Subject: Rims and tranny question
Date: Wed, 17 November 1999
From: zdoc <zdoc@yosemite.net
To: "James G. Lark" <James.Lark@ey.com>James writes:
Hi Doc,
I'm hoping you can help me out. I'm a member of ZONC and I appreciate your words of wisdom every month. I've got a couple I am hoping you can help me with:
I saw your 240z on the net - nice. My question has to do with rims and tires. I noticed that you have 225/50/16s. I would like to start racing on the weekends and my puny 195/60/15s obviously don't do the trick. I've asked different people, some of whom say get 16" rims, some say 15" rims. Additionally, I believe the offset should be neutral or approx. 11mm positive, but am not sure. I don't want to spend $$$ on rims unless I know exactly what to get (by the way, what do the Prime Stars generally run? And where can I get them?). I have heard of people putting 16x7.5s on the front with 225/50s, and 16x8.5s on the rear with 245/50s. I don't have coil overs, just the standard strut/spring setup. I have curled the inside fender lip which gives me an extra 1/2" or so. Would you please help me out.
What is the widest rim/tire combination I can put on the car without rubbing on the spring or fender with what offset? Additionally, do you have any recommendations on tires? I've been told Yokohama A032Rs, BFGood., Hoosiers. I'm just getting too much info.
I have a 1973 240z (manufacture date 10/72) with a 4 speed. I would like to put in a 5 speed because of the closer ratios. I read in the newsletter that somebody has a ZX 5speed (he thinks a ZX - not sure) he is selling. I spoke with him and he told me the tranny has an L2 on the side and a flat plate on the top in the back (I guess I'm wondering the year also - late 70's, early 80's???). Will this work in my car without mods? I would like to just take my 4speed out and put the 5 speed in. Since I only have an L24 engine, I'd like to get the best acceleration I can. (He's asking $75. Do you think this is reasonable if it's in good shape?)
Also, I have heard that if I upgrade to a 5 speed, I should also change the differential to maximize the benefit. I don't want to spend big $$$. Will changing to a 5 speed make that much difference if I don't change the differential?
Thanks very much.
Jim Lark
Doc replies:
James,
Doc here, the contact patch on the 225\50x16 tires is great. The advantage of going to the 50 series tires is that you have a greater array of tires and tread compounds available. The rims are 7" wide and the offset is "O". I have the standard struts without the coilovers and have rolled the inside of the fender wells so that the tires can use cables too without
interference. I have the ST sport springs and sway bars too. The car sets pretty level and handles very good with the Tokico Illumina's. The only drawback is that the 15" rims lowered the center of gravity on the 225\50zr15" Comp TA's. The tires that I use for Autocrossing on the Hyashi Racing 3 piece rims.As far as the 5 speed transmission the earlier type is a better ratio than the later ZX trans. due to the differential ratio if you still have the standard one found in the 240Z that was a 3:36. The later R-200 differential can be found in a 3:90 ratio that will be necessary for you to have the grunt that you want in Autocrossing. The later 5 speed will be great for gas mileage with the 16" rims and I have setup my 70 240Z for Crusin' and with triple Weber's I still get some good mileage too.
I hope that this gives you some food for thought. The tire shops would mount up tires and rims to put on the car so that you can check for clearance behind and turning at the fender wheelwell areas. Go to some more events that ZONC has and check out some of the other members "Z's" to see what they have found. Right now I am currently using Bridgestone's that are M&S rated Z Rated 16" tires and they are Quiet! The choice is yours, ENJOY THE RIDE!!!
I hope that this helps you.....
ZDOC OUT