Largest Functional Tire Without Mods

[Commodore]

Fantastic. I really want the 255/85 but not particularly drawn to the Mickey tread pattern. Have you driven them in mud?

I have driven them in terrible Utah mud and they preformed well for an all terrain tire. Actually they did much better than the truck that was with me on Nitto Grapplers. The Nitto’s are absolute crap and worthy of their own post. The Mickeys are not a mud tire but I believe they are better in mud than the KO2’s and Wildpeak AT3’s that I have experience with.

 

[TCMColorado]

Curious about the speedo how far off it has become?

I am on the 255/85R17 Mickey Thompson tires. At 75mph my speedo is slow by ~3mph compared to GPS reported speed. Actual speed is ~78mph. The effect on gearing is noticeable but it is still very drivable because of good low end torque provided by the turbo engine.

 

[Tom109]

@Commodore & @TCMColorado - thanks for the Mickey insights. Given the non-commuting use of my Grenadier, I think I’ll go 255/80 in a true mud tire. About the only RT-type I’m considering is the ST/Maxx…

 

[Tenac]

I am on the 255/85R17 Mickey Thompson tires. At 75mph my speedo is slow by ~3mph compared to GPS reported speed. Actual speed is ~78mph. The effect on gearing is noticeable but it is still very drivable because of good low end torque provided by the turbo engine.

That is great to hear then thank you. Yeah power wise not too worried about, I'm working with local BMW performance shop on getting the ECM's sent out a downpipe and tune should see about 150hp/90tq jump without moving any OEM safe guards. I'm a big BMW guy so I have zero concerns on the ZF8 which we have already has the upgraded clutch pack according to ZF so good to about 800TQ or so, and the B58 platform is a tank anyway.

 

[mcdoogs]

That is great to hear then thank you. Yeah power wise not too worried about, I'm working with local BMW performance shop on getting the ECM's sent out a downpipe and tune should see about 150hp/90tq jump without moving any OEM safe guards. I'm a big BMW guy so I have zero concerns on the ZF8 which we have already has the upgraded clutch pack according to ZF so good to about 800TQ or so, and the B58 platform is a tank anyway.

I’d personally be more concerned about the stock brakes adding that much extra power to such a heavy vehicle.

 

[Tenac]

I’d personally be more concerned about the stock brakes adding that much extra power to such a heavy vehicle.

Oh I haven't seen any issues with them? To be clear not about speed or changing top speed just the grunt it needs to move this beasts. I've only had one emergency braking at an intersection someone turned left in front of me 50mph to zero was just fine for me at that point. Are they known to fail or unsafe ?? Might be new to me.

 

[mcdoogs]

Oh I haven't seen any issues with them? To be clear not about speed or changing top speed just the grunt it needs to move this beasts. I've only had one emergency braking at an intersection someone turned left in front of me 50mph to zero was just fine for me at that point. Are they known to fail or unsafe ?? Might be new to me.

I wouldn’t say there are issues with them in stock form (although i do think the Grenadier feels its weight when braking hard), just adding ~50% hp presumably means you’ll generally be accelerating harder and driving faster in general with no improvements made to stopping distance. I’m super interested in the final hp/torque numbers you achieve!

 

[Tenac]

I wouldn’t say there are issues with them in stock form (although i do think the Grenadier feels its weight when braking hard), just adding ~50% hp presumably means you’ll generally be accelerating harder and driving faster in general with no improvements made to stopping distance. I’m super interested in the final hp/torque numbers you achieve!

ahh I see, yeah from a speed perspective I mean 65 is 65, acceleration yea should move a bit faster but I'm not talking crazy numbers when you factor weight. I know adding nearly 50% crank HP seems crazy but considering the weight that should put it more in line with what I'm looking for. You raised a concern now for me thinking I was going to be towing with this thing and if there is concern with just the vehicle my tow was going to be 5800lbs, should that be a concern? I think adding weight to a vehicle impacts its braking more than adding HP numbers.

 

[MileHigh]

That is great to hear then thank you. Yeah power wise not too worried about, I'm working with local BMW performance shop on getting the ECM's sent out a downpipe and tune should see about 150hp/90tq jump without moving any OEM safe guards. I'm a big BMW guy so I have zero concerns on the ZF8 which we have already has the upgraded clutch pack according to ZF so good to about 800TQ or so, and the B58 platform is a tank anyway.

1. I thought the issue was the IG ‘layer’ of engine control overtop of the BMW control. Tweaking the B58 is well known, but I’ve heard the hold up is the IG part?
2. This is the first I’ve heard of the upgraded clutch pack. To me, the ZF transmission is the weakest (not necessarily a weak link) in the drivetrain- when you consider it also is used to drive the Supra. I had heard that it was the same engine/trans combo- as BMWs general offering to ‘third’ parties’. The Supra is what, half the weight and has about 50grams of towing capacity? It would be nice to know that the trans is actually beefed up.

I’d personally be more concerned about the stock brakes adding that much extra power to such a heavy vehicle.

The only performance issue I have is with braking. 80-90s mph speeds on I25 are common here and hauling it down from those speeds is… an endvour. Of course I think if you complained to Sir Jim about the braking from 95mph, he might just Sir-slap you- but upgraded braking would be nice. How much does running 17inch steelies affect braking?

On tires, I still don’t get why the measurement is XXX/XX-RXX and not just giving width, height and rim size. It’s like polar versus x,y plot information.

 

[anand]

1. I thought the issue was the IG ‘layer’ of engine control overtop of the BMW control. Tweaking the B58 is well known, but I’ve heard the hold up is the IG part?

Ineos isn't running anything "on top" of BMW control... The DME's (engine ECU) programming (calibration as it is referred to in the industry) is completely bespoke for the Ineos application. Those that have delved into pulling the actually coding off the DME to develop flashed software have found that it isn't just a remapped BMW-spec DME, but vastly different. While the DME is the same type (same Bosch unit), everything related to how the programming is written for it is unique.

On tires, I still don’t get why the measurement is XXX/XX-RXX and not just giving width, height and rim size. It’s like polar versus x,y plot information.

This is the metric sizing scheme utilized globally

 

[Brandtnm]

I have the 255/85r17 Mickey’s. You will notice a slight difference on gearing but with 8 speeds and abundant torque it isn’t a problem. I have towed 5,000 pound boats up mountains without an issue.

Same. I have towed as much as 7500 on this same setup.

 

[kbdgr]

I am on the 255/85R17 Mickey Thompson tires. At 75mph my speedo is slow by ~3mph compared to GPS reported speed. Actual speed is ~78mph. The effect on gearing is noticeable but it is still very drivable because of good low end torque provided by the turbo engine.

Agreed. I've experienced the same thing.

 

[Tenac]

1. I thought the issue was the IG ‘layer’ of engine control overtop of the BMW control. Tweaking the B58 is well known, but I’ve heard the hold up is the IG part?
2. This is the first I’ve heard of the upgraded clutch pack. To me, the ZF transmission is the weakest (not necessarily a weak link) in the drivetrain- when you consider it also is used to drive the Supra. I had heard that it was the same engine/trans combo- as BMWs general offering to ‘third’ parties’. The Supra is what, half the weight and has about 50grams of towing capacity? It would be nice to know that the trans is actually beefed up.

The only performance issue I have is with braking. 80-90s mph speeds on I25 are common here and hauling it down from those speeds is… an endvour. Of course I think if you complained to Sir Jim about the braking from 95mph, he might just Sir-slap you- but upgraded braking would be nice. How much does running 17inch steelies affect braking?

On tires, I still don’t get why the measurement is XXX/XX-RXX and not just giving width, height and rim size. It’s like polar versus x,y plot information.

With this rig I don't think I've seen anything over 75mph yet. lol maybe that is why I haven't had brake issues, might go test that out. Like said above no IG layer on the ECM just the head unit itself all other modules are mostly BMW or Merc. ZF has many many options even tunes to install in the ZF platform, once the vehicle gets above certain weight they install a different clutch pack or if you order one like I did for my M8 so I'm good to about 1200 and above now. ZF is probably the best traditional transmission you can find in the modern era. Only way for me to actually tell is if I can get inside the ZF but calling my shop they have talked with their ZF rep and were informed there isn't anything at this time better to put in the one the Ineos has.

 

[Tenac]

Same. I have towed as much as 7500 on this same setup.

That is great to know!!! Adding weight and big heavy tires seems like a no win situation but glade to see many who have zero issues with it.

 

[mcdoogs]

ahh I see, yeah from a speed perspective I mean 65 is 65, acceleration yea should move a bit faster but I'm not talking crazy numbers when you factor weight. I know adding nearly 50% crank HP seems crazy but considering the weight that should put it more in line with what I'm looking for. You raised a concern now for me thinking I was going to be towing with this thing and if there is concern with just the vehicle my tow was going to be 5800lbs, should that be a concern? I think adding weight to a vehicle impacts its braking more than adding HP numbers.

It's a fair concern. When I picked up my travel trailer which is about 5600lbs dry in TN and towed it back home to RI over two days I only had my '22 Defender P300 (this is the smaller gas engine 296hp/300tq, with the smaller brakes to fit 18" wheels) which isn't dissimilar to the Grenadier in size, power, and brakes with the exact same towing capacity. I ended up warping the front rotors a bit that trip.

As a comparison I've towed the same trailer loaded up with full tanks with a '23 Defender P400 (so bigger v6 400hp/400tq and significantly larger brakes) for ~20k miles including up and down and through the Rockies with absolutely no issues brakes or otherwise. I still have this Defender, and my Grenadier will be at most a backup tow vehicle, but I'm a little leery of it's towing chops mainly with respect to its stock brakes (and it'll obviously be a different towing experience without the air suspenstion and all the active dampening the LR is doing a million times a second).

 

[ADVAW8S]

It's a fair concern. When I picked up my travel trailer which is about 5600lbs dry in TN and towed it back home to RI over two days I only had my '22 Defender P300 (this is the smaller gas engine 296hp/300tq, with the smaller brakes to fit 18" wheels) which isn't dissimilar to the Grenadier in size, power, and brakes with the exact same towing capacity. I ended up warping the front rotors a bit that trip.

As a comparison I've towed the same trailer loaded up with full tanks with a '23 Defender P400 (so bigger v6 400hp/400tq and significantly larger brakes) for ~20k miles including up and down and through the Rockies with absolutely no issues brakes or otherwise. I still have this Defender, and my Grenadier will be at most a backup tow vehicle, but I'm a little leery of it's towing chops mainly with respect to its stock brakes (and it'll obviously be a different towing experience without the air suspenstion and all the active dampening the LR is doing a million times a second).

You can buy a bigger brake kit from Buzz Overland. They built and tested them on their rally Grenadier.

 

[Commodore]

It's a fair concern. When I picked up my travel trailer which is about 5600lbs dry in TN and towed it back home to RI over two days I only had my '22 Defender P300 (this is the smaller gas engine 296hp/300tq, with the smaller brakes to fit 18" wheels) which isn't dissimilar to the Grenadier in size, power, and brakes with the exact same towing capacity. I ended up warping the front rotors a bit that trip.

As a comparison I've towed the same trailer loaded up with full tanks with a '23 Defender P400 (so bigger v6 400hp/400tq and significantly larger brakes) for ~20k miles including up and down and through the Rockies with absolutely no issues brakes or otherwise. I still have this Defender, and my Grenadier will be at most a backup tow vehicle, but I'm a little leery of it's towing chops mainly with respect to its stock brakes (and it'll obviously be a different towing experience without the air suspenstion and all the active dampening the LR is doing a million times a second).

I have towed two of my ski boats with my Grenny up and down from Lake Arrowhead. That is a 5,500 foot elevation change in 16 miles. The larger boat is about 5,500 pounds and the tailer brakes don’t work. That put a strain on the IG brakes but didn’t warp the rotors. I suspect that better brake pads would go a long way to eliminating the brake fade or course the right solution is to fix the trailer brakes. The lighter boat is maybe 4,500 pounds with the trailer and that one has working trailer brakes. The IG brakes worked perfectly with this that boat.

The bottom line is that if the tailer is correctly setup then I believe the IG will effectively tow to its rated limit even with 35” tires.

 

[Krabby]

ZF8 which we have already has the upgraded clutch pack according to ZF so good to about 800TQ or so, and the B58 platform is a tank anyway.

Can you expand on this? I haven’t heard anything about the trans other than the diesel trucks get a beefier version.