75R16 tyres (BFG AT). Speed showing 100, actually doing 101km/hr.

Now of course these were only measured with a few different GPS units (cause I thought maybe it was the GPS that was out at first), so it could still be inaccurate.

Tyre dia could definitly be playing a part. The grandtreks were worn on both vehicles, and the BFG's were pretty new.

Of course going to larger tyres again (265/85R16) will require some form of correction for sure.

Hope the info is of some benefit..........

John

[gv1600 Lurker Find all posts View Profile Close gv1600]

Hi all,

I,m from greece and we own an LC-J120-3d-4000cc-executive.
The tires that we bought it with are the stock Dunlop Grandtrek AT20 265/65/17.
Not a good tire for me especially when going offroad
I,m trying to get some ideas cause after the summer i,m planning to change them with BFG or Bridgestone Revo (694 here) AT's in 265/70/17.
Do you guys have any problems with any of these 2 tires ?
I already know BFG's cause i,m running the 2nd set in my Grand Vitara now, and i love them!!
But i want more opinions, about heavy tires, fuel consumption ect...

Thanks in advance, vasilis.