Lst2 cvds and hubs on a Savage
 

I have some new ideas and wanted to put this up in the right section.

So far I have figured a way to put the lst2 hubs on a stock savage arm. Not difficult at all.

Here are the pics, pretty self explanatory:

http://i206.photobucket.com/albums/b...e/DSCF4765.jpg
http://i206.photobucket.com/albums/b...e/DSCF4764.jpg
http://i206.photobucket.com/albums/b...e/DSCF4763.jpg
http://i206.photobucket.com/albums/b...e/DSCF4762.jpg

Problem is the lst cvd required a 6mm longer lower arm, and a 126mm long upper arm.

After looking alot I am finding it quite hard to find a suitable replacement for the lower arm.

So I figure I can make some new hingepin braces that are 6mm wider on each side. The bulks will have to be trimmed so that the hingepin can sit 6mm farther away from the bulk. The hingepin braces will be the only thing holding the pins, but most truggies are held this way, so it should be strong enough. I will likely use much thicker material so I can thread holes next to the pin holes and use m4 thread scres to hold the pins in.

This is the hingepin brace, as stock, imagine the holes 6mm farther away from the center.

http://i206.photobucket.com/albums/b...humb-step8.jpg

Here is a pic of the plastic bulk. The red area indicates where I would remove material. I will try to retain as much material as possible, so a 6mm slot would provide clearance.

http://i206.photobucket.com/albums/b...p/85235_01.jpg

So we have retained the stock lower arms, and hingepins. Only part to make will be the pin brace.

On to the custom upper arm. The lst2 hub uses 4mm hingepins. Same diameter as the stock savage hingepins.

So I am thinking of using the savage X SS adjustable upper arm kit with some mods and a new turnbuckle.

Have a look at this pic with my notes on it:

http://i206.photobucket.com/albums/b...I85066-450.jpg

The nomal end hole that has a ball end is too big for a 4mm hingepin. But the next hole is slightly less than 4mm, so it can be enlarged to fit. The area I have marked white would be removed. This will require a 60mm long m5 thread turnbuckle. About 10mm of the turnbucle on each end goes into the plastic ends.

Spacers will be required to shim each side of the end where it connects with the lst2 hub. This will be nice as the shims can be moved to alter the caster.

Off to look for a suitable turnbuckle...

Only thing I have found so far that is 5x60:

http://www3.towerhobbies.com/cgi-bin...?&I=LXALWC&P=7

Any ideas?

wow... i had a feeling that you were going to want to remove that area of the bulk... i guess this mod is a no go for me with my alloy Bulks...

but here is some help...
Considering you will need to make the hinge pin holders out of something tough like stainless steel... you will also need a solid system...
Here is a guy that made something for the stock savage, but maybe new braces which offer the extension needed either side to fit the CVDs... here are the pics of what he created...

here is what he sells on ebay.. it took him ages to come up with this... he is over on savagecentral and is called MRSNUGGLES...

http://i13.photobucket.com/albums/a2.../HPIM03521.jpg

http://i13.photobucket.com/albums/a2.../HPIM03511.jpg

http://i13.photobucket.com/albums/a2.../HPIM03501.jpg

http://i13.photobucket.com/albums/a2.../HPIM03491.jpg

http://i13.photobucket.com/albums/a2.../HPIM03418.jpg

http://i13.photobucket.com/albums/a2...c/HPIM0373.jpg

http://i13.photobucket.com/albums/a2...c/HPIM0352.jpg

I saw a guy that had ripped his bulk apart and it was being held together with just these ridiculously strong braces!

What do you think

edit...
Where he sells tham
http://cgi.ebay.com/ws/eBayISAPI.dll...ht_1001wt_1139

Looks like he WAY overtightened those allen cap screws and it is distorting the bulkhead.

maybe he did... but what ever... you would have thought he would have ruined the thread before distorting anything

Just grind the area off the alloy bulk, I really do not see it doing much at all for strength.

I would use thicker material than he did for the braces, or shorten the pins so I could use a screw to retain them.

Like this, see arrows in pic:

http://i206.photobucket.com/albums/b...p/IMG_0380.jpg

I would use thicker material than the stock hpi braces, and likely trim/grind the hingepins to the correct length. Then just use a m4 thread short cap head screw to hold the pin from sliding out.

I have moced up most of what I have to do, will keep searching for turnbuckles and see if I can score a set on the cheap.

Found some helfire turnbuckles, m5x60mm. Should be perfect, bought 2 packs (4 total).


http://cgi.ebay.com/HPI-93627-FRONT-...item35af45dabd

Mocked it up some more. Cut the upper arm as described. The hole behind the pivot ball hole is alomst 4mm, used a 4mm drill bit by hand to open it up. Cut the shaded are off and rounded it, fits very nice.

In the pic I have a spare lst hinge pin acting as a turnbukle. I have ordered the hellfire m5x60 turnbuckles and will swap them out when they arrive.

http://i206.photobucket.com/albums/b...p/DSCF4771.jpg

1st pic shows the lower arm attached to the bulkhead as it is on a stock savage, 2nd shows the spacing on the other end of the arm.

http://i206.photobucket.com/albums/b...p/DSCF4769.jpg
http://i206.photobucket.com/albums/b...p/DSCF4770.jpg

1st pic shows the savage lower arm connected to the lst2 hub, 2nd is a close up of the spacing between the stock hingepin brace and the stock arm. Measured it is right at 10mm. This gives enough clearance in the diff output cup for some negative camber to be dialed in via the upper arm turnbuckle.

http://i206.photobucket.com/albums/b...p/DSCF4772.jpg
http://i206.photobucket.com/albums/b...p/DSCF4773.jpg

So I will pull off one of the braces, trace it on some al stock I have and add 10mm to each side.

I also measured the width difference and I should end up with more than 1/2" extra width per side. Probablt 15mm or more, and that was just eyeballing it with a ruler. The hingepin brace will add 10mm per side, and the longer cvd axle and hub design add about 5mm. I may even widen the hingepin brace so that the hingepins will clear the center bulkhead area so that the bulks will not need to be modified at all.

Now for some issues I have noticed. Since the upper arm will be longer than the lower arm the truck will experince positive camber as the suspension is compressed. Not good. I am working on an idea to fix this. Best thing I have come up with is to make a spacer block that mounts to the top of the c hub thru the hincepin hole and effectively moves the hingepin pivot closer to the bulk, so that the upper arm can be shortened to the same length as the lower arm. Bur we will cross that bridge when we come to it. Right now I would like to get it working as show.

Positives:

No mods to lower arm.
Minimal mods to c hub, cheap part
Minimal mods to upper arm, cheap part
Addl parts inexpensive.
Better axle, stronger, cvd type allow for better steering throw(will also require mods)
Larger inner bearing, wider bearing spacing, possibility of 3rd added bearing in hub
Stock lst2 rear hubs will eliminate rear tierods
wider stance without using axle extenders
Use of std hex adapter from 1/8 scale buggy/truggy
and I am sure there is more stuff I am not thinking about.

this might sound stupid, but maybe you could use a heat gun and stretch the middle of the savage arm the 6mm that you need? One of my old co-workers was really into frankensteining rc cars and i remember him telling me he used a heatgun to stretch some plastic parts before. he even said it was still strong after he was done. Couldnt hurt to try it out.

linc... thanks for that detailed write up with all the images as well!!!!

really shows how close it is to working!

I think the FLM XL arms would really work!!! but, i never thought about the problem with the upper arm being longer than the bottom... i guess flm would cure this problem right...
Im quite interested to see how you get round this one!

I wish i had the cash to fork out for the XL arms! i would only want the bottom arms as the top arms are not necessary.

JOsh9 does have an idea though!!! i am going to heat up one of my broken savage lower arms tomorrow and see how well it reponds to heat and being stretched... ill get pics for you.

Made a new hingepin brace just now. Real ugly, but it proves that this will work. Lower hingepin fully clears the bulkhead, so no trimming or grinding needed.

Even though I do not have a turnbuckle that will work I have rigged something up to give me the correct length for the upper arm.

Sitting with the lower arm dropped, so normal ride height I move the arm thru its travel and the longer upper arm is not changing the camber much at all. Camber may change 1/4 deg thru the travel, so we are all good with this.

I have a feeling I know why. When I figured it was going to be a problem I thought the pin spacing on the bulk was the same as the c hub. Turns out the ch pin spacing is more than the bulkhead, so it negates the effect of the upper arm getting longer than the lower arm as the arms move thru their respective motions.

End result: I have something that works. Properly.

I will make another pin brace tomorrow and clean this one up. Then I will take pics.

Oh yeah, I put the new hole 10mm out from the old ones. So about 15mm per side wider than stock.

NICE ONE BUD!!!

cannot wait to see what you have come up with!

So you have extended either side by 0.59-0.60" which is a nice increase... plus the increase of the LST hub which prob brings you to around 1.3-1.5" increase either side!!! Nice added width without any bearing strain!

Looks like the FLM arms would have fallen short haha

Thanks!

Not sure if we have that much extra. I will lay out a lst2 cvd and a savvy dogbone and axle. By comparing the pin locations we can get an idea of the addl width.

cant wait to see how your brace system works!

Linc, awesome ideas! can you please take a pic with both of the cvds and dogbone side by side? just want to see how thick is the dogbone compared to the cvd shaft.

I will make the other end at some point today and then take pics

I measured the parts and the lst cvd will add 15mm per side. That is the difference in the drive pin holes.

Will do, give me a few minutes.

I have noticed that the lst2 cvd bone end is slightly smaller than the original savvy diff output cup. So I will take apart a diff and see if the lst cups will fit the savvy diff.

Pics for the driveshafts are on my phone and the auto upload to photobucket is not working. Go figure, it is a "smart phone", and I am a dumbass for buying it.

But the good old 3meg camera is working fine so here are some pics of the finished hingepin braces. Made out of 6061, not sure on the widths but the outside one is as thick as possible to fit in the slotted area of the arm (just slightly thicker than stock). The inside brace is easily 3 times thicker than stock. I had this material laying around, bought for some project at some point.

I drilled and tapped the inside brace for 3mm screws to retain the pins, and did the same on the arms to keep the pin from getting out that way. Using the short traxxas servo screws, widest head m3 thread screw I had on hand. Did not want the threaded holes too close to the hingepin holes for strength reasons. One could make flat retainers that sit over the pin holes, like the ones pictured in post #4. I did not feel like cutting any more al so I did this.

As soon as the turnbuckles show up I will assemble everything else.

http://i206.photobucket.com/albums/b...p/DSCF4780.jpg
http://i206.photobucket.com/albums/b...p/DSCF4781.jpg
http://i206.photobucket.com/albums/b...p/DSCF4782.jpg
http://i206.photobucket.com/albums/b...p/DSCF4783.jpg
http://i206.photobucket.com/albums/b...p/DSCF4784.jpg
http://i206.photobucket.com/albums/b...p/DSCF4785.jpg
http://i206.photobucket.com/albums/b...p/DSCF4786.jpg
http://i206.photobucket.com/albums/b...p/DSCF4788.jpg
http://i206.photobucket.com/albums/b...p/DSCF4789.jpg
http://i206.photobucket.com/albums/b...p/DSCF4790.jpg

I did have to trimm off the stock hingepin retainers on the plastic skidplate. Not the ones on the bumper end, the ones closest to the pinion.

I also removed about 1mm of length on the hingpins, as they were slightly too long.

This was very straightforward and easy. I could have done it all in under 1hr, and likely made both a ft and rear set in that time.

I think on the thick end you could have shortened the pin even more and then not drilled all the way through the hingepin brace. It would have eliminated the use for the retainer screw.

Yes, this could be done. However I like being able to remove the pin from that end, the plastic skid does not have to come off for this. If you want the pins out the other way you have to remove it. Just 4 screws and the bumper mounts, but I like the option.

Be interested to see what measurements you get for width from outside hex to outside hex.

From my measurements tonight I have:

Savage X: 14.25"
Savage XL: 15.25"
RC8T: 15.125"

I was a bit surprised by this. But on the flip side, the suspension arm is longer so the you should have more suspension travel. Also, the axles and extenders are far more robust than the Savage junk.

Should be around 30mm more than a stock flux. Do you measure at ride height or while the driveshafts are parallel with the ground?

awesome job bud!!! looks very solid... im thinking some Titanium hinge pins to finish it off?

Have you got any pictures of the finished produt with the hubs and cvds installed?

Can you please tell me what thicknesses of alloy did you use ?

This was with the suspension arms flat on the ground.

Also because you now have the hinge pin pulled away from the bulk... doesnt this open a whole load of opportunity to run truggy arms and hubs instead...??? offering better steering possibilities?
BUT
i am unaware of how strong truggy CVDs are? can they handle 6-10s power?

You can modify the bulkhead to allow the use of truggy arms; what creating new end plates does means that you don't have to modify the bulkhead and you get a bit more width, 30mm is what he's estimating now.

As far as how strong truggy arms/cvds are. Its a give and take. Truggy arms are usually made of stiffer plastic to reduce flex, etc. to give more predicatble handling, etc. So while they seem to be tougher, they may break when the Savage arms end up flexing a bit.

As far as the CVDs... I bash my RC8T with no problems on 6S on a MMM with a 1518. But once again, its a trade off. Truggies are meant for racing, so things need to be decently tough, but also lightweight. The shafts on my RC8T are 3.75mm diameter vs the 5mm diameter of the Flux drive shafts. The axles are 8mm just like the Savage, but use truggy adapters with the pin going through the adapter and axle, unlike the Savage. All in all I would say that it should probably handle 10S.

But then again, 10S is frankly on the ultra extreme end, unless you are running a really lower KV motor (something between 1000 and 1580). After all an out of the box Flux running 10S on 1580kv with 1.07 rollout (out of the box is 1.26) is like ~58.91mph according to Script Asylum calc.

If you are running a lower Kv motor, I would think that the 8-10S won't matter on the abuse of the parts, other than added weight of the batteries.

And you have to take the difference in weight into account when comparing the durability. Truggies are fairly light when compared to MT like Savage..

People have been using Jammin CRT universals on their supermaxx but they did not last long..

Wish the ue supersavage cvd is still in stock. I bet that is the best money can buy for the savage owners.

Yes, that is true. However a Flux and a e-truggy aren't that far apart in weight and both are fairly rugged 8th scale vehicles; if I recall I think my truggy is like 9lbs or so loaded for bashing and my nitro Savage is like 10 or 11 and about that in Flux mode too.

Talking about 10th scale or smaller vehicles is kinda pointless.

LST CVDs on a non Losi MT eh! Whar dju git dat crazy idea eh? I like it. I'm not a fan of the truck but the mod is awesome. And it looks fairly easy to do. Very ingenious. Very cool that you can use the Losi hubs too.

Thanks MC, I know you like the lst.

Yeah, the losi hubs are much better design than the savvy stuff. In fact i think the lst is just better all ways round, save for the steering setup.

I just got the cen hubs in, and the hingepins. Arms and cvds are still in transit.

The cen hubs would not be a good choice to mod for use with the savage arms, both the arm and the hub would have to be trimmed and not enough meat would be left on either.

So hopefully the cen arms will fit the savvy bulks well. And looking at the cen lower bulk hingepin length I think the cen arms will fit perfectly between the stock savage hingepin braces. I am crossing my fingers.

I also received another shorter 4mm hingepin with the cen pins. Must be used for the upper arm to hold it to the bulkhead. It is 4mm diameter and has a nice locknut to hold it one. And it is the perfect length to hold the lst2 hub to the savvy lower arm. Nice, as I was going to have to find a 50mm long 4mm pin with eclips or something to hold that area together.

I will have to make a parts list when I am done, should someone else want to attempt this mod! Pretty easy to do, trimming the pins and making the braces is all of the fab work.

Really? I thought the steering in Savage is bullocks... I'm tempted to use a truggy steering in my 5T conversion...

The lst steering is just weird. 2 belcranks that one servo acts on each, then a thin wire thingy connects them. The servo savers are mounted to the servos, and are kinda weak. People use mgt servo savers and a mixture of other parts to make the lst steering better. I only bash so I do not really care, seems to work fine to me with the stock stuff.

The main thing you have to change for durability purposes are the steering knuckles. The new era ones are considered the best. Most people leave the plastic c hubs on the front and stock hubs on the rear. The stock front c hub on the lst2 can serve as the weak point, as it is cheap and easy to change. I have never broken one, but I have broken lst2 arms. Rpm arms cure that issue.

Linc! have you tried fitting the tvps? it looks like the tvps may hit on the extended alloy hinge pin brace?????

Have you tried fitting the rest of the hubs, cvds etc??? im interested to see how much lock you get when turning?

To me... if i cannot maintain a tight turning circle like i get with my savage suspension conversion kit, then i am not sure i would benefit much... Unless the LST hubs are modifyable to increase the steering throw?

Do you think the hinge pin could bend as it is not supported in the middle by the bulk?
is it worth putting a piece of alloy tubing the right size around the hinge pin to reinforce it?

edit...
i know that the LST CVDs are too small for the SHD savage axles... i am just wondering.. .do you think the vorza diff axles would work? the only reason i say, is because i just got a pair of vorza diffs and considering they use the tougher Hotbodies internals than the stock savage spider gears, i was just going to install the BP ring and pinion and be done with it... ???

It might, but it might even with the bulkhead there. Most of the truggies I've seen don't have the pin through a bulkhead but rather are mounted like Linc put it together as it allows you to adjust the toe-in for the rears and some other settings.

Unless I miss my guess the LST CVDs probably have a 8mm ball which is fairly standard on 8th scale vehicles so should work without any issues. The "SHD" axles use a 9mm ball.

thanks bud... thats true regarding the truggies... but they all tend to have arms that cover the entire hinge pin rather than just at points like the savage. Im sure it will be plenty strong enough... and if an arm fails, there is now no need to remove the plastic bumper to access the pin as it protrudes from the truck.

I hope Linc can show us if the lst cvd can use the savage diff axle, as it looks like he has put some HD axles which are not SHD...

Nice job linc but I have one question. Wouldn't it have been easier to modify the cvd shaft? Cut the shaft and take out a piece 6mm and then get some tubing that has an ID the same as the OD of the shaft and weld it together. That should result in a shaft that is plenty strong and wouldn't have been much work

imagine everytime you bend a shaft from a bad cartwheel or bad landing... you can not just replace with a new cvd... you would need to mod it.
It would be so much effort.

In 4 years I have bent one cvd, it was with my truggy two years ago on it's maiden voyage. That CVD is still in the truggy after two years of racing