The progression of my XR10 into a Berg.

[95geo]

I guess that it seems really simple in my mind and that common sense would have said when you tightened up your wheel nut and it got tight to check it out. I have had several sets(none of which where mine) that guys didnt have to trim there hexes. I used to write fairly detailed directions for installing. I get less pms now then I used to when I included them. At some point I guess I decided to just build parts and quit hand holding. If someone can figure out how to take the axle apart and put in the new ones great if not they will pm me. Besides you dont strike me as the kind of guy that would have read the directions even if I had included them. Hell I never do. the packaging and directions all end up in the round file, and I just build.

I dont feel like going in circles over things that have already been mentioned and remedied. I said what I wanted to, you gave your reasoning and it is what it is. I got the new shafts last night and they look good. Thank you for getting them out as soon as you did. "thumbsup"

I would say approx. 20 sets where ran at nats. no issues. Nice lookin build by the way

Thanks!

Truck looks great. Are you going to put that extra cf brace out the front where the shock mounts to stiffen that extra long shock standoff?

I hadn't planned on it. I dont particularly like the look of the broken up front end when they are moved out so I'm making some stand-offs with a bell/flange on them to spread out the load and I will still be running a spreader between them since I dont need to sacrifice strength for weight savings. There are a lot of other areas where there are non structural savings and the chassis bracing is critical IMO. I'm still about 2 lbs heavier than where I would feel ok with removing structural material.

I can respect the hell out of guys like Nabil (no offence to others, he's just the only one I've seen drive in person) who can make a mostly plastic mid 4 lb car last while making it dance over the rocks. Myself on the other hand, I have not been blessed with the ability to make things last where others have been so fortunate so my only option is to build as strong as the weakest link and take away everything that isnt required.

It's amazing how things can get taken the wrong way on the internet via posts while having mixed emotions about a topic.

Being a dick and trying to lighten the situations has obviously gotten mixed up.

The difference between a dick head comment and lightening the mood is as definitive as this little emoticon right here ->

John, like myself pays someone to make the shafts and works a 40+ hour job on top of it. It makes it hard to test and eyeball every issue. Having you get 4 wrong items after having parts from the same batch be fine hurts john just as much as it aggravates you.

Having only seen your post I see very negatives posts, whether fair or valid, and John trying to get the issues fixed, even when done so he still gets ragged. I don't think I read anything good about your purchase. It sucks as a vendor to go through all this, try to get it fixed and still look relatively bad on the forums. Makes it alot easier when the customer can see both sides.

I'm not saying praise him, or think you should be pretending to be happy. Both of you got the poop end of the stick, but at the end of the day, he tried to make it right. I know first hand alot of vendors would have refunded your money or blew you off. It's happened to me.

I have only been negative on one topic. That was about the spacer that was .25mm too small to be a correct fix. I went into detail about why, if that gets lost on anyone, they must not need the fix.

In this build I decided to make note of my "luck" since from day one it has been on a downward slope and nobody wanted to believe that my luck was as bad as I say it is (see the first half of the build). That is the only reason I have been pointing out the "negatives", upon first impression.

Aside from that, I built this car around John's 300HD front axle shafts. That was the single item that made me build bergs and not try to save the XR that has taken a toll on my summer due to constant up-keep. It has been a long time in the making but I wouldnt run different shafts unless the option was no longer there.

To clarify further, I have never been anything but professional and appreciative towards John. He has done everything I have asked or expected out of a situation. I'm probably the largest pain in the ass customer he's had in a while but all I ask for is what was sold. If I get that, you'll get more of my business and everyone ends up happy, that's how it works. The luxury of the internet and online communities are two fold; the entire demographic you're seeking in one area which makes day-to-day business more streamlined, but it can also work against a business if too many people have negative experiences. In this instance, I have/had nothing against SDS Customz, I was simply documenting "my luck" over the course of this build. I was very careful to not throw anyone under the bus because I understand how things can snowball, that is why I didn't say anything about the spacer in any of his product threads, only in my build thread.

If your offered by my comments it's not my intentions. I've been viewing your build because it's very similar to mine and has turned out very nice.

Not offended, just replying in the same context. It's the internet.... I'm only here for the exchange of information.

Thank you for the compliment. It's taken a long time to think this car up and so far I'm very happy with how it has turned out. In time, I hope to be lightening mine up as much as you have lightened your up. I'm looking forward to seeing how yours comes together! "thumbsup" Two different builds, same front axle shafts, similar end results! :mrgreen:

Truck looks awesome man.... I'm super excited to see both of ours side by side to compare!

Thanks bud! Tomorrow is going to be a blast! :mrgreen:

Too much typing.... Maybe I'll be back after states, or maybe I'll disappear for good.

 

[The Violator]

I think the OP problem lies in his background. I think he stated somewhere he was an engineer. These TOY cars, most RC cars in general are just not tight. When I first started I shimmed my Losi 8ght t Truggy until it had no wobble anywhere. I could not keep it on the track. Crawlers are all a little loose. That is what allows most of us with nothing more than hacksaws and files to do the things we have done and have success. Common sense in the real world means dont piss on an electric fence. Common sense in the RC world says a little wobble is OK and long as it keeps working. I think the toughest part about people who make parts is the base from which they are working. I would bet the tolerances on these cases and tubes are pretty wide, and once you add multiple people all building parts .05" here and and .05 there ends up being a lot in the finished products.

Nice build, and good luck with it.

 

[TSK]

I think the OP problem lies in his background. I think he stated somewhere he was an engineer. These TOY cars, most RC cars in general are just not tight. When I first started I shimmed my Losi 8ght t Truggy until it had no wobble anywhere. I could not keep it on the track. Crawlers are all a little loose. That is what allows most of us with nothing more than hacksaws and files to do the things we have done and have success. Common sense in the real world means dont piss on an electric fence. Common sense in the RC world says a little wobble is OK and long as it keeps working. I think the toughest part about people who make parts is the base from which they are working. I would bet the tolerances on these cases and tubes are pretty wide, and once you add multiple people all building parts .05" here and and .05 there ends up being a lot in the finished products.

I HAD to quote this because it is the most reasonable, well thought out and worded post I have ever seen from this member.

Not to say I am agreeing with 95geo on some of his comments, or with Ted for that matter.

 

[jcboof]

I feel your pain Bryce. Tolerances were something that I tried and tried to keep in check for a long time but finally gave up when parts and bearings kept breaking. I finally just let everything get loose and sloppy and it seems to work well. Sorry for your tough luck on this build so far.
But I do look forward to seeing the truck tomorrow and chillaxin. "thumbsup"

 

[95geo]

Got the new shafts installed, turned the ID of the supplied spacer out so it would sit between the shaft and the big bearing, doing that centered the joint in the knuckle but it also made a gap between the small bearing and the shaft so in order for things to not bind up, I used 9 .1mm thick shims between the small bearing and the shaft. Then I machined the back side of the hex so it had the same profile as it did originally but I took .5mm off and everything lined back up and I can finally tighten the wheel nut up without hitting the pin and without locking the shaft up.

Let see how long things can stay together now that all of the not perfect things have been taken care of.

 

[95geo]

I took the additional weight out of the front wheels and drove it for half a dozen packs on Sunday. Aside from not holding a side hill line very well, I'm pleased with its performance. I have a few things I will be trying in order to strengthen the weaknesses it currently has but it's getting there. The rtr weight is 4 lbs 9.5 oz with about 6 oz easily removed by swapping wheels and taking some additional weight out of areas that I have dileberately left heavy for easy removal later on down the line.

The front shafts are working well and they are holding up to stalling my brood 5 segment motors.

I think this platform will get me where I want to be for reliability and strength, stay tuned for where things end up....

 

[Farmer]

Thanks for letting me drive this gem. Wasn't sure I would like the wraith/300hd setup. Wrong....I love it:mrgreen: Your lucky your rig did t come up missing on sunday:lmao: Keep it up man, just plain SICK!!!!
Later,
Farmer

 

[binaryterror]

Bryce the truck is doing pretty good man. Easy to drive and follows lines well. Also able to fix itself when not driven well.

Just need to gather some fix for the sidehill slide you had. Seemed to be the only issue I felt in the truck.

 

[95geo]

I win.

The tires touch the case and the end bell of the motor.

 

[Krawler Kev]

Thats awesome.:shock:

How many degrees?

 

[95geo]

I haven't taken a protractor to it yet but I'll have to prove I'm not stretching the truth a little since my eyeball angle-ometer is giving me a reading of 68-70 degrees. But the angle and loads on the joint is just too much at that angle so I will be making some hard stops somewhere in the high 50's to low 60's depending on where the sweet spot ends up being.

Before getting the perfect length arms (can't remember the vendors name but I'm running his weight holders now too) I was design limited to 55 or so. These few extra degrees should allow me to control the front end wash while working off camber climbs.

 

[superduty03]

That's flat out amazing steering dude! I couldn't believe how your truck held lines when you let me test it out, great job man, I know you will continue to impress with your ingenuity .... Keep up the good work man, see you in a couple of weeks!

 

[EverettY]

Before getting the perfect length arms (can't remember the vendors name but I'm running his weight holders now too) I was design limited to 55 or so. These few extra degrees should allow me to control the front end wash while working off camber climbs.

Was it Tomy? Wow that steering is amazing! You still running the 300 HD's?

 

[95geo]

Was it Tomy? Wow that steering is amazing! You still running the 300 HD's?

Yep and yep.

The key to keeping the HD's happy and tight is to spend as much time as absolutely possible to get the joint centered in the kingpin axis and shimmed properly so the bearings get clamped by the wheel hex and they are not allowed to float at all. I also run a delrin bushing in the tube that allows for a little deflection without letting the shaft flop around too much.

 

[95geo]

I finally have all of the bugs worked out of this thing and I have it tuned to my style of driving for the most part. It sits at 4 lbs 9.1 oz with one full VP .300" weight ring per knuckle, a 3 cell 600 mah battery and 1" SLW's with a minor light weight treatment to the rears which consists of 12 3/8" holes and a total of 5 grams shaved per wheel.

I'm very happy with its performance and I plan on leaving it alone for the most part. If anyone cares to see what I'm up to now, see 'The Pinnacle' thread in the berg section. It'll be a revised version of the ideas you see here.

 

[Erik D_lux]

I haven't taken a protractor to it yet but I'll have to prove I'm not stretching the truth a little since my eyeball angle-ometer is giving me a reading of 68-70 degrees.

Your picture might be deceiving but using my protractor on your picture I came up with 60-61*. I checked awhile ago. I am making my own shafts and I can only get 60* with all my stuff clearanced and I wanted to make sure I was on par with what everybody else was getting. All the other pictures I could find online that were worth measuring came in about the same 59-60* usually.

That 10* sure does make a huge difference over 50*.

I wanted to ask you a question as it seems you really took some time with your shafts to get them correct.

I got some universals that I made up. They turn about 70* smoothly in my lathe. I can put them into my car, full turn at 60* they are smooth as butter. The second I put a tire onto my shaft, go to 55+*, it gets a weird..... lag? hop? I dont know what to call it. I am assuming that its my U joint trying to catch up with itself. I am pretty sure the joint is aligned in the king pin pretty perfectly. I have gone over everything multiple times and cant find anything. Wondering if this is just the nature of the design or if I need to look at something else to fix.

 

[Nabil]

Your picture might be deceiving but using my protractor on your picture I came up with 60-61*. I checked awhile ago. I am making my own shafts and I can only get 60* with all my stuff clearanced and I wanted to make sure I was on par with what everybody else was getting. All the other pictures I could find online that were worth measuring came in about the same 59-60* usually.

That 10* sure does make a huge difference over 50*.

I wanted to ask you a question as it seems you really took some time with your shafts to get them correct.

I got some universals that I made up. They turn about 70* smoothly in my lathe. I can put them into my car, full turn at 60* they are smooth as butter. The second I put a tire onto my shaft, go to 55+*, it gets a weird..... lag? hop? I dont know what to call it. I am assuming that its my U joint trying to catch up with itself. I am pretty sure the joint is aligned in the king pin pretty perfectly. I have gone over everything multiple times and cant find anything. Wondering if this is just the nature of the design or if I need to look at something else to fix.

Thats the nature of a universal joint. both sides of the joint will never be perfectly synced up rotationally while turning. in our case the stub will accelerate and decelerate with respect to the inner shaft depending on the position of the cross and shaft angle

EDIT: even though it is wikipedia, this does a good job of explaining the math behind what im saying

http://en.wikipedia.org/wiki/Universal_joint

 

[TSK]

Thats the nature of a universal joint. both sides of the joint will never be perfectly synced up rotationally while turning. in our case the stub will accelerate and decelerate with respect to the inner shaft depending on the position of the cross and shaft angle

EDIT: even though it is wikipedia, this does a good job of explaining the math behind what im saying

Universal joint - Wikipedia, the free encyclopedia

That's exactly what I told Erik. Just with much less words and cool graphics:mrgreen:

 

[95geo]

Your picture might be deceiving but using my protractor on your picture I came up with 60-61*. I checked awhile ago. I am making my own shafts and I can only get 60* with all my stuff clearanced and I wanted to make sure I was on par with what everybody else was getting. All the other pictures I could find online that were worth measuring came in about the same 59-60* usually.

That 10* sure does make a huge difference over 50*.

I wanted to ask you a question as it seems you really took some time with your shafts to get them correct.

I got some universals that I made up. They turn about 70* smoothly in my lathe. I can put them into my car, full turn at 60* they are smooth as butter. The second I put a tire onto my shaft, go to 55+*, it gets a weird..... lag? hop? I dont know what to call it. I am assuming that its my U joint trying to catch up with itself. I am pretty sure the joint is aligned in the king pin pretty perfectly. I have gone over everything multiple times and cant find anything. Wondering if this is just the nature of the design or if I need to look at something else to fix.

You could be correct on the angle, I haven't measured it but it looked to be about 15 degrees sharper than my XR with VP vvd's that are maxed out at 50 degrees. Next time I pull a tire off I'll measure it and post some pics.

As for the goofy behavior of the tire, Nabil explained it perfectly. This isn't a huge deal at lower operating angles but as the angle increases, so does the amount of accel and decel that happens as a result of the single u-joint's traits.

If you want to see this mechanically, turn both wheels one direction, place a piece of tape on each tire at the same spot rotationally from one another. Slowly and consistently turn one side and watch the opposite tire speed up and slow down as the u-joint goes through its motion. The process of speeding up and slowing down (speed up then slow down = 180 degrees) happens twice per 360 degree revolution of the axle.

The only way around this is to phase two joints together like a drive shaft or a CV joint that had two u-joints next to one another or a unimog shaft at the steering knuckle pivot. The two joints speed up and slow down but if you are able to phase them properly when one speeds up the other is slowing down and as long as they both have the same operating angle, the output speed will remain constant, the same as the input speed.

 

[jacobflyin]

The only way around this is to phase two joints together like a drive shaft or a CV joint that had two u-joints next to one another or a unimog shaft at the steering knuckle pivot. The two joints speed up and slow down but if you are able to phase them properly when one speeds up the other is slowing down and as long as they both have the same operating angle, the output speed will remain constant, the same as the input speed.

This is why CV stands for Constant Velocity"thumbsup" and U joint well, just is what it is, a U joint 2 U's held together with a joint.