Blackfoot steering knuckle adjustment

[old skool^s kool 6]

As well ducumented the blackfoot re-re suffers with bad bump steer, as I've already spent to much on my son's recently modified knuckles are out of the question so instead I just purchased a couple of 6mm male - female adapters to raise the steering arms,  (See picture), this has reduced the bump steer but not enough, does anyone know the best height by which too raise them? 

[Juggular 4964]

AMPro engineering has a 3D printed set.  

https://www.shapeways.com/product/K9P4MH726/058012-00-blackfoot-orv-zero-bump-steer-knuckles?optionId=61865185&li=marketplace

 

 

[old skool^s kool 6]

Cheers, I have seen them but previous abs printed parts have only lasted a week or two at the hands of my son.

 

Guess I'll have a play around with some spacers tomorrow to get an estimate of length needed without fouling the wheel/tyre

[BattleTrak 61]

The Parma steering blocks are raised 15mm.   A center mounted steering servo will help too.

[old skool^s kool 6]

Thank you,  15mm ones now ordered,  good point about centralising the servo, 

[BattleTrak 61]

I will be interested to know how well those 15mm standoffs hold up..alotta leverage going on there.  Don’t dismiss the AmPro stuff..it is 3D printed nylon, not ABS.   And Shapeways does a great job..  I have been very impressed by their work and haven’t broken any of their nylon parts yet.  If you can’t find the Parma parts,  the Ampro ones are a close second.

[Frog Jumper 3663]

In addition to the bump steer knuckles, you can mount the steering rods on the underside of the servo saver. This helps a little.

Frankly, the BF front end is pretty jiggly and fixing bump-steer only solves half the problem!  Lol!

 

[BattleTrak 61]

21 minutes ago, Frog Jumper said:

 

And right there is what you need to do, old skool!  

[Killajb 1546]

I purchased a set of these and added long ball studs with spacers to gain the height needed to reduce bump steer.   https://www.ebay.com/itm/133295132753?hash=item1f09025051:g:WD0AAOSwieZZepWb  

[old skool^s kool 6]

Thanks for the advice, this is my 9 year olds car that he just uses for bashing. and we have only just dug it out again after neglecting for the last couple of years so have already spent a bit too much over the last few weeks (Lipo battery, frog axel, driveshafts, new esc (as old one died after a couple of runs), brushless motor them MIP diff).  so am looking at budget mods for the time being

[old skool^s kool 6]

So far the 15mm stand offs are doing well,  bump steer has has reduced but there is still a lot of play in the steering, (sockets are well used so a little slack there, plus too much flex in the servo saver). 

Frog jumper, can I ask what steering arms you used in the photo? 

 

[Frog Jumper 3663]

7 hours ago, old skool^s kool said:

So far the 15mm stand offs are doing well,  bump steer has has reduced but there is still a lot of play in the steering, (sockets are well used so a little slack there, plus too much flex in the servo saver). 

Frog jumper, can I ask what steering arms you used in the photo? 

 

I want to say Duratrax turnbuckles. I don’t remember the length.

Get some 4/40 or M3 rod and cut to length. This will help determine what length t-buckle you’ll need. 

[old skool^s kool 6]

On 7/27/2021 at 12:05 AM, BattleTrak said:

I will be interested to know how well those 15mm standoffs hold up..alotta leverage going on there.  Don’t dismiss the AmPro stuff..it is 3D printed nylon, not ABS.   And Shapeways does a great job..  I have been very impressed by their work and haven’t broken any of their nylon parts yet.  If you can’t find the Parma parts,  the Ampro ones are a close second.

we took the truck out a few weeks back, and the leverage through the standoff bent the standard knuckle in no time at all.  

Have now resorted to the aluminium knuckles with the brass standoff's adjustable steering arms with an almost central servo (new 20kg one), tweaked the servo saver, and added loads of washers and shims in between any of the slack joints in the front suspension. the car has been total transformed and handle pretty **** well now.

[Killajb 1546]

Indeed, the steering knuckles are a point of contention when trying to improve the character of this truck.  I was weary that the new geometry would simply transfer the load to the suspension arms next and cause fractures in the plastic eventually (and in anticipation I've used anti-wear grease on the kingpin bolt) but so far things are holding up nicely and I don't worry as much any more.

[BattleTrak 61]

1 hour ago, old skool^s kool said:

we took the truck out a few weeks back, and the leverage through the standoff bent the standard knuckle in no time at all.  

Have now resorted to the aluminium knuckles with the brass standoff's adjustable steering arms with an almost central servo (new 20kg one), tweaked the servo saver, and added loads of washers and shims in between any of the slack joints in the front suspension. the car has been total transformed and handle pretty **** well now.

Nice...Sounds like you have the front end figured out!  Next upgrade would be aluminum front suspension arms.

For future reference on vintage parts... CRP made the #1607 Front arms with brass inserts and the #2521 shim kit to fix the sloppy ORV front end.  They also made the #1618 steering blocks.. but the Parma #12848 blocks have the bump-steer correction.