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Why no fit?
:willy_nilly:
Guys, need some advice. I read RETed's wheel and tire advice pages. I ordered a set of TSW Jaramas in black for my son's Christmas present. I was going for a real racecar look, sidewalls flush to the fenders, no stretch, no 4x4 sticking out, no illegitimate camber, etc. Rolling the fender lips would be ok, pulling the fenders not. Like this... http://circuitoftheamericas.com/imag..._supercars.jpg Based mostly on RETed's pages, I ordered: 2 TSW Jarama 18X9.5 5-114.3 20GBL 2 TSW Jarama 17X8 5-114.3 40GBL and 7/16" (11mm) spacers for the front along with ARP lug studs. Per RETed's page with Min being flush and Max getting awfully close to the suspension bits... For the fronts... Rim width: Minimum offset: Recommended offset: Maximum offset: 8"---------+25-------------+30-----------------+35 Given that, we should have had the recommended offset (+/- 1mm). And yet the front wheels (no tires mounted) stuck out quite a bit - maybe 1/2" (13mm). We thought it might be because of the unloaded suspension but even with the suspension blocked at ride height and fully loaded they still stuck out. The rears were worst. Rim width: Minimum offset: Recommended offset: Maximum offset: 9.5"-------+20-------------+25-----------------+30 In theory our 18X9.5 5-114.3 20GBL should have been nice and flush. But instead we got this (suspension fully compressed)... http://i366.photobucket.com/albums/o...psswozme2p.jpg As you can see its not even close. RETed obviously put a lot of thought and care into those suggestions and commented at length in the thread about side wall bulge. So, that suggests something is very goofy about our car. Current wheels look symmetrical side-to-side. Car has been aligned and when we bought it 2006 the CarFax was clean. Any thoughts? We put a straight-edge against the hub (well, brake rotor face) and got the following measurements... Front 64mm from wheel centerline to outside of fender 170mm from wheel centerline to shock Rear 90mm from wheel centerline to outside of fender 170mm from wheel centerline to trailing arm I'm going to use those numbers to try to calculate our the correct widths and offsets. I'm just bummed we were so off. Thanks for sharing any insights yall might have. |
http://www.jegs.com/i/Percy's/760/01...FcQ9QgoddA8AEA
http://www.summitracing.com/parts/PHP-01201/ Sorry to hear about the fitment. |
Doing the math:
Fronts: 8" wheel = 203mm half of 203 = 101mm 40mm offset means 61mm to outside of wheel 141mm to inside of wheel measured distance from hubface to outside of fender = 64mm measured distance from hubface to suspension = 170mm So our 40mm offset 8" wheel should be 3mm inset from outside of fender and have 29mm of clearance on inside. Rears: 9" wheel = 240mm half of 240 = 120mm if we switch from a 20 to 40 offset... 80mm to outside of wheel 160mm to inside of wheel measured distance from hubface to outside of fender = 90mm measured distance from hubface to trailing arm = 170mm leaving 10mm both inside and out. That all sound right? |
I'm starting to wonder if there are different suspension dimension out there...
Is this on an S4 or S5 chassis / suspension? I've been talking to another guy who ordered some 8.0", +25 for fronts, and he sent pics that have the wheels sticking out a good 1/2" - 3/4" too... I have a set of Panasport G7's that are 8.0", +27 (R32 wheels) that have no problem tucking under the front fenders...does 2mm make that much of a difference!?!? In fact, I've used these wheels with a 5mm spacer, which effectively makes them +22 on the offset with no problem fitting under the front fenders. Also, can you confirm the specs match the wheel dimensions? I've heard of shops trying to pass on "wide" wheels that are not measured per industry spec; some shops are quoting *OUTSIDE* rim edge to rim edge as the "wheel width", which it's supposed to be *INSIDE* - this can add a full 1" of width to the wheel. Also, can you measure the backspace on this wheels? Backspacing on the fronts should be closer to 5.0"...maybe 5.5" at the most. Backspacing on the rears should be closer to 6.0"...might be able to go 6.5" deepest. This has me all worried, cause then my numbers are all off... :( -Ted |
For reference I run a 17x8+35 with a 245/40/17 and a 17x9+35 w/a 2552/40/17 and the fit is damn near perfect.... These are measured per BBS and Work but I have not double checked them as they fit as they should.
There isn't a difference in suspensions that I have ever noticed and I have interchanged parts from known S4's and known S5's with no ill effect at all. I'm wondering if Ted is right and the new co's are trying to pass off the wrong size wheels in an effort to increase profits.... I have the Works off the car now and getting ready to take them to get refinished so it you guys need some measurements, let me know.... Cheers |
It's 90 S5 vert.
Ted, I did a couple of searches on how wheels are measured and both DiscountTire and Gemplers says its from bead seat to bead seat. That makes sense to me as the bead seat is the interface to the tire. So assuming the rim/flange is 1/2" a 9.5" wheel will have a total width of 10.5". Of course that realization totally negates my calculations in that previous post. :banghead: Here are some shots of the front wheel measurements. My wife doesnt wait for the iPhone to focus and she wears weird socks. http://i366.photobucket.com/albums/o...psjzpzsr3i.jpg TOTAL WIDTH http://i366.photobucket.com/albums/o...psdbq0mgqm.jpg BEAD WIDTH http://i366.photobucket.com/albums/o...psxatvkrqg.jpg HUB TO INSIDE EDGE http://i366.photobucket.com/albums/o...pss6vbu0dm.jpg And the rear TOTAL WHEEL WIDTH http://i366.photobucket.com/albums/o...ps7hc4hnau.jpg BEAD WIDTH http://i366.photobucket.com/albums/o...pshcrxbvs9.jpg HUB TO INSIDE EDGE http://i366.photobucket.com/albums/o...pshcrxbvs9.jpg |
Re-doing the math...
Doing the math: Fronts: 8" wheel with a total width of 9" = 228mm half of 228 = 114mm 40mm offset means 74mm to outside of wheel 154mm to inside of wheel measured distance from hubface to outside of fender = 64mm measured distance from hubface to suspension = 170mm So our 40mm offset 8" wheel should extend 10mm beyond the outside of fender and have 16mm of clearance on inside. Rears: 9.5" wheel or 10.5 total width = 266mm half of 266 = 133mm if we switch from a 20 to 40 offset... 93mm to outside of wheel 173mm to inside of wheel measured distance from hubface to outside of fender = 90mm measured distance from hubface to trailing arm = 170mm leaving 3mm jutting out beyond the fender and smashing into the trailing arm 3mm :ack2: |
It would be interesting to compare TT's measurements of the Works.
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On average, rim lips are usually around 1/2" or about 12mm, IME. This is for "J" or "JJ" type rim lips. See: http://www.carbibles.com/tyre_bible_pg4.html (Scroll down about half way.) I tend to add this 12mm to the (rim width)/2 + offset, and this should equal "backspace". If this is a true 8.0" wide wheel, the we get 141mm + 12mm = 153mm. 153mm is right about 6.0". So, your backspace on this wheel should be about that number...6.0". I dunno where you're measuring the "170mm" number from, but if you're using stock type springs, the clearance issue is the lower perch of the front strut. Some coilovers will interfere with the lower adjust collar or the bottom part of the spring, if you're using largish diameter springs. Can you tell us where this 170mm measurement clearance is coming from? At least with your fronts, you can play with a smaller / thinner spacer to get them to sink back in... Try without a spacer and see if it'll fit? Quote:
230mm / 2 = 115mm (offset = 0) 115mm + 20mm (offset) = 135mm 135mm + 12mm (rim lip) = 147mm, which is our backspace. 147mm / 25.4 = 5.7874", which is about 5-3/4", backspace Would like this backspace more inward, but the 9.5" wide wheel shouldn't get that close to the fender lip... I've run 9.0", +35 with easily an inch more space to spare in the rears... Your 9.5", +20 only adds another ~18mm less clearance outward to the fender lip... Weird. -Ted |
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...and this is for the fronts, 8.0", +40? That looks like right around 6.0" on the tape measure... The wheel widths are correct... -Ted |
So they should fit beautifully with the spacer...
The 170mm was from the straightedge on the hubface to the outmost portion of the spring. We have the half-ass psuedo coilovers. In the back the 170mm was from the straightedge on the hub to the trailing arm. |
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The rears tend to hit the trailing arm that snakes forward... What size tires were you planning on using? In the rears, even with a 255 / 265, the sidewall should be pretty vertical. Some of the "curb protection" sidewall profiles might take away another 1/2" of clearance... Bridgestones tend to have bulgy sidewalls, for example... -Ted |
I was leaving tire selection to the kid (and DiscountTire). I bought him the wheels, he can spring for the tires! I have Yokahama S.drives on the G35 coupe and to your point the sidewalls are pretty even with the wheels. Very square, no bulge. Same for the Hankook Ventus I have on the front.
The only other factor I can think of here is the brake rotor thickness. It essentially acts like a spacer. In yall's experience do they vary much? I have some 18g sheet that I may make some templates based on our calculations. That'll provide a better view I think. |
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I do run a set of prototype BBK Wilwoods up front, but they are maybe 1.0 - 1.5mm sunken in. This is why I need to use spacers on my fronts, but I haven't mentioned them until now. Now, I'm assuming that the wheels are fitting flush to the face of the hub - i.e. the area where the wheel studs come out of. That should be consistent over all the FC models...? Can you confirm if you brake rotors are flush with the hub face? I would think even with aftermarket OEM replacement brake rotors, it should be pretty consistent and even... -Ted |
FWIW my 17x9 +22 RPF1's with 255/40 tires fit the same in the rear. I have Centric slotted rotors and with -1 degree of camber I needed to roll and pull the rear fenders about 1/2 in. to clear. I have +20 mm front fenders that barely clear with -1.5 degrees of camber with the same wheels and tires. Just for reference...
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We put the car on four jack stands and pulled the wheels so we could easily get under it to chk clearances and load the suspension with the jack.
The brake rotors are all flush with the hubs. We tightened the wheels with the lug nuts to make sure they didnt move or shift like they do when held by hand. Net-net - there is no way a 9.5" 20 offset wheel (nominal 10.5" width) will fit the rear without sticking out. There simply isnt room. Even if we went to the 40 offset the wheel still sticks out. In front, without the 7/16 (11m) spacer the 8" 40 offset (nominal 9") the outer edge of the wheel is even with the outside of the fender and my finger fits between the shock adjustment collar and the wheel. So I think we are good there. The TSW Jaramas (most of the TSW wheels) come in either 20 or 40 offsets and 8" and 9.5" widths with no steps in between. Putting the 8" 40 offset wheel on the back with the 11mm spacer showed we could go to 15mm to be flush. That would effectively be a 25 offset wheel. So i ordered a set of Eibach 15mm emdedded lug spacers 90.4.15.001.4. That way I dont have to disassemble, re-bearing, re-seal and rebuild the rear hubs just to install longer studs for a non-stress bearing spacer. We have an S4 lsd to rebuild and we will go the longer stud route when we swap diffs. I bought the wheels from discount tire direct. So we called the local discount tire to find out about exchanging the 9.5s for 8s. The guy was clueless so I called direct and they were phenominal. They emailed me prepaid return ups labels and shipped the new 8s. They also said theyd call the local store and explain to them thats its all one company and how they should have handled our call. Thanks for the help. I'll post pictures once we get it all wrapped up. |
I thought I'd post the pictures of the wheels installed. They are:
TSW Jaramas 17x8 40mm both front and back. The rears have Eibach 15mm spacers with embedded lugs model 90.4.15.001.4. They included new lug nuts but they arent the same pitch as the Mazda OEM ones. Not a big deal but worth noting for completeness. FRONTS http://i366.photobucket.com/albums/o...psdufzxuxn.jpg http://i366.photobucket.com/albums/o...pshkxfzgjg.jpg REARS http://i366.photobucket.com/albums/o...psluva4mdw.jpg http://i366.photobucket.com/albums/o...psgbbrcldv.jpg I think the outside of the wheels are perfectly flush with the outside of the fenders. There is no rubbing and he took it to 90mph with no vibration. I'd like to get a clearance measurement to the trailing arm. Hope someone finds this useful someday. |
Tire sizes?
It looks like a 235 / 35 / 17 front and back? What brand and model tire? -Ted |
245/40/17 as per your list.
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