LS1Porch

Hi all,
I've got a set of hollow spoke Turbo Twist II's currently mounted on the car. I like the wheels a lot and i got a great deal on them, but they're a tight fit in the back. Thanks to Brian Broderick(!!!) i got my fenders rolled and the car is now usable, but i'm worried that a big hit will send the tire into the fender (again...ugh!).

I did some searching and it appears i can use an '86 hub to move the wheel into the wheel well a little bit? I couldn't find any information on how much difference we're talking. These are 18x11's and I have about 1" on the back side of the tire that it can be moved in. I have upgraded torsion bars & those fancy poly-bronze bushings in the torsion tube, so i'd rather not swap the whole torsion assembly out.

Also, what affect will that have on my rear brakes? Will i need new rotors, or a completely different setup back there?

Mine is an '87 951, BTW. Thanks for any info!

samluke

Obviously if you have ABS you can't do it without giving up the ABS. I ran the 18X11ET 45 rears on my 89 with 285 tires. I had approx 2degrees negative camber. The fenders were already rolled as it was an S and I had to work a couple of areas to get clearance, but I got it to work just fine.

When I re-shelled with the 87 I put the wheels on the rear and tore the hell out of the sidewalls. I Haven't had chance to work the rear yet to get them to fit.

If you jack the rear up under the shock absorber mount until the front lifts, you are putting the rear into close to full compression so you should be able to see where it might rub. On the track the wheel moves more due to dynamic loading, but it gives you an idea. If it were me I would rent/buy a fender roller again and squeeze the fenders out a little more if needed. Cheaper, easier, and a better solution IMO.

LS1Porch

Thanks samluke! I don't have ABS so that's not a concern.

I've currently got about -1.5 rear camber and 265/40 tires and they're clearing fine, but if possible it would be nice to move it in 3/4" so i don't have to replace another set of tires. I tore the hell out of my sidewalls because i didn't roll the fenders far enough the first time (the 9 o'clock position on the driver side wheel just shredded it...). They're fixed now, but I have fairly soft torsion bars (250#) in the rear so i worried that a hard hit will shred my new tires.

Van

Do you also need new control arms if you go with new hubs? I don't know, but you might.

rlm328

The spindles were improved from the 86 to the 87 model and again when the 968s came out. If you do not mind going backwards in reliability.....

LS1Porch

@Van: Yeah, that's what i'm wondering about. I found a lot of information about swapping the front to the late offset, but not much info on the rear...
@RLM: I'm curious how how much of an improvement was made. I know the fronts were really improved, but nobody ever talks about the rears being a real weak link.

Bri Bro

Van, you just need to replace the hubs on the rear, the rear arms are the same.

If you look at the site below, he did a very good job of showing wheel offset vs backspace measurements. A nice drawings of the measurement is in the upper right of the page, click on it to expand it. There is a table that shows offset and backspace for front and rear on several model years. One thing to look at, as you move the tire towards the body, you can rub on mounting bolts inside of the wheel well.

http://members.rennlist.com/951_race...surements.html

Main site..glad this info is stored on the rennlist server.
http://members.rennlist.com/951_racerx/

ramius665

With the early hubs, you should be able to run up to about 295s in the rear. I currently have 285s on the rear of my '86 951 and have never had an issue with rubbing.

LS1Porch

Thanks for the link, Brian!

What kind of offset are you running on the wheels?

ramius665

ALT by Miro Type 371 wheels. Rears are 19x10, et 56mm and 25mm pass-through spacers on the hubs. Fronts are 19x8.5, et 47mm with 7mm spacers.

Chris White

You will need the 86 hubs, rotors and a new set of wheel bearings.

Your wheel beargins will get trashed when you remove the current hubs - 99.9% possibility!

If you want to do this swap I have a set of 86 hubs that I will swap for your current hubs!

LS1Porch

Hmmm, i didn't realize this could turn into a rear wheel bearing job! I read the writeup on Clark's Garage and it looks like i'd probably just want to do the bearings while i was in there, though.

I think i'm going to hold off on the hub swap for now, but i'll keep your name handy and send you a PM when i'm ready to do this swap! I'd love to just swap hubs. I was hoping it was as simple as zipping off some hubs and replacing the rotors, but as usual it's another $180 in bearings + $100 or so for rotors and countless hours of my time

Thanks!

951Saga

I’ve seen several people selling the complete trailing arm assemblies on RL and eBay from time to time. This may be your easiest option.
IIRC, when using that exact rear wheel on the early offset car, spacers are also required.

Keithr726

295s fit in the back with 15mm spacers and rolled quarters. Also had to move the parking brake cable a little. I've experience rub before but that was because I had a large passenger and a stock suspension.

Chris White

Yep, the bearings always fall apart when the hubs get pulled out!