By Zippy (Zippy) (152.163.197.62) on Friday, June 01, 2001 - 07:56 am:

Well, my engine is done (thank you Todd for the parts)and I'm fixin' to drop it in the hole, so I guess it's time to start thinking about the underpinnings. In the spirit of lowering my unsprung weight, lowering the moment of inertia for my spinning parts, and lowering my center of gravity, I was considering the option of using 10" wheels like you might find on a formula F-550. I am planning to use the car for autocross only(I have not yet decided what class)(with some dream of possibly IT club racing in the distant future). I am looking for your thoughts: both a critique of the general concept and practical issues like clearing the brakes. Thank you much.

By Zippy (Zippy) (205.188.197.171) on Friday, June 01, 2001 - 11:48 am:

By the way it is a '79 eb3, 1.3 crank, 1.2 pistons, balanced, ported and matched head, 4-1 headers, anticipated 2" exhaust w/ glasspacks and homemade supertrapp type back pressure device, anticipated medium hot cam from webcam, stock Kehine carb and intake manifold, stock 4 speed tranny, stock suspension.

By Todd (63.52.17.36) on Friday, June 01, 2001 - 07:14 pm:

Hey Rog,
Your next step should be a Weber carb and the early 4 speeed with the 4.93 diff. The rest sounds right on. 10 inch wheels would be great for auto-xing, but I'm pretty sure they wouldn't clear the brakes.
Wagon springs in the front with front 1200 springs in the rear work very well together.

By Charles R. (64.170.157.145) on Saturday, June 02, 2001 - 12:06 am:

There are some pretty low profile 13" slicks on the market. Several companies make a 20" outside dia. tire for a 13"rim. Hoosier makes a "cantalever" type slick, one that fits on narrower rims. I think there are two common widths. An 8" and a 10". I've found same sized oval track slicks in a 9" width as well.

I'm assuming you'll be running slicks, since your engine mods make you illegal for any of the street prepared classes.

DISCLAIMER: I've never had the budget to move beyond 13"Accord rims and D.O.T. legal race rubber, so this next part needs to be "taken with a grain of salt". It's what I'd try, if I were making a serious effort at autocrosses.

You'll need custom rims to move the slicks away from the struts. So, I'd use the softest "non-cantalever" 10" slick mounted on an 8" or 9" wheel in the front. I'd use an 8" slick on the rear.
Yes, this sounds big, but I look at it this way. Our cars can't power out of the corners like rear drivers (especially with an "open" diff) or fly down a straight like cars with more ponies. So I build, to carry as much momentum through the corners, as I can manage. I still use the "slow in-fast out" and late apex cornering methods, but I make the thresholds higher. I don't think the extra rolling resistance of the tires will out weight the benefits.

My one nagging doubt; I know there is data regarding optimal "weight of vehicle" vs "compound" vs "contact patch size" dealing with getting the tires up to proper temperatures for maximum grip. I'm not sure if my car is heavy enough, to work the slicks hard enough, for the compounds available. Thus, the recomendation for the softest "gumball" you can find. Autocrosses are so short, you shouldn't ever overheat them.

I also worry about rolling the car. But that can be controlled with springs and swaybars.

By Todd (63.52.5.152) on Monday, June 04, 2001 - 11:05 am:

Hey Charles,
The tire budget isn't as bad as it sounds. I'm using Hoosiers 2nd softest compound 8" slick on 5.5" rims(20"). They were a closeout tire and only cost 70$ each. I use a 1/4 inch wheel spacer and clearance is not a problem. Matt uses a 9.5" Hoosier on his 6" Panasports. They just barely rub the coil-overs in the front.
Matt and I regularly get the cars on two wheels, but haven't had a problem with roll-over.
Roger, Call Hoosier. They may have some more clearance tires.

By Zippy (Zippy) (205.188.197.24) on Wednesday, June 06, 2001 - 05:51 pm:

Well I got the engine in and it runs beautifully. It really revs up fast with all that weight cut off the flywheel. Idles at 700 rpm as smooth as can be. What a pain getting it going. Had a weak spark on Mon. The parts house didn't have points or a condenser so I tried to start it with the old ones. As it turned out, at some point I took off the old condenser but didn't realise it when I put the distributor back on. I was getting a very weak spark and was racking my brain trying to figure it out. I don't know how I was getting any spark at all. Finally got it on Tue. but the carb filled with lint from the new fuel lines and my needle valve was stuck open flooding out the engine. Straightened it out today and it is wonderful.

I have a few questions.What is the dwell supposed to be in degrees? My Chiltons dosen't have a listing. Right now it is at 49 degrees. How far advanced do you keep your timing? I need to quiet the car down alot. Right now it has open headers. Will a 2" pipe with a 25" glass pack make it reasonably quiet?

Thank you all very much for the advice. I think I'll stick with the 13" wheels. Sure would be fun to do the 10" thing though.

OK, this rolling the car thing bothers me. I don't have an LSD so I thought I would make the rear really stiff (springs struts and sway bar) that way the rear inside tire will come up and leave the front inside planted. I plan to stiffen up the front as well, but not quite as much. I also thought I'd make the track as wide as possible using off-set and mabye a spacer. Additionally, I plan to lower the car about 2".
Does this sound reasonable? What factors influence rolling?

Thank you Todd and Charles.

By Charles R. (64.170.157.170) on Thursday, June 07, 2001 - 01:10 am:

The stiffer the suspension, the less likely it is to roll. It will also limit your available grip. With an open diff, it can be better though. It sounds like you have the right ideas about your setup. Try it with and without the front sway bar too.

Don't concern yourself too much about rolling it. My car is softly sprung and the times I've lifted both inside tires was with the "assistance" of a berm. It was never intentional, and a couple of times, a little hairy.
But there's something to confess here. Everytime I did this, I had early apexed the turn. After clipping the berm, I was still turning 'in' and, I was on the gas. Without the welded diff (or a LSD)the car would have slowed imediately, as soon as the front tire came off the ground, and kept it down.

As for budget... It's never been the tires. It's been the rims, and my other spending habits. I'd never heard of the cantalever style tires until last year. Until I get a chance to try them, my verdict is hung. They look like they'll have more side flex(not compression, a shifting) than I'd like for autocrossing. That, and the fact that I've been mostly concerned with DOT legal race tires, means I'm still after an 8in.(or so) rim.

and a way to make myself save up for them.;)

By miniman (12.146.128.15) on Thursday, July 12, 2001 - 03:21 pm:

do you have a 7.5" disc brake setup? i own a mini cooper and unless i have this setup (which cost $1200 just for parts) i can only use 12" or 13" with the cheaper disc brakes. I'm still using my old drum brakes so I can keep the 10" wheels. 10" wheels and tires are available (if they have same bolt pattern as the mini). 165/70/10 yokohama A008 are still available for around $65 and kumho 145/10 are $30 (from tirerack.com). panasport makes 10x5 & 10x6 for around $130 each.

By Zippy (Zippy) (152.163.213.184) on Monday, November 26, 2001 - 10:17 am:

I want to revive this discussion. I would like to put 10" rims on the rear end. I think they may fit over the drums with a bit of work. Say, grind off the ring near the open part of the drum and put a spacer between the wheel and drum etc. Does anyone have or know of a Mini or F-550 car that they could try this with. I don't know of anybody with a Mini. Man, everybody in the NE is so boring. Everyone has to have a car that is bigger than the neighbors. More giant SUVs up here than cars. Blond housewives with cellphones driving Excursions. Everybody needs an Excursion, after all there is snow on the road 1 or 2 times a year, and the kids can't miss soccer. There are more trucks up here than there are in Texas, and they are all F-350s. In Texas most people drive reasonably sized trucks like Rangers. Yankees suck.

Roger

By Zippy (Zippy) (205.188.201.191) on Tuesday, November 27, 2001 - 01:37 pm:

Anyhow, about the wheels. Sorry about the rant. Anyone???

By Adrian (Civicguru) (203.42.97.227) on Tuesday, November 27, 2001 - 02:48 pm:

ok, ok ... goes off and grovels in the garage for a drum and a mini wheel ....

Yes, by the looks of it it will fit. Depending on the design of the inside of the rim you may or may not need a spacer. Doesn't look like any machining would be necessary, even the handbrake lever has plenty of clearance.

By Zippy (Zippy) (152.163.213.53) on Wednesday, November 28, 2001 - 11:29 am:

Great, thank you very much. Roger

By Todd (63.50.56.103) on Wednesday, November 28, 2001 - 11:48 am:

Does anyone know the pcd of the early Hondas (s600etc)? They came with 10" wheels.

By Zippy (Zippy) (205.188.195.148) on Tuesday, January 01, 2002 - 01:10 pm:

My 10" wheels for the rear have come in. They are J.A. Pierce brand cast aluminum alloy for an Austin Mini. They will need to be redrilled and probably will require a 1" spacer. I'll post more as the job nears the end.

Roger

By Zippy (Zippy) (64.12.106.33) on Tuesday, February 12, 2002 - 09:35 am:

Well, I drilled out my new 10" rims to fit my bolt pattern and everything seems to have worked out (no spacer needed). Boy do you have to be precise. I ordered a set of tires for the rear, Goodyear 18x6-10 with a really sticky compound that they make for Formula 500 cars. Now I need to tire the front. I see discontinued tires on the Hoosier web site and take a look. They have a bias-ply 20x6-13 R25 (very sticky) compound that they designed for F-500 cars for $82.00. The salesman at Hoosier says that the tire is built for a lighter car and won't "perform right" for my application even though it is adaquately sticky. He says my car is too heavy. He recommends a $150.00 cantelever tire and says I'll be much happier. He also says I'll be unhappy with the rear tire. I'm strongly inclined to ignore him and go ahead and get the F-500 tires anyway. What does he mean when he says it won't "perform right"? These are racing tires. I'll be using them for 50 seconds at a time. It's not like they will get too hot. Will they roll over the side walls too much? My car will be very light as I have no bumpers, windows, interior, 1200 block, etc. Yes, I know that they are not D.O.T approved. I'm going to be DP (or Pro so I can have someone to play with). Am I a fool to ignore the tire pro at Hoosier? I saw a AM F-500 car running these tires. There is no way that I can even approach putting as much force on these tires as that AM car. He runs the course in less than 80% of what I run and weighs at least 3/4 as much.

Thanks, Roger

By Zippy (Zippy) (152.163.201.209) on Thursday, February 14, 2002 - 02:55 pm:

Well my plans died in a flaming ball of burning rubber. The other auto-xers didn't like it very much at all. Don't try it. For the record the wheels do fit over the rear drums and the Goodyear tires should be just fine. Anybody want my 10" rims?????? For more details (actually it's interesting to see how I got flamed) go to the yahoo club named PHAX and see what happened when I launched this trial ballon. Look under "Tires"

Roger

By quikrick (63.204.16.66) on Thursday, February 14, 2002 - 03:52 pm:

Hey Roger, Do you create this much controversy every where you go? Sounds like those guys had a lot of fun kicking you around. Oh well, CHIN UP!!

By Mike S (202.12.144.21) on Thursday, February 14, 2002 - 05:56 pm:

Roger,

What's the issue here? If it's legal (under your rules) to change wheel size, then do it. That other competitors don't like it is their problem. The rules are there to be used. If you think of something that gives you an advantage within the rules, then go for it.

The first time Colin Chapman trned up at an F1 race with wings on his Lotuses (Loti?), everyone wanted them banned, but there was nothing in the rules that said he couldn't do it. Pretty soon everyone was doing it. Someone always has to be first and innovators threaten the status quo - hence the hostility.

By Zippy (Zippy) (152.163.194.183) on Thursday, February 14, 2002 - 07:30 pm:

Well Mike, thanks for the explanation. I have never understood why some of the ideas I have get people so worked up. Most of the people argued that it would be slower, look stupid, etc. They told me to trust the expert, until the expert said it was ok. Mabye they saved me alot of trouble pursuing a crappy idea. Mabye not. What I do know is that people tend to get workend up when I do unusual things. I had a pair of 110 cm trick skis back in '88 and everone laughed. I was told that it was unsafe because the shorter edge increased my stopping distance. Now look at the skis the slalom skiers use. Just as short.

Rick, thanks for the chin up.

Roger