S&R Gearset

[99Super]

I like Drew's logic, but I need a bit more than 75mph.
They look great!

[Jordan]

Pretty much ignore everything Crazyswede says

They are strong. Really Strong.

[Geoff]

I put together a spreadsheet a while back to plot speeds with different gearing options (S&R gear set, ring & pinion, primary gears, standard 5spd with 4spd primaries, etc.)
See below:

Speeds w/gravel tires

The graph above shows speeds at 7000rpm in a car with 1928mm diameter gravel tires. I used a few different options:
Gear set: S&R or standard GM45612 (note that this chart looks at short ratio gearing - to do that cheaply with a 5spd you can use a short ratio primary drive gear set in such as a #4 which is 30:31 - Because the short primary makes 1st gear very short, I excluded it from the graph for the 5 speed gear sets)
Primary Drive: I included stock #4 of 31:30 and a special, rare, 29:32 that was used by the competition department at SAAB.
Final Drive, R&P: I included the stock 9:35, the standard S&R (6:31), and the "big box" S&R (7:34) (note that for the 5 speed box I used the stock 9:35 because the S&R 5spd R&P is super rare and I don't know what that ratio is).

The typical setup for the S&R gear set (at least the boxes I know about in the US) is the #4 (31:30) primary and the standard S&R R&P (6:31). That is the setup that Crazyswede is talking about. Note that if you used the S&R gear set, the #4 primary, and the stock R&P (9:35) 1st gear would be so tall that you'd probably stall it nearly every time you tried to start from as stop. The best bet would be to use the S&R gearset coupled with the S&R 6:31 R&P and then vary the primary drive ratios to achieve suitable gearing, keeping in mind that 1st gear will get too long very quickly.

[Crazyswede]

Pretty much ignore everything Crazyswede says

They are strong. Really Strong.

The limitation will come in the form of your stock 4 speed case.

[Geoff]

4 speeds and reverse?

I think this uses the stock reverse gear and reverse idler gear.

Does this help with the case flex or the case still flexes, but there is more tooth engagement thus less likely to fail.

The cluster gear shaft is also a larger outer diameter which means it's stronger and wouldn't flex as much. It still rides on the layshaft supported by the same bearings on both ends...

Don't forget that pricing quoted is in SEK including VAT. If you don't have to pay VAT I think you could save 25%?

Nkro,
Is the cluster gear once piece or is it assembled in multiple pieces?

[KPAero]

So I need to buy this gear set, a sport & rally R&P and decide what primary would best suit me and buy that as well? And I should start looking for a 4 speed, or will a 5 speed case work? After that everything else is all standard parts?

[Geoff]

So I need to buy this gear set, a sport & rally R&P and decide what primary would best suit me and buy that as well? And I should start looking for a 4 speed, or will a 5 speed case work? After that everything else is all standard parts?

If you get a complete 4spd (more common than just a case) with the chain-drive primary you'll have a #4 primary to start with. That will probably work pretty well. Then you just need the gear set and R&P to get a nice strong box started. Ideally you'll want a limited slip, steel diff cover, and some stronger selector fingers, forks, and shift rod. There's always something more you can do like 4 chain primary, oil cooler, etc.

Strengthened shift rod and selector forks:

http://www.kyrkmotorsport.se/gallery_22.html

One thing to know:
The S&R R&P (and the reproduction that Selholm sells) has a different inner diameter to the ring gear. Mounting this on a stock, Gripper, or Quaife diff means there will be a gap between the OD of the diff and the ID of the ring gear. This will result in movement which will quickly wear out the R&P. You need to get a spacer made to go between the S&R ring gear and the diff to eliminate this movement (unless you're using a S&R or Jorgen limited slip diff, which are both appropriately sized for the S&R ring gear).

[nkro]

Its the larger cluster bearings.

Im not sure when saab have larger bearings, maybe from 89 5 speed.

Niklas

[paulh]

I put together a spreadsheet a while back to plot speeds with different gearing options (S&R gear set, ring & pinion, primary gears, standard 5spd with 4spd primaries, etc.)
See below:

Ratios.jpg

The graph above shows speeds at 7000rpm in a car with 1928mm diameter gravel tires. I used a few different options:
Gear set: S&R or standard GM45612 (note that this chart looks at short ratio gearing - to do that cheaply with a 5spd you can use a short ratio primary drive gear set in such as a #4 which is 30:31 - Because the short primary makes 1st gear very short, I excluded it from the graph for the 5 speed gear sets)
Primary Drive: I included stock #4 of 31:30 and a special, rare, 29:32 that was used by the competition department at SAAB.
Final Drive, R&P: I included the stock 9:35, the standard S&R (6:31), and the "big box" S&R (7:34) (note that for the 5 speed box I used the stock 9:35 because the S&R 5spd R&P is super rare and I don't know what that ratio is).

The typical setup for the S&R gear set (at least the boxes I know about in the US) is the #4 (31:30) primary and the standard S&R R&P (6:31). That is the setup that Crazyswede is talking about. Note that if you used the S&R gear set, the #4 primary, and the stock R&P (9:35) 1st gear would be so tall that you'd probably stall it nearly every time you tried to start from as stop. The best bet would be to use the S&R gearset coupled with the S&R 6:31 R&P and then vary the primary drive ratios to achieve suitable gearing, keeping in mind that 1st gear will get too long very quickly.

I'm confused slightly, 1928mm is 75.9in, typo perhaps? Any chance you could run the calculation for the last combo there, but with shorter 205/50-15 slicks? 22.8in is the diameter of those, wondering if 1st would still be really really tall, or just tall at that point.

Paul

[Geoff]

Yeah, that's a typo. 1928mm is the tire circumference (does not account for tire "squish"). A 22.8" tire diameter is 1827mm, so about 5% difference in circumference and speeds.
With 1827mm circumference tires at 7000 rpm with the S&R gearset, 31:30 primaries, and stock 9:35 R&P you'd have a 5% reduction:
1st = 66mph
2nd = 89mph
3rd = 113mph
4th = 143mph

Not a real big difference overall.

[Crazyswede]

I see your graph is written for engine rpms of 70,000. Mine doesn't rev so high.

[KPAero]

Do you by chance have a copy of your graph available somewhere where I could manipulate it? Or would you mind emailing me a copy?

[Jordan]

I did this a while ago... I *think* it is right

http://saabgears.heroku.com/

[Geoff]

Damn, full of typos. Pascal, send me a PM with your email address.

[nkro]

to clarify. To US Its export outside EU. The price is 19600 Sek + shipping.
Tax and customs is payed in US.

Niklas