Thoughts on Grant anti-theft steering wheel lock? Options

[marka]

Howdy,

I don't know how the hell you'd calculate any of it, but I _would_ say that 50 lbs isn't all that much for the steering wheel to be able to support...

I'm thinking of times when folks use the wheel to brace themselves in braking, pull on it to get in/out of the car, etc. Seems like you'd exceed 50 lbs doing that.

Mark

[Blainefab]

Rob - I don't have a problem with the 3ea 1/4" bolts - every QD that I have seen has this fastener size on the same circle, and the increase in the lever arm length acting on them is only 5% more because of the 1 7/8" spacers.

My thought (and my engineering background is electronics, so someone please correct me if I'm wrong) was that worst case load on the 6ea 10-32 bolts would be turning the wheel with no power assist, car stationary. It takes a pretty good tug to move a 295 Hoosier. It that case I don't see shear doing much but trying to tilt the 1/2" dia spacers, translating to tension on the bolts. If the area of the 6 bolts adds, then there is 17,000# min tensile strength. Even if the driver can tug 100#, that is 2750# of force, over 6x margin.

You and Mark bring up the other force - fore and aft. This is in a race car, so wheel will be off the column while driver is getting in/out. Harnesses keep the driver in place on track so no need to brace against the wheel. But say I ignore that and figure the driver will try to do pullups on the wheel, how many of those six bolts are carrying the load? If some are in compression (or net zero load cause the spacer is in compression) then the rest are taking all the load. If 3 are taking the load then my margin is cut to 3, if everything is on 1 bolt then I have no margin.

I have a couple of weeks before this car sees the track, I will redesign the spacer setup if this is the case.

[robz71lm7]

Oh I don't think there is a damn thing wrong with the industry standard 1/4" bolts. I think they and the 10-32 screws both have roughly the same likelihood of failing.

I'm pretty sure most stock car boys have the same setup and they have no problem obscenely bending the steering wheel.

I don't see anything wrong with any of the setups honestly-I don't even know why I asked initially-I'm just paranoid.

You're really supposed to use the proof strength rather than the tensile strength (proof<tensile) when you size bolts. I don't know what it is for 10-32 screws but I can look it up for the 1/4" bolts.

Yeah shear would be greatest at low speeds when there is a lot of friction preventing the wheels from turning.

I made some pictures in paint to show all the different loads the screws see depending on what the driver is doing and how he is pushing on the wheel. It's really quite complicated, which is why there is what appears to be a large factory of safety. I'll post them later.

And I don't think making the spacer longer 1-3" will add that much more stress, but I'll check it out when I have time.

Man I must be bored lately. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/ph34r.gif)

[slowTA]

If anything I would connect the 6 spacers so they will stay parallel to the steering column. Think flat plate welded between the posts, it might be easier to bolt up too. Or machine a round slab of aluminum then drill and tap it.

[Blainefab]

I beefed up the mount - changed 10-32 144ksi bolts to 1/4-20 170ksi, and spacers from 1/2" dia to 5/8" dia. Calculated tensile strength goes from 2865# to 5389# (each of 6), and lever ratio drops from 27.6 to 22. Car gets its first shake Sun at Thill.

(IMG:http://members.cruzio.com/~ablaine/stiwheelbig.jpg)

[CrashTestDummy]

Nice adapter, Alan! We just put our QD in our firebird. Took three tries!! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif)

I finally discovered we had to pull the lockring out to get the QD to latch on the hub (our pimp-daddy CP Firebird is fully-optioned with tilt wheel). After having to _pull_ the splined hub off the car a couple of times, I had to dress the splines so the QD would go on and off smoothly. Now that it is on, it is very nice. It would have been nice for the thing to have come with _some_ instructions.

This post has been edited by CrashTestDummy: Apr 16 2006, 04:56 PM

[Blainefab]

Nice adapter, Alan! We just put our QD in our firebird. Took three tries!! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif)

I finally discovered we had to pull the lockring out to get the QD to latch on the hub (our pimp-daddy CP Firebird is fully-optioned with tilt wheel). After having to _pull_ the splined hub off the car a couple of times, I had to dress the splines so the QD would go on and off smoothly. Now that it is on, it is very nice. It would have been nice for the thing to have come with _some_ instructions.

I've been using the Summit GM splined QD with good results - I do some minor trimming of the shroud for finger clearance. The aluminum disc that ties wheel to QD needs a 1" hole in the center for clearance to the big nut (locktited) on the end of the column. I get the QD working free enough that it snaps in place securely, and lube the splines lightly.

There is a video clip floating around the intarweb of Justin Hall exiting T11 at Laguna, and the steering wheel pops off...mighty distracting for most folks.