jebster's creeper

[rmdesignworks]

The only thing Ive done to the front end on mine is to spread the front uppers a bit at the stock location on the axle and I added a 5mm spacer inside the chassis which brings the uppers a little closer to parallel. I also put about a 30 degree bend in them to help clear the OTA steering links and the shocks...this make them bow inward a bit. Total angle was changed with about 12 - 15mm of spacing changes if you only did it at one end or the other.

Im glad the diagram helped.

 

[jebster]

ok. i'm still tuning my front end so i might make some mods like you mentioned. things are working pretty well. i've made some mods to my rear end like you suggested and i've noticed some improvement. still have the saddle pack on the rear. i'm using that weight as an alternative to wheel weights and it seems to be working out pretty good. next i need to invest in tires (rovers). if that is all working i might start upgrading other parts (servo, hubs, lockout, etc).
i'm still playing around with the remote diff lock. i know, everyone votes that it is worthless but i like trying to get everything functional! i'm not competing (yet) so for playing around in the back yard i might make use of it.

 

[rmdesignworks]

jeb,,,by all means man play with the diff locks,,,let us know if you find a way to affectively make it work. pics pics pics too

 

[jebster]

i will keep you posted. i'm looking at increasing the diff ring pins from 3 to 6 (press pins in the ring and add additional holes in diff housing) to make for a more positive engagement. to prevent it from disengaging when under power i want to add a spring behind the diff ring to keep pressure on. it would require a strong servo to disengage but given the default should be diff lock that might not be bad. just don't want to burn out servos all the time. and yes, if i make progress i'll post picks.

 

[jebster]

another question. i've been running with a 55t (venom fireball) and feel like there are times i just don't have enough wheel speed. how much of a difference in speed would i see if i went to a 45t (assuming everything else is equal)? what about a 35t? i got a goat 3s esc originally in case i decided to switch over to a sensored brushless motor but i'm not sure i'm ready to make that change.

 

[rmdesignworks]

Im actually changing over to a 45t lathe motor soon too...it will sacrifice some low end torque but will gain some wheel speed. I will also be changing from a 19t pinion to either an 18t or 17t to gain some of the difference back. Remember though that the higher the winds on the motor the higher the torque and lower speed,,vice versa for lower turn motors. i highly advise agaisnt bBL systems cuz most suffer from cogging at lower speeds when you need to really crawl slow the motor becomes choppy,,,but some people do have great success with them.

If you are gonna drill a diff carrier out for 6 pins instead of the stock 3 then youll need to do it with the alloy carrier housings. When you drill out the plastic ones youll be decreasing the stress area of the carrier that the locker pins move in and out of. You will also be increasing the force necessary to engage and disengage the lockers,,,I am not sure if the plastic shift fork will work wit the increased stress.

 

[jebster]

Im actually changing over to a 45t lathe motor soon too...it will sacrifice some low end torque but will gain some wheel speed. I will also be changing from a 19t pinion to either an 18t or 17t to gain some of the difference back. Remember though that the higher the winds on the motor the higher the torque and lower speed,,vice versa for lower turn motors. i highly advise agaisnt bBL systems cuz most suffer from cogging at lower speeds when you need to really crawl slow the motor becomes choppy,,,but some people do have great success with them.

If you are gonna drill a diff carrier out for 6 pins instead of the stock 3 then youll need to do it with the alloy carrier housings. When you drill out the plastic ones youll be decreasing the stress area of the carrier that the locker pins move in and out of. You will also be increasing the force necessary to engage and disengage the lockers,,,I am not sure if the plastic shift fork will work wit the increased stress.

keep me posted on how you like the 45t. not ready to invest in the new motor yet. i too have concerns about brushless but i've seen some posts/videos of people really taking advantage of them.
as for the diff lock i already switched over to the alloy diff housing so i should be set there. i'm talking to my brother (machinist) about making an aluminum shift fork to deal with the increased load that would be added if i use a spring to add tension to the diff lock plate. this might all fail miserably but got to give it a try!

 

[jebster]

i've seen a couple threads with people talking about little to no TT. i've raised and spread my rear links (see picks) and can get to about 60 degrees vertical climb but it seems like the right front still picks up a fair amount. i was curious if anyone had a measure of torque twist. something like amount of weight required to keep the right front on under power. more weight needed, more TT you have. any thoughts?

 

[rmdesignworks]

Jebster,,,youll never get rid of all the TT. Period. How much weight are you running in the front end?

Try a little more spring preload in the right front and left rear and a little less preload in the left front. One thing to remember is that when you get the front axle closer to the apex of the vehicle angle,,in other words the front axle is close to vertically parallel with the rear axle it starts losing vertcle eight and becomes spinning mass on the ends of the links. The more verticle you get the harder it will become to keep the axle from trying to wrap to the left. Alot of our TT comes from rotational forces fighting each other and the differences in weight placement versus shock/spring-link geometry.you can also try spreading the front links a little further apart. Add another 6mm spacer between the link tabs and the rod ends for both front upper links. Remember too,,60 degrees aint no joke.

 

[SpeedyG]

Check out page 2 of my thread... I'm getting 58 degrees incline Creeper-wise without ANY wheel weights at all... Kinda surprised me, since I put a fair bit of work into my AX since I got it and I thought it would be better... I actually kept all 4 tires on the board, even when it started slipping...

RMDW knows link geometry yo... :mrgreen:

 

[jebster]

RM, i'll make some pre-load adjustments as you suggested. i'm also going to try spreading my front upper link spacing at the axle. currently i have 5.25oz in each front wheel, none in the back.

getting to 60 degrees was a goal of mind for no better reason that most people in these forums see that as a good benchmark. in all honesty i've only had a couple hours runtime on the rocks (you've probably noticed the lack of action pics) due to work schedule but i'm hoping to get a lot of time to try my rig out this weekend. pics and results on the way.

 

[Abavuso]

I think I stand corrected about the weight placment. I did a little bit of digging on in the tech section and read thought about 20 pages of posts and this is what I learned about weight ballance.

1. With shafty's the first and formost issue is TT. I think with the help of RMDW we've estabilished the proper way to take care of that.

2. The weight of the creeper should be centered in the middle of the chassis and as low as possable.

Earlier I told you I was running about 30 oz total up front and 12 oz in the rear. I found I could climb almost 70degrees on a plank... wicked cool... however my rig seamed to be kida unpredictable when I got to the tipping point. I would slide to the left or right realativly quick.

The post I was reading put it like this. By over weighting the front make the rig like balancing a bowling pin upside down. You can do it but I like to fall alot. With the weight balance dead center on your rig, it helps make it more controlable at the tipping point and less random.

Another think I personaly notice, with all the weight up front , it makes decending a little on the tough side. Drop a front wheel off a ledge too far and the weight will drag the rest of the truck with it again, making it drive un predictable.

My findings...

My rig was set up to balance about 1/4 of the way up the lower links. My thought was that this would require less of the truck to make it over the edge for the much needed front traction. It works, but you've got one chance to make it right.

Now I rebalanced the rig. I took out 8oz from the front and added about 4 oz to the rear. Not I balance about 1/2in forward of the center of the trans. The diference, before If i tried to motor up a slope and hope the front end over, the weight would cause me to plant and slide at the top.

Now with a more even balance weight, If given the correct amount of wheel speed, when climbing that 60 degree slop, the front end holds that same angle till the rear wheels hit the top causing the hole truck to land on all fours. Not to mention it just feels so much more predictable. Oh, and I can still climb 70 degrees.

So my recomendation, add a little weight to both the front and rear wheels to keep them planted and get more traction. Then add weight where it's needed to set your center balance about 1/2 in forward of center.

 

[jebster]

i've been playing with the weight distribution myself. i've found 5.25oz in each front wheel is working pretty good. for the rear i have a saddle pack battery that adds about 9oz total to the rear axle. so, i'm pretty balanced right now and it feels stable. i was able to crawl up a 60 degree slant. when i put a small lipo on the front axle (no saddle in the back) i get a more forward weight bias and can get up to 65 degrees. i happy with the way it is running right now. i need more time on the rocks to check things out. that and a new 4VP chassis!

i've raised my steering and rear axle links to help on clearance. i'm working on a BTA steering mod now. still working on bulletproofing the front diff lock system but no news on that yet.

i did have time yesterday to get out on the rock pile and got some pics.

 

[jebster]

next up is new tires. it looks like rovers are the top choice. given venom factory wheels have a somewhat unique beadlock system has anyone had problems getting them to fit? i would like new aluminum wheels but i might not be able to afford that yet.

 

[rmdesignworks]

Rovers will work on the stock wheels...BTW,,the rig looks good,,how do you like running the bat forward?

 

[jebster]

Rovers will work on the stock wheels...BTW,,the rig looks good,,how do you like running the bat forward?

the battery on the front axle works pretty well. it does feel a little heavy when traveling over ledges but not bad. i haven't decided which way (front or saddle pack on the back) i like best. i will say the saddle pack (40C 4200mAh) runs so long i almost get bored...almost!

 

[rmdesignworks]

yeah with the weight in the wheels, the steering servo and shift servo and the bracketry plus the lipo youve got around 20-25 oz on the front axle...that quite a bit.

 

[jebster]

yeah with the weight in the wheels, the steering servo and shift servo and the bracketry plus the lipo youve got around 20-25 oz on the front axle...that quite a bit.

good point about the servos, plates, brackets, links, etc adding extra weight to the front already. i ran again yesterday afternoon and given the rocks i'm running on i think the saddle pack in the rear gave me a better feeling of control. that may be different on different surfaces but it works for me. now, once i get some tires with better traction i'm sure i'll be able to handle more challenging lines.

 

[SpeedyG]

The Rovers fit on the stocker wheels, altho I'm having some trouble keeping the bead from pulling out... I leave the ring on using 3 screws and tuck the bead in under the ring, then tighten the 3 screws and check the sidewall for inconsistencies... Then I install the remaining screws, but it seems they aren't clamping tight enough... Also, I have one tire out of four that has torn treadblocks - right out of the bag!! (won't hold air like all the others - they seem to work better when they're puffed out) I will have to take pics, maybe HPI will send me a replacement...

PS - sorry for the hijack!!

 

[jebster]

not a hijack if you're giving input. i've seen your issues with the rovers mentioned by a couple others. there are also people saying they haven't had any issues. could this be an issue with the rovers quality?

on the topic of tires/wheels if i wanted to pick up a set of aluminum wheels is there anything i should be particular about? i was looking at these http://www.ckrccrawlers.com/narrow-black-aluminum-22-wheels-4-wgreen-rings-p-858.html. i love the black and green colors and the price seems reasonable. they are listed as narrow but when i contacted ckrc they said the wheels were 1.5in wide, which is the same as the stock creeper wheels.