Steering shaft spline count - Moto-Lita wheel - sanity check

[evan9eleven]

Hey guys, please help me sanity check something.

My 1981 has a 40 spline steering shaft measuring 21.44mm. My understanding is that this was standard for all 911’s though the 3.2, possibly even the 964 and 993.

Sanity check #1: I’m getting ready to install an aftermarket steering boss and wheel from Moto-Lita. Their Porsche steering boss is 40 spline with and ID of 21.74mm. Sounds right to me, without the .3mm tolerance, I think you’d only get the boss installed once and never be able to remove it, so this must be correct. Yeah?

Sanity check #2: OEM Porsche, Momo and others have a collapsible boss in case of an accident to absorb some of the energy of an unfortunate driver smacking into the steering wheel. Moto-Lita’s bosses are solid. Should I find something better to worry about?

TIA

[917_Langheck]

If you find an alternative to the Moto Lita boss (F80) please let me know! I'd love to mount my wheel without forking over nearly $500 just for the boss and spacers. My God they think that block of "aluminium" is precious.

I counted 40 splines on my '84 shaft, with a dia of 21.30 to 21.40mm depending. The detail I got back from Moto Lita was that the F80 should fit and their dia was ~21.70mm

[Uwon]

Evan,
Re:sanity check #1: the Moto -Lita F80 I’ll not get stuck on the steering shaft. I have had mine off several times without issue.



Re:sanity check #2: Well, this is a personal compromise that many of us are willing to take…looks, feel, period correctness vs Safety…. I personally do not think that a collapsible boss will do much in case of a front end collision as I think that the three spokes and rim of the steering wheel will do allot of collapsing to a point. In either case, the steering shaft remains pointing at your chest ready to impale you. If you are really worried, then a fully padded steering wheel from a late model will do the trick…but not the looks!
M2CW
Johan
P.S. I’m a transplanted Swede who in the past embraced all things Safety. When the kids grew up, out went the super safe Volvos and such for more exhilarating transportation modes. LOL

[evan9eleven]

Tjena Johan 😊

Nice wheel!

Thanks for the input. I wasn't actually worried that the F80 boss would get stuck. I just wanted to double check that I'm thinking correctly that the 0,3mm tolerance between the boss and shaft must certainly be intended. I sanity checked this here, because the lady at Moto-Lita made a point of the fact that the measurements were different, as if to suggest not-compatible. Safe to say she wasn't very technical-- if the measurements were the same you'd never get the parts together, or apart again.

As for safety, I'm not really that hung up on the benefits of the collapsible boss. Just curious really... Moto Lita is decidedly old school, which is about right for our cars anyway. For the record, I wouldn't drive a Volvo unless it was an old PV 😊


P.S. I've been transplanted to Norway from upstate New York, just a few hours from where you live now... life is funny, how it uproots us.

Originally Posted by Uwon

Evan,
Re:sanity check #1: the Moto -Lita F80 I’ll not get stuck on the steering shaft. I have had mine off several times without issue.



Re:sanity check #2: Well, this is a personal compromise that many of us are willing to take…looks, feel, period correctness vs Safety…. I personally do not think that a collapsible boss will do much in case of a front end collision as I think that the three spokes and rim of the steering wheel will do allot of collapsing to a point. In either case, the steering shaft remains pointing at your chest ready to impale you. If you are really worried, then a fully padded steering wheel from a late model will do the trick…but not the looks!
M2CW
Johan
P.S. I’m a transplanted Swede who in the past embraced all things Safety. When the kids grew up, out went the super safe Volvos and such for more exhilarating transportation modes. LOL

[Otter74]

Steering wheel isn't to my taste, but that's a terrific-looking interior.

Originally Posted by Uwon

Evan,
Re:sanity check #1: the Moto -Lita F80 I’ll not get stuck on the steering shaft. I have had mine off several times without issue.



Re:sanity check #2: Well, this is a personal compromise that many of us are willing to take…looks, feel, period correctness vs Safety…. I personally do not think that a collapsible boss will do much in case of a front end collision as I think that the three spokes and rim of the steering wheel will do allot of collapsing to a point. In either case, the steering shaft remains pointing at your chest ready to impale you. If you are really worried, then a fully padded steering wheel from a late model will do the trick…but not the looks!
M2CW
Johan
P.S. I’m a transplanted Swede who in the past embraced all things Safety. When the kids grew up, out went the super safe Volvos and such for more exhilarating transportation modes. LOL

[evan9eleven]

I'm going with this one from the same manufacturer, but mine will have the polished spokes like Johan's above.

[PeteKz]

If safety is your concern, then don't let the shoulder belt get loose enough that you will hit the steering wheel. The inertial seat belts in your SC should prevent that anyway.

[evan9eleven]

Originally Posted by PeteKz

If safety is your concern, then don't let the shoulder belt get loose enough that you will hit the steering wheel. The inertial seat belts in your SC should prevent that anyway.

Thanks for that. I’ve got correct seat belt use dialed in, and relatively new belts too

The main point of this thread was asking about the tolerance between the steering shaft and wheel boss, with a curiousity about collapsible bosses like OEM and Momo. I’m not a safety weenie…

New wheel and boss ordered, btw.