Tyre Size Question

[Agteros]

Can you gentlemen tell me what is the maximum tyre size I can fit on my Hilux? It has the 15 inch rims and a OME suspension upgrade. Would the OME make a difference to what size rubber can be fitted?

[Family_Dog]

I'm using 31" with excellent results. Gearing is good, speedometer reading is spot on.


-F_D

[Agteros]

Thx for the reply Eric. Current tyre size is 30x9.5 R15

If I want to fit a Lexus 5spd auto I think my refs will be too high with the current ratios. I was thinking what the biggest size tyre would be to fit without other hectic modifications i.e. body lifts, axle movement and so on....

[Agteros]

BTW the 4Y can barely turn the 30's

[Dewald Posthumus]

BTW the 4Y can barely turn the 30's

Correct, I remember my S/C performed really well with the 30's on, but struggled with 31's. If you go bigger engine, then you should be able to fit at least 32x11.5R15's on there. if I remember correctly, there is ample space with the OME suspension - I had the same setup.

[Agteros]

Dankie Dewald! Waardeer jou respons. Met 32's behoort die revs darem seker bietjie af te kom.

[Dewald Posthumus]

Defnitief, maar daai 4Y het darem maar net die perfekte ratverhoudings as mens van die teerpad afgaan en hom in 4x4 sit...maar ai tog, ek onthou die ou dae wat ek mos Mosambiek toe wou neuk - 17 ure op die teerpad Inhambane toe, om die laaste 20km 'offroad' in die sand kan ry en se dit was lekker.

Daai 4Y was n kanniedood, maar as dieselfde boom na 30 minute se ry nogsteeds op die horizon sit, dan raak dinge moeilik...

[Family_Dog]

Go EFI - all you need for the 31s ;)

Bulldog handles the road, hills etc much easier on 31s with the EFI conversion than it could before with the 4Y non-EFI engine and the standard tyres.

-F_D

[Agteros]

Hi Eric

I think I might have found the right guy - waiting for a quote on a V8. But I don't want to "jump the gun"
I have been here before...

[Mud Dog]

Personally I agree with Eric that 31's are the ideal all-round tyre size for this vehicle but if you're going the V8 route then bigger tyre diameters can be justified. The drive-train is however going to come under a lot more strain and is not suited to the V8's torque.

If you're going the V8 route then I would replace the gearbox and diff for KZTE units. Those diffs also have slightly longer legs so you won't be revving as high ..... and you can still play around with tyre sizes. I would then go minimum 31" but you might just be lucky enough to be able to fit 32's without modifications depending on how much lift you have actually achieved with the OME setup and of course, tyre width. Even with the KZ drive-train, the V8 should be able to handle 33" tyres, but then you will have to do the axle shift and might even have to 'massage' the back of the front wheel wells a bit.

That all said, the SFA with 1UZ Lexus V8 and KZTE drive-train is a great set-up, but considering the costs involved in such a conversion it might be a better option to sell the SFA "as is" and put the bucks (plus what you would have spent on the conversion) into a nice 2nd hand Vigo 4 lit V6. That way you keep the vehicles reasonably standard and retain resale values at a small extra cost. Fuel consumption figures will be pretty much the same and you will have all the towing power you need without having to worry about reliability and drive-train issues.

Just my 2CW.

[Agteros]

Thx Andy for your input - much appreciated!

I hear exactly what you say - the search for a good 2nd hand vehicle is a bit of a PITA. And then you run the risk of latent defects. I will "check the cat from the tree" as we say in Afrikaans

[Mud Dog]

[Spikkelvark]

Hey guys.
Agteros, if I may I want to add to your thread and ask a bit of advice on the same topic.
I have na 88 import SFA, but I bought it with a sick import 4y engine. My friend gave me a 3l 2.8 hilux diesel engine and I rebuild it. The feul consumption is much better with the 2.8 diesel and got nice torque in low range. But on the open road it revs a bit high and my speedo is out by about 10kmph at 1ookmph, gps showing I'm doing 90kmph. I have 30''tyres now. What would the effect be if i maybe go for 32'' tyres on my feul consumption and on my drivetrain strain?
Thanks guys, I'm new so sorry if I missed the answer somewhere.

[Family_Dog]

I would rather try 31" tyres, I think you would be very close to spot-on with them. No mods required for these either.


-F_D

[Mud Dog]

Agree. 31's will bring the speedo back into line and drop the open road revs down a tiny fraction (will be hardly noticeable) but you will also retain the low rev torque in the rough. As Eric also says, you won't need to do any modifications to accommodate the 31's - with 32's you might have to raise the suspension if not already done and you will have to move the axle forward (which means modifying the spring pedestals, bump-stops, torque rod and drag-link).

[Thabogrobler]

AFAIK from 33 inch and bigger the axle has to be moved forward by 15/30(?)mm.

Louis Zanolli do that mod without batting an eye lid.

Eish, are we on the V8 route again? You will be destroying avpiece of history! Not many unmolested SFA's around anymore. You have the FJ for distance cruising, please save some history for the children!!

[Spikkelvark]

Thanks guys.
Will go the 31'' route. Old man would look rather nice then.

[Haboob]

You going to lose a lot of power with bigger tyres with that engine.
I recommend that you stick with what you have.
First Geer on the forum (Tony) had the same vehicle, which is a bit of a Donkey on the open road, but a champ in the bush.
Putting on bigger tyres will make it just that much worse than it currently is.
If it is currently 10 kms out from the GPS, then you are at least getting to 90 kms/h.
With bigger tyres you may not get there.
If you want to get closer to 100 kms/h then ride 110 kms/h on the speedo, then you will be close to your desired speed.
Just my 2C/W.

[Spikkelvark]

Hey Edge.

Thanks yes. The old man is slow but it makes it to 120 gps speed rather easily, admitting on flat roads, not uphill, but yes probably not worth the money to do that if its going to influence the performance that much.