Luke714

Hello all,

I'm a little bit confused regarding the whole "early" and "late" offset thing with our cars. Could someone clarify what is meant by that?

From my understanding the cars pre 86 had essentially a narrower width between the mounting faces of the hubs, is that correct? If that's the case is there somewhere I that lists this measurement on the various 944 models?

I also read that all 944's (except the S2 and 951S) have the exact same track width, ie width between the center-lines of L and R tire. Is this valid information? The numbers I found were 1451mm rear and 1477mm front, would those be correct numbers for an 86 951? I'm hoping this is true because that means I can just calculate the width between wheel mounting surfaces using the stock et and rim widths. The reason I'm asking is because I want to build a simple spreadsheet that will give me overall width from the outside surfaces of the L and R rim, to do this I need some sort of reference like a track width.

For verification these are the stock et's for an 86 951: front: 10.6mm, rear: 23.3mm. Could someone tell me if that's correct. I've gotten three different numbers from various tables and sources and I don't know what to believe anymore.

Thanks for answering a newbie question!

MAGK944

All the track widths pre and post 86 are the same. Porsche just moved the hub out on the later 944 cars to allow abs to be fitted and on doing so they had to change the offset of the wheels so that they would still fit in the fenders.

That is why if you try and fit an early offset wheel, like a Fuchs, onto a later car it will stick out past the fender. But, you can fit a later wheel to an early car with spacers.

bad_monkey

Not that spacers are recommended - they're safe, but they are heavy, adding to unsprung weight (more work for your suspension to do in bump) and reducing acceleration. Plus removing them each time you want to get at the hubs etc is a PITA.

The 85.5 or 86 car is an in-between model. The number you have for the front doesn't seem correct. I think they had the same offset as the early cars, but with the aluminium arms. But someone may correct me on that.

Rear seems right, but the early cars also ran a removable sandwich-type ~7mm spacer that brought them up to et 23mm.

Best way to do what I think you are trying to achieve is to measure up. Use the face of the hub as the datum plane, measure back from there to the inner arch, out to the outer arch to define the space you have to work with. Pay attention to where the calliper is too. Draw up a diagram edge-on to the disc and you'll soon see what will fit.

It's important to remember that moving the centre of the tires contact patch in or out with respect to the pivot point of the steering will change the feel of the steering, especially with a manual rack.

Finally, if you want a precise/flush fitment, then consider getting a set of 3 piece wheels rebuilt with lips that place the wheel exactly where you want. Make sense?

More info on what you are trying to achieve could help?

Luke714

Hey, thanks for the help. Things are becoming clearer. I've just been getting so many different opinions on what will work that I'm trying to take things into my own hands. What makes it difficult is that I'm in AL for the summer but my car is back in ME, I'd love to have a set of wheels and spacers waiting for me when I got back so that's why I'm trying to get the stock measurements. I've had a few threads going here so I don't want to start another on wheel/tire fitment.

I was just really curious about the track width numbers, because I should be able to work from there! So you're saying that the front of the 86 951 is actually 23.3mm as well, not the 10.6? Other than that how do my track numbers look?

The other thread I started is called "my wheel plan" in this same forum. For some reason when I go to it there isn't a specific URL that shows up in my browser bar so I can't give you a link Basically I want to figure out what I need for offsets on a set of 17x11" and 17x9.5", and whether 295's rear and 255's front will fit.

Thanks again for the offset information! Below is the link to the chart I've been referencing for offsets. The 10.6mm is listed specifically for the 86 turbo:

http://www.connact.com/~kgross/FAQ/944faq13.html

Luke714

Thanks for the help understanding what the whole late/early offset thing is all about. I've done some more reading and I've come up with two more threads saying the the 86 951 is 23.3 F,R and then I found two more threads saying it was 23.3 R, 10.6 F. I think the 10.6 F is correct for the 86 because it has a reputation for being an odd duck, but if it was 23.3 F,R it would be just the same as any early car. Thoughts?

Anyone want to break the tie? :P

Regarding track width, I just realized that I'm only concerned about the change in width so track width cancels out and I don't need an actual number. It would be great to know if track is the same for all 944's, regardless of year though. Obviously it will change with non-stock offsets and wheels; although I suppose you should try to keep it consistent for the sake of handling.

Happy 4th! Enjoy the fireworks!

pjburges

Exactly, change the track width, you change the handling and you definitely would like to avoid changing the ratio of track width -front to rear from that that Porsche set up, unless you really know what you're doing.

All 944's except TurboS and S2 have the same track width. The offset changes as mentioned so that the 86+ cars could have ABS on the hubs. That moved the hubs further outboard, and Porsche compensated by putting on rims with more offset so as to keep the wheels still fitting in the fenders.

Luke714

excellent, that's what I wanted to hear! That makes the comparison I'm trying to do possible!

PS. I've tried to insert a link for a another thread on this forum, but when I navigate to the thread to get an address it still just says forums.rennlist.com in my browser bar. Does this happen to anyone else? Is there a way around it to get a link?

bad_monkey

Little number, top right of each post, links to that post in splendid isolation. Edit the URL to get a link to the thread.

Like this links to this post.