What is the difference between a 512TR steering wheel and a 348 Steering wheel

They look identical to me, down to the 10 'punchhole' pattern and location; Are they different diameters? Something else?

Different part numbers for each model:
140945 - 348
165946 - 512TR and 512M

(For completeness sake the other similar wheel of this group is the Mondial T (PN 140944), but I think this one is larger diameter? Maybe?)

 

- The 512TR steering wheel goes faster : )

 

Perhaps you need your eyes checked . They are different shapes, and the 512TR has sort of a two-section outer rim at the 10 and 2 positions (although it would not surprise me if the 512TR is also slightly larger diameter, but have no info about that):

165946
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140945
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165946 - as pictured although compatible with the 512TR is actually the 512M wheel and was never offered on the 92-94 cars.

 

Yea that is not a 512TR wheel. I’ll post my wheel later.

 

You gave the part numbers! . I will say that the pic of the 512TR steering wheel in the GBProgetti book at the LA Auto Show 512TR introduction looks identical in style to the 348 wheel (but I'd still guess it would be slightly larger in outer rim diameter than a V8 model since the TR steering wheel is so darn large).

 

Touché my friend.

 

I posted the wrong part number in my original post, it should have been 148457 vs 140945.

Im curious if there is a diameter difference. I’ll measure mine later

 

Bump a dead thread

For comparison the OEM 512M wheel (165946) is 360mm from 9 o'clock to 3 o'clock, or 355mm from 12 o'clock to 6 o'clock.

I will get the OEM 512TR wheel (165946) measurements when I remember to next.

I really wonder if the 348 wheel (165946) is any different.

 

I finally got the info. It is an extremely subtle angle difference for the 3/9 o'clock spokes between the 348 and 512. Even when you know what to look for its extremely hard to see without having them on top of one another.

In detail:

• OEM 348 (PN 165946)/512TR (PN 165946)/512M (PN 165946) Momo Steering wheel - 360mm diameter (Extremely slight difference in the horizontal spoke angle between 348/512TRs; the M uses a completely different design center and rim build on the same basic architecture)
• OEM 355 4 spoke Airbag Steering Wheel - 375-380mm diameter
• OEM 550/456M 3 spoke Steering wheel (Momo) - 365mm diameter (widely used Momo 90s 3 spoke airbag wheel, also found on similar era Maseratis and even rare Hondas; differ in the rim design between 550/456M)
• OEM 360/CS/575 Airbag Steering wheel (Momo subcontract) - 365mm diameter (horn button design (Al on 575, leather on others) and location (moved on the CS wheel with added sculpting); note OEM carbon versions of the steering wheels add a carbon upper rim half)

 

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The different part numbers already answers the question I believe. Anything other additions is just reaching for the clouds to invent one

 

Thanks lagunacc. Case in point...the structural/design is extremely close with only a slight angle difference. The finish varies as function of age and isn't a reliable distinguishing factor.

And part number difference doesn't mean anything...they get superseded and overlap all the time (see a long list of 550/456 parts for example)

 

Does the 512 wheel fit 84-91 Testarossas?

 

Spot on on both points.

 

They all fit.

 

yes as does the 348 (much cheaper and easier to source)
Careful though, the smaller diameter makes the steering much heavier if nothing else is changed (tire pressures/tire selection/etc)

 

The Agnelli Testarossa Spider has an interesting wheel. Kinda of a cross between the 400i and Testarossa wheel.

 

Funny you mention that, I thought of that right after I posted - as boring as the large flat schooner wheel appears, I'm finally used to that level of crank needed to get out of my parking lot. Going to the 18" wheels and lower profile tires did help a lot though.


Me driving the car for the first time, as we left the seller's house... Image Unavailable, Please Login

 

I can't believe those diameter values (especially the 375-380mm value) -- the stock TR steering wheel is 365 mm, and is ginormous compared to any of the V8 model steering wheels. Are you sure about those measurements? I think that the V8 model steering wheels are more down in the 350mm diameter size.

 

Funny you ask, with the exception of the 355 steering wheel, others are measured from my parts collection (I don’t have a CS wheel but I have the others). As such, that is the measurement I have the least faith in.

 

I’ll post photo later but I don’t have the diameter for the old testarossa steering wheel so Ryan that’s on you

 

My spare 575 steering wheel destined for my 456m below

I have a Momo 350mm steering wheel I restored (such it’s slightly thicker now), that’s a 350mm. I’ll pull it from storage so you can do side by sides.
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I realized measuring circumference is probably a more accurate measurement of the overall diameter:

My OEM 575 carbon has a circumference of approximately 1155mm aka ~367ish mm, which considering user error is 365 (given Momo makes them in 5mm increments); the non-carbon/standard version diameter is shown above.

My NOS F512m steering wheel is 1140mm circumference, a.k.a. 362-363mm diameter (which, considering it has the added ribs on the rim makes 360 the correct number)

My 512 or 348 (I forget, which one this one is) has a 1125mm aka 358mm diameter = 360mm given user error.

Compare those to my refinished 350mm Momo wheel that is at 1110mm circumference, a.k.a. 353mm and noticeably smaller in the hand despite the thicker rim.

My garage is too cold to go and measure the 456m/550 Momo 3 spoke wheels. As mentioned, I do not own a CS, original testarossa, or any of the factory 4spoke wheels as none are of any relevance to me/my cars of interest. Therefore those number were as referenced by other members and I cannot attest to their validity.

PS Ryan, do you still have my cell phone? Feel free to call or text If you ever want to talk TR. You’re one of the few people that know how long I’ve overthought those cars!

 

The Testarossa wheel is 365mm

That design also comes in a 380mm size - 400i, probably some Mondials also