Larry T.

I am looking for new wheels for my 930. I really like the low offset (deep dish) look. Please help me with some ideas. TIA

JackOlsen

2-piece Fuchs from Lindsey Racing. Made with Fuchs centers and later rims. 9.5x11x17.

JackOlsen

The fronts would be deeper, but we widened the track to improve steering (scrub radius).

Paul491 Cadrobbi

Jack, I’ve admired your car and must admit: IMHO, you’ve put together one of the most absolute killer-looking 911s I've ever seen! And your wheels are equally stunning and really set it off, very nicely…

The more time I spent around my M-491 Carrera, Larry, the more I began to become aware of the anemic look of the ‘narrow’ 7 & 8” Fuchs wheels on my ‘84. The stock wheels and tires just didn’t fill out the fenders especially the fronts. I’ve always liked the ‘deep meaty-look’ of the 1974 IROC/RS 3.0 wheels. For grins, I opted for a ‘Cheapo Production’ solution and moved my rear 8x16 Fuchs and tires to the front and added a pair of 9x16 Fuchs to the rear. Running 225-50-16 tires up front and rear 245-45-16s definitely improves the lateral grip. As soon as the rears wear out, I plan on replacing them with a little beefier 255-50-16 tires. After some interesting and enjoyable sleuthing, I found these tire heights are virtually the same as a 74 RS 3.0 street version with 8x15 and 9x15 Fuchs! This 'econo-approach' gave me the 'deep look' I was trying for. The good news… all this by simply buying only two additional Fuchs! Just my 2 cents.

Hope this helps.

g-50cab

Looking tame compared to the other two... 8x16 9x16

Trust me

Jack, Them some deeeeeeep rims. Very cool.

Bill Verburg

Paul, You are correct that the street version of the '74 RS 3.0 used the 26.1" tall Pirellis on 9x15 +15mm o/s rims( I had a choice of that car or the C3 which I bought, What a fool I am!) but that doesn't mean that it is a good choice today. Back then a 60 series tire was a radically low profile, they used them becauce there was no other choice. Yes, a 255/50x16 has the same 26" height as the RS originally used, but you do not have the 7:31 final drive used on that car.

I think that you may be disappointed by the acceleration hit that you will take when switching from an ~24.6" tall tire to a ~26" tall tire

Anyway my gratuitous car pic

Paul491 Cadrobbi

Bill, I'm glad you've brought up this point because I too have been concerned about the taller tires in the rear... and the possible effects when accelerating. I am not exactly sure what the final drive ratio of my car is... Did the '74 RS 3.0s come with a 7.31 final drive just to compensate for the taller tires or were all 911s geared that way in general? Do you have any idea of what my '84 M-491 coupe's final drive ratio is now and what it should be? How much of a difference you think it will really make?

Bill Verburg

There were 4 different cwp(ring & pinion) available back then

• 8:35
• 7:37
• 7:31
• 7:27

Standard and most commonly used was 7:31, which was changed to the new standard 8:31 in '75

Your '84 has 8:31.

This chart shows the effect on forward thrust of the change from 245/45 to 255/50 x16 on a US Carrera the M491 is the same assuming it is a US version


The difference in acceleration will be very noticable. There is a region where the bigger tire gives better acceleration, but it is at the very top of the rev band for that gear(where the blue and red lines for a given gear cross), not generally useful, but on a race course could get you to a particular corner w/o having to shift. We play w/ this on our track cars but not on the street.

Paul491 Cadrobbi

Bill, don’t beat yourself up too badly about the ’74 RS 3.0… Hey, I chose a ’65 911 over a ’64 904 because I thought I was being more 'practical’… Yikes!! Believe me; I know your pain… lol

Thanks for the great info and chart! Yes, it is a North American M491. But now, a few more questions arise...
1. What’s the price tag to change the ring & pinion gearing?
2. Is it the time to install a limited slip?
3. Or go to a different tranny? (It’s a matching #s car)
4. If I mount the 255-50s without changing the gearing, will my car turn into a real 'slug-dog' that only looks good?
5. Does different/lower gearing affect the classification/division in Time Trialing or Solo racing?

I’m sorry Larry, I didn't mean to pirate your thread but this information is really great stuff, isn’t it!! Thanks in advance for all your help, Bill.

Bill Verburg

Middling expensive, I searched all over for some of the oddball cwps, to my knowledge only the 7:31 and 8:31 are currently available. The 8:31 is reputed to be much stronger.

I love lsds, but they are not for everyone. In everyday street use they are not very useful and can create some odd vehicle dynamics. But for any sporting use, absolutly, again middling expensive to add. lsd will create a bit more understeer which you may or may not wish to tune out.

You have the last and best of the 915s I went out of my way to get the euro version of that transmission for my car, I think that it is a great unit. Again there are some that will take a mag case (for weight) gut it and hand select various 911, 930 and custom parts w/ custom gear stacks. This is great for racing but a $9k trans is more than I want spend(at least for a 5 spd)

No it will just be a bit slower and feel sluggish compared to before. Here's 1 specific comparison pt. from the spread sheet data both sets are in 3rd gear

• short 245/45 max thrust is 833#S @ 72mph
• tall 255/50 max thrust is786#S @ 77mph

You would have to check w/ your class association.

SoCal Mike

Hey Guys, back on this wheel thing. I saw a east coast pca website that mentioned that you could run 9x16 fuchs(off the back of my turbo) in the front and run 17's in the rear. I know that some P-race cars have had different wheel sizes. I love the look of your car Jack. I'd like to add Lindsey 17x11 to the rear. What are the downsides to this. I don't do any track stuff. Just a daily driver and weekend canyon runs. Would I be better off keeping the sevens up front(lower steering effort) until I can upgrade them to 17. What are the handling issues. I'm currently all stock suspension though I'm planning on 22/30mm upgrade soon. Thanks, Michael

Bill Verburg

If you have a 930 w/ the removeable 21mm front spacers then the +15mm o/s 9x16 Fuchs can be used, discard the spacer.

cmoss

The old SC

http://boards.rennlist.com/upload/chrisYtarga.JPG