Tyre & rim sizes?

[Ratau]

Do all the Patrols have 16” rims or did some came with 15” rims?
My reason for this question is I have 3 sets of 15” tyres: 30x9.5 x15(New), 31x10.5x15 and 33x12.5x15 that could go on the Patrol if a 15” rim will fit past the calliper.

What size tyre works best on the 4.2 diesel without losing power?

I was told there are two standard options: 265x70x16 (±31”) and 265x75x16 (±32”). With the 265x70x16 on the car the speedo is about 11% slower than the GPS.

[Gerrit Loubser]

Danie, as far as I know all the Y61 Patrols (like yours) have either 16" or 17" rims. The older, more boxy Y60s had 15" rims (or at least some had). I don't know from own experience whether 15" rims will touch the brake calipers, but I looked on http://www.patrol4x4.com and found some info that seems to indicate that they will fit:

http://www.patrol4x4.com/forum/showthread.php?t=26995&

http://www.patrol4x4.com/forum/showthread.php?t=24918&

Do you have rims to go with your 15" tyres? If so, just fit a rim to the front and rear and check brake clearances.

I think the standard tyre size for your vehicle would have been 265/70R16. There should be a sticker on the driver's door pillar with the standard tyre size. The 265/70R16 is nominally a 30.6" tire, while the 265/75R16 is nominally a 31.6" tire. Some of the later models also used 275/70R16 tires, which are also around 31" diameter.

[Ratau]

Gerrit

If one look at tyre prices 15” is on average up to 25% cheaper than 16” on the same size. One original steel rim is badly bend and one slightly so I’m considering buying mags. The existing tyres are Bridgstone and have about 4 to 6 mm tread left. That could go another 15K if lucky. I could fit the Isuzu’s 31x10.5x15 on steel rims for a test.
From 265/70/16 to 265/75/16 could bring the speedo closer to 100% and I think 1” wont make that much difference in power loss.

Thanks for the links.

[Gerrit Loubser]

I would give the Isuzu rims a try then.

There is only just over 3% difference in the OD of the 265/75R16 and 265/70R16, so you definitely won't have to worry too much about the loss of tractive effort. Your speedo will also be slightly more accurate (to the tune of 3%) as you said.

You will have to speak to someone who owns a 4.2 about the loss of tractive effort when going for something like 33" tire. On my 4.5, I am quite happy with the acceleration on 285/75R16 tyres (32.8" nominally).

[Tjaart]

Gerrit

Did you use more fuel when you went up to 285/75? And did you loose your low range ''power''? Do you take longer to get up to speed? 'm looking at a bigger tire also.

Thanks

[Gerrit Loubser]

Tjaart, when I got my Patrol it had ridiculously small 245/75R16 bakkie tyres on (it looked as if the rear diff would scrape). I only ran it like this for a short while and I seemed to get about 4.8 km/l around town as indicated by the odometer or about 4.6 km/l when corrected for the rolling radius of the tyres.

Now with the 285/75R16 MT tyres, which are about 5% larger than standard I seem to get an indicated 4.5 km/l in town or 4.7 km/l when corrected for the rolling radius, so it seems that the big tyres don't cause too much of a difference on the consumption front.

There is a definite reduction in acceleration and engine braking, but both are still quite acceptable to me. Bear in mind that I am comparing tyres that are too large with ones that were too small.

[G-MAN]

I run 305/70/17 mud terrains on my 4.8 and there is loads of power on command! Consumption is worse than with my standard wheels.