MRA 68

Hello, new member here, and my first nitro truck (Tmaxx) is showing up tomorrow (bought off Ebay). I come from a motorcycle roadracing background, and have some decent suspension knowledge in that area, and am trying to learn more about the suspension requirements of the Tmaxx. I've spent several hours reading through various searches on this board and other sites, in particular fhm101's posts have been very helpful and informative. But I've got a few other general suspension questions that I hope you guys can help me out with.

I should probably preface this with my intended use of the truck: I plan on mostly riding fast and hard, and not crashing hard. I may eventually try some racing with RAT down in Denver, assuming those race dates don't conflict with my roadracing. So race-oriented setup tips would be most helpful. I'm currently considering purchasing either the AE FT shocks, or the Big Bores.

1 - Shock springs - For roadracing, we use linear rate springs, and only adjust preload to get optimal sag settings (free and static). However, I believe in dirt racing that progressive rate springs are commonly used to handle jumps. Many springs for the Maxx that I've seen appear to be linear, with a few progressive offerings. Opinions on progressive vs. linear springs?

2 - Spring rates - Again, in roadracing, the spring rate is determined by your sag settings. For these trucks, do you normally have a need to change spring rates beyond the spring that gives correct sag? I'm currently guessing "correct sag" to be somewhere around 1/3 of total shock travel. I can see higher spring rates if you want to primarly go over huge jumps, but I'm more interested in hauling ass over all sorts of terrain.

3 - Shock pistons - I'm intrigued by the Two-Stage pistons from RPM, even after reading that fhm101 had problems with them scoring his shock bores. I can see the advantage less rebound damping over quick bumps, but it seems on a big jump you'd want more rebound damping to keep the springs from bouncing the truck upon landing. Can a piston that provides equal rebound and compression damping truly be effective?

4 - Shock oil - From what I've read so far, silicon based shock oils seem to not heat up during use. If this is true, then what's the purpose of the piggyback shocks, and especially the ones with the cooling fins? I'm currently planning on starting with 30-45 weight oils, with a heavier oil in the rear than the front.

That's what I've come up with for now, are there any critical flaws in my thinking here, or characteristics that I haven't considered? I'm really interested in the shock piston design, and plan on doing some experimentation in that area making custom pistons and trying different setups. I'll let you guys know how it turns out.

I appreciate any info you all can provide, and I'll continue reading through old posts to learn more about this exciting new sport.

Thanks!
Alex

dr_killer_uk

Seems like you know enough your self lol what you need to do is test your settings on a small simular track to the one you will be racing on or the actual one you will be racing on if you could. Try some settings see what best times you can get, oh ya get a lot of practice in as if you havn't raced one before you are probably gonna get beat even if your car is faster lol.

psycooclimber

there is no advantage to piggy back shocks. sillocone will heat up but does not change viscosity (sp). piggy back shocks are achualy bad in race set-up becouse it allows air to mix in the sillicone.

MRA 68

Thanks for the replies, I figured as much about the piggybacks. And yes, I expect I'll get beaten in racing, my intent with these questions was to get more info on these trucks suspensions, not learn some secrets to beating everyone else without being an experienced driver.

For now it's all a moot point, the truck I purchased off Ebay arrived today, and turned out to be an SMT Smartech truck with a T-Maxx body, radio, and EZ start controller (even though the SMT is pull-start ). I'm planning to do whatever it takes to get a refund from the seller, he has a lot of good feedback so I'm hoping he made an honest mistake and will correct it.

At this point I'm leaning towards just buying a new truck, and am torn between the Revo and the T-Maxx. I like the availability of parts for the Maxx, but the performance of the Revo is very appealing, and they're only about $75 different in price. Oh well, I'll let you guys know how it turns out.

ils

Here's a link to a pretty recent topic that has a few links to videos:

http://www.rcuniverse.com/forum/REVO...2238968/tm.htm

fhm101

You are much too kind to an old man that can't stop playing with toy cars. Sorry to hear about your ebay problems. I hope you can get an acceptable resolution.

If you are considering the new truck route, my vote is for the revo. The only reason I don't have one already is I'm doing some testing for my friends at Pro Hobby Racing on a new maxx racing chassis and what little time I have to devote these days is taken by that. The maxx is going to be around for quite a while yet and properly prepped will always be a contender in skilled hands, but out of the box a revo is by far the better truck of the two. It takes a highly modded maxx to be on par with a near stock revo and in terms of performance enhancement the maxx is just about peaked out while the revo is just getting off the ground.

dr_killer_uk

That truck is roughly the same design but made from crap meterials and a much crapper engine, i'd be pissed off if he advertized it as a t-maxx lol Make him pay you to send it back too as its not the item he even advertized.

MRA 68

Yes, it took all of about 5 minutes for me to realize that this wasn't a Traxxas truck, and most of that time was unpacking the box it arrived in. I've demanded a full refund including return shipping, I hope he goes along with it. In case anyone would like to see the auction, here's the item #: 5525757926 (I don't think this forum lets you post Ebay links).

I went ahead and placed an order for a new Revo this morning, it is supposed to arrive on Thursday in time for break-in and some weekend driving on Saturday. I'm excited!

dr_killer_uk

Yes says t-maxx and you can't tell its not from them pics in that auction, he has very good feedback maybe he didn't even know it wasn't a t-maxx if he dosn't sell allot of RC cars he probably couldn't tell lol. Anyways as for the REVO i read a review in RC Driver and aparently its realy good for racing out of the box they loved it, load better handeling then the t-maxx.

foreverNight

I looked at the ad and it does say traxxas t-maxx 4x4.. It would have been a good deal if it was a t-maxx. Lets us know how it turned out.

MRA 68

Well so far he's being fairly uncooperative. I've sent 3 emails and called him once, he wouldn't answer his phone, and in his email said he "used the traxxas name mainly as a reference" and that he didn't think I deserved a refund. I've looked into dispute resolution, and since the auction had PayPal Buyer Protection, I'm fairly confident I'll be convered under the "item significantly different than described" clause. I'm giving him another couple days to make things right, then I've done all I can and it's off to Paypal to fix it.

The good news is my new Revo is supposed to show up tomorrow! Woohoo!

dr_killer_uk

I own a ebay business so if you need any help with all this pm me as i have dedicated eay customer suport through my ebay shop ;P
I can't beleive he could have such good feedback and be so stupid as to not even mantion its not a t-maxx in the whole auction you deserve a full refund, he broke the ebay rules big time.

dr_killer_uk

Oh ya don't send the item back till he pays for it to be sent back, even if you get a refund, just say ok you can pay for the item to be sent back in your own time now.

Texdav

Pre-load is used off-road just as onraod to set the ride height on both front and rear.Very seldom do you see anyone using progressive wound springs off -raod but pro-line has new shocks with true progressive dampening and dual rate springs as used in real off-road but their too new to know if they have a true advantage. Sometimes simple is better. Silicone maintain viscoity better with weather temperature changes but will change with extremes. In shock pistons with overall same openings in pistons;morw holes but small will have more pack and fewer holes but larger will have less pack. In off-road dmapening and springs often depend on track conditions and most often is a compromise between lighter for rough and stiffer for handling jumps and roll in cornering and of course steering . Having race both there is a huge difference in setting-up for on-road and off-road but tires are still the most important in set-up in both.

MRA 68

Good info, Texdav, and thanks for getting this thread back on track.

I'm not sure how more small holes would be any different than fewer large holes, assuming they both have the same volume transfer characteristics. And by "pack", do you mean a tendency to stay compressed? For example, in road-racing, if you have too much rebound damping the shock will not extend quickly enough, and a quick series of bumps can fully compress the shock ("packing-down" the suspension).

I'm looking forward to trying all the setup configurations on my Revo when it shows up, to see how the changes affect the driving characteristics.

Asmodi

As far as the Pro-Line shocks go, look back a few topics I did a review on them, they are nice however they do need heavier springs. But if you intend to race you can set them up quite nice and they work great, truck is glued when dialed in.

foreverNight

dont forget to file a fraud report. I wish i was getting a revo tomorrow!

fhm101

You are on track about the volume transfer, and minute changes in hole size will have an effect on action. You can also bias the compression and rebound speed by beveling the holes in the pistons. The variations in shock tuning are endless, but it's a rare driver that can exploit the fine differences so I wouldn't be too concerned about that for now. In truth there is no voodoo or inside tricks to top notch suspension on our off road cars, it all really comes down to strict attention to the basic details and getting things smooth and consistent from side to side and front to rear.

pack refers to resistance to compression.

As a new driver you may want to get the basics of control down before you get too involved in chassis tuning. The thing that usually takes the most time is steering. While left is left as the car moves away, left becomes right when it's coming toward you. Until you can steer correctly without thinking, suspension changes will not make enough difference to matter.

As tex said about racing, tires are the single most important tuning option you have. Everything else will be set up around the right tire for the track you are running on. Of course if you are just out running around most any tire and suspension setup will do fine.

The single most important thing to remember, more important than tuning and tires. Have fun.

MRA 68

Thanks fhm, I got the Revo yesterday and broke her in, man that's a fun machine! The suspension articulatioin is amazing. I'm pleased, I hadn't forgotten my controller skills (from playing with friends RC vehicles as a kid) so I had no trouble steering, even in reverse going away from me.

The front suspension in particular seems pretty soft, and the rear bounces a bit when I drop the truck from a couple feet in the air, so I'm going to start by increasing the oil weight in the shocks, and perhaps get a few different springs to try different combinations. I'm totally amazed at how well this thing handles.

For tires, are people generally putting new wheels on the Revo? It doesn't seem there are many tires available yet for this truck...

The guy on Ebay is still giving me a hard time, now he's saying that he "never claimed it was a Traxxas truck". He's got until end-of-day today to refund my money, then I'm contacting Paypal and Ebay.

fhm101

Out of the chute a lot of revo racers were running proline 40 series bowties. Most are switching over to cut down standard maxx bowties on revo wheels for the weight savings. Hopefully traxxas will have a winner in their response tire and we won't have to cut tires every time we want to mount a set. A good rule of thumb for racing suspension setup is bones level at rest and when dropped from about waist high the suspension should compress and rebound back to the at rest height. A bit of bottoming out won't hurt, but if it slams, increase pack, if it bounces lighten it up.

avery4jc

My Feedback: (10)

Asmodi, I see that you have the Power Stroke shock kit, I have a trick racing e-maxx that I built from the ground up this summer and I am putting the finishing touches on it. I bought the Power Stroke kit today and of course, with my luck they didn't fit. I have Integy aluminum bulkheads with RPM shock towers and arms and the angle that the shocks come off of the upper shock mount (on the shock tower) they hit the arm going down to the lower shock mount (on the lower arm). Any Ideas?

P.S. I could always thread down the upper collar but then I would be adjusting the shocks just to fit the truck and that wouldn't make very much sense.

Asmodi

Hmm I dont have any ideas how to fix it other then maybe grind alittle off the A-arms and using a 2.5 Maxx's or another aftermarket shock tower. I had problems with them hitting my .23 but manage to grind enough off the roto-start to keep them from hitting the back plate. As you can see from the picks I have the Racer-X suspension and it has alot larger holes the the stock A-Arms.

I think the the RPM shock towers are the same design as the original Maxx and only have the one mounting position.

I think for just racing the grinding of the A-Arms won't effect thier strength too much, but might weaken them for bashing.

I intend to make a racing Maxx, as soon as I get done with my NTC3 and after the I get a Revo, this will be sometime down the road, but will do what I can for a review.

avery4jc

My Feedback: (10)

Don't worry about it, I figured out a way to mount them. These things are sweet!!!

Squishycannibal

Replace the twin titan motors with speed 700 turbo w\BB mak sure it's 12v not six. VROOOOOOOOOOOM

avery4jc

My Feedback: (10)

The Speed 700's sound cool, but I need to be in the "stock" class, so those probably won't be in the future.

P.S. lets try to stick with suspension questions and stay on subject, I've had people ticked before because we lost sight of the subject.