Confusion, contradiction and dismay....

[mud4fun]

OK, I've got my Avante 2001 (my dream car as a teenager) up and running, was due to start some performance testing against a Terra Scorcher but had a few problems:-

Now, I must be crazy or just stupid but the Avante 2001 is a total contraction. It is marketed as a buggy, it looks like a buggy but it handles like a touring car and is about as robust as a piece of Balsa wood!!! So I'm confused, is it a buggy?

if so why did Tamiya come up with the worst suspension articulation of just about anything I've driven with the exception of a group C which doesn't have any. Buggies need long travel suspension to soak up bumps and also why go to the trouble of designing those gorgeous suspension arrangements that look like works of art when a simply wishbone would have worked OK with such short travel? not to mention the stupidly harsh shocks which cause bounce.

Then the car is fitted with diffs front and rear AND a ball diff in the center, this is pure road racer stuff and totally over the top for a buggy. To get traction off road you don't need a center diff. I fitted a Dyna Run Super Touring motor to mine and modified the chassis to take 8.4v packs. The torque of the motor kept the car standing in one place because of that center diff. I had to lock it up completely to get traction and motion!

Next problem, the motor mounting is a joke, very fiddly just to get the motor in the car and even worse to get decent pinion alignment you have to take the gearbox cover off which also means removing the rear wing.

Next problem, the steering is far too quick for a buggy, I prefer understeer if anything but this oversteers very badly.

Then I finally got the car running and it lasted just 2 laps of my track before the rear hub snapped off its hinge pins, it was a brand new hub with no cracks or damage. I put in my last spare and guess what, a couple of dozen laps later both the front and rear hubs sheered off when I swung around a corner over a 1" step in the ground. My Terra Scorcher has done over 1000 laps without damage on this same ground! The suspension arms and hubs are not robust enough for use over even mildy rough ground. In fact TL01 arms and hubs are stronger!

I apologise for the rant but I'm gutted, gobsmacked and dismayed at the poor overall package which was my dream car. I've never had a vanquish or Avante 2001 until now, I couldn't afford one when they came out so I got a terra scorcher instead. I've always been told these things are star performers but obviously anybody that has run them is either an exceptional driver or they haven't really run them over rough ground.

On a positive note the Avante 2001 is exceptionally quick with a Dyna Run ST, 8.4 and 18t pinion. It is stable at speed on the flat and corners very well after you get used to the quick steering. It can corner very quickly compared to a terra scorcher. On tarmac it is both quicker and better handling than my stock group C chassis and it out performs the TL01 tourers by miles! Once I get the thing fixed again I'll hopefully get some test results done but initial timings suggest that it will be the fastest car tested yet and by far the best handling on the flat. On the rough it is outclassed by the Manta Ray and Terra Scorcher and on robustness it is outclassed by even most QD Tamiyas!

Has anybody else had similar problems with this car or is it just me[][]

[sosidge]

Well I raced one for a couple of years and it felt fine to me back then. Don't remember breaking much, maybe a few of the front uprights.

But I was a child.

[GPZ1000RX]

My sons don't remember the racing breakages either, probably because I bought all the parts and did all the spannering!!!

[WillyChang]

Bear in mind things have changed over the years, such as:

1) tracks these days are "blue groove", whereas back then it was

all loose stuff & it changed as the raceday wore on.

2) you can put skinnier front tyres say from Hotshot or Vanquish

if you have too much steering.

3) plastic has aged.

[Lucodeath2]

You have shattered my childhood dreams!

The Avante 2001 is one of the cars I have always wanted.

I will have to settle for an Egress now.Im glad I have a Terra Scorcher though.

Luke

[mud4fun]

quote:plastic has aged.

id="quote">id="quote"> Do you think that is possible WillyChang? I was surprised myself, the replacement hubs I fitted were brand new still in wrapper and they broke with same problem. In fact all the suspension arm/hub pivot points are showing cracks after just 15mins use. I don't have this problem with my thundershots? Most of the TS parts are many years older than the Avante2001.

Hi Luke - don't get me wrong, the car still remains beautiful and fast over the flat. I was just surprised at the lack of articulation, there is only 12mm travel on the front wheels (the terra scorcher has 30mm!!) not much better at the back end where there is more travel but the suspension doesn't seem tuned. It rides harsh on rough ground causing bounce but bottoms out too easily on jumps! I will try and make a replacement front shock tower so I can fit longer shocks, that should help lots.

Next time we meet up at Clumber you can have a go for yourself. You know that stretch of track that we were racing up and down? well the Terra Scorchers and Thundershots could remain in a straight line even at high speed over the pot holes, this Avante would really struggle because it is almost like a pan car on big wheels - likes it smooth!

I've got a VGC vanquish due to arrive here in a week or so, that uses the same suspension and hubs. I'll see if that fairs any better.

[mjohnston39]

Couple of points in no particular order:

1. You can replace the center diff with a center 1-way or a locked unit.

2. IIRC these cars were designed for smooth tracks which didn't require a great deal of suspension travel.

3. As WillyChang suggested get some narrow front tires to remove a bit of the oversteer.

4. These cars are fragile, not much you can do about it. Unfortunately parts are horrendously expensive and difficult to come by as I'm sure you have/or will find out.[]

Mike.

[mud4fun]

Cheers Mike, that explains things. I'll try the narrow tyres up front, center diff is fine now since I locked it up, I'm guessing previous owner was running quite a mild motor so the open diff causes no problem.

Parts are indeed difficult to find and very expensive but strangely I have managed to get a complete VGC vanquish for £65 which is cheaper than buying individual parts. I've also seen quite a few vanquish/Avante2001 go for not much money on ebay. I assume people don't want them as parts are so rare? or they know the cars are not that robust? Terra Scorchers have gone for more money![:0]

I believe the weakness of the rear hub is simply that unlike nearly all other Tamiya rear suspension units the Avante2001 has two individual shoulder screws from both sides whereas most other cars use a single long pin. The single pin provides more robustness in minor impacts. I understand the reason why Tamiya did this - it reduces weight and number of components because the rear hub is also the rear lower arms and the drive axle runs along the center line of the hinge point making it impossible to fit a full length suspension pin.

[oldfrogshot]

Hi, Ian!

If you'd bought it from another owner, then perhaps he might have used the wrong lubricant on the arms? I remember on my old 1:35 scale M60A1 tank, I lubricated the idler wheels with sewing machine oil and the arms started breaking, and kept on breaking! I was about 12 yrs old at the time...

Cheers,

Don

[mud4fun]

Hi Don, I think even at age 36 I still wouldn't have known sewing machine lube would 'corrode' plastic!! []

Only reason I'd say that this wasn't the case here is that when I got the car one of the rear hubs was already broken so I replaced it with a brand new one. That broke and I replaced it with another NIP one. The two NIP ones had come from different sources on different sides of the world!

Although having said that, I have noticed that all 3 broken hubs have the same dark green hint of colour in them whereas all other plastic parts are very black??? maybe they were made of a different quality plastic?

[mud4fun]

UPDATE:

Fitted Terra Scorcher yellow CVA' front and rear with medium springs and schumacher 30 grade damper oil. Ride and handling have improved dramatically, it used to bounce out of control when you hit a small bump or stone but now it rides alot more smoothly - a completely different car. [8D][]

Re-located front upper control arms to top hole in front hub which induces mild bump steer in corners, this has solved the severe oversteer problem!

Changed servo horn and steering rod geometry which has also helped slow the steering a bit.

Made my own 'bodge' fixes to rear hubs (pics will be in showroom later) which involve a couple of bits of aluminium bar and some biscuit tin....hubs are now REALLY strong and haven't broken after an hours hard abuse around the track, why Tamiya couldn't have done this in the first place????!!!

Changed the wheels and tyres (Cheers for that suggestion guys) to CML wide rears/narrow fronts and corners even better, approaching neutral steering with just a little oversteer. []

What a difference some small changes and modifications make. The front suspension has almost double the travel compared to a stock Avante2001, the rear is now more subtle and less bouncy too. I don't understand why Tamiya never made it like this in the first place! [:0]

[grusomkis]

I guess for the price of a decent Avante you can buy a Real off road buggy like the Losi XXX-4.

[WillyChang]

Hey Don, how about machining up some Avante front knuckles?? [8D]

quote:

Originally posted by mud4fun

What a difference some small changes and modifications make. The front suspension has almost double the travel compared to a stock Avante2001, the rear is now more subtle and less bouncy too. I don't understand why Tamiya never made it like this in the first place! [:0]

---

id="quote">id="quote">

Egress has high shock towers; original Avante's laydown shocks looked good but were probably too laid down to do their job.

Got this Egress that saw some racing; previous owner/s have put on custom shock towers that are even taller than standard. They stand the shock up more. Stock "platinum" shocks work fine like that, springs can be softer (non-standard).

Runs great at the beach.

[oldfrogshot]

You've got to wait til I've finished my Sshot first!

[mud4fun]

quote:I guess for the price of a decent Avante you can buy a Real off road buggy like the Losi XXX-4.

id="quote">id="quote"> Very true Grusomkis but problem is I'm a sucker for Tamiya! Plus the fact that this was one of my 'dream' buggies when I was younger

quote: Hey Don, how about machining up some Avante front knuckles??

id="quote">id="quote"> WillyChang, surprisingly the front knuckles haven't broken on mine (yet), the main weakness was the rear hubs/uprights which crack around the 3mm shoulder screws the hold them to the rear arm. The only other breakage has been the front lower suspension arm which cracked in similar place where it mounts to the chassis. My bodge fix to the rear arms has lasted well, was out with it for another hour or so last night and still no more breakages [8D] Ideally I'd like the rear uprights machined out of solid aluminium and that'd sort me out!

quote:Egress has high shock towers; original Avante's laydown shocks looked good but were probably too laid down to do their job.

---

id="quote">id="quote"> Absolutely spot on, the lay down shocks only work on tarmac. I've already decided to make my own new shock towers, will be done today hopefully so I can fit long travel shocks up front. Although the car still bottoms out quite a bit over the rough as it doesn't have anything like the ground clearance of a Terra Scorcher.

Interesting point now, after fitting the CVA shocks, softening the springs and damper oil and adjusting the geometry of the front suspension I have ironed out all the oversteer to the point where I've actually got some understeer! Car powerslides beautifully into corners now and is real easy to pull out square with a blast of throttle - chuffed to bits [8D][][]

Now if only I was a decent enough driver to use it to its full []potential......

[tanker(2)]

OK, some of the 1/10 buggies has only front and rear differentials. Only the older one has a middle differential. however, almost all 1/8 gas buggies has middle differentials. My question is; how does middle differential affect handling?

[mud4fun]

A centre diff is ONLY required on high traction surfaces and is therefore worthless off road.

The reason it is there is because the front and rear axles rotate over differing radius and therefore rotate at slightly different speeds. With no center diff it would put strain on the transmission possibly causing failure of the propshaft or gears.

Most full size 4WD's also have center diffs, EVERY 4WD with permanent 4WD must have one, however they also have some way of locking it up for off roading.

On a lightweight buggy it is not required because the 'wind up' in the transmission will simply spin out over loose ground. On early series Land Rovers they had no center diff so 4WD could only be used on low traction surfaces. I tried to use it once on the road and the 'wind up' caused a massive spin out of one of the wheels which almost put me off the road!! []

The center diff has several drawbacks, it is extra weight, extra resistance in the drivetrain and without being locked up can result total loss of drive/traction if just one wheel lifts off the ground. As you'll know if one wheel lifts on an axle all the power goes to path of least resistance, ie: the wheel off the ground, this is why we have locked diffs for off roading. If you imagine a center diff as well, when one wheel on ANY axles lifts all the power goes thru the entire transmission to the one wheel leaving the vehicle stranded. To gain maximum traction on rough surfaces you should lock the center diff and tighten or lock the rear diff.

The effect on handling would really only be noticeable on high traction surfaces were you would suffer slight understeer with no center diff. I guess the heavier 1/8 buggies may need it because the extra weight and power would tend to put more strain on things and give higher traction so not allowing the stress to escape without risk of breakage. To be honest, I've driven the Avante2001 with the diff open and locked, I much prefer it locked as the car has more traction and therefore more speed. It also acts like a clutch and in my case I fitted a motor that was maybe twice as powerful as the stock kit one. This resulted in the center diff slipping like a clutch and not allowing full power thru to the wheels.

[WillyChang]

quote:

Originally posted by tanker

...almost all 1/8 gas buggies has middle differentials. My question is; how does middle differential affect handling?

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id="quote">id="quote">

1/8 buggy's centre diff has brake discs on BOTH outdrives, so you have a separate brake for F & R. You can use these to setup a brake-bias that affects your handling eg stronger rear brakes for more on-brake cornering.

But if you have 3 diffs and none are LSDs, just lift 1 tyre and the whole car "diffs out". Torsen or silicone-filled diffs reduce this.