Project: Steering wheel hub extender for stock 3-spoke wheel. (photos)

[samoc]

I originaly posted this on rennlist, and then posted it in response to the
"Too tall for the 911" thread, but readers of that thread thought I should start a new thread.

I've just finished a project to extend the stock 3-spoke steering wheel on my '83 SC-cab. I posted here a while back asking for hints for making my ride more tall-guy friendly (I'm 6'7"), many people suggested going for a momo with spacers to get the wheel closer to me when the seat is all the way back, but I want to keep the car as stock as possible...
So I decided to make a spacer to go between the collapsable column part of the stock wheel and the wheel itself. The problem with this is that these two parts are riveted together and I wasn't keen on the idea of attacking by original wheel with a grinder, so I found a period-correct wheel on ebay for $100 and went to work on that. I ended up making a 60mm spacer stack of 5 layers of 7-ply. The result is that the stock look is retained and the driving position is much more comfortable, and I have the original wheel, untouched in case a normal sized person wants to drive the car at some point I can also see much more of the speedo than I could before.
Pictures of the whole process are here:

http://homepage.mac.com/samoconnor/911sc_steering_wheel/911sc_steering_wheel.html

I've included a few of the photos here...










Cheers,

Sam

[safe]

I have done something similar.
I made 4 spacers about 1 inches long, that was the maximum I could do and still fit the backside plastic without cutting it up, of course its still an inch to short...

Someone with fiberglass-skills could do a cover that would allow a big spacer.

[oly]

Excellent work samoc, thanks for all the pictures!

[ianc]

Nice idea and nicely carried through.

However (and I hate to be an ass), I don't think I would have gone with wood in this application. Wood will shrink, compact, rot and warp over time in a moist atmosphere like a car's interior. You should probably check those bolts that are holding things together for tightness after a bit, since the wood will relax slightly.

Just as an idea, I would look for some kind of hard plastic block instead, and try to design a way to key it to the wheel and column to prevent relative rotation. Just my thoughts, and I hope they are received as constructive criticism...

ianc

[samoc]

Ianc,

Thanks for the feedback, it is very much appreciated.

My original plan was to use the ply simply as a prototype
and once I was happy with the spacer distance, to have
a spacer machined from a block of aluminium, using the
ply as a template. But, the result using plywood turned out
to be more solid than I'd expected, so I think I'll stick with
it for a few months.
I've used double nuts, locked against each other
to counter possible shrinkage of the plywood. I've also put
a bit of epoxy on each nut.
I expect I'll notice any looseness or slop as it develops, but
hopefully before then I'll have a more permanent solution.
As an alternative to the original aluminium block plan,
I'm thinking of simply gluing the ply spacers together
with structural epoxy and painting the edges with as
much resin as they'll soak up. As well as being stronger,
this will create a moisture barrier and prevent expansion/
shrinkage.

Although is seems out of place in a car, the strength of
plywood should not be under-estimated. I've sailed ocean
races on yachts built from plywood, where the "strong points"
that the primary winches connect to are nothing more than
and extra layer of plywood laminated to the underside of
the plywood deck. These winches carry loads of many
tonnes of static load and may more tonnes of impact load
when the boat hits a wave at high speed.



Again thanks for the feedback Ianc.

I'll post a follow-up in a month or two...

Sam

[oly]

My only concern would be that the wood (or a solid block of metal or plastic) would be too strong. The original column is designed to collapse out of your way if you crash but the wood won't. Maybe my head would hit the top of the steering wheel and the whole thing would bend out of the way. But it would be nice to have an extended wheel that was completely collapsible.

[safe]

Originally posted by oly
My only concern would be that the wood (or a solid block of metal or plastic) would be too strong. The original column is designed to collapse out of your way if you crash but the wood won't. Maybe my head would hit the top of the steering wheel and the whole thing would bend out of the way. But it would be nice to have an extended wheel that was completely collapsible.

The collapsible part is still in there and If you are tall your still at the "designed" distance from the steering wheel.