245 75 16 ?

labudski

New member
Anyone go to this size tire? I just like the fact that theyre rated for more weight (120 vs 115/112) than the 225's. Seems like a good idea?
 

NelsonSprinter

Former Nelson BC Sprinter

turbodave

06 Tall 140 DIY Campervan
I've got 245/75/16 Kumhos that were take offs from a 2011. According to the gps the speedometer is spot on but the odometer is reading 7% low.
Hope that helps
Dave
 

RedFord77

New member
I had 245/75/16 test fitted 6 months ago (on my aluminum rims), and they cleared on the front. I am also about to switch to 245/75/16.

I can get tires + rims off an NC3V. I would probably get the Kumho tires moved to my aluminum T1N rims, because they look better.
 

L8RSK8R

2006 2.7 Mercedes 2500
My 2006 came with Michelin 255/55/18's. I recently went back to Discount Tire to have one tire replaced. They told me the tires mounted, were of the wrong load rating.
I asked them "why'd you mount the wrong tires" They had no answer.
I'd run up 20K miles on the wrong tires, they replaced them free of charge.

They mounted Pirelli Scorpion 255/60/18 112H XL BSW. Clearance on fronts is 3/4" from fender. I had to remove the front mudflaps.
 

Nautamaran

2004 140” SHC T1N 2500
This size will fit on a 2004 Dodge Sprinter T1N without rubbing? Is there an advantage to going to the bigger tire?
Yes, unless it's a 118" built with 15" rims (check your door plate).

Some mods to mud flaps and tabs in the wheel wells may be required for 140" and 156" models.

Bigger tire gives higher sidewall, which can be let down for off-road use in sand and other soft surfaces. This gives a larger contact patch and lower ground-load, which can often (but not always) help traction and reduce sinking in sand and mud.
Downside to a larger contact patch on highway is increased tendency to hydroplaning in rain or to float on slush rather than pushing down through to the road surface.

The larger size also helps correct the speedometer under-read, which in turn increases the actual top speed when driving at the factory speed limiter.

-dave
 

alexk243

KulAdventure
Yes, unless it's a 118" built with 15" rims (check your door plate).

Some mods to mud flaps and tabs in the wheel wells may be required for 140" and 156" models.

Bigger tire gives higher sidewall, which can be let down for off-road use in sand and other soft surfaces. This gives a larger contact patch and lower ground-load, which can often (but not always) help traction and reduce sinking in sand and mud.
Downside to a larger contact patch on highway is increased tendency to hydroplaning in rain or to float on slush rather than pushing down through to the road surface.

The larger size also helps correct the speedometer under-read, which in turn increases the actual top speed when driving at the factory speed limiter.

-dave
How does this effect engine RPM, gas mileage?

Any issue with towing a trailer?

Sent from my Nexus 5 using Tapatalk
 

Nautamaran

2004 140” SHC T1N 2500
How does this effect engine RPM, gas mileage?

Any issue with towing a trailer?

Sent from my Nexus 5 using Tapatalk
I run the stock size so can only theorize, but the larger tires will spin slower, which mimics slightly higher final drive gearing. This will raise engine load and reduce cruising rpm, which should improve fuel economy to a point (hills and head winds will be harder to face, so you’ll gear down earlier), but will hurt acceleration and the brakes will feel softer under foot (but ultimately brakes will still lock up so it shouldn’t impact panic stops in dry conditions; rubber compound has a stronger influence on braking).

You’ll feel the weight of a trailer more when accelerating or climbing a hill, but tires don’t effect tongue weight rating. I don’t believe there’s a max tow weight change going from the 3.72 diff to a 4.11, so you shouldn’t see a downgrade going from 3.72 to the effective 3.55:1 on the taller rubber?

-dave
 

freestyle72

New member
My van lists tire pressure at 55 front 79 rear with stock tires (225/75/16).

What pressure should I be using with bigger KO2's (245/75/16)?

Sent from my Nexus 5 using Tapatalk
You have to use the manufactures recommended tire pressures. Use the pressure rating listed on the sidewall of your tire.
 

Nautamaran

2004 140” SHC T1N 2500
Tire rating is just the maximum pressure the tire structure can safely hold, and should always be at or above the vehicle's door plate recommended pressure.

For a given axle weight, the tire's contact patch will have the same surface area at a given pressure regardless of tire diameter and width, so for same width tires as stock just use the pressures on your door plate. This will give you a slightly shorter contact patch, less tread deflection, and longer tread wear. You can use a proportionately lower pressure if you've gone to a wider tire, giving you the same length of contact patch (so still slightly less tread deflection due to increased diameter) while the extra width gives you more surface area and lower ground loading pressure, which is better over fluid materials like pea gravel or dry sand.

You *may* use less pressure with a larger diameter, since it's the length of the contact patch that determines the amount the tread will deflect when going from round to flat as it rotates through the contact patch, and this tread deflection decreases as the tire diameter increases. It's the tread deflection that determines the heat loading in the rubber, which feeds into the tire's weight and speed ratings, as exceeding the heat loading is what makes a too-low tire overheat and become a blow out risk.

Be aware that the extra width will also lead to earlier hydroplaning over puddles, regardless of pressure, and choose your speed accordingly.

-dave
 
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Nautamaran

2004 140” SHC T1N 2500
My door panel says the same. The 79 psi rear pressure is for running rear at GAWR, which I’m nowhere near, so I run 55 front and adjust the rear according to my axle weight, generally around 70 psi.

-dave
 

desertdog

Member
Possibly some of the decreased mileage is due to the larger tire effecting the odometer accuracy? Let us know what your next fill up mpg is. Thanks!
 

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