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Have things really improved in chassis design?

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After spending far too much money recently on carbon chassis conversions and/or race spec buggy purchases and suddenly finding myself having to bash, run and race on our back lawn instead of the rec ground due to lockdown restrictions, I found that on a muddy/wet grassy lawn that my vintage Thundershot achieves the best lap times and the most laps when doing the latest postal racing track design.

I was curious because most of the following buggies are using the exact same motor, ESC, receiver, steering servo, tyres and in most cases even same wheels. The DT02 is using a NiMh and a Kyosho Magnetic Meyhem motor but all the other are using 2S LiPo and Dyna Run Super Touring motors. All the gearing is pretty similar other than the DT02. All the buggies have a top speed in the range 30-35mph.

The fastest buggy on the muddy wet grass by a country mile is the vintage Thundershot which is now a 35yr old design, the slowest is the carbon chassis Avante2001/Egress.

So why is this? :wacko:

Many would argue that my driving skills are so rubbish I can't take advantage of the superior chassis designs but surely if that were the case all the cars would be on the same lap counts and lap times as I had reached a maximum threshold for my driving ability? BUT the Thundershot has currently got 5 laps more than the next best chassis and is 1.5 seconds faster per lap than the next best chassis and this is on a track design that is only a 6-8 second lap time!

Many would argue that my previous historical experience of racing Thundershots means I have a natural bias to them BUT I have now done 600-900 laps of this track design with EACH of these chassis so surely I would have got used to them over that time?

So the 'pinnacle' of Tamiya chassis was the Avante2001/Egress carbon chassis which is the slowest here. It is also the heaviest of all 4 chassis shown.

Then we have the Schumacher Cougar, true it is a 2WD and you may expect it to be slow compared to a 4WD on mud BUT it was 3rd fastest, beaten by a 2WD DT02 and it is also 3rd lightest chassis.

Then we have the DT02 Sand Viper. Basically a kids toy, base model Tamiya chassis. Handles very well, superb tight turning and is the 2nd fastest and 2nd lightest chassis.

Finally we have the Thundershot. Now yes, mine is modified with lowered suspension, bespoke shocks and modified tub to fit a square section LiPo but it is the lightest and fastest chassis shown here.

So the two top performing chassis on pukka muddy, filthy, wet grass that is bumpy, covered in exposed tree roots, leaves and twigs are the basher spec plastic bathtubs......

So I'm beginning to form the opinion that in wet muddy grass or dirt the 1980's buggy designs are still race winning even today and actually the only reason they are not winning and the chassis is considered archaic is because the tracks themselves have changes to carpet/astro and have artificial jumps and mostly very smooth/flat surfaces. So in essence the improvements have not been in the chassis at all but have simply been down to ever more 'road orientated' tracks. My personal experience shows that a 1980's vintage chassis is still capable of beating a brand new modern race chassis on old fashioned basher terrain such as mud, dirt and wet grass.

Am I being an idiot in thinking this? probably but I thought it would be fun to see the comments on this......:D

963708111_round7(8).thumb.jpg.65b849759db3cb66a28cb49a2b520d09.jpg

And yes, of course you could spend hours or days setting up the race spec chassis to compete and fitting loads of hop up parts BUT my point is that in largely out of the box spec the vintage chassis is still competitive on terrain it was originally designed for?

I might even go as far as saying that modern race spec buggies are just glorified touring cars that can handle big artificial jumps...... This trend seemed to start in 1990? 

 

 

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28 minutes ago, mud4fun said:

After spending far too much money recently on carbon chassis conversions and/or race spec buggy purchases and suddenly finding myself having to bash, run and race on our back lawn instead of the rec ground due to lockdown restrictions, I found that on a muddy/wet grassy lawn that my vintage Thundershot achieves the best lap times and the most laps when doing the latest postal racing track design.

I was curious because most of the following buggies are using the exact same motor, ESC, receiver, steering servo, tyres and in most cases even same wheels. The DT02 is using a NiMh and a Kyosho Magnetic Meyhem motor but all the other are using 2S LiPo and Dyna Run Super Touring motors. All the gearing is pretty similar other than the DT02. All the buggies have a top speed in the range 30-35mph.

The fastest buggy on the muddy wet grass by a country mile is the vintage Thundershot which is now a 35yr old design, the slowest is the carbon chassis Avante2001/Egress.

So why is this? :wacko:

Many would argue that my driving skills are so rubbish I can't take advantage of the superior chassis designs but surely if that were the case all the cars would be on the same lap counts and lap times as I had reached a maximum threshold for my driving ability? BUT the Thundershot has currently got 5 laps more than the next best chassis and is 1.5 seconds faster per lap than the next best chassis and this is on a track design that is only a 6-8 second lap time!

Many would argue that my previous historical experience of racing Thundershots means I have a natural bias to them BUT I have now done 600-900 laps of this track design with EACH of these chassis so surely I would have got used to them over that time?

So the 'pinnacle' of Tamiya chassis was the Avante2001/Egress carbon chassis which is the slowest here. It is also the heaviest of all 4 chassis shown.

Then we have the Schumacher Cougar, true it is a 2WD and you may expect it to be slow compared to a 4WD on mud BUT it was 3rd fastest, beaten by a 2WD DT02 and it is also 3rd lightest chassis.

Then we have the DT02 Sand Viper. Basically a kids toy, base model Tamiya chassis. Handles very well, superb tight turning and is the 2nd fastest and 2nd lightest chassis.

Finally we have the Thundershot. Now yes, mine is modified with lowered suspension, bespoke shocks and modified tub to fit a square section LiPo but it is the lightest and fastest chassis shown here.

So the two top performing chassis on pukka muddy, filthy, wet grass that is bumpy, covered in exposed tree roots, leaves and twigs are the basher spec plastic bathtubs......

So I'm beginning to form the opinion that in wet muddy grass or dirt the 1980's buggy designs are still race winning even today and actually the only reason they are not winning and the chassis is considered archaic is because the tracks themselves have changes to carpet/astro and have artificial jumps and mostly very smooth/flat surfaces. So in essence the improvements have not been in the chassis at all but have simply been down to ever more 'road orientated' tracks. My personal experience shows that a 1980's vintage chassis is still capable of beating a brand new modern race chassis on old fashioned basher terrain such as mud, dirt and wet grass.

Am I being an idiot in thinking this? probably but I thought it would be fun to see the comments on this......:D

963708111_round7(8).thumb.jpg.65b849759db3cb66a28cb49a2b520d09.jpg

And yes, of course you could spend hours or days setting up the race spec chassis to compete and fitting loads of hop up parts BUT my point is that in largely out of the box spec the vintage chassis is still competitive on terrain it was originally designed for?

 

 

It's a tight track this one, I ask you, how do they all contend on a faster longer track?

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7 minutes ago, DayRider said:

It's a tight track this one, I ask you, how do they all contend on a faster longer track?

Avante2001 and Cougar do better the faster the track BUT not by much, barely 0.25 seconds in it compared to thundershot even on a 15 second lap time track!

The Thundershot is the best tracking of them at high speeds too. At 40mph+ the Thundershot is rock solid stable, the Avante2001 is far too 'loose/nervous'

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Some things just get meaner as they get older. :)

My own view is that once you get above a basic level of performance (your thundershot), you get diminishing returns in terms of performance as the costs go up. People will try to sell you a very expensive car that has marginal performance benefits over a much cheaper option, because when people want to win they'll grab every advantage no matter how small.

Also, Newton said it best, Force = Mass x acceleration

Which is well demonstrated in the 1:1 world by the caterham 7 and the AC Cobra. Both donkeys years old designs, but still very fast round a race track thanks to being lighweight and having an excellent power to weight ratio. 

Weight is the killer of fast lap times, it makes slowing up take long, and also accelerating up to speed, so on a very short track (6-8 seconds a lap), a lightweight car is going to do well.

All the cars there have double wishbone suspension, which is as good as it gets as far as suspension design goes, so it's all down to grip, turning capability, and power.

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49 minutes ago, MadInventor said:

 

All the cars there have double wishbone suspension, which is as good as it gets as far as suspension design goes, so it's all down to grip, turning capability, and power.

Yes true and as the Avante2001, Cougar and Thundershot have identical 'as new' Dyna Run Super Touring motors and pretty similar gearing we can probably rule out power?  ignoring the slight variation in transmission efficiency, which would not account to 1.5 seconds a lap difference!

It could be argued, probably correctly, that the Cougar needs better front tyres BUT the Avante2001 and Thundershot (and Cougar rears) are all identical Schumacher yellow compound full pin spikes on 2.2" wheels and have medium foams fitted. The DT02 has same front  tyres as Cougar yet turns better.

I genuinely believe that the Thundershot is the best 4WD chassis Tamiya made for genuine dirt tracks. After that it went down hill and their buggies were progressively engineered for smooth tracks with artificial jumps. However those artificial jumps got bigger and bigger and thus ruggedness, strength, flight characteristics and shocks became more important and hence why the Schumacher and Associated buggies are so good and Tamiya lost ground. Of these four buggies, the Schumacher is by far the most rugged, easiest and cheapest to fix and jumps the best.

 

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Well, a 6-8 second garden track is not exactly representative of racing, and one that includes tree roots is a bit extreme even for early 80s buggy tracks!

Obviously 2wd is a disadvantage, especially if you are traction limited. And the stagger rib tyres you have chosen for the front won't have a great deal of bite on poorly prepared surfaces.

I guarantee that you can get the Cougar's supension set up to ride a very rough track better than the older buggy can.

The Avante family do not have good suspension systems, so I'm not really surprised that your Thundershot can beat them.

You must have a very long straight to be hitting 40mph on your track. The 13T Dyna run motor is not especially fast, also running with NiMHs is not helping with power. I don't think buggys on a big prepared track will be doing much more than 40mph.

So to answer your question - yes, things have improved massively. I would never consider a Thundershot for a competitive race.

But if an old car is the best around your rather unusual garden track, then enjoy it!

(Below video is an example of what a Cougar can do, Michal Orlowski is second on the grid, he's a European champion among other things)

 

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2 hours ago, sosidge said:

Well, a 6-8 second garden track is not exactly representative of racing, and one that includes tree roots is a bit extreme even for early 80s buggy tracks!

Obviously 2wd is a disadvantage, especially if you are traction limited. And the stagger rib tyres you have chosen for the front won't have a great deal of bite on poorly prepared surfaces.

I guarantee that you can get the Cougar's supension set up to ride a very rough track better than the older buggy can.

The Avante family do not have good suspension systems, so I'm not really surprised that your Thundershot can beat them.

You must have a very long straight to be hitting 40mph on your track. The 13T Dyna run motor is not especially fast, also running with NiMHs is not helping with power. I don't think buggys on a big prepared track will be doing much more than 40mph.

So to answer your question - yes, things have improved massively. I would never consider a Thundershot for a competitive race.

But if an old car is the best around your rather unusual garden track, then enjoy it!

(Below video is an example of what a Cougar can do, Michal Orlowski is second on the grid, he's a European champion among other things)

 

No, our garden track is much bigger. The 6-8 seconds was the postal racing track. The speeds are tested on our local rec ground car park which is maybe 500 feet long although we only use 300 feet of it and obviously speeds vary based on gearing. Currently all four buggies are geared low so top speeds are 30-35mph. With higher gearing most are capable of 45mph comfortably.

The Avante2001, Cougar and Thundershot use LiPos. The Cougar uses a 120c HV LiPo too BUT none of the LiPos can match my old 8.4v NiCD for outright performance but do give lovely long run times.

I wasn't talking about modern pro race tracks. They are not what the Thundershot was designed for. The tracks I raced on at club level back in the 80's were not too different to my garden track and were often muddy, corrugated, wet and rough :) Hence my point, modern chassis have not actually improved outright performance when compared to an 80's buggy when run on an 80's track. The biggest gains have been in motor, ESC, battery and tyres IMHO. So when the vintage buggy is fitted with identical modern electronics it performs as well if not better than the modern heavier low slung chassis on those 80's style tracks. So yes, modern chassis have changed to suit modern tracks and they do look impressive and have great materials but performance wise on an 80's track I honestly can't see that there is much actual improvement in the chassis itself. 

Edit: Dyna Run super touring not fast??? It is the 2nd highest revving brushed motor Tamiya made for mainstream use AFAIK and my buggies have slaughtered brushless buggies on numerous occasions. 8.4v NiCD and a 33K+ rpm motor is not to be sniffed at, more than a match for many cheaper brushless setups on 2S IMHO. But that is irrelevant as three of these buggies are running identical motor, similar gearing and 2S LiPos so the lap time differences are due to other factors such as chassis design and suspension geometry.

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2 hours ago, mud4fun said:

Avante2001 and Cougar do better the faster the track BUT not by much, barely 0.25 seconds in it compared to thundershot even on a 15 second lap time track!

The Thundershot is the best tracking of them at high speeds too. At 40mph+ the Thundershot is rock solid stable, the Avante2001 is far too 'loose/nervous'

I wonder if it's down to weight? For example I have started using lipo batteries and I have noticed that it has comprised the grip due to a little less weight on the tyres and now I find myself having to find more down force or to add weights to the hubs.

We keep adding carbon parts making are chassis's lighter, although making them faster but with less pressing on the tyres thus loosing grip into tight bends.

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PS @sosidge yeah we are aware of the Schumacher drivers, my kids watch all the RC racers YouTube channels from around the world. They are keen to join a club this year and start club racing.:)

In all honesty though racing around on carpet doesn't really appeal to us as it is not proper 'off road'. Gaffer taping a few ramps onto a touring car circuit doesn't make it an off road track :D We all prefer the outdoor US dirt tracks that feature on Ryan Harris videos. Shame the UK seems to have gone mostly carpet.

A couple of videos we watched last year highlighted how 'spoilt' modern buggy racers have become. One was an IFMAR worlds event in China where the clay track got wet in the rain and dear lord, the whining and complaints of the drivers was hysterical. They were almost in tears because they couldn't keep their cars on the track in proper off road conditions.

 

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25 minutes ago, DayRider said:

I wonder if it's down to weight? For example I have started using lipo batteries and I have noticed that it has comprised the grip due to a little less weight on the tyres and now I find myself having to find more down force or to add weights to the hubs.

We keep adding carbon parts making are chassis's lighter, although making them faster but with less pressing on the tyres thus loosing grip into tight bends.

Yes, it could be weight related, although the Thundershot is the lightest car and the Avsnte2001 is 150g heavier despite the carbon chassis.

However, you may be on to something. I think it is more to do with weight distribution though? For example the Thundershot has near 50/50 weight distribution but the Cougar is 60% to the rear in kit form. I'm thinking that moving the battery forward, adding the optional brass weighted radio tray etc may help? Both the Avante2001 and Cougar are badly understeering compared to the Thundershot.

I'm going to try a few things over the next few weeks to pinpoint the problem. Obviously better front tyres for Cougar is a start, probably pin spikes or rib&stud? The lawn is very muddy at the moment. Not sure why the Avante2001 is not turning as tight as the Thundershot under power. Possibly too stiff? 

So I am looking forwards to playing around with setups to learn what works and where I can gain. I am hopeful I can get the Cougar to beat the Thundershot. It is certainly not down to lack of traction when accelerating, the main loss of time is cornering under braking or when backing off throttle to enter a turn. The Thundershot can turn very tightly on the mud under power. When I lift the throttle slightly the nose dives and it turns even tighter. The Cougar and Avante2001 are not doing that, if I lift off the throttle with them, they remain fairly flat. My suspicion is that this is by design as on high grip carpet you don't need extra steering but on mud/wet grass you do!

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Sounds like you need better front tires on the Cougar and softer suspension on both, with as much usable travel as possible since the track is so rough.

Also, don't forget, it's a brand spanking new, full-on race car. You've set it up with the "factory tune" but there are a lot of little adjustments to dial in before it'll feel comfortable for you to drive quickly, which would be true no matter who the driver is.

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11 minutes ago, El Gecko said:

Sounds like you need better front tires on the Cougar and softer suspension on both, with as much usable travel as possible since the track is so rough.

Also, don't forget, it's a brand spanking new, full-on race car. You've set it up with the "factory tune" but there are a lot of little adjustments to dial in before it'll feel comfortable for you to drive quickly, which would be true no matter who the driver is.

Yes true, still getting used to Cougar although have now done about 2000 laps in total (round 6 and 7 plus bashing) with Cougar so am getting used to it. My accuracy at entering bends is vastly improved just need to sort out the understeer.

As for the Avante2001, I've been driving that for 20 years quite regularly BUT mostly in flat tarmac where it performs well. I think you are correct, front suspension needs to be softer and rear suspension firmer. The Thundershot has firm rear soft front which clearly works on the mud. I think it allows the weight to transfer onto front wheels when cornering under braking?

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PS @El GeckoGecko I'm loving your track design. Really challenging but unlike some of the other figure eight designs it is alot more fun due to the nice straight down the diagonal and the arrangement of the mini figure 8's in the middle AND it fits on our lawn!!! :D

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I love the tinkering bit, getting the most out of what we have, it's what keeps it so much fun for me.

You probably already know what I am going to say but just change one thing at a time so you know what makes the difference.

Best of luck mate and let me know what changes

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6 minutes ago, DayRider said:

I love the tinkering bit, getting the most out of what we have, it's what keeps it so much fun for me.

You probably already know what I am going to say but just change one thing at a time so you know what makes the difference.

Best of luck mate and let me know what changes

Thx, I will report back. :)

It was one of the reasons I bought the Cougar, lots of tunability so I could learn about setup and how changes affect performance. However I will admit, as a novice with setup, that I was surprised that the Cougar would be 1.5 seconds a lap down on the Thundershot on grass even with kit setup. It was near identical on last round on tarmac. Can't believe the difference when running on mud. Good fun though. I am determined to get the Cougar to beat the T'shot, I have set myself a personal challenge :) (even if it sounds mad to expect a 2WD to beat a 4WD)

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2 hours ago, mud4fun said:

PS @El GeckoGecko I'm loving your track design. Really challenging but unlike some of the other figure eight designs it is alot more fun due to the nice straight down the diagonal and the arrangement of the mini figure 8's in the middle AND it fits on our lawn!!! :D

Ok, I will tell you the secret... it's a slot car layout ;)

Hoping some more of my HO track designs can find new life for postal racing... I gained a lot of experience packing fun little tracks into as tiny of a space as possible :D

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OK, a quick update. I have been watching a load of Trishbits youtube channel (the guy that works for Schumacher) and I have picked up a few hints as to why the Cougar is struggling with apparent understeer on the muddy wet grass.

1) Anti-roll bars or rather the lack of any on the Cougar as built from the kit. The Thundershot (terra scorcher chassis) has front and rear anti-roll bars, the fronts being very flexible and the rears being stiff. From what Trish was saying, it seems a moderately stiff (not too stiff) rear anti-roll bar will tend to push the nose down and get more steering on dirt when trying to apply power in a turn. This sounds very plausible and as the Thundershot is now 6 laps ahead of the Cougar the evidence supports this! :) I am going to order a set of rear anti-roll bars in various thicknesses to try on the Cougar.

2) Laydown front shocks or rather the lack of them on the Cougar as built from the kit. My Thundershot front shocks are significantly more laid down than the Cougar front shocks. Trish suggests that laying down the shocks increases side bite on the front tyres. This would of course result in the front tyres biting more in the muddy wet grass. For high grip tracks you would not want this as the buggy could grip roll so I can see why the kit setup would be more stood up than for a low grip track. He also suggests that if laying down the front shocks you need to soften the damper oil. My Thundershot is using softer oil  (350cst) in its front shocks and firmer (500cst) oil in the rear. So it seems my Thundershot just happens to match exactly the setup that Trish recommends whereas my Cougar doesn't. So I will change the shock oils.

3) The tyres. The Cougar kit doesn't include tyres so I used what I had in stock and that was Schumacher 2.2" low profile cut stagger rib tyres (albeit in silver compound). We had found these worked really well on wet moss covered tarmac. Sadly it seems they are just not suitable for muddy wet grass. So I have ordered a wide range of tyres to try including some 1980's style stud/rib tyres designed for CAT. I figured that as I'm now running on a surface that a CAT would have felt at home on back in the day then maybe using the vintage style tyres may work? failing that I have mini pins and studs to try too.

All good fun!!! Quite excited to try these changes. Should have the next update at the weekend after my new tyres arrive. :)

 

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I get what you are saying I have been there, but remember one person's set up doesn't work for everyone. I would try the shock adjustments first and then try the stabilisers. When it comes to stabilisers try both soft then hard and then mixing them. Also take good care with the fitting with them because if they are not the same (centered and strate) can put everything out of wack. You probably already know this but I had to say it.

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Interesting thread. One thing I would say is, on low grip surfaces 4wd is far faster than 2wd. We see this at our club days where 4wd times are signifcantly faster than 2wd.  2wd mod and stock times are essentially the same, and 4wd stock is much faster than either.

When we run our cars in our backyard track (its roughly the same size as yours) the race cars have no advantage over a box stock Boomerang, and while they are a lot faster on 17.5T brushless(properly geared with motor fans for heat) and 2s, they dont have any real advantage over a silvercan on NiMH as the track is too small to take advantage of the speed. 2wd tend to be slower as they don't steer as well (I think that is actually too much rear grip and needing weights on the front. We run dirt tyres which grip really well in grass so the nose can lift). I don't change the setup as they are setup for our clubs track. We run Ae B6D (4 gear standup) and HB D413/8, and a mix of rere.

 

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1 hour ago, Jonathon Gillham said:

Interesting thread. One thing I would say is, on low grip surfaces 4wd is far faster than 2wd. We see this at our club days where 4wd times are signifcantly faster than 2wd.  2wd mod and stock times are essentially the same, and 4wd stock is much faster than either.

When we run our cars in our backyard track (its roughly the same size as yours) the race cars have no advantage over a box stock Boomerang, and while they are a lot faster on 17.5T brushless(properly geared with motor fans for heat) and 2s, they dont have any real advantage over a silvercan on NiMH as the track is too small to take advantage of the speed. 2wd tend to be slower as they don't steer as well (I think that is actually too much rear grip and needing weights on the front. We run dirt tyres which grip really well in grass so the nose can lift). I don't change the setup as they are setup for our clubs track. We run Ae B6D (4 gear standup) and HB D413/8, and a mix of rere.

 

Thank you Jonathan.

We are just starting to re-landscape our back garden to increase our garden track length. It used to be 18 seconds, with a 20m straight and complex infield design. Then we built the workshop and veg garden and sadly the track ended up at 10 seconds and then more recently 12-15 seconds when jumps were added. That was fine for the kids when they were younger and running silver cans but now they are grown up, running hotter motors and are budding racers we need a big track again. I'm tempted to sacrifice the patio and veg garden and go for a much bigger track, possibly 20 second lap or even more if we include some tricky jumps and kickers (as suggested in another thread).  Can you tell me what an average club lap time time would be now?

I agree that 4WD by rights should always be faster on low grip surface, however I'm not convinced I'm getting the full potential from my Cougar yet. If I can get those front tyres to bite I am positive I can gain at least 2 or 3 more laps. True, may still not match the Thundershot but I think it could be close :)

Another thing I noticed about the Cougar, Schumacher do a special version for the US market called the stock spec. It is primarily designed for 17.5T motors and dirt tracks and is significantly lighter. It uses a carbon chassis, has no heavy slipper clutch, has lightened gearboxes and a lightened shell. In total some 200g lighter! I suspect that would perform much better on these tiny tight postal racing tracks so there is scope to upgrade my Cougar to that lightweight spec. The Cougar is currently the 3rd lightest, the Thundershot is the lightest. I wonder how much of a difference weight makes on tight twisty tracks on low grip surfaces?

The weird thing is that Trish Neal reckons more weight to the back is better for low traction surfaces on a 2WD yet my experience and thinking is that the fronts are washing out because there is no weight on them. Curious. Will be interesting to see what works!

There is also the factor of wheel base. The DT02 and Thundershot have very short wheelbases, some 40mm+ shorter than the Cougar. Even Trish said himself, he runs a shorter chassis as it gives tighter turning. Maybe a 287mm wheelbase is just too long for such a small tight track?

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My offroad club runs both 8th and 10th scale and the track is big and dirt.  I think a 17.5T blinky 4wd buggy would be about 40 - 45secs, 2wd 45 - 50secs.  4wd mod about 38secs, nitro 8th buggy low 30s (for the fast guys, we get a lot of the top NZ drivers come along).  I'm vague on the numbers as racing was interrupted a lot last year and the track was just rebuilt in December for a big meet and I've only run once on it.  Will know better after the weekend as we're due to spend the weekend there.

My onroad club (and the indoor offroad club uses the same venue) runs in an indoor sports arena, using 2 indoor cricket pitches/netball courts for a track.  They run 13 - 17secs per lap depending on class.  Offroad is similar as they just add a few jumps but will be essentially the same layouts.

My backyard track is about 12secs (Top Force on a good day) but really about 14secs consistently, or 18secs for people who don't race it often or in a Lunchbox.  Its about 14m x 8m I think (from memory, it was a few years ago when I measured it) with quite a long straight as it has an easy curve (around the lemon tree).  We have jumps made of plywood which we sometimes use.

Those stock spec tend to lighten the drivetrain a lot, hollow shafts, thinner gears etc too and so some of that weight reduction is taken from rotating mass to reduce loss of power from the (relatively) low power 17.5T motors.  I used to run a slipper eliminator on a Kyosho RB6.6 but was faster with the slipper.  I'm also faster with a centre gear diff than a slipper in 4wd.  a 200g weight saving will make a difference, but for most people that advantage will be offset by their first crash!

Its true that more weight at the back is better for low grip, but there is the caveat now that means a 4 gear standup provides the most rear grip as no one makes rear motor anymore.  Then 3 gear standup, then 3 gear laydown gives the most steering.  The Kyosho RB6.6 had all 4 options (incl rear motor), but the RB7 only comes with the laydown transmission.  You can convert it to rear motor with 6.6 parts.  The trend is definitely towards more weight up front, and the change between front or rear bias is moving the motor by about 25mm.

Funny that a guy 2 seasons ago used to be a mid-pack racer (front sometimes, he's a good driver but not taking it as seriously now) with an RC10 Worlds rere.  Rear motor.  He said that the new Yokomo he bought gained him 2secs a lap over the RC10 Worlds.  Doesn't seem a huge amount for 30 years development!  But then we run low grip dirt, which is what the RC10 Worlds was designed for.

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The new front tyres arrived today so I can start doing some tyre testing on the Cougar.

Does anybody know which way around the CAT Rib/Spike tyres are meant to go? is it spike to outside or inside? 

I have various front foams too but will try the tyres without foams first and work up from there. 

171157067_tyres(1).thumb.jpg.1375c11c7320f8eddf5a03136f2c26c5.jpg

 

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9 hours ago, mud4fun said:

The new front tyres arrived today so I can start doing some tyre testing on the Cougar.

Does anybody know which way around the CAT Rib/Spike tyres are meant to go? is it spike to outside or inside? 

I have various front foams too but will try the tyres without foams first and work up from there. 

171157067_tyres(1).thumb.jpg.1375c11c7320f8eddf5a03136f2c26c5.jpg

 

ooooh! I like the look of a few of them, U6847 Is catching my eye very much. I'm really eager to know what works for you. I must admit I like the commitment.;)

BTW ribs in!

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I can see why 4WD would be faster on low grip surfaces, but would 2WD be faster on high grip? 

All other things equal, a 2WD car weighs less and has fewer drivetrain losses.

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Thanks @DayRider I'm hoping to get out at some point today to start testing. Sadly it was heavy rain here all day yesterday. I have fitted the rib/spike to the Cougar so all ready to go :)

Yes @Mrowka I believe you are correct, logic says on high grip 2WD could be faster BUT the caveat there would be if you can get the power down through two tyres? In theory a 4WD may still be faster even in the dry if running alot of power? I may be wrong though. Will be interesting to see once the warmer dry weather arrives :)

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