| Author | Message | ||
| Dr. George Petito (Doc18015)
Junior Member Username: Doc18015 Post Number: 63 Registered: 12-2001 |
Ferrarijoe: Please supply the info on purchasing the torque-o-matic. I tried e-bay with no results. Thanks.....George | ||
| Justin Randall Kenyon (Kenyon)
New member Username: Kenyon Post Number: 33 Registered: 10-2002 |
Guys, Check this website out www.powerdog.com/tiresize.cgi Put in your stock tyre size and the upgrade you want to make, it then calulates the diferences. Justin | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 11 Registered: 10-2002 |
Thank You Mitch for the education. I always think about the basics like diameter and offset a little. But never to the extent you explained. Makes sense to me now...how at first glance what seems simple may have more complications that you realize. | ||
| Mitch Alsup (Mitch_alsup)
Junior Member Username: Mitch_alsup Post Number: 205 Registered: 4-2002 |
When you look at replacement wheels and tires there are basically 3 rules that keep you out of trouble. 1) retain the same rolling radius, 2) retain the same ratio of front to rear tread widths, and 3) choose a wheel offset to leave the centerline of the tire at the same position. 1) When the replacement wheels and tires have the same rolling radius the spedometer will not have any error, nor will the suspension require any ride height adjustment. This is the next to last column in tire rack's SPEC charts. For example the original 255/50-16 TR rear tires have a 26" rolling radius. These can safely be replaced with 255/45-17 or 275/40-17 or 255/40-18 or 285/35-18. As long as the rolling radius is within a couple of percent, the speedometer error is nill. 2) the original TR fronts 225/50-16 and rears 255/50-16 have a 255/225 == 1.13 ratio. If you went with a 285/35-18 rear, you would want to couple it with a 251 (= 285/1.13) width tire. You would increase this to 255 and end up with a 255/40-17 front or a 255/35-18 front. This leavs the oversteer/understeer relationship as before the new wheels and tires (or with a triffling more understeer). 3) You choose the offset to retain the same tire centerlines as before the conversion. This leaves the weight transfer unaltered and leaves the suspension in exactly the same position (ride height, caster, camber, toe) as before. Thereby obviating any requirements to adjust the suspension (assuming its aligned correctly to begin with). | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 277 Registered: 5-2001 |
Hey Ben, Steve has a thread going on what tire to get called 'TR Tire Brand Selection' Post there too if you can. Thanks, Joe | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 851 Registered: 1-2001 |
FerrariJoe I have those tires (in stock sizes) on my TR now. I think they are great (after about a year), I'm not directly sure how they compare to the Michelin Pilot Sports that everyone raves about (pricey), but they are much better than the hard old Michelin MXXX-v4 that were there before. Sorry for getting off topic. -Ben | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1166 Registered: 1-2001 |
Robert -- Thanks for the info. Now if I can just find some appropriate street 275~295s in 16"... Joe -- Thanks for the tip -- I'll give it a shot. Based on the comments (here and on TireRack) and the price, the Firestone Firehawk SZ50EP is still on my final possible list too. | ||
| Robert Ziino (F355bob)
New member Username: F355bob Post Number: 28 Registered: 8-2002 |
My SAC rims were 8" front and 10" rear/18" | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 274 Registered: 5-2001 |
Steve, Have you tried to call Tirerack? I had to in order to get the Firehawk SZ50EP's because they were not listed in my size online or in CD. It's worth a shot 888-541-1777 (USA) or 574-287-2345. Joe | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1165 Registered: 1-2001 |
Joe -- Thanks for the SAC link, but I'm staying with the stock 10" wide rear TR wheels and was/am just interested in Robert Z.'s tire width -to- wheel width ratio (although searching on TireRack's site shows no wider 16" street tire that would match the OD of the stock 255/50-16 so I think I'm stuck with the 255s.) | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 271 Registered: 5-2001 |
Steve, Try here. http://www.sacwheels.com/ You can select your year/model and it tells you the widths. I think you have 3 choices of wheel styles for your 5-lug. You can get 8-8.5X18 for fronts and 10-10.5X18 for rears. Joe | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1164 Registered: 1-2001 |
Robert Z. -- What are the widths of your SAC TR wheels? (I'm due for a TR tire-ectomy soon too so I'm thinking about going with a wider tire in the back.) | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 270 Registered: 5-2001 |
Jeff, Mine are single-lug (look at my profile). Very nice Robert!! Joe | ||
| Robert Ziino (F355bob)
New member Username: F355bob Post Number: 27 Registered: 8-2002 |
I put SAC wheels on 295/35/18 rears and 235 fronts with no problem. Handles much better and looks much better. Speedo error minimal because diameter is similar to stock.  | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 8 Registered: 10-2002 |
Wow Joe, that's a nice set-up! Thanks for your help and guidance. I've heard that the cost for converting from single-lug to 5-lug is quite high. So I"ll probably stay single...in more ways than one - now that I've got a Ferrari. Now if I could just get the various wheel companies to respond. Are your OZ wheels of a 5-spoke type? You did extremely well financially on your wheels and tires investment. I really like the look of the later factory wheels like on the 512M. And I would like to use P295 tires or wider in the rear (no comments please!). I better figure out the offset I'll need to clear everything, and go from there. I'm sure some TR owner out has stuffed the widest tires possible under his car without interference on some great looking single-nut wheels. So if you are reading this, please chime in. Thank You; Jeff | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 269 Registered: 5-2001 |
Jeff, If you stick with the single-lug, I advise you to get a torque wrench set to maintain the torque on the wheels. I put together a set for my TR as you can see below. I bought the Torque-O-Matic on eBay for $50 and the socket from TRutlands for $310. I un-tighten and re-torque my wheels every month. You should do this while they are cold for a more accuracy. Liberally use the Loctite copper based anti-cease on the lug and inside the hub. Joe  | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 268 Registered: 5-2001 |
Jeff, A early TR single-lug wheel without the spline attached with 5 bolts, looks like it would be good for both as you mentioned. But I do not think it will work as both a 5-lug and single. I will look at the spline tommorow on the wheel because I have to remove them to mount my new wheels. I will let you know what I see. What a coincidence, I just received today from Japan 4 new single-lug wheels that I mentioned above (I think they are OZ�s). They are brand-new and look great. They were made in Italy in May 1989 according to the date stamp on the inside. I paid $690+$170 shipping which took 7 weeks to get here and probably because the container ships were backed up on the left coast. I got new valve stem from Gentry Lane in Toronto for $40. I also bought from the tire rack new Firestone Firehawk SZ50EP's for $610 with shipping and I will have them mounted and balanced tomorrow. Total was $1510 for everything new. Joe | ||
| Arnaldo Torres (Caribe)
Member Username: Caribe Post Number: 435 Registered: 2-2001 |
Bruce, if the overall diameter of the wheel plus tire does not change, you should not have to adjust anything as far as I know. What am I missing? | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 7 Registered: 10-2002 |
Thank You Ferrarijoe for this information. It's odd that they "appear" to be in such good shape but keep changing hands. Question: Do they make wheels that are both 5-lug and center-lug on the same wheel? Can you modify a 5-lug to use center-lug? | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 267 Registered: 5-2001 |
Jeff, The response is below and it appears that they would not fit a single lug TR. Joe Hello I have no idea what model Ferrari these wheels came off...I bought them used a few months ago for my 348tb...I've used them a total of 3 times on my car...I'm looking to buy a 18" set. There are no lug nuts included. Only the center lug nut cover with the Ferrari logo is included, as shown in the photos. I hope this helps... VK | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 6 Registered: 10-2002 |
Aahhhh...so you are referring to the overall tire height/diameter. I see where this could cause a problem. So if the tire diameter grows it could have fitment problems with the TR inner wheelwell? So bigger rims, shorter tires to maintain the clearance? Makes sense to me. | ||
| F-J'87EuroTR (Ferrarijoe)
Member Username: Ferrarijoe Post Number: 266 Registered: 5-2001 |
Jeff, Keep in mind that the front tires on the eBay Speedlines are also 50 series (as are the original 16� wheels). With the taller wheel you should have either 45 or 40 series to make the clearance needed, I would think. Are you sure they come with the single knock-off nut. I emailed them and asked exactly what model Ferrari they came off of since they did not state as such. I will let you know what their response was. Joe | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 5 Registered: 10-2002 |
Thanks Mr. Wellington for your repsonse. What type of suspension adjustments are needed? I can understand 17" or 18" rims for a car that originally came with 16"s may need a recalibration of the speedometer. But what other types of changes are needed? If the wheel offset and tire height are close to the original dimensions, it seems that any adjustments would be minimal. I have seen 11" wide tires on the back of an 88 Testarossa without clearance problems using speedline wheels. That is the direction I would like to go. Please help me see the light. Thanks to All. Jeff | ||
| Taso Anastasopoulos (90rossa)
New member Username: 90rossa Post Number: 43 Registered: 5-2002 |
I'm waiting for mine from Kinesis. Email if you have questions, maybe they can make yours at same time and we can get better deal. Thanks, Taso | ||
| bruce wellington (Bws88tr)
Intermediate Member Username: Bws88tr Post Number: 1109 Registered: 4-2002 |
jeff remember 87 trs are factory oem 16 inchers, if 17 0r 18 rims put on suspension and other things have to be adjusted.. good luck bruce | ||
| Jeff Green (Carguy)
New member Username: Carguy Post Number: 4 Registered: 10-2002 |
Hi Everybody! I'm wanting a set of 17" or 18" aftermarket wheels for my '87 TR. Email both SAC and speedline 3 times with no response. Ebay has a set of 17" speedlines with pirelli p-zero tires at $2500 "buy it now" price. Wheels look great, tires good. Is this a reasonable price? Tires are stock TR sizes for the mid 1980's car. Any suggestions? Thank You, Jeff |