md11plt

I just got a set of Techart Daytona’s. The wheels are 18X8 1/2 ET40 in front and 18X11 ET 25 in the back. I looked in the Techart catalog before I bought these and they are the recommended size for the 996 TT. The guy I got them from said they would fit the 993 TT no problem. I just put the wheels on the car (no tires, just wheels) and they stick out pretty far. There is not much clearance between the spokes and the brakes, so machining the wheels is out. The guy I got them from said to put tires on them and let the car settle and they will fit just fine, but I don't know. Any thoughts?. Yes those are my feet.

TRINITONY

the lower the number, the further they will stick out. With tires ..hmm don't look like they will fit. but the experts will chime in..ask the ? on the 993 forum..more activey over there..

think tim w had those on his 993tt.

PierreTT

I just installed 8X18 ET 40 and 11X18 ET 40 and they fit but its very tight... With 1/2 inch larger upfront and ET 25 will for the rear ones... I doubt you'll be able to fit it, even with a lot of camber... .
Hope for you I'm wrong
Pierre

kdurg

The guy who sold them to you is an idiot.

The 993TT offsets are ET52 up front and ET40 in the rear with 8 and 10 inch rims respectively. The fronts will be 12mm further out than stock but should be fine. The rears will not fit, in fact, putting tires on will do NOTHING to help. The guy telling you they'll settle with tires mounted is clueless.

Even on a 996TT the rear offset is ET45 with an 11inch rim....these rims would be 20mm further out on that car.

Can you get your money back ?

David in LA

The fronts should fit...I previously had 8.5" ET46 on a narrow body cab and am now running 9" ET40 with 245s (will likely go to 255s next time around). You may have to roll your fenders depending on the size and brand of tires.

For the rears, you cannot "test fit" them by just mounting them on the hubs and looking to see how well the profile lines up against the fenders...you need to install tires and then let the suspension settle. If you look at the 993 rear suspension, you will notice that the camber increases significantly once the suspension is weighted. The ET52 wheels on my cab below when viewed against the fenders looks somewhat similar to yours when the car is raised, but as you can see from the pic, it does work (with some fender rolling) and the tops portions of the tires cambers in and settles once the car is off the jack.

In my case I lost 13mm of offset plus the additional 12-13mm from going wider to 11"...so net is that my wheels are almost 1"/25mm further out and my fender clearance was reduced slightly less than this...perhaps 21-23mm. That said your new rims MAY fit, but will will likely require fender rolling and you won't be able to go crazy wild with wide tires...you may be limited to 285 or 295 max. You are losing 15mm of offset plus the additional 12-13mm from the 11" width, so your net reduction in fender clearance is a bit less 27-28mm...IMHO the choice of brand of tires will make a difference here. By the way, IIRC the aggressive fitment for my wheels for the 993TT (which require fender rolling as generally you can only reduce clearance by about 15-17mm without without rolling) is 11" ET28 or 11.5" ET33, so your Techarts are slightly more aggressive than these. IMHO ET25 would work fine if the rims were 10.5".

If I were you I would strongly consider getting a less aggressive offset in the rears...something in the ET30s would be a better choice IMHO. Good luck with the wheels, they do look good on 993s. (btw, IIRC the 996TT has about 10-15mm more rear fender clearance than the 993TT and I have seen ET25s work on a few)

sfju

I agree with md11plt.
To strong saying you are ripped off ??

Claim you money back ; much so if seller was familiar with Porsche`s.
If it was a family man (Porsche addict ) he should show some decency.

smddanny

The rear offset is plain wrong. These will never fit and tires have nothing to do with it. These wheels have to go back they have made a bad recommendation to you.

md11plt

I kinda thought the same thing. The guy is being a REAL jerk about it and does not want to take them back. I guess I'll go to Small Claims. Bummer.

Thanks for all the help.

Tom

Felix

If my understanding of offsets is right the outer edge of the wheel is effectively 15mm (the difference in the offsets) plus 12.5 (half the extra width) = 27.5mm further out. As a crude measurement you can put a factory 18x10 ET40 wheel back on and watch its travel as the suspension goes from fully unweighted to compressed. Is there 27.5 mm of clearance between the tire and the fender lip? I doubt it. Plus under load the tire can shift slightly so you would need to allow for that as well. Based upon your picture that wheel does look like it has the wrong offset. And don't mount a tire on it; that'll make it even more difficult to return as the mount and unmount is likely to leave some marks, however slight.

md11plt

Phelix,
I did exactly that, and your measurements and conclusions are right on. I thought the same thing about the tires. Once I put tires on, they are mine forever.

Tom

TB993tt

The Techart 993 catalogue recommends the 40 offset for the front and a 34 offset for 11" on the rear.....
These are not going to fit a 993tt.

If you end up needing to "unload" them let me know

BTW can you put them on the scales, I am intrigued to know their weights ?

David in LA

You're partially correct. Your calculations regarding the wheel's lips are right, but the amount of additional clearance needed will be a bit less than 27.5mm.

If move a 285 tire from a 10" rim to an 11" one, the tread width remains the same and the section width increases some...the sidewall stretches a bit, but not by 12.5mm on each side (the rims do but not the tires unless your car is so low that the fenders are right at where the tire sidewall meets the rim lip)...so instead of 12.5mm more clearance it's probably around 7-8mm depending on the tire's shoulder profile. If instead you had moved from a 285 on a 10" ET40 to a 305 or 315 on an 11" ET25 then your entire calculation is correct and you would need pretty much the full 27.5mm of additional clearance since you are also increasing the tire section width as well as the rim width.

md11plt

Well, it looks like I dodged a BIG bullet with these wheels. I called the owner of the company and gave him a message from Techart Germany as well as all the posts from you guys and he finally caved. I found out from CEC wheels (US distributor) that they had a set of ET34’s in stock (recommended size for the 993 TT), so I was able to make a swap. ET34 is still a bit aggressive, but Tirerack specify an ET36 for the SSR GT3 on an 11 inch wheel, so I am hopeful. Pics when I get them on the car.

Thanks for the help you guys. I am 100% sure that your responses helped my case.

Tom