Welcome all 928 forum refugees!
User avatar
By Shifted
#35636
I think that I need to bite the bullet and get proper wheels for the car. Wider front and rear to support the increased power and improve cornering for autocross.

I've sent an email to 928 Specialists to get the ball rolling.

My preferred tire is Yokohama Advan Neova AD08, so the rim would need to accept one of their tires:

https://www.tirerack.com/tires/tires.js ... ova+AD08+R

Do you have any recommendations to consider? Width, diameter, stance, design...it's all on the table at the moment.
User avatar
By JMW928
#35649
Landsharkoz.com has a 928 wheel guide in pdf format that’s probably the single best document written on the subject. Very informative and worth your time reading.

The factory had a “Cup Racer” spec that utilized Cup I’s in 17x9.5 ET68 offset. That’s about as wide a fitment you can use on the front of a stock 928. The rear can accommodate up to around 11” width without extensive modifications and ET is not as critical except at the extreme widths.

Years ago over on RL, user Andrew Olsen (“AO”) created a wheel fitment calculator in Excel format. You can probably search and find it though who knows whether or not the link to the spreadsheet still works.
User avatar
By Shifted
#35654
I've got the calculator and went through these gyrations a couple of years go in the hunt for off the shelf rims. I started a thread for it on RL in 2018 and ended up with Carrera III's. Fine rims, but not quite perfect. Now, I want custom.

I've sent an email to 928 specialists, but am open to input.
Last edited by Shifted on Sat Nov 21, 2020 2:25 pm, edited 1 time in total.
User avatar
By ladybug83
#35692
These Rotiforms popped up on my Instagram. I think it’s a cool modern interpretation of the phone dials. Love the color too. Maybe someday.

Image

But for now, I’m sticking with the satin black CIIIs. Really impressed with the comfort of the Hankook Ventus V12, quieter and softer ride than I had expected from an 18” tire

Image
User avatar
By worf
#35772
Augment Wheels can (supposedly) make any offset you want.

Best money I ever spent on any of my 928s was going from 7.5”/9” wheels to 9”/10” and from 225/245 to 255/265.

Don’t ask me the offsets. This is 1999 FFS.

Fikses with offsets available only via 928 Specialists because D.R. indemnified Fikse against ‘doesn’t fit’ returns.
User avatar
By Shifted
#35776
It looks like I can order any offset I want for the Fikse wheels from other places, but with similar or worse pricing than 928 Specialists. And I like to keep the money in the "family" so to speak.

Regardless, I've been doing some research and calculating, and this is what I'm zeroing in on:

Front:
Tires - 255/35R18
Wheels - 18x9 ET67

Rear:
Tires - 285/30R18
Wheels - 18x10.5 ET40

I need to check some measurements on my car with the current wheels to confirm the offsets, though. My rear fenders are rolled, so I have more room than stock. I would love wider tires, but anything wider on an 18" rim isn't as sticky as the 285 R compounds that I have now. So, it would be sacrificing performance just to get a wider look and better inclement weather traction. 10" wheels would be fine for the 285's, but by going with 10.5" it makes mounting easier and it gives me more options in the future if I decide to go with non R-compound tires.

I'll check out the Augment wheels. I know that I can custom order wheels from lots of places, but there has to be a limit at some point to the cost :)

The Rotiforms are wild! Not my style, but cool. And the C3's have been good, but the rears need a spacer to fix the stance, and the fronts can't handle wider than 235's (properly). So, custom seems to be where I need to go.
User avatar
By worf
#35778
Shifted wrote: Thu Nov 19, 2020 7:42 pm Do you have any recommendations to consider? Width, diameter, stance, design...it's all on the table at the moment.
Here are my recommendations:

- pick the tires first. Make sure the width, aspect ratio, and diameter you want are available. You may need to iterate. Your favorite Yokos wouldn’t work for me: no 17” 265

I had a whole bunch more recommendations and text, but fucking iOS safari ate my post when I switched to edit a photo.

TL;DR: Stay light. Stay at the OE overall diameter. Unless you’re a suspension savant.

Remove “stance” from vocabulary. Here’s ‘stance’, really great for track and A-X. Not.
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User avatar
By worf
#35779
Shifted wrote: Fri Nov 20, 2020 8:34 am Front:
Tires - 255/35R18
Wheels - 18x9 ET67

Rear:
Tires - 285/30R18
Wheels - 18x10.5 ET40
I think those are very close to what I’ve selected for a set of 18” phone dials from Augment.

And I need to get off my ass and get my Fikses straighted. Last ‘authorized repair’ shop I spent 3 hours (round trip) lugging the wheels to blew me off after I’d made appointment on phone with owner.
User avatar
By Shifted
#35780
When you have a chance, would you mind checking what the wheel and tire sizes and offsets are that you ordered? Also, are your fenders rolled?

Thanks! :)
User avatar
By worf
#35782
Shifted wrote: Fri Nov 20, 2020 9:02 am When you have a chance, would you mind checking what the wheel and tire sizes and offsets are that you ordered? Also, are your fenders rolled?
Dude. When I wrote "Don’t ask me the offsets. This is 1999 FFS." what did you think I meant? :)

1999. That paperwork and neuron ship sailed a long time ago.

Wheel sizes are 9"x17" and 10"x17 in whatever offset D.R. specified. D.R. may remember but only Fikse knows and only if they've not thrown away those paper files.

Tires, OTOH:
255/40-17 and 265/40-17, which last time I checked, I can't find anymore. So, once my Fikses are straight I've got to do something different.
User avatar
By worf
#35799
Shifted wrote: Fri Nov 20, 2020 9:43 am I meant your new augment wheels. :)
Oh. Selected isn’t the same as ordered. My todo list includes double-checking my selection off offset against the Jim Doerr-offered offsets on his never-produced wheels and against the only prototype wheel RE test fitted versus available rear spacers.

As to the other question: GT; fenders rolled at the factory, but I've got plenty of room with the 10” Fikses.
User avatar
By linderpat
#35806
I have 18" Carrera 3's on my 85 shark. My fronts are 235/18/40 mounted, no spacers. I think they are 57 mm offsets. As to the rears, 265's did not fit my car on my wheels. With 20 mm spacers and then 15mm spacers, my left side in particular rubbed the fender on the outside. Without spacers, they rubbed on the inside. I ended u[p with 255/35/18 for the rears and use 15 mm spacers. They will fit with that configuration and result in the correct factory diameter, which affects speedometer readings. One thing I think is that 18's are really too big for the car from a handling perspective. I think 17's are ideal. I plan to put 17'' Cup 1's on next spring, plus I think they are the best looking wheels anyway. I had them on my garnet 85 and really loved them.
User avatar
By Shifted
#35825
I do like how the Carrera 3 wheels look on my 928 from the side. With a rear spacer they might even have a decent stance. But, they will never support the front width that I want.

Augment Wheels doesn't have any designs on their web site that I like, but they also don't post any of their custom wheel designs, only the OEM designs. I can talk to them about a custom design, but they're based in Canada. It might be better to work with a US based manufacturer. I'll have to do some looking around.
User avatar
By maddog2020
#35829
One thing to keep in mind with custom wheel sizes. What tires are available today will not be available 5 years from now. Pick a size of front's and rears that are on a production car. This will ensure that the tires you buy today will have a better chance of being around later. When you start getting into some oddball combo's a few years down the road you will find lots of tires in the front or the rear sizes but maybe not in both front and rear sizes.

Stick with the 18x9 in the front and the `8x10 in the rear. the extra half inch isn't anything that you will notices but will drastically limit your tire choices down the road. Most car manufacturers don't do half sizes. make it easier for yourself down the road.

When I had my current fikse wheels made in 2007 the tire choices were endless. now I have 2 choices and neither of them are available in the winter or early spring.
User avatar
By Shifted
#35837
Thanks for the input.

If tire sizes change so much that I really can't find a tire that fits on a 10.5" rim....I'll buy new rims or switch to one of my backup sets. Not a big deal.

Besides, many MORE DOT race tires fit the 10.5" rim than the 10" rim. Tires are designed to fit on a range of rim widths, not just one specific width. They do specify what rim width the section width specification is accurate for, but that doesn't mean it's the only rim that the tire performs well on.

Also, since I do my own mounting and balancing, I know from first hand experience that it is easier to fit a low profile stiff sidewall tire onto a rim that is closer to the maximum width supported by the tire as opposed to the middle or low end of the range.

At this point, the only thing left to do is pick a style and offset. Modular or monoblock.
User avatar
By worf
#35838
linderpat wrote: Fri Nov 20, 2020 10:23 am One thing I think is that 18's are really too big for the car from a handling perspective.
Factory 18" (and bigger) wheel sets for the later cars are heavy. I weighed my wife's 11.5x20" 991 rear summer wheel last week and it was ~58 pounds. The front <whatever>-x20" was ~51 pounds IIRC.

It's all about keeping unsprung weight as close as possible to what the factory suspension "wants." The wider tire is, itself, likely - if not definitely - going to be heavier that an OE-sized tire, thus making it more important to get a light wheel.

That's actually one of the open questions I have for augment: weight of various offerings. You can get forged magnesium which is nicely light. On the other hand, probably not a great idea for a street car that might see potholes. They ain't exactly cheap either.

Now, you can run a heavy wheel on a 928 but not with the stock dampers. You'd need custom valving for the dampers if not stronger springs too. I used to have a client that was a suspension idiot savant who could drive anything, come back and say "You need x% more/less bump and y% more/less rebound" and damn if he wasn't right every time. His 928 was *set up* and had some big-assed 18" wheels.

If you want to experiment you can order (maybe still order) Bilsteins (from them directly) with "Leguia 928" valving that might just work better with heavy wheels.
User avatar
By Shifted
#35858
I just spoke to Jeannie at 928 Specialists. She's a very nice and knowledgeable woman. She's getting me package pricing, weights, lead times, etc. And she's doing some additional research on tire options. I have some pretty limiting tire requirements, but maybe she'll turn up something better for my needs than the Advan's.

After poking around at some other options online, there doesn't seem to be an advantage to buying elsewhere. The 928 Specialist pricing is competitive, they know what works on the car so the order is more likely to be done properly the first time, and they are part of the "family".

Am I missing something?
User avatar
By Shifted
#35894
Jeannie (928 Specialists) got back to me with the details. Fikse is having a Black Friday sale, so this is a good time to be ordering them. Lead time is 6 to 8 weeks, which should give me plenty of time to get them mounted before the Amelia event.

Once they are here, I'll post some photos and specifics.
User avatar
By worf
#35929
Shifted wrote: Fri Nov 20, 2020 12:15 pm Am I missing something?
Nope. Not a thing.

Just make sure to double-check once you think everything’s ‘set’ and that the order’s in at Fiske.
User avatar
By worf
#35938
Shifted wrote: Fri Nov 20, 2020 3:51 pm You mean by some other method besides asking 928 Specialists for the status?
That’s what I mean. With “2020” going on I just assume that a larger-than-usual percentage of things will not be perfect. Since I get many orders from the big three and, additionally, deal with many other service providers I can tell you that the general error rate throughout the supply chain is higher than usual. Key folks here and there get distracted. Following-up early is risk mitigation.

For example: a part I ordered - not from our Big 3 - that I need tomorrow is now either not shipped or has been misrouted after arriving in my state. Had I checked the status the day after I ordered I might have been able to mitigate the risk of the first case.
User avatar
By Shifted
#36156
For tires, I've decided to go with Yokohama Advan A052 in 255/35R18 and 295/30R18:

https://www.yokohamatire.com/tires/advan-a052

They have a little less tread depth than I would like, but they have very good wet traction reviews. I plan to use them on the street most of the time with some occasional autocrossing. Hopefully I'll be able to get 2 to 4 years out of them, but I guess we'll see.

Once things start arriving, I'll post photos.
User avatar
By maddog2020
#36336
Shifted wrote: Fri Nov 20, 2020 11:40 am Tires are designed to fit on a range of rim widths, not just one specific width. They do specify what rim width the section width specification is accurate for, but that doesn't mean it's the only rim that the tire performs well on.
I don't think this is news to anyone on this forum. Different tire sizes overlapwheel sizes. The point that I'm making is that not every tire goes from a 195 to a 345. There are gaps in sizes for a reason. Tread models are designed for specific car models or classes. I went with 18x9 and 18x12, because there were tons of tires in the 265/35 18, and also in the 335/30 18. Nobody makes a 325/30/18. Now there are only 2 street legal options. I don't like the stretched look where the tread is more narrow than the wheel. I'm on my 3rd set of custom wheels on the 928, and 2nd set of Fikse's. You might want to wait on your order, as Fikse is coming out with some new finishes. The current technipolish is a fragile finish and if it is marred or srcatched, you have to get a new center as it can't be re'cleared because getting off the clear will change the surface. not to mention what ever gouged of the clear coat damaged the wheel center.

just trying to help out. Because tire models are seasonal, and some sizes are only made one production run per year, and if you have a blow out or failure you have to wait until they are available to get a matching tire. I've had all this stuff happen, and I'm OCD about my wheels and tires.
User avatar
By Shifted
#36906
New tires are here. 255 for the front, 295 for the rear. Wider tires are cute and all, but what really matters is traction. These are Yokahama Advan A052 tires. They are even stickier than my old Advan Neova AD08R tires, which didn't break loose under full throttle (~530whp) in first gear in 90+ degree weather.

Now, just waiting on the wheels to arrive.
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