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Grenadier

Member Since: 23 Jul 2014
Location: The foot of Mont Blanc...
Posts: 5869

2011 Defender 110 Puma 2.4 DCPU Corris Grey

What's the highest sidewall on an 18" rim?

Bonjour,

What's the highest (sensibly highest) sidewall that I can put on an 18" rim on an unmodified 110 with standard ride height? I'm looking to fill the gap between wheel and arch just a little more. And I've also got slightly hooked on the larger tyre look (but not to the degree os some silly US style monster truck. Indeed, not even the tyres on a Spectre.

Any answer shouldn't adversely affect ride-height, handling, speed indicated on speedo, fouling under the wheel arch whether on or off-road etc.

I'm currently running 65s, was wondering at 70s, 75s?

Any thoughts?

Monsieur Le Grenadier

I've not been everywhere, but it's on my list.....

2011 Puma 110DC - Corris Grey

19th Oct 2023 7:05am

Chicken Drumstick

Member Since: 17 Aug 2020
Location: Near MK
Posts: 761

Not 100% convinced on 18" rims on a Defender, they always look, well a little odd.

Also on a 4x4, you normally don't want to fill the arch. You want clearance, even more so if you plan to off road.

Stock tyres are 31-32" tall. Generally 33's are fine and if you drive gentle plenty have run 35's, else you really need to be modding axles and diffs. Max for the axles is probably 37" tall. But you'll want supporting mods most likely for anything over 33".

Wide tyres generally perform worse off road over narrow ones and also allow more steering lock. With less chance of rubbing or sticking out of the arches.

Best bet is just to look at what 18" tyres are on offer and their diameter and go from there.

19th Oct 2023 12:16pm

LJMARSDEN

Member Since: 08 Jun 2021
Location: Nottingham
Posts: 342

There are calculators online for tyre diameter and circumference if needed.

People suggest 33" is enough. 4.0 V8 Defender 90

My Instagram

19th Oct 2023 2:37pm

Ianh

Member Since: 17 Sep 2018
Location: Essex
Posts: 2081

As others have said use a tyre size calculator site .i.e https://tiresize.com/comparison/

And put in the specific wheel and tyre details. you can also put in offsets to see how that impacts stops , rubbing on arches etc.

Note the 60, 70, 75 etc number is a percentage of the width or the tyre not a measurement in itself, I.e a 265/75 will be a greater diameter than a 255/75.

19th Oct 2023 3:00pm

jimbo55

Member Since: 15 Jul 2020
Location: Midlands
Posts: 400

I run 275/70R18 toyo muds on my 90, if you want a mud terrain it’s about the only sensible option that isn’t a 33x12.50r18

Bfg do all terrains in 285/65r18 and I think there are others that do 33” but not overly fat tyres for 18” rims

Either way a 33”diameter tyre on 18” rim will give you pretty much the same sidewall height as a stock 235/85R16

On road handling is considerably better than the 255/85r16 bfg muds I had previously, especially in the wet

I find my td5 speedo runs pretty bang on with a 33” tyre

If I off-road standard height (it’s on air so can choose) then it can just about catch the corner of the rear wheel arch, (9Jx et0 twisted rims) when I max out the suspension flex but it is pretty rare -if I’m on a pay and play I might hear it once or twice in a day at most.

Would definitely recommend them 👍

19th Oct 2023 3:58pm

Likeomg

Member Since: 29 Jun 2012
Location: Lake District / Newcastle
Posts: 2651

2010 Defender 90 Puma 2.4 HT Stornoway Grey

I previously had BFG 285/65/18 however moved to the cooper's 285/60/18 and in my opinion fill a defender out properly...

Click image to enlarge

Click image to enlarge

No issues off-road either although I don't have a factory suspension setup.

Click image to enlarge

20th Oct 2023 7:31am

LJMARSDEN

Member Since: 08 Jun 2021
Location: Nottingham
Posts: 342

Damn, I think they look spot on Jimbo. This may be what my 90 needs..

I feel I may have to change my tyre soon nnow, I'm quite jealous of the look.

Click image to enlarge

Click image to enlarge

Radar renegade 275/65/18 4.0 V8 Defender 90

My Instagram

20th Oct 2023 7:51am

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