Right where do I start with all this gratefully received info

I need tallish tyres because of where we go, I know this from experience. I'm new to forums but not to off roading, land rovers and geometry etc but everyone should be open to advice (and I hope that didn't sound offensive or arrogant, just trying to save typing time cos it takes me aaaages ) but asking on here is like asking loads of experienced people with different vehicles for deferent jobs and I like that

Body roll or Gearing doesn't worry me, I've used plenty of land rovers with tall tyres and there's always more powerrr, or a defender t box. It's pulling all over the place that concerns me, so let me start from the other end of things...with an "as near as possible to perfect" vehicle with a 2" lift (to get chassis further away from the floor cos the break over angle could be better due to the length of the wheelbase) and 50mm arches, which of the following do you all think will travel most true on the road and give a better on the road experience...

33x12.5/15 on 10" modulars, with the offset that sits them to the edge of the arches

OR...

Let's say, 255x85/16 on 8" modulars also with offset and spacers to push them out to the edge of the arches aswell

Let's pretend the tyres are the same diameter, make and tread. Wot I'm interested in is the tyre width at the same offset and how they would drive on the road, how good or bad will each one be???

Thank you for your time and patience

Towsey

I'd go for the 255/85R16. It might not look quite as monster truck, but it's still a big tyre and on the right rim, I'm sure it'd look spot on. And in the case of BFG's, the 255/85 is actually a taller tyre than most of their 33.xx.50R15's

On the road, the 255 should have less weight, so less unsprung mass. And being narrower will help the steering in general. My vote would be the narrower tyre will handle and drive better. It'll also be easier to get under the body work and won't require such a large offset rim. Large offsets can affect steering due to how they alter the geometry.

There is a good video here that explains it:


Note the vid is about wheel spacers, but a wide offset rim is doing exactly the same thing.

With a lift you may need to look at some new props. Some people get away with stock ones, but the change in the pinion angle of the diffs will put strain on the UJ's. So you may need to look into some wide angle props down the road.

Also, depending on how you lift the vehicle, you may need to get extended brake lines if you increase the travel. But this will be very dependant on how you lift it.

Spot on thanks

I don't mind having a narrower looking tyre but I don't like the idea of arches with wheels tucked under unless I really hav9e to. That video shows exactly why I don't want to go too wide with offset/track width and I defo agree with you that it just increases leverage on steering and other components which is why I always just wanted to go flush with standard arches.

I suppose I'm just wanting to find a balance I'm happy with between tyre diameter and wheel offset, with diameter as close to 33" as possible. I'm just waiting to see wot peoples experiences have been, and I suppose I'm waiting for people to say "i had big tyres, big arches and big offset and as long as all components were like new, it drove fine, go for it"...but I can't see it happening ha.

Propshaft phase/angles, brake lines, bump stops and all such like are in hand, but thanks for mentioning it.

Thanks again

Towsey

No probs.

Probably an ideal tyre size for you would be the 8.25 x 16, but sadly it's a very rare size and never much choice of tread patterns. It's an old English size, you have 6.00 x 16, 7.50 x 16, 8.25 x 16 and 9.00 x 16

As the tyre gets wider it gets taller. But 8.25" is very narrow in today's money but is just over 33" tall. Significantly taller than a 7.50 of the same tread pattern. In a modern metric size it would be equivalent to something like a 210/105R16, but these don't exist sadly.

This is my brothers lifted 90 on some Michelin XZL's in 825 x 16, they don't look big, but actually are. Shame I don't have a pic of an XZL 7.50 to compare too, as they look way smaller.

Interesting sizes there isn't there.

I really don't know wot to get, like I said before I'm trying to get one vehicle to be a good all rounder. I'm trying not to have a second car if I can, but if I did and this was a toy then I would just dive in but as it is I'm trying to keep it as drivable as possible and as good as I can off road at same time. It might get a Detroit locker or something aswell.

To be honest I was hoping a lot more people would seen the thread and put up wot they have and how it works, but then I'm new to forums and I'm not sure how it all works

Towsey

I've just swapped out my 7.50r16 Michelin XZLs on 5j Series 3 rims no offset, on my Disco which has 2" lift, to BF Goodrich MT 265/75/16 on Terrafirma's Wolf Rims 6.5j with a 20 offset.

The basics that needed to be done to make them fit were:
- Trim rear arches (camel cut)
- Adjust steering stops so they don't foul radius arms
- Install new bump stops as my rears were missing! Causing rubbing at full travel on the top of the arch!

I've also optionally trimmed back some of the inner arches, getting rid of the lip on the inside edge, and also trimmed back the front wing sections at the rear.

The BFGs are great - nice and grippy, not too aggressive for the road, and should last a long time. Probably the best all rounder. I think 235/75 would be an ideal size for minimal modification to get them on. I'd heartily recommend the BFGs, the footprint is very reassuring compared to the skinner XZL. If i'd have used a bigger offset i'd be cutting arches more - the tyre can currently articulate inside the bodywork just fine with no catching.

I've since put HD springs on the rear as in the pic you can see, it's sagging too much under weight of tools in the boot.

towsey956 said:

I really don't know wot to get

Click to expand...

tbh it really comes down to a compromise. The bigger you go, the more hassle and effort they will be. Taller tyres do have some advantages off road, but not always. And big fat tyres might look cool, but sometimes just don't perform to expectations.

Personally I love the monster truck look. But I was happily prepared to hack the arches to make the tyres fit. And while it drove ok on the road, there is no denying it drove better on 31.10.50R15 AT's.


235/75R16 or 245/75R16 will mostly likely fit straight on. No issues at all.

True 7.50 x 16 will need a camel cut and maybe front bumper corners

31.10.50R15 will need a camel cut and maybe front bumper corners

Fake 7.50 or 235/85R16 or 265/75R16 will need more trimming and/or lift


Anything bigger will need more work and make a much more noticeable difference to power/gearing and how they might drive on the road.

If you don't mind the work, then I'd say 235/85R16 as they are pretty tall, not too wide and loads of choice. They are also a standard size for a Defender and just a good size for off road work in the UK.

True 7.50's work slightly better than 235's, but are hard to find with limited tread choice. Fake 7.50's are just re-stamped 235/85's and are the same size.

255/85R16 is a nice size tyre. But will rub a lot more and require you to trim a lot more to make them truly fit, esp if you are off roading.

Cheers for the input Ben, some good info thanks

300, yeah like ya say it's finding that ideal compromise that works best for me, most of our discos are running a 2" lift with 265x75/16 special tracks on modulars that fit flush with standard arches (are these the -35 offset, I'm sick of calling them flush fit ) but I was hoping that 285x75/15 BFG MUDs would fit about the same because they are a bit bigger size but they don't have the big nobbles hanging off them

I don't mind doing a camel cut or a bit more, I just didn't want to have to cut the whole arch out, similar to when ya putting plastic arches on, without putting the plastic arches on. But then I don't want plastic arches without the wheels being sat to the outer edge of them. And... I didn't really want the wheels sat rite out there because of the effect on steering. So I need to know what's the biggest m/t I can put on 8" 'flush fit' modulars with a 2" lift with just a mediocre amount of hacking my very tidy discovery up, but having said that, it wants to be worth cutting her up.

Thanks again

Towsey

Can anyone answer my wheel offset question please, I'm curious

Cheers

Towsey

towsey956 said:

Can anyone answer my wheel offset question please, I'm curious

Cheers

Towsey

Click to expand...

with the correct offset the wheel will pivot about the king pin line,with the wrong offset wheel will be pushed forward or rearward of axle line as well as been turned, hence odd steering

Cheers James, but I'm wondering wot the standard offset (mm+\-) is and wot the available offsets are, like the usual one that pushes wheels out flush with standard arches

Cheers

Towsey

So can anyone tell me what offset I should ask for when ordering new modulars please, I want the ones that sit furthest out from the hub, is that -35mm???

Cheers

Towsey