BIG problem, SIMPLE solution

[Erik D_lux]

Kbrog pointed out in my high clearance link thread that the axle wraps really bad in the rear. Ever since he pointed this out it has really bothered me. My car was running so poorly the other day that I ran back to my shop to figure it out.

The problem is that the vertical separation of the lowers and uppers at the axle is not enough. It measures roughly .75 inches.

I have never delt with it because I did not want to go through the trouble of building a whole new mount. When I sat down to figure this out though, it occurred to me that all you need to do is space it up with spacers.

I threw some .25 spacers in between the link mount and the axle. Wow! What a difference! I knew I had a ton of hop but did not understand the source. I was trying to band aid the wheel hop with stiff springs and thick oil. Once I put the spacers in it was a MAJOR difference not only in performance but also because the drive shaft does not bind. I have always blamed the stock drive shafts for binding so I got driveshafts with bigger cups to help fight this. Now I am back to LNC driveshafts and I could not be happier.

The spacers ideally need a taper to them. I have some bushings that work perfect. If anybody needs a set I can do 4 for $5.

Here are some pics of the rear...

[Erik D_lux]

After seeing how much of a difference the rear made I tried to figure out the front. Not as easy and not as ideal. I ended up drilling and tapping the servo mounts. This has also stoppped axle wrap in the front. This will give you ALOT more anti dive in the front. I dont really notice as I am running droop in the front now so I am not effected. If you want to fix this you could drill a hole higher up on the chassis an equal amount that you rasied the front links at the axle.

You also need to make sure your upper links clear your shocks at full flex. Mine did not so I bent them in and they work great.

Also, if somebody needs AL bent links I can do some for the same price as my regular AL links.

Having ZERO axle wrap make a HUGE difference. Try it, I know you will agree.

[guidetti_angelo]

Photos didn't look..
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[Erik D_lux]

Originally Posted by guidetti_angelo

Photos didn't look..
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Should work now

[guidetti_angelo]

Originally Posted by Erik D_lux

Should work now

they work

[Tydl]

I love your idea of using spacers! I've been tossing around this same issue and knew the answer. I was considering trying to mill a new mount, but this is way easier. Atleast until I find the height I like. Did you try other lengths or just 1/4in? Are you still using stock length upper links?

[Erik D_lux]

Originally Posted by Tydl

I love your idea of using spacers! I've been tossing around this same issue and knew the answer. I was considering trying to mill a new mount, but this is way easier. At least until I find the height I like. Did you try other lengths or just 1/4in? Are you still using stock length upper links?

My first ones were just over 3/8 and they worked but the spacers were a full .250 diameter and that did not work as they were too big at the top of the mount. I have these bushings that taper from .188 down to .250 wide and overall .250 tall. They still have zero axle wrap and thats what we are looking for.

Also, I was concerned about strength of the added length. My rear axle was a recycled front axle. I had the back to screw holes stripped out. I ran just the back two screws with spacers and it held up great until I could install a new axle and use all 4 screws/spacers

Stock length uppers. It did not change my pinion angle much at all.

[Sneed]

I've done the same thing, only I used axial spacers. 3mm I believe. I had to dremel my upper link mount a little. It was a simple fix. Just use a round sanding attachment and work on the mount until everything fits flush. I'll post a pic later

[tapped-out]

Kbrog pointed out in my high clearance link thread that the axle wraps really bad in the rear.



Can someone explain axle wrap ???? I made my own rear high clearance links. Want to know what to look for.....Thanks

[Sneed]

Next time your crawling, pay attention to the rear axle. It will rock forward and the pinion will nose down. This action messes up the suspension geometry . It mostly makes the rear of the truck hop

[Erik D_lux]

Originally Posted by tapped-out

Kbrog pointed out in my high clearance link thread that the axle wraps really bad in the rear.



Can someone explain axle wrap ???? I made my own rear high clearance links. Want to know what to look for.....Thanks

Like Sneed said, it causes the axle to rotate back and forth, pinion/driveshaft bounces up and down.

This is not a link issue. It will happen with any links whether they are hi clearance or stock. Its a separation issue at the axle.

With the stock setup you may as well have leaf springs in there. The constant bouncing of the axle takes away all your traction.

[rob_b]

Is it rod-end flex/slop? I am running revo ends with 3mm hardware on all the links and don't have this problem at all. The truck had no bounce in it on vertical climbs at yesterdays comp.

[Erik D_lux]

Originally Posted by rob_b

Is it rod-end flex/slop? I am running revo ends with 3mm hardware on all the links and don't have this problem at all. The truck had no bounce in it on vertical climbs at yesterdays comp.

No.

Grab the two rear tires of your rig and lift it in the air while watching the driveshaft. The driveshaft should not move a tiny bit unless its your shocks compressing. Now while holding it in the air by the tires lift and drop the front end and you can watch the axle wrap.

Another good way would be to have your battery tray that is attached uner your front steering servo. Without a body on give your car full throttle and watch the battery dip/rise. When you have something hanging off of the axle that is extended you can see it well. If you check my weight thread you will see my ESC/RX mount that is just like your battery mount. I could see it VERY well since it is so long.

[Sneed]

If the Losi Team increases link separation, then I guess we should too.

[rob_b]

Twisting the axle as hard as I can the plate moves about 1/16" measured 4" out from the axle CL. If my math is right that's 1.8 degrees. Seems pretty damn solid to me.

[Tydl]

Originally Posted by Sneed

If the Losi Team increases link separation, then I guess we should too.

I noticed this at nationals too

[KBrog]

Originally Posted by rob_b

Is it rod-end flex/slop? I am running revo ends with 3mm hardware on all the links and don't have this problem at all. The truck had no bounce in it on vertical climbs at yesterdays comp.

I didnt have so much of a issue in stock form. I started having trouble after I made delrin bent links. Some of it was stock rod end flex, some was delrin flex. So I put a bend in the stock AL links (less bend than what it was on the delrin), re-drilled and tapped the threads to 6-32 with 1" studs to go deeper into the stock rod ends. The set-up is working at the moment, but I still have to pay attention to the rear axle clocking itself under heavy bind to keep from shattering the driveshaft cup. Raising the mounting point on the axle of the upper links sure would be a fix for the issue, and easy to do on the rear if your not running your ESC on the axle. Not so easy on the front with the servo. I like the idea and think Ill give it a try. Thanks Eric D_lux.

[shelljeep]

Originally Posted by rob_b

Twisting the axle as hard as I can the plate moves about 1/16" measured 4" out from the axle CL. If my math is right that's 1.8 degrees. Seems pretty damn solid to me.

Are you running straight links? Bent links will flex more easily. Link flex is what's causing the wrap.
Increasing seperation at the axle reduces the force that the links see, increases the link's leverage to hold the housing solid.
It will ease strain on the rod ends also. Might pop a ball less often.

Good idea Erik. Did you address the change in suspension geometry re: A/S%? Moved the frome mounts up to compensate?

edit- Long term, I'm interested to see whether this mod will allow the housing to strip threads and seperate sooner.

[rob_b]

Lowers are 3/16" heat treated O-1 tool steel, straight in the front and bent in the rear. Uppers are straight 3/16" 6061 aluminum. They are all threaded 10-24 on the ends and screw directly into revo rodends. The rodends are attached with 3mm hardware. The lowers will never flex under any loads that the truck can generate, same with the uppers but I have had a few uppers bow during nasty tumbles in the last year...

[Erik D_lux]

Originally Posted by shelljeep

Good idea Erik. Did you address the change in suspension geometry re: A/S%? Moved the frome mounts up to compensate?

No. I did not see the need. When in stock form I changed my AS from the lowest to highest setting and could not tell much of a difference. As soon as I get other setting dialed in I may mess with it.