is lite really = better or is it a myth?

the frog

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everybody seems to accept the concept which says "lighter = better" for all vehicles, for offroad cars and especially for race cars like desert racers.

is it really right or is it a mith?

can anyone prove it mathematically?

and if it is right, why do all TTs weigh at least 5000-5500lbs??

obviously, it should not be a problem for those expert designers and builders in America to build 2x4 TTs as light as 3500-4000lbs and even much less, using all those exotic metals and tubes, chromo axles, aluminum engines, etc. etc.

is there another hidden reason why all those TTs weigh that much?

or is it that a heavier car running a 800hp motor is better than a lighter one??

i wonder
 

trent06

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Re: is light really = better or is it a mith?

I cant really answer your question, BUT I do have an opinion for this, I dont see the 5000-6000 pound Trophy Truck being at a disadvantage to the other trucks or class ones, where I see weight being the biggest disadvantage is in class one. Not for class ones racing against class ones, but for class ones racing for the overall. I understand starting 70 deep in the field you are already at a huge disadvantage, in a class one lacking the rear wheel travel of a Trophy Truck you have really got to focus on your strengths, which I always believed was in the narrow, tight, twisty stuff trying to be nimble. It seems most class ones now are going away from their strengths and getting heavier and heavier, but still lacking the rear wheel travel, where it can almost seem the exact opposite for some Trophy Trucks now, and that they are getting lighter. I am in no way a qualified person to really talk about the strengths and weaknesses of buggies, but it almost seems to me that one could take an older class one car with a good HP/Weight ratio and do better then alot of the newer heavier cars being built? Maybe some of the "buggydorks" can chime in and really answer my thoughts better? Along with what The Frog was interested in.....

P.S. Just another person looking to join the "Country Club" shortly!:eek:
 

the frog

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Re: is light really = better or is it a mith?

maybe it is really a qestion of weight : hp ratio and when the ratio is right/good, then weight not only not being a detriment but even may be an advantage??

i simply cannot find any other explanation for the known fact according to which all TTs weigh +/- 2.5 tons :confused:
 

Atombomb

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Re: is light really = better or is it a mith?

Lighter is better anytime inertia is involved. Whether it be on-road, off-road, airplanes, or motorcycles. Almost more important to overall vehicle mass is mass placement.

The reason off-road vehicles are so heavy is............. the wheels and tires.

if we can build a wheel and tire package that weighs >50 lbs, as opposed to 150lbs, a trophy truck could weigh 3500lbs as opposed to 6000lbs.
 
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Re: is light really = better or is it a mith?

Atombomb nailed it. It's the sprung vs. unsprung weight ratio that is all important.
 

the frog

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Re: is light really = better or is it a mith?

The reason off-road vehicles are so heavy is............. the wheels and tires.

if we can build a wheel and tire package that weighs >50 lbs, as opposed to 150lbs, a

trophy truck could weight 3500lbs as opposed to 6000lbs.

my desert racer runs 37"s on steel rims and each wheel weighs105lb, that's all.

the expensive TTs run light aluminum rims and even with 39.5" tires, those wheels do'nt weigh much more than 110lb if at all.

sorry, but this is definitely NOT the reason for this masive weight of the TTs.

even if it was, 150lb wheel cannot be the reason for a 2500lb gap.

so, i'm still in the dark here....;)
 
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Re: is light really = better or is it a mith?

Compare a lightweight buggy and the Landshark hitting a small bump. In the buggy, the front of the car reacts, in the truggy, the SUSPENSION reacts.

The suspension needs sprung weight to work. And remember, it's not just the wheel and tire that is unsprung.
 

Atombomb

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Re: is light really = better or is it a mith?

my desert racer runs 37"s on steel rims and each wheel weighs105lb, that's all.

the expensive TTs run light aluminum rims and even with 39.5" tires, those wheels do'nt weigh much more than 110lb if at all.

sorry, but this is definitely NOT the reason for this masive weight of the TTs.

even if it was, 150lb wheel cannot be the reason for a 2500lb gap.

so, i'm still in the dark here....;)

Yes, a 39" wheel and tire package can and will weigh upwards of 150lbs..... I have a 37" toyo package on T/R wheels sitting here and they come in at 137Lbs each.

All because you do not understand the answer, does not mean that it is not the correct answer.
 

Wild bill

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Re: is light really = better or is it a mith?

Weight matters in two ways. First, you need enough HP to push the weight (HP/weight ratio). I feel anything over 8 lbs./HP is either too heavy or underpowered. Second, where the weight is located matters. I feel 40/60 to 50/50 ratio is ok. Anything over 50% of the weight on the front end will eventually cause problems.
 

Scott_F

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Re: is light really = better or is it a mith?

The greater the sprung to unsprung ratio, the better the suspension can work. The lighter the unsprung weight, the lighter the sprung weight can be.
 

Shannon

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Re: is light really = better or is it a mith?

Bigger car+big parts=heavy=more hp needed( to go fast)=bigger parts(so it doesn't fall apart)=more weight=the most hp possible(so you can go faster)=biggest parts=lots of $$$$!!!! what a circle jerk!!!!!
 

Baja Fool

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Re: is light really = better or is it a mith?

Atombomb nailed it. It's the sprung vs. unsprung weight ratio that is all important.
The issue of sprung & unsprung weight is one that the off road motorcycle industry has dealt with from the beginning. While they have coped well, it is really because the threshold of the unsprung weight it had to deal with was far lower than anything we may see in a TT, Class 1 , et al. Aluminum, titanium, magnesium, chrome moly steel are all wonderful but as strong and light as these materials are, the fact is; even without wheels and tires a Trophy Truck is one heavy mother and is capable of inflicting tremendous forces on any and all pieces attached to it.

BTW, Great post.
 

motorhead

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Re: is light really = better or is it a mith?

sorry, but this is definitely NOT the reason for this masive weight of the TTs.

even if it was, 150lb wheel cannot be the reason for a 2500lb gap.

so, i'm still in the dark here....;)


You missed Atombombs concept. He is not claiming the tire weight is directly responsible for the 5000+ lbs. vehicle. He is claiming the heavier the tire, rear axle, hub, brakes (ie. unsprung mass) the heavier the chassis, motor (ie sprung mass) must be, in order to keep the vehicle stable through whoops and uneven terrain. When one of the tires encounters an impact it cause a force to be applied on the sprung mass, causing a more severe jolt on the occupants the lighter the sprung mass. This is a perfect example of Newtons laws of motion. Hopefully I expliained the concept well enough, I remember the first time someone explained it to me, it opened up a whole new set of compromises to be considered during the design stage.

If you want the vehicle to perform best in strait rough terrain, a big tire and a hefty sprung weight seems to make the fastest vehicle. If you want the vehicle to be responsive and nimble you will have to compromise stability in rough terrain.
 

randy68

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Re: is light really = better or is it a mith?

Ditto on the great post!
 

TauMau

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Re: is light really = better or is it a mith?

There's an aged (few years) class 1 running that weighs around 3500-3800 lbs and gets away running a pump gas LS1. It's able to be competitive due to it's weight. It'd be even more so if it had a stronger motor, but at San Felipe it proved it's capable of hitting the podium.

For a TT I don't think weight is the "deciding factor" but will certainly contribute to the outcome of overall performance...easier to turn, easier to stop, easier to set in motion...easier on all the parts, tires, etc. Unless someone offers up a compelling argument to the contrary, I couldn't conceive any reason why more weight would be an advantage unless there is a functional/structural advantage tied into it. Taking into account the ratio of sprung/unsprung weight of course...
 

bajaxp

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Re: is light really = better or is it a mith?

I agree...great thread! Frog guy...the thing about wheel weight that you might be missing is race tire weight vs regular off road tire weight, bead locks vs non, and the weight of the bead lock bolts (maybe 5 - 10 lbs depending on wheel diameter)

I have wondered about why the buggies and trucks keep getting heavier (in general) and not lighter. I have thought about Rob Mac, while obviously a great driver, being able to get top 10's against unlimited vehicles in a 1500 lb 80 hp limited 1/1600. How would he do in a 150 hp vehicle of the same weight? He would probably break! Because he would hit stuff that much harder.

I also agree with the 'circle jerk' comment. When something breaks, we reinforce it and it becomes heavier...which in turn inflects more damage to the car...think of a heavier hammer being able to do more damage than a light one. It becomes a vicious circle.
 

Zambo

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Re: is light really = better or is it a mith?

Frog, imagine a wheel all by itself rolling down the course at speed, not attached to anything. It would hit the first decent size bump and fly 30 feet in the air. You need weight in the vehicle for the springs in the suspension to push against and keep the wheels planted on the ground.

The bigger the tire you run the better it smoothes out the bumps. Imagine the angle that a 39" tire hits a six inch rock at compared to the angle that a 20" tire hits that same rock. Big tires are heavier than little tires. Not only does it require more weight in the truck to hold the tire down when it wants to bounce up, but the axles, mounting points, and everything else has to be bigger and stronger (and heavier) to prevent damage due to the mass of the wheel and tire. Then since the truck is now heavier the motor has to be stronger to make it go fast, and stronger motors are usually heavier, and on and on.

Like atombomb said in his first post, at the end of the day the weight of the truck is the eventual result of the size and weight of the wheels and tires. If desert racers weren't limited to 40" tires, I have no doubt somebody would be trying to race a 10,000lb truck with a 3000hp turbojet engine driving 60" tires.
 

nimrod

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Re: is light really = better or is it a mith?

It takes an absolute tank to run the speeds that TT's do over the rough stuff. They are built to run 95 mph all day over 3 to 4 foot whoops. No way a buggy with IRS can do that. No way the transmission in a TT can do that either (at least not ALL day) but the rest of the truck is fully up to it. (okay the third member might not dig it all day either) It's not so much about just building a heavy TT. It's about building one that is as light as possible but can take the punishment of running faster than any other vehicle on earth over the roughest terrain imaginable.

I am a Buggy Dork, my dream car is a Class 1. I love lighter and nimble......My dream buggy would probably have some little light weight Subaru naturally aspirated boxer 6 cylinder motor in it for the lightest and lowest center of gravity possible.....See what I mean I'm a Buggy Freak!

However, A Trophy Truck is the Formula 1 car of the off-road world. They are the baddest off road machines on the face of the earth....PERIOD!

You really need to come on over here and stand on the side of the course as one of those things goes blasting by.........INSTANT GOOSEBUMPS!!!!!

Happy Birthday Israel.
 

trent06

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Re: is light really = better or is it a mith?

It takes an absolute tank to run the speeds that TT's do over the rough stuff. They are built to run 95 mph all day over 3 to 4 foot whoops. No way a buggy with IRS can do that. No way the transmission in a TT can do that either (at least not ALL day) but the rest of the truck is fully up to it. (okay the third member might not dig it all day either) It's not so much about just building a heavy TT. It's about building one that is as light as possible but can take the punishment of running faster than any other vehicle on earth over the roughest terrain imaginable.

I am a Buggy Dork, my dream car is a Class 1. I love lighter and nimble......My dream buggy would probably have some little light weight Subaru naturally aspirated boxer 6 cylinder motor in it for the lightest and lowest center of gravity possible.....See what I mean I'm a Buggy Freak!

However, A Trophy Truck is the Formula 1 car of the off-road world. They are the baddest off road machines on the face of the earth....PERIOD!

You really need to come on over here and stand on the side of the course as one of those things goes blasting by.........INSTANT GOOSEBUMPS!!!!!

Happy Birthday Israel.

Insert Hector's class one here for you! You have your dream car, the best of both worlds, and even a seat to throw an additional donkey in with you Nim!!!!! Isnt it nice to dream!:D
 
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