Tire size, axle articulation, and steering lock

[davran]

All,

I've been trying to decide what tires I'll put on the '74 SIII 88 I'll be picking up in the Spring (which has 16" wheels and bias-ply 225/75x16" tires on now but I don't know the wheel width). I've been doing a lot of research, but I've not found exactly the information I want.

With stock suspension what is the biggest tire that won't rub on full axle articulation and/or steering lock? 225/75x16"? 215/85x16"? 235/85x16"? What about with Parabolics: they're 2" higher aren't they? Huge flotation tires seem en vogue, but do they really work with the older rigs? Also, what is the maximum diameter of tire that the small engine will pull properly?

Thanks,

[ANDYD]

Hi David,

This paragraph is copied from an earlier Tire discussion on our technical Articles tab...

Series Landrover BFG tire sizes:
15" rims = 33 x 9.50 x R15 Mud-terrains, 8-ply sidewall
16" rims = LT255/85 x R16 Mud-terrains, 8-ply sidewall
16" rims = 7.50 x R16 Track-edge, 4-ply sidewall
Old Landrover Rims need tubes best results with Michelin heavy-duty truck tubes.
Other Notes:
Stock Defender 90 BFG Mud-Terrains are LT265/75 R16
98 Camel Trophy Disco BFG Mud-Terrains are LT245/75 R16

[davran]

Andy,

I saw that information in the technical section, but it makes no sense to my limited learning: should it have read 235? A 255/85x16" tire on a stock series LR? The BFG mud tire in this size is 33.3" tall, 10" wide, and needs a minumum 6.5" wide rim. I assume it needs not only a wider rim but one with more offset to allow any steering lock. This tire doesn't fit on my wife's Disco II without a 2" lift, so I find this information highly suspect for a stock series. Please correct me if I'm wrong.

Does anyone in the club use a 235/85x16" tire on a series LR? Does it need a lift for clearance?

Thanks,

[Greg S]

Dave, my 109 has 255/85/16's on stock wheels essentially without modification or wheel stop adjustments. (It was set up like that when we went up Mount Brenton.) Mind you, it is on a military chassis with the extra 2" spring mounts. The tires don't "have to" have a 6.5" wheel, that's what the manufacturer "recommends". They come stock from the factory with 7.50 x 16's which crosses to the nearest metric size of 235/85/16. The tire size you say is already on your new S3 is a radial size, not bias. I'd suggest you drive it a while on those radial tires to see how it is, then be thinking of a change if they don't work for you. With the 225/75's you'll have more power and acceleration than with the larger tire. If you change, I'd recommend not going bigger than the 235/85/16; I went to the 255 because of my higher lift from the military suspension. I have noticeably less speed and acceleration because of the taller tire.

Remember, the Series Land Rover comes stock with the optional 7.50 x 16 (235/85 x 16). For a J**p or any other make of SUV except Land Cruiser, they have to do suspension and body lifts to get a tire that size under them except for the newest J**ps off the line.

[davran]

Greg, thanks for the info. The front tires on Roddy are split and quite old, or I'd just leave them.

Am I correct that while the 109s had 760x16s stock, the 88s had 700x15s?

Having worked at my Cousin's shop where we sold many tires, I learned that putting too wide a tire on a rim not only starts to cause functional problems (pinches the tire so it's "pointed"), but it also may absolve the tire company of liability if the tire has any manufacturing defects; the company can say that you didn't follow their recommendations (I wish I was kidding).

Thanks again,

[Greg S]

The Land Rover 88 had MANY different stock and optional tire sizes over the years so you can't simply say size X was standard. The 88 had an option of having a 7.50 x 16 tire (aspect ratio 100%) I don't know if this was on the 5 or 5.5 inch wheel for the 88. It was the standard size on the 109 which, by the way, had exactly the same motor, running gear and gear ratios as the 88. These rim widths were considered normal for that size tire in days gone by. The 235 85 is considered essentially the same size as the 7.50 and tire shops around here are happy to install it on the standard LR rim. When queried about the width difference, I've been told multiple times that it simply isn't an issue. A 235 or 7.50 tire on the stock rim isn't much width problem, now if you were trying to put a 12.5" tire on a 5" rim, now you've got something. Many 4 wheelers with other makes try to go to 12.5 wide tires. Sorry, it simply won't work on our narrow wheels. But Yes, the rim is supposed to be narrower than the tire, within reason.

As said, I wouldn't want to go much bigger on stock equipment than the max size already spec'd by LR and that is in the new sizing available to us, 235 85 x 16. In other parts of the world, you can still buy brand new, still made, 7.50 R16's. Simply not available in North America it seems. I am a firm believer in tall and narrow and the 7.50 X 16 gave both. Also stock was a 9.00 X 16 tire on a Land Rover rim for the Forward Control LR's but I think that rim was 6" (1.5" extra tire on each side of the rim). Maybe someone could correct me on rim width for that one but I'm pretty sure it was only 6". So 7.50 on a 5" rim is only 1 1/4 overhang on the rim. Pretty paltry to the eye.

A 7.50 (235 85) tire fills the stock Land Rover fender very nicely and gives good tire height. You should have no articulation or rub problems but the steering stops may still have to be adjusted. The 235 tire is a bit wider than a 7.50 but most of that is section width, not tread width so the side wall sticks out farther without much benefit IMHO. By going to the 225 85 tire you mentioned, you still get pretty good tire height compared to other makes and seemingly more power and better acceleration from your stock Land Rover.

For the US market in the late 60's till they stopped importing them in '74, the 88 had a 15" wheel that was wider ( I can't remember how wide) that they supplied with an 8.20; 8.90; or 9.00 X 15 tire.

16" sizes, stock, included 600; 650; 700; 750 and as mentioned on the FC 900. (Damn, or was that 9.50?)

[sailourboy]

Yes my 101's have stock 6" rims however Craddock's has just stocked some aftermarket 6.5" rims but for 5 rims they are $1400- out of my reach right now!!
Cheers
ted

[davran]

Thank you gentlemen, I appreciate the enlightenment; I did a number of hours of reasearch on this topic before posting, but I just wasn't getting the information I wanted. I can't afford to make an incorrect tire choice for the SIII as my commuter and Cyndi's Disco need tires next. The LT215/85x16" tire is common for dually pickups, and will probably be what I go with.

[Glenn D.]

I was going to go for 235-85 R16 BFG-AT until found some nearly new 7.5x16's off a recent import.

[gudjeon]

I love the 215/85/16 size. It is roughly the equivalent to the 7:00x16 and is not as heavy as the 235. Good clearance and cheaper to get too as it is a size used on fleet trucks.

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