Question on upsizing tyres by 1"

[babweupatree]

Hi there,

I currently have 265/70R16 tyres on my truck and am getting muds for my next set of tyres but the only sizes I can find are 265/75R16 which I am soon to purchase (Maxxis MT764) but I am unsure of whether I can commit until I feel 100% that I have done my research. I was hoping to get some feedback on the following:

1. Speedometer inaccuracy (recalibration?)
2. Is fuel efficiency a real concern?
3. Strain on the vehicle drivetrain etc.
4. Is the vehicle warranty affected?
5. Are insurance claims a big concern?
6. Anything else to be mindful of?

From the attached screenshot below the tyre size would go up by one inch. I have been happy with the current sizes, they work fine for me and I'd rather have my truck working properly than do silly mods that could damage it.

Thank you!

[jelo]

1. Most speedos are inaccurate anyway and display a faster speed than actual
2. I doubt it
3. negligible
4. I doubt it
5. I doubt it
6. Your 4.5D might not be strong enough............

[SJC]

Hi there,

I currently have 265/70R16 tyres on my truck and am getting muds for my next set of tyres but the only sizes I can find are 265/75R16 which I am soon to purchase (Maxxis MT764) but I am unsure of whether I can commit until I feel 100% that I have done my research. I was hoping

Just do it.

[SJC]

PS, I noticed on my Patrol(s) that the speedo is more accurate with 33" tyres on...
The odo meter is out by about 10% though...

[Kiri]

Just my opinion...:
265/70-16 (31.5) = Wrong size fitted as OEM
265/75-16 (32) = Better
235/85-16 (32) = More logical size for Africa overland, and in general.
285/75-16 (33) = Very popular, and good size.
255/85-16 (33) = My choice for you (only down side is few Manufacturers)
315/75-16 (35) = Looks so good with a suspension lift....

[babweupatree]

Thank you for the replies!

[RogueFrontier]

Apologies for being rude, but you are complete over paranoid!

Lets get a few facts to understand you problems.
My Kumho muds have a thread depth of 22mm. That means when they are run down, I would have lost 44mm on the diameter of the tyre. That is nearly 2 inches!!!

And you worry that 1 inch will make your cruiser fall apart. Not a chance.

Only real advice I can give, is to choose a size you can buy under every 2nd bush in darkest africa. Most folks do not find the fun in waiting 2 weeks to have some arb size tyre imported from joburg at 5 times the normal cost.

1. Speedometer inaccuracy (recalibration?) Most speedos read 10% under. Upsizing 3% will still put you 7% under real speed. Verify this with your GPS.
2. Is fuel efficiency a real concern? Since most people who complain about this cannot use a calculater, you will see a 3% increase in consumption. (Dont tell anybody, but you also traveled 3% further than before, but your car's odo doesnt know this)
3. Strain on the vehicle drivetrain etc. Yeah, cruisers are know to be weak. Beware potholes aswell.
4. Is the vehicle warranty affected? Yeah, valid point. Then again I doubt they know what the proper size is in the first place.
5. Are insurance claims a big concern? Insurance could give a toss. Just DONT be worn down to the wear markers.
6. Anything else to be mindful of? Go for common sizes. They are way cheaper and more readily availible.

I think when you have to start doing body lifts and body cuts to get the tyres in, then you are in a place to start worrying about the above issues.


My experience on the Frontier:
I went from 215x75R15 to 265x65R17. That is 2 inches wider and 2 inches taller.
1: Speedo now reads 1% slow. I'm yet to receive a ticket for going 122kph when the speedo reads 120kph. Between the top and bottom of the 120kph line on the speedo, is already 3kph variance.
2: Once I corrected my distance to the new, real distance travelled, my consumption stayed the same.
3: At 300kkm, I'm still on my factory fitted bearings. I do however think it is time to have a look at bushes and balljoints, but I cant blame tyres for general wear and tear.
4: I never had a warranty (2nd hand), so I cant be bothered how the stealers would want to worm their way out of it.
5: I've had 3 insurance claims and everytime they come take a photo of the tyres to see if worn tyres can save them some money. Nothing said about size.
6: I actually feel the 280 pulls better on the bigger tyres, but that is what Fluffy would call "a subjective opinion"

Just go forth and fit what makes you happy. The 4.5 will not notice it.

[Kiri]

"My Kumho muds have a thread depth of 22mm. "
Really?

[babweupatree]

Apologies for being rude, but you are complete over paranoid!

Lets get a few facts to understand you problems.
My Kumho muds have a thread depth of 22mm. That means when they are run down, I would have lost 44mm on the diameter of the tyre. That is nearly 2 inches!!!

And you worry that 1 inch will make your cruiser fall apart. Not a chance.

Only real advice I can give, is to choose a size you can buy under every 2nd bush in darkest africa. Most folks do not find the fun in waiting 2 weeks to have some arb size tyre imported from joburg at 5 times the normal cost.

1. Speedometer inaccuracy (recalibration?) Most speedos read 10% under. Upsizing 3% will still put you 7% under real speed. Verify this with your GPS.
2. Is fuel efficiency a real concern? Since most people who complain about this cannot use a calculater, you will see a 3% increase in consumption. (Dont tell anybody, but you also traveled 3% further than before, but your car's odo doesnt know this)
3. Strain on the vehicle drivetrain etc. Yeah, cruisers are know to be weak. Beware potholes aswell.
4. Is the vehicle warranty affected? Yeah, valid point. Then again I doubt they know what the proper size is in the first place.
5. Are insurance claims a big concern? Insurance could give a toss. Just DONT be worn down to the wear markers.
6. Anything else to be mindful of? Go for common sizes. They are way cheaper and more readily availible.

I think when you have to start doing body lifts and body cuts to get the tyres in, then you are in a place to start worrying about the above issues.


My experience on the Frontier:
I went from 215x75R15 to 265x65R17. That is 2 inches wider and 2 inches taller.
1: Speedo now reads 1% slow. I'm yet to receive a ticket for going 122kph when the speedo reads 120kph. Between the top and bottom of the 120kph line on the speedo, is already 3kph variance.
2: Once I corrected my distance to the new, real distance travelled, my consumption stayed the same.
3: At 300kkm, I'm still on my factory fitted bearings. I do however think it is time to have a look at bushes and balljoints, but I cant blame tyres for general wear and tear.
4: I never had a warranty (2nd hand), so I cant be bothered how the stealers would want to worm their way out of it.
5: I've had 3 insurance claims and everytime they come take a photo of the tyres to see if worn tyres can save them some money. Nothing said about size.
6: I actually feel the 280 pulls better on the bigger tyres, but that is what Fluffy would call "a subjective opinion"

Just go forth and fit what makes you happy. The 4.5 will not notice it.

Thank you for this very helpful response - much appreciated! No offense taken either

I really like the advice about getting tyres that are readily available - I've recently read that somewhere on this forum while digging around. What brands would you suggest are a common brand and size around Southern Africa?

[RogueFrontier]

"My Kumho muds have a thread depth of 22mm. "
Really?

Sigh. Dont believe everything you read.

You made me get the vernier out and measure my unused spare. 15mm deep. That still makes makes it 30mm (1.25 inch) shrink over it's life.

It also bugs me to get stuff that wrong and I found the culprit.

http://www.fourwheeler.com/how-to/08...ff-road-tires/

Looking at the spec sheet, it is supposed to be 22/32 inch and the article says 22mm. I guess the metric system still confuses the yanks.

[RogueFrontier]

Thank you for this very helpful response - much appreciated! No offense taken either

I really like the advice about getting tyres that are readily available - I've recently read that somewhere on this forum while digging around. What brands would you suggest are a common brand and size around Southern Africa?

Sorry, but I dont know what is popular across the border. It is too far from CT!

Maxxis is however a solid choice. There are many happy users here on the forum. Brand I believe is less important than a popular size. Any brand will get you home, but you are stuck if size is wrong.

[babweupatree]

Sorry, but I dont know what is popular across the border. It is too far from CT!

Maxxis is however a solid choice. There are many happy users here on the forum. Brand I believe is less important than a popular size. Any brand will get you home, but you are stuck if size is wrong.

I've been looking at the Maxxis MT764 for some time now. That VS Cooper STT Pros - both similar price. Jesus, I've even gone as far as researching Achilles Desert Hawk MTs for the cheapness of them and it's just a damn confusing world out there. So price is a concern but reliability is a bigger concern. I choose the brand that has the best overall feedback based on my searches and I've come to the point where it's either Maxxis or Coopers.

My current tyres are Goodyear Wrangler ATs - almost turned into racing slicks now. I have not had one puncture or problem with them. I've driven them over all kinds of terrain - not so much black mud and when I did they weren't much fun. I had a look around at their muds and they are about R1,200 more than the Maxxis or Cooper per tyre and I want to get six for my next set.

[Disco-Deon]

Your tyre size change should not make much difference.
Moving from AT to Mud will have more effect than the actual tyre size change. Some beautiful music and heavier tyre and tread not conducive to fuel consumption.
MAXXIS 764's are BRILLIANT and even I could not destroy these tyres on 2 of my Discos.

[Garreth G]

Go with the 265 75 16 Maxxis 764, you won't be sorry. I had them on two of my 4x4's. Best tyre I have every bought.

I would not worry about what's in Africa or not. But saying that, good luck with finding those 285's and 315's in Africa to fit your van and still be able to travel on them.
The point is, go better prepared, don't carry one spare carry two or 3. The best was to travel is being properly prepared.

[babweupatree]

I'm going with the MT764s! Thank you for all your replies, much appreciated!

[Disco-Deon]

I still have 1* Maxxis LT265/70/17 MT764 - never been on the road, spare was never needed.
Give me a shout if interested.
082 832-7620

[bfreesani]

1" up makes nearly no difference to the speedo or performance, and I'm basing that on my donkey 2.7TD performance. As mentioned, the aggressive MT's tread will probably be a bigger factor in fuel consumption than the "loss of power" due to the gearing change.

When I went to 31", 2" bigger than stock, my Hardbody was spot on with the speedo. Another 2" bigger on 33's and I am over speed by around 12km/h at 120 on the clock. Now getting ready to go another 2" bigger with 35's, and will probably end up just blanking off the speedo, and watching the GPS...

[babweupatree]

I still have 1* Maxxis LT265/70/17 MT764 - never been on the road, spare was never needed.
Give me a shout if interested.
082 832-7620

Thanks but that is the wrong size. I've already ordered my set of 6 x 265/75/16s (only 11 in stock!). Really keen to try them out on the trails!

[RogueFrontier]

Thanks but that is the wrong size. I've already ordered my set of 6 x 265/75/16s (only 11 in stock!). Really keen to try them out on the trails!

Do report back how you find the Maxxis.