Pros and cons to oversize tires (1 Viewer)

[ElementalE]

I am new member to IH8MUD, but have been a ghosting member for about a year now. I will post some pics of my 03 LC soon. But I just wanted to drop-in an interesting thread here about oversized tires. I have oversized tires on my LC and absolutely love them. Here are a few pros and cons (subjective) to oversized tires:

1. You are traveling a lot faster at high speeds, the discrepancy in odometer reading to true speed is exponential (calculate it using math). I also learned the hard way when CHP pulled me over for going 103 mph lol. Some people will actually get their vehicle re-calibrated.
2. You are recording less mileage to your 100 series
3. In turn, it's going to show that your gas mileage is much worse, but in actuality you've traveled equal distance (with normal sized tires)
4. Easy way to get a minor lift your 100 series without spending an arm and a leg.

 

[Manhattan]

Your user name is spot on
Yes, the bigger tires = inaccurate mph/odo readings thing is well-known. There are fixes - some hardware-related, some math-related. However, if you're unable to tell the difference in 70 mph and 103 mph... neither is going to help.

By the way, I like to think of my 275/70/18s as "right-sized" and the factory size as "undersized"

 

[chrisratz]

I also learned the hard way when CHP pulled me over for going 103 mph lol.

Dear mother of pearl what did 103 feel like in the land cruiser?

 

[vcheng]

Dear mother of pearl what did 103 feel like in the land cruiser?

I have had it up to the 112 mph governed top speed many times. It is rock steady and smooth at that speed.

 

[4Beast]

As @Manhattan said, this is elemental stuff. I use the Torque ap which allows me to have both the registered and GPS (actual) speed displayed, but yes, the speedo error does not account for the 103, that's on you. Most tire size calculators provide comparisons of tire sizes, so you know what percentage difference to calculate in for mileage etc (mine is 6%, I believe).

 

[mrahc]

I also learned the hard way when CHP pulled me over for going 103 mph lol

Are you on the right forum? You sure this is a Land Cruiser you're talking about?

 

[ElementalE]

Dear mother of pearl what did 103 feel like in the land cruiser?

In agreement with @vcheng she was great! ROCK STEADY & SMOOTH at 103 mph (CHP said I was going much faster, but penciled me in for 103).

Yes @Manhattan, big difference from 70mph and 100mph but under certain county laws fines are much less when they are under 100 mph.

 

[ElementalE]

Are you on the right forum? You sure this is a Land Cruiser you're talking about?

lol yes...... but I am a safe driver ( safe driving means a combo of both aggressive and defensive driving). I don't typically speed that way unless its 911 but I was literally all alone on the freeway and felt like pushing the envelope. It was definitely a speed trap arranged by CHP planes. The CHP car came from the other direction when I was coasting at 75-80 mph before pulling me over. In any case, a learning experience to share here to prevent other "over-sized" tire owners from making similar mistakes. For you @mrahc possibly going 77 mph in a 70 mph zone.

 

[95Fantasma80]

one additonal con is bigger tires are more widely available as load E which decreases your ride comfort, you feel more of the minor bumps on the road and ride becomes harsh... due to being a stiffer 10 ply tire requiring lots of psi. I ride at 30 psi to gain comfort back but most recommend 40 for load E.

if I'd have heard about this tradeoff in research i would have researched a load c or d while upgrading to bigger tires but my research only involved whats the biggest tire without rub (33"), and which tire is best (ko2, wildpeak, etc.)

ride confort wasn't in my scope as i knew anything other that stock would sacrifice that, well it turns out i had a choice of how much i would give up and choosing load E was on the worse side of the spectrum.

 

[MongooseGA]

You can correct the speedometer with a Yellow Box module for about $120 and 20 minutes. This will also remedy a few other problems listed.

The only real 'pros' for bigger tires are better clearance/traction off road, and aesthetics. Everything else is objectively a con. Maybe there's something I'm not considering. Oh... Mine stick out past my fender and have sliders in between so, bumper to bumper impact protection from people trying to change lanes without my permission.

I've had mine (since lift and putting on 34s) up to 95 or so (corrected) while running 'somewhere in Mexico'. With the heavy sidewall tires and firm suspension, that was about all I really needed to see. There's not much power up there anyway and it definitely feels like the drivetrain is working. But... If I was really concerned about 90mph+ travel, I've got a bike and a very large Mercedes for that.

 

[128keaton]

Hoo boy.. this is something I've toyed around in my head for a while. I had a '00 4Runner with 33s (stock size was 31s) and that sucked, especially with the load range 'E' tires.

275/65/18 seems to be a happy spot (with 275/60/18 being the stock size for my 2003 LX470) that I'm willing to purchase tires for.

(also, I had my LX470 up to 110 mph on day of purchase--was around 3.5k RPM but chugging nicely)

 

[jLB]

The only real 'pros' for bigger tires are better clearance/traction off road, and aesthetics.

Since most of the tires, in the larger sizes, are "E" rated LT tires, I'd also add durability and/or cut resistance to the "pro" column.

 

[flintknapper]

Here are a few pros and cons (subjective) to oversized tires:

1. You are traveling a lot faster at high speeds, the discrepancy in odometer reading to true speed is exponential (calculate it using math). I also learned the hard way when CHP pulled me over for going 103 mph lol. Some people will actually get their vehicle re-calibrated.

Actually, you are traveling a certain 'percentage' faster at ALL speeds. The speed does not increase 'exponentially'. For instance I went from a stock 270/70R16 to a 285/75R16 tire. An increase in diameter of roughly 5%. And went from 648 revolutions per mile down to 615 (again about 5% difference). When my speedometer reads 70 mph....I am actually going 73.5 miles per hour. A modest increase, but something you need to aware of if your habit is to run at the upper end of the speed limits.

If you were doing 103 mph and didn't know it...it wasn't because of larger tires (unless you have tractor tires on your rig). Worst case...if you had 40" tires and your (un-calibrated) speedo was showing 70 mph, you were actually doing about 85mph.

1. You are recording less mileage to your 100 series
2. Yes, fewer revolutions will result in fewer miles (on the odometer).

1. In turn, it's going to show that your gas mileage is much worse, but in actuality you've traveled equal distance (with normal sized tires)
2. Yes, it will appear that you are getting 'fewer' miles per gallon (not necessarily MUCH worse). But of course you have traveled the same distance...only with fewer revolutions of the tires. Added weight of the tires and the decrease in final drive ratio can result in greater fuel consumption (real life)
3. Easy way to get a minor lift your 100 series without spending an arm and a leg.
4. Yes. In my case, just going up one size (1-5/8" diameter difference) gave me about a 3/4" lift.

^^^^ Expand for replies.

 

[geanes]

Well, other than being the ONLY way to achieve greater ground clearance for the LCAs and rear axle, bigger tires weigh more and will impact mpg (kind of silly since we already get terrible mpg anyway). Additionally, since they weigh more, you increase the rotational weight working on your axles. 40 lb 31" passenger tires put WAY less stress on the drive components than 69lb 34" AT tires. That increased rotational weight also works against your brakes (they won't last quite as long). Just remember, rotational weight increases don't have a linear impact. It looks like an amortization table where the first few pounds of additional weight barely impact anything, but then the impacts begin to grow exponentially beyond a few pounds. Finally, if you go too big (i.e. 34" or greater), your low-range will be impacted meaning you won't have the same control when descending off-road and will very likely need to re-gear.

Ultimately, 33" (275/70/18) seems to be the common "big" size that doesn't adversely impact any of the above mentioned scenarios. That's what I run and am very happy with the compromise. I understand that my axles and brakes may have a few thousand miles shortened life, but it's worth it to me for the added clearance and off-road performance.

 

[flintknapper]

Since most of the tires, in the larger sizes, are "E" rated LT tires, I'd also add durability and/or cut resistance to the "pro" column.

Agreed. I could gotten the tire I chose in a D range...but very much like the tougher E range tires. Also on my LX I have AHC and can control the ride stiffness to some degree. Not so with my 80 series (also riding on E rated tires) but I don't expect a lot of comfort from it anyway.

 

[ga12r1]

You can correct the speedometer with a Yellow Box module for about $120 and 20 minutes. This will also remedy a few other problems listed.

The best way to correct the speedometer for larger tires is to install the correct front and rear gears. My speedometer is dead on again with 4.88s

 

[MongooseGA]

Lemme get those 4.88s from you. I'll straight swap you my yellow box

 

[MTKID]

By the way, I like to think of my 275/70/18s as "right-sized" and the factory size as "undersized"

I completely agree. 37’s are the appropriate size for the proportion of our trucks. I can’t wait to install an “oversized” tire!