Hex pins... Lets fix the issue.

[Erik D_lux]

I have had a lot of time on my hex pins before I broke any. All my other test cars are STILL running them. I was really surprised to hear that anybody was breaking them.

After I broke one it was not long before a broke another. After I broke that one it was all down hill. I started breaking 5 or 6 per day (3 hour runs). I knew this is when we needed a better answer.

When looking into why the pins were failing, I found that all my aluminum hexes were worn out. All of the cars that are still successfully running the pins have hexes that are in great shape. What I believe ended up killing my pins was the fact that once I broke one or two, it bore the hex out so much that now that the hex had play back and forth and allowed the hex to shock load the pins (Imagine trying to break a door down by standing and pushing on it. Now imagine that you get a running start from down the hall.) I believe the stock/softer pins can handle this because they may bend enough to fill the gap and make it so it does not shock load the pin. Is it the hex or the pin that is the problem? If you are having problems and want to run the stock diameter pin, getting new hexes could solve the issue.

The stock pin is close to .060 diameter. This is tiny. I took a minute or two and thought about an even stronger pin. Maybe 300m? That thought ended really quick. Who really wants to spend a lot of money on a pin that may or may not work? The problem with the pins is the design, not the material.

This is my next step in solving the problem. I am now running pins that are .075 diameter. A .060 to .075 does not seem like a big step but it results in almost TWICE the strength. TWICE the strength! The beauty of it is that it does not take much material at all from the axle shaft.

In order to run these you need to drill the axle and the hex. Both are VERY simple and should only take 5 mins or so. I used a #47 drill bit. This is a very tight fit for both the hex and the shaft which is a great thing.

Please understand that I am only offering these pins right now to help people in need. You could permanently ruin your axle shafts and hexs if this does not work. I have been running them for over 20hours now with zero issue. Again, I broke 5-6 each day before this so that should somewhat speak for itself. You could do this, and have them break in 1 second. In my opinion this is a step in the right direction but may not be the final answer. I would have no problem stepping up to an even bigger pin if these end up having problems. Another .015 for an .090 pin would be a very strong pin if we need it and I really doubt anybody could have a constant problem with that big of a pin.

UNDERSTAND THE RISK THAT YOU ARE TAKING. IF YOU DO NOT FEEL COMFORTABLE, WAIT UNTIL I HAVE MORE TIME OR FOR OTHERS WHO ARE WILLING TO DO THE MOD TO REPORT BACK.

Here is the pin thread in the vendor section if you need the pins:

http://www.rccrawler.com/forum/showt...14#post2644114

[Erik D_lux]

Drill the hex and the axle shaft. I used a #47 bit for both. This is give a tight fit.

Drill the shaft:



Drill the hex cross ways and upright to clearance for bigger pin:

[losikid]

i think your right, i've broken many pins and hex pins break, also, in my cvd my slots are no longer straight, more of a oval, so that gap probably is causing pins to break so much, How do you think these bigger pins would work on the cvd side, will they fit in the cups (v3)

[Erik D_lux]

Originally Posted by losikid

i think your right, i've broken many pins and hex pins break, also, in my cvd my slots are no longer straight, more of a oval, so that gap probably is causing pins to break so much, How do you think these bigger pins would work on the cvd side, will they fit in the cups (v3)

Have not checked the CVD's out since most dont have problems with the Chromo axle shaft pins. This also supports the worn out hex theory. Both the axle pin and hex pin should see the same torque, the axle pin is just supported in a much better manor.

I know my CKRC and V2's look like they cannot be drilled out for a bigger pin. You would also need to clearance the entire slot on the axle ball. I need to look at the V3 again. If they have enough meat on the bell I would drill them out if I had problems, thats just me though. I am willing to make mistakes to find a solution.

[losikid]

Originally Posted by Erik D_lux

Have not checked the CVD's out since most dont have problems with the Chromo axle shaft pins. This also supports the worn out hex theory. Both the axle pin and hex pin should see the same torque, the axle pin is just supported in a much better manor.

I know my CKRC and V2's look like they cannot be drilled out for a bigger pin. You would also need to clearance the entire slot on the axle ball. I need to look at the V3 again. If they have enough meat on the bell I would drill them out if I had problems, thats just me though. I am willing to make mistakes to find a solution.

I'll go look, i have two sets of v3's about the same condition so it won't matter if i ruin 1 set, lol

[axelram]

Thanks for posting another option to fix this issue.

The stock pins will either snap or bend, drill bit will snap, Gunnar Pin will bend then I tried 2 days ago what Davec suggested in the other thread - 1/16" L hex wrench. I just came back from a comp this morning and I am glad that upon inspection, the pins made out of the hex wrench survived. I know I had so much loads in this pins today because a removed a lot of fishing lines wrapped around both front hubs and I have so much front torque on my MOA 17.5T BL motor with 14mm rotor.

Its now my habit to check any binding by turning the exposed gears in MOA before and after a crawl. I will try the bigger pin option whenever the L hex wrench will fail.

[losikid]

Originally Posted by Erik D_lux

Have not checked the CVD's out since most dont have problems with the Chromo axle shaft pins. This also supports the worn out hex theory. Both the axle pin and hex pin should see the same torque, the axle pin is just supported in a much better manor.

I know my CKRC and V2's look like they cannot be drilled out for a bigger pin. You would also need to clearance the entire slot on the axle ball. I need to look at the V3 again. If they have enough meat on the bell I would drill them out if I had problems, thats just me though. I am willing to make mistakes to find a solution.

On the cup it looks to be about 1 mm from out side dia to edge of cup, i don't got calipers today but i can get better results tommorow when i have a set of good calipers near by

[djjiz]

I'm happy with your old design myself because their still holding strong, and the couple that did fail were fine with me.

I don't have any other fuse left besides stock gears.

[Rootar]

Originally Posted by losikid

i think your right, i've broken many pins and hex pins break, also, in my cvd my slots are no longer straight, more of a oval, so that gap probably is causing pins to break so much, How do you think these bigger pins would work on the cvd side, will they fit in the cups (v3)

new cvds will fix your problem, with 1/10th scale electrics (2wd truck,buggy,sc and 4wd buggies) thats pretty much a sign to replace to the bell part of the cvd is when you start shearing cvd pins.



hey eric ..... exactly what i was talking about in your old thread but you could go much larger with the pin, whats the diameter of the axle where the pin goes through?

[stubs179]

I got tired of breaking pins all of the time too. I justed drilled the axles and ran Axial pins and hexes. They also give you a little more width. I ran a set of CKRC cvd's and a set of V3's without any problems. I think that is the best and cheapest option IMO.

[Hulksta]

Im running axial pins & hex's on one if my rigs, i drilled the axle to take the pin then machined the hex down to the size of the losi ones, they work a treat I can grab a pic if you want?

[Rootar]

if its a 5mm axle get slash rear aluminum hexs and the slash drive pins which definetly wont break they are about the largest 1/10th drive pin

[Erik D_lux]

Originally Posted by losikid

I'll go look, i have two sets of v3's about the same condition so it won't matter if i ruin 1 set, lol

Just took another look at a V2.

There is .040 from the stock pin hole to the end of the bell. I dont think another .0075 would hurt it one bit.

[Erik D_lux]

Originally Posted by axelram

Thanks for posting another option to fix this issue.

The stock pins will either snap or bend, drill bit will snap, Gunnar Pin will bend then I tried 2 days ago what Davec suggested in the other thread - 1/16" L hex wrench. I just came back from a comp this morning and I am glad that upon inspection, the pins made out of the hex wrench survived. I know I had so much loads in this pins today because a removed a lot of fishing lines wrapped around both front hubs and I have so much front torque on my MOA 17.5T BL motor with 14mm rotor.

Its now my habit to check any binding by turning the exposed gears in MOA before and after a crawl. I will try the bigger pin option whenever the L hex wrench will fail.

Thanks for the info. Its good to know that will work in a bind. I dont ever want to worry about a hex pin again though.

[Erik D_lux]

Originally Posted by djjiz

I'm happy with your old design myself because their still holding strong, and the couple that did fail were fine with me.

I don't have any other fuse left besides stock gears.

Do you know what your hexes look like on the pin side? Just wondering if they are hogged out.

[Erik D_lux]

Originally Posted by Rootar

new cvds will fix your problem, with 1/10th scale electrics (2wd truck,buggy,sc and 4wd buggies) thats pretty much a sign to replace to the bell part of the cvd is when you start shearing cvd pins.



hey eric ..... exactly what i was talking about in your old thread but you could go much larger with the pin, whats the diameter of the axle where the pin goes through?

We could go larger. I just want to find the happy point where the pin is bullet proof while keeping as much meat on the axle shaft as possible. I dont want to go from breaking pins to breaking stub shafts. I would much rather break a pin than a stub. Even if it is every 2-3 packs.

[sledge57]

I have another thought on this too, but I think the Hexs being worn could also be the problem.

What I'm wondering is are guys who are breaking pins using aluminum knuckles and c's or the stock ones.

I'm using aluminum and we found during the last comp (after I snapped your chromo pin like a twig ) that if I put the washer on that's supposed to go between the bearing and pin, when I tighten my wheel nut the wheel binds.

This could be caused from sloppy hexs even though mine don't seem all that worn to me, or maybe the outer bearing is protruding to far from the knuckle, in which case the only fix is to machine the pocket the bearing sits in a bit deeper (that ain't happening for me).

Not sure exactly what the answer is but I have 3 complete sets of Losi Hexs (all used unfortunately) and I'm going to try them all and see if I can find a pair that work (up front).......

[Erik D_lux]

Hmmm,

I never broke any with my AL, HR knuckles/C's. I did start having problems when I switched back to my stock C's and AL RC bro knuckles.

[Toyo496]

To date I have only broken one pin, and that was on the rear. I run the Losi Alumin. front knuckles with stock plastic C's.

[AZrcdriver]

To date...Parts broken count = 0

It's either driving styles, hours run or both I guess....

All original on mine so far.