wheel size issues

[w3stie]

Hi all

I've been trawling this site for info on wheel sizing without much luck. My question is if I wanted to build a streamliner for 200 mph what is the minimum wheel size I can get away with. I'm assuming a smaller wheel is better as it has less frontal area, but it also means more stress on the bearing etc. as it spins faster. Can I use a 13" wheel or even less? What tyre choice is recommended. Thanks 

[dwarner]

Conventional wisdom will suggest that you investigate available now and in the future tire sizes.

DW

[w3stie]

OK let me clarify. I'm not rich so any engine I get will probably be a turbo-charged jap import eg Toyota 1JZGTE. Shoestring budget etc. I reckon the most I can get out of this will be 250 kW/ 330 HP. If I want to go fast I'll need to design a streamliner as small, low, and slippery as I can. That's where wheel size comes in. The bigger the wheel, the greater the frontal area = more drag. So ideally I want something like 5" wheels. I'm guessing that's not going to handle 200mph.   So rather than build it and show up at the lake and get laughed and, I thought I'd ask first. How small can I go? Cost is the deciding factor here.

thanks again

[sockjohn]

OK let me clarify. I'm not rich so any engine I get will probably be a turbo-charged jap import eg Toyota 1JZGTE. Shoestring budget etc. I reckon the most I can get out of this will be 250 kW/ 330 HP. If I want to go fast I'll need to design a streamliner as small, low, and slippery as I can. That's where wheel size comes in. The bigger the wheel, the greater the frontal area = more drag. So ideally I want something like 5" wheels. I'm guessing that's not going to handle 200mph.   So rather than build it and show up at the lake and get laughed and, I thought I'd ask first. How small can I go? Cost is the deciding factor here.

thanks again

You can never end up with less frontal area than the largest object you have to cram into a car, whether that is the engine, driver, or something else.  I see little point to trying to get significantly smaller wheels when they won't be the largest object in the car.

Take a look at the photo gallery, there are many small slim cars with relatively large diameter wheels hidden inside.

I second the go with a wheel size that gets you the necessary tires to do the job.

[RichFox]

What people are trying to say here is that you are going to have to get tires that meet the rules for an over 200mph car. Such tires are limited in size and availability. If you have a rule book look at 2.F "In excess of 200 mph: Special tires for racing as designated by the manufacturer." If you don't have a rule book, get one. So first you should find tires of the size you have in mind that are certified for over 200. That may well be the hard part. At least here. maybe not in OZ

[kiwi]

Goodyear do a range of landracing tyres for a 15x4.5 rim. The smallest being 21.5" OD. They are not that cheap though. Probably around AU$550.
They are rated to 300mph.

[dwarner]

My first reply may have come off a little curt so, I will make up for it with an idea for you to ponder.

As stated by Sockjon, you cannot get a smaller frontal area than the largest item that must be packaged.
Look at cars like Al Teague and Ron Main. Get a pair of tires that you will be able to use per the rules and put them in line at the front. I can almost say for certain that anything behind the front tires will be bigger than the frontal area of the tires. Don't think that the driver must be laid out flat to decrease the frontal area. The driver MUST be comfortable. Ask anyone who has driven a streamliner in that postion such as Rick Yacoucci .

DW

ps - see my avatar, ask me how I know

[w3stie]

Thanks for the feedback guys. DW, you have guessed where I'm coming from. From a purely theoretical starting point, I am thinking of a prone driver (laying flat out) and aiming for a minimal frontal area, something like the solar challenge racers . However this is theoretical, and you guys are practical and that's why I'm asking why this can or cannot be done.

Thanks heaps 

[sockjohn]

Thanks for the feedback guys. DW, you have guessed where I'm coming from. From a purely theoretical starting point, I am thinking of a prone driver (laying flat out) and aiming for a minimal frontal area, something like the solar challenge racers . However this is theoretical, and you guys are practical and that's why I'm asking why this can or cannot be done.

Thanks heaps 

Somebody needs to mention the PVC pipe mock up idea soon

After you work out some drawings, try building a full scale setup of the necessary rollbar with PVC pipe, and plywood if needed.
Cheap and easy to try out, and if it's a complete failure have spare plumbing supplies on hand.

Take a look at the Buddfab streamliner, it's a motorcycle but gives a good idea of how laid out one can get.
http://www.geocities.com/buddfab/buddfab3

They also have a thread going in the build diary.

[Glen]

The PVC mock up has been mentioned to many over the years by me. One can learn much from mock up and patterns. I spent 40 years in aerospace and we built full size plywood or alum mock ups for everything. It will surprise you what you find in the way and changes to be made.

[JackD]

Hot tap water will soften the plastic pipe to bend it to the desired shape.
A hair drier works also, just don't tell the curls.

[Speed Limit 1000]

My first reply may have come off a little curt so, I will make up for it with an idea for you to ponder.

As stated by Sockjon, you cannot get a smaller frontal area than the largest item that must be packaged.
Look at cars like Al Teague and Ron Main. Get a pair of tires that you will be able to use per the rules and put them in line at the front. I can almost say for certain that anything behind the front tires will be bigger than the frontal area of the tires. Don't think that the driver must be laid out flat to decrease the frontal area. The driver MUST be comfortable. Ask anyone who has driven a streamliner in that postion such as Rick Yacoucci .

DW

ps - see my avatar, ask me how I know

Someone got in our Lakester today and his comment was "no way, this is not good". Then he ask how fast it was and when we said it has been 230 MPH he said he liked to go fast but he wanted a much bigger car.

[Dr Goggles]

..............someone got in ours today and said "sheesh , your brother won't be driving it( he's legally blind anyway ) and sadly ,I won't be either , how fast is it gonna go?"  he was my height but heavier and he could barely get his foot on the clutch pedal and his fat a_ _ _ meant that he couldn't have sat in it with a helmet on......

 A couple years back out at the lake I was having a fizzy drink at the end of the day with a couple of the bike guys when one enquired as to why no-one built streamliner cars with the driver prone head first ........Instinctively , to me , it's an uncomfortable idea, heck I can't sleep on my stomach in a bed and if I'm gonna stop quickly I want to have my feet in front of me and really, when I think about it I'd rather be kicked a hundred times in the backside than once in the guts     ... or nuts

BTW I" thin wall mild steel tube is cheap and strong enough to build a static 1:1 model of your car...with a mig it's quicker , stronger and cheaper than anything else

[JackD]

One person lay down on the floor on your back and look between your toes.
Another roll onto your belly and look at somebody else and their toes above your head.
And the third, lay on your side in the fetal position, sucking your thumb, and wrapped in your favorite blankie.

QUESTION: Now we have to pick a driver.

ANSWER : Pick the smallest package, usually it is going to be a young girl, that can see the best for a long time.

Sorry if I didn't consider the fat , old guys.  LOL

[Bob Drury]

One more small detail, consider the sidewall width of the tire to be used.  It ain't a real good idea to have the scrub line of the car lower than the bottom of the rim unless you like to plow salt when a tire goes flat, and yet I see lots of new and old cars at Speedweek built exactly that way.  Start from the bottom and work up............... p.s.  they don't steer very well when driving below the surface...........