What is your experience with significant increases in unsprung weight and rotational mass?

[jreichek]

What is your experience with significant increases in unsprung weight and rotational mass?

I have been doing a bit of research regarding the issue of Hutchinson beadlock wheels for my vehicle a 2005 Lexus LX470 (same as a 100 series Landcruiser). (For a 2 page thumbnail picture gallery of the vehicle with complete specifications of all the modifications on page two please visite www.reichek.org/lx3v )

First I weighed an existing 285/65/18 Cooper A/T3 on one of my Lexus stock wheels (a brand new rear mounted spare). The combined weight is 87.1 lbs

Hutchinson beadlock wheels for the 100 series weigh 39.4 pounds each.

Cooper AT/3 XLT 305/70/r17 tires weigh 61 lbs. (combined weight 100.4 lbs)

Cooper AT/3 XLT 285/70/r17 tires weigh 56 lbs. (combined weight 95.4 lbs)

That is either 8.3 lbs per corner or 13.3 lbs per corner of additional unsprung weight and worse yet -rotational mass.

with 4 corners, that is either 53.2 or 33.2 lbs of additional unsprung weight.

At a rule of thumb of roughly a 10:1 ratio of effect between sprung and unsprung weight (and even higher ration of effect for rotational mass), upon mileage and handling (and a 3:1 effect on acceleration, and braking) -- assuming this is a reasonable rule of thumb, that is equivalent to adding between 332 lbs and 532 lbs to the sprung vehicle weight (and even more to the rotational mass)

The "math and science" of unsprung weight

https://www.cjponyparts.com/resources/what-is-unsprung-weight

What is your experience with these kinds of significant increases in unsprung weight and rotational mass?

Best regards and respects, Joshua

 

[unklwedy]

You probably won't even notice any change. Landcruiser is not a Ferrari.

 

[highonpottery]

Besides a drop in fuel economy, acceleration and braking? Maybe sore cheeks from smiling so much now that you've got a blinging wheel setup?

 

[FxFormat]

It's nothing bad, terrible fuel economy, woh woh woh woh noise on the highway, braking takes longer, acceleration is civic-like, tire rotations will herniate your discs, more stress on balljoints, bearings, control arms, etc...

Is it worth it? hells yeah

 

[atnolan94]

It's nothing bad, terrible fuel economy, woh woh woh woh noise on the highway, braking takes longer, acceleration is civic-like, tire rotations will herniate your discs, more stress on balljoints, bearings, control arms, etc...

Is it worth it? hells yeah

100% worth it.

 

[geanes]

You lost me when math got involved. I run 275/70/18 KO2 (60lbs) on Vision Rocker 18 (33lbs) for a total of 93lbs/corner. My LX doesn't feel any slower than when I had the 82lbs/corner setup. Of course, my rig has always felt slow

@ikarus would probably have excellent feedback as he runs the Hutchison Beadlocks on his LX.

 

[abuck99]

Cooper 285/75-17 ST Maxx??

 

[gwatts]

My data points

Stock 16" with Duratracs were 33" & ~80#
Stock 18s from a Tundra + Cooper SST Pros were 34"+ & ~100#

Big difference and older OME shocks made it worse. Bumps were harsh, stops were slow and acceleration over 10,000' mountain passes was anemic. Maybe if you live where it is flat and no passes above 5,000' the penalty might be worth it. It was not for me. I then went to 17" TRDs with 34" Nitto RGs and I am back ~85# I believe and accel/decel are improved. Plus Ironman Foam Cell Pros.

Since then I have re-geared to 4.88s and now it feels way normal again. When I switch back to Duratracs (smaller diameter too) for a winter Alaska trip and drop to sea level, I expect it to feel much quicker.

 

[ikarus]

Yeah, agree with everyone else.

Like everyone said, acceleration and braking takes a hit. And yes, I'm sure it's stressing my components - I just replaced my steering rack and will be replacing my UCA ball joints. I drive more slowly everywhere and leave more of a gap in front of me. It's made me a safer driver. ha. Part of that, of course, is the tire size - I'll be installing 4.88 gears soon.

Gas mileage is around 10-12mpg. Get about 240 miles out of a tank

You just have to decide if it's worth it to you. I do probably 50-100 miles offroad a month and often work in the desert or mountains, with another 300 miles/month on pavement. If I had to drive more I'd probably have different wheels. Or two sets of wheels, or a daily driver.

Aside from the weight, regular tire shops won't touch them and you may need to find an offroad shop to even balance them
If it leaks, you'll have to tear down the tire and replace the O-ring. Had to do that on one wheel the week after first installing them.

Also you'll need a torque wrench and tire bead breaker. Some would probably think it's a headache, but I love them for my use. 8-10 psi offroad feels amazing - almost more comfortable than on road. Better grip, too - and you could theoretically run lower than that, especially in deep snow or sand. I like them so much that if I were to do a SAS I would try to use 105 hubs and keep it 5x150. (I prefer the look of these over the 6x139.7 Hutchinsons)

Anyway, lots more info over in my build thread if you're interested:

Builds - Ikarus' LX470 Offroad Build and BS

Current state: I had a Tacoma for several years but eventually decided I needed cab space instead of bed space. Was an awesome truck - lifted, 33s, front and rear lockers, compressor, regeared to 4.88s, skids, front bumper, snorkel, rear tire carrier, etc: I'd always loved Land Cruisers...

forum.ih8mud.com

 

[krice118]

Considering sqitching from my ~92lb set up - TRD (Silver/ black 18s) and 275 70 18 set up to 16 or 17 with 255s. This would shed about 13lbs per corner. IS this worth it?

I am hoping to get a little more pep back..... I know this is the wrong rig for mpg but another 1-2 would be nice for a little further range.

As a refrence point, I will say that going from my 285 75 16s to the 275 70 18s had a noticeable impact. Before I was able to climb Teton Pass and gain speed. With the 18s (heavier wheels and tire) I could hardly maintain speed up teton pass.

 

[nissanh]

Higher weight makes anything difficult to get up and go.

 

[FxFormat]

Considering sqitching from my ~92lb set up - TRD (Silver/ black 18s) and 275 70 18 set up to 16 or 17 with 255s. This would shed about 13lbs per corner. IS this worth it?

I am hoping to get a little more pep back..... I know this is the wrong rig for mpg but another 1-2 would be nice for a little further range.

As a refrence point, I will say that going from my 285 75 16s to the 275 70 18s had a noticeable impact. Before I was able to climb Teton Pass and gain speed. With the 18s (heavier wheels and tire) I could hardly maintain speed up teton pass.

Unsprung weight esp from the wheels and tires has a huge impact on accelerating, braking, cornering etc... we were never able to calculate unsprung weight to static weight but it's something around 5x .. so shedding 52lbs all together you're essentially removing 250lbs or so off the vehicle.

 

[krice118]

thanks all. I am wondering if it is worth the $ and time to swap / sell existing setup. Tires dont need to be replaced but It would be nice to have a lighter setup. I am always looking to improve. but I did just get sliders and a rear bumper so I may put tires off until next year.

 

[trdcorolla]

thanks all. I am wondering if it is worth the $ and time to swap / sell existing setup. Tires dont need to be replaced but It would be nice to have a lighter setup. I am always looking to improve. but I did just get sliders and a rear bumper so I may put tires off until next year.

I run a 33" load c tire on 17's (71lbs total) and I didn't like how my 100 drove (4 speed tranny). Drove like that for 2 years then regeared to 4.88's. It made it driving a lot better, regearing also lowered my transmission temp on the streets. I have a 1/4" front lift, stock rear height, front/rear bumpers,, sliders, winch and skids. I don't think saving 13lbs will help you much on the freeway. Our 4 speed tranny's just don't have the gearing for these big tires. Just a little FYI from my experience, i'm contenplating going to a 34" tire (+5lbs) when my 33's are done (in about 2 years), not much info about 34's on 17's at stock height here on mud.

 

[FxFormat]

I run a 33" load c tire on 17's (71lbs total) and I didn't like how my 100 drove (4 speed tranny). Drove like that for 2 years then regeared to 4.88's. It made it driving a lot better, regearing also lowered my transmission temp on the streets. I have a 1/4" front lift, stock rear height, front/rear bumpers,, sliders, winch and skids. I don't think saving 13lbs will help you much on the freeway. Our 4 speed tranny's just don't have the gearing for these big tires. Just a little FYI from my experience, i'm contenplating going to a 34" tire (+5lbs) when my 33's are done (in about 2 years), not much info about 34's on 17's at stock height here on mud.

Which wheel do you have that weighs 21lbs? lightest 33" load C is 50 lbs, i'd love to have that combo. I'm running 84lbs wheel/33" tires

 

[trdcorolla]

FN Wheels Five Star 17x8 +30. I bought them in 2017, not sure if they are still available.

 

[FxFormat]

Very nice, thought you'd have to get Volks and pay a crap ton to get a 21lbs wheel, good stuff.

 

[OwnerCS]

I went in the opposite direction and reduced wheel and tire weight. Sill running eRated tires with SCS F5 rims.

Stock wheels with Nitto Terra Grapler tires 285/75R16 weigh in at just over 75lbs.

SCS F5 wheels with Cooper Evo MT 285/75/R16 eRated at 72.4 LBS No complaints with braking, accelleration, or hills. I drive in the mountains with OD turned off.

 

[scrt80]

FN Wheels Five Star 17x8 +30. I bought them in 2017, not sure if they are still available.

They are coming back. I hit them up on IG about it. Sometime soon.

 

[LostAfrican]

Don’t forget to use the ECT (Extra Circumference of Tire ) button to compensate for those larger wheels!

It makes it drivable again and a lot cheaper than regearing, especially for those of us 4-speeders.