works 93 steering help

[rccars4sal]

Hi guys. Im trying to finish a works 93 from scratch. Having trouble with steering. Im using the upgrade carbon fiber steering rack with ball bearing. It adds about 11mm to the length on each side of the steering assembly. So, steering rods are about 11mm shorter using the rack.

Problem. Not enough ackerman! Its like reverse ackerman. There seems to be more angle on the outside of the arc, and less on inside. In running, this will cause terrible scrubbing.

First thing, is I am not using Yokomo steering knuckles. I dont have them. So, its got some Kyosho knuckles that have similar geometry. Not sure if thats the main issue with the ackerman though.

Question: does the longer steering rack actually change ackerman angles? Would it be better to mount the steering rods directly to the servo saver arms, and lengthen the rods? Its also a matter of finding turnbuckle tie rods the correct length. I guess thats not big deal, except I dont have any 11mm longer. Will have to cut some longer ones down.

Anybody with pictures of their 93 works steering set ups please post.

Thanks!

[jwscab]

the longer rack will affect bump steer, but could also affect perceived ackermann while the suspension is in full droop. You might get better ackermann geometry by moving the outer ball end to the other set of holes closer to the kingpins. this will likely better align your geometry.

the ackermann is defined by the imaginary line drawn through the kingpin through the steering link ball all the way to the rear where the left and right imaginary lines intersect. for true ackermann, they should align with the centerline of the rear axles.

http://www.rctek.com/technical/handling/ackerman_steering_principle.html

[Peakey]

According to the manual they need to be 73mm if that helps any

http://www.retromodelisme.com/scan_pages/467/super-dogfighter-works-93-yokomo-page-16.html

[rccars4sal]

I switched to the inside hole on the steering knuckle, and got more outside angle, and about the same inside angle. Bump steer is all but non existant with this carbon rack! Ive got a long ball stud at the knuckle and a short non threaded ball stud on the rack, so the angles match very closely between steering rod and A arm,, and I can not see any bump steer.

So, how is it other buggies adjust ackerman? I think on Losi cars the steering bell cranks get angled inward or outward to affect knuckle travel forward and back. Not really possible on this 93,, unless I switch back to wire joiner or perhaps a tierod joiner...

My pics denote max steering travel angles.

[rccars4sal]

O/K, so factory has the steering rods mounted to the saver arms, rather than the rack. Ill try that.

[jwscab]

yeah i didn't get to reply yesterday, other cars adjust ackermann by moving the inner ball position/tie link around. See the rc10B2 manual at the end for a good description of ackerman changes with bellcrank settings.

[rccars4sal]

Interesting. On the b2 manual, ackerman is changed by repositioning the steering crank joining rod from closer to the crank fulcrum to further out. It appears the angle of the steering cranks stays the same.

No options on the 93 works. Ive got it built and set up as close to factory as possible. Its missing the correct ball studs for the top of the steering cranks, so it has to have screw and nuts, instead of the cute little kingpins and ball studs.... ALOT of special hardware on the 93!

Hinge pins, steering ball studs, camber brace ball stud thing... WHat else?! Is it the 93 that got special 2.1 wheels?

As for the steering, Im tired of messing with it, so its as close to standard as can be under the circumstances,, and I think its sub standard. When some proper knuckels magically appear,, it will get done again. For now,, its a roller.

[Peakey]

Interesting. On the b2 manual, ackerman is changed by repositioning the steering crank joining rod from closer to the crank fulcrum to further out. It appears the angle of the steering cranks stays the same.

No options on the 93 works. Ive got it built and set up as close to factory as possible. Its missing the correct ball studs for the top of the steering cranks, so it has to have screw and nuts, instead of the cute little kingpins and ball studs.... ALOT of special hardware on the 93!

Hinge pins, steering ball studs, camber brace ball stud thing... WHat else?! Is it the 93 that got special 2.1 wheels?

As for the steering, Im tired of messing with it, so its as close to standard as can be under the circumstances,, and I think its sub standard. When some proper knuckels magically appear,, it will get done again. For now,, its a roller.

They came with black carbon re enforced 4 hole wheels

[jwscab]

effectively, they are altering the arc of travel and length of tie rods.

[rccars4sal]

[Peakey]

Looks really good but these are the ones I was talking about

[rccars4sal]

Dang. Closest I have are the pink wheels or a set of rough trinity wheels. Oh well, poor car is a mutt anyway.

[Peakey]

They pop up buddy

[zzzubbb]

Black wheels - 4 hole - i may be able to help..

Also re Akerman, what are those front knuckles you have there, they dont look to be Yokomo. maybe YR4 or more like Kyosho with the reinforcement and kicked out arm.. could they be causing the issue?

Peakey may be able to help you with a picture of a standard works knuckle..

Could be wrong but think they are the same as YZ10 ones.

Z