My theory on 19s and FWD

[Slappster]

Ok to start off I'm gettin this theory from things I've heard and puttin them together in a thought process. So their not very good sources but here goes.

Wouldn't runnin 19s on a FWD help launchin from the line. Since with a gst stock with stock rims/tires it spins in 1st and only gets worse with each mod. Obviously 19s slow a cars acceleration more and also the weight of the 19s would slow it some more. So slowing the acceleration down some with the 19s I'm thinkin launchin in a GST would be helped with those larger rims. Now they wouldn't compare with slicks with would help acceleration so much that the "spinnage" would be bad but much faster. Sure everyone wants a fast launch but when I've tried launchin mucho fasto I sometimes spin all the way to third and it doesn't help anything. I've found that layin off the gas from a launch then punch it when tires get some traction helps or at least seems to.
However the strength of the gst lies on the highway. And from what I've heard somewhere that big rims somehow help at large speeds so maybe it would even help with that. I highly doubt that one though. Ok im done.



Let the flames fly.

 

[90GSX]

Humm... I don't know much about FWD, but the words "Bogarts" and "Slicks" came to mind.

edit: I changed it from "M.T." to the more generic "slicks" b/c I don't want this thread to turn into a "who's slicks are best" flame war.

 

[Slappster]

I'm not familiar with "Bogarts" and "Mickey Thompson". They sound cool thou.

 

[larryd]

i know for a fact that you will actually get worse 60ft times with larger wheels. Or atleast I did. when I had 18s on my Celica I couldnt maange anything better then a 2.4, with my 16s I ran 2.2s..

I cant giev you a technical reason but this I know for sure, a larger wheel will nto help you at the track, wider would becuase of the contact patch of the tire being larger to get more grip but larger wouldnt.

 

[Slappster]

Ok I'm wrong. Not like I'm not used to it

 

[GreddySpyder]

The problem with larger wheels when it comes to launching is the fact that most people get lower profile tires with the larger wheels. taller sidewall tires expand more when you launch so they grab better, but when it comes to handling, lower profile tires are better. So by this rule, the stock 205/55 16s will grip better on the launch than say, 205/35 18s, but the 18s will most likely handle better in the turns.

 

[Got Grip]

Originally posted by GreddySpyder
The problem with larger wheels when it comes to launching is the fact that most people get lower profile tires with the larger wheels. taller sidewall tires expand more when you launch so they grab better, but when it comes to handling, lower profile tires are better. So by this rule, the stock 205/55 16s will grip better on the launch than say, 205/35 18s, but the 18s will most likely handle better in the turns.

This is correct, Since DSM's have a relatively small diameter tire that fits (compared to all out drag cars) the best thing to do would be to get the smallest wheel that will clear your brake and run more sidewall, that way you can air it down some and get a huge contact patch. Also, the more intended for drag racing a tire is, the lower the PSI you can run in them and still be effective. Ever notice that most drag cars run 15 or 16" wheel max? That gives a good amount of sidewall to flex and allows for a big contact patch.

edited because I can't spell, and I probably still have typos

 

[Scrymerr]

Well, wanting to add larger wheels to slow the tire so it wouldnt spin, is like weighing it down with bricks. It will reduce tire spin but it will slow down acceleration. What you need is anything that will increase tracion without adding weight, such as a wing (like F1 cars have in the front) or slicks, or just putting on small rims and letting a little air out.

 

[nutshot]

In theory, you could run a lighter wheel faster. The motor would not need to launch at high RPM's because there is a lower moment of inertia, kinda like to launch a skateboard would take fewer revs than a dumptruck. Drop weight, let the ET's come to you. I like your thinking, though.

 

[RocketDSM]

Hey, here is a unique response.....I did just that. I went to 18s against the common theory. I held the same theory you have. Yes it helped. Yes my 60ft times were worse for wear. BUT, I had built the car for top-ending (hit 145 and still had more to run but the highway ran out). So I wasn't expecting great 60ft or even 330ft times. I made up a LOT of ground in the last 1/8th. I still lost a lot. If you build the rest of the car up around it, running a higher diameter tire MAY work. But you have a lot of things working against you. I can also say that it cured a lot of my tire squealing in daily driving. I now run the same tires on my GS-X and I can tell it's hurting the performance. I'm just not willing to swap out 225/40R18s for 205/55R16s on a daily basis. Good luck, hope this helps.

 

[Slappster]

Thats kinda've what I am going for. Building the car allround its strength which is the top end. Sure I lose from the line except against hondas (most). But the thought that I should be able to keep up the lightly modded supras on the highway gets me more excited than a 1/4 time in the 13s. Of course with appriopriate mods . Anyways would 18s or 19s be best at high speeds?

 

[GreddySpyder]

Larger wheels would make your gearing taller, theoretically, if you had enough horsepower for that to matter. But from what I've read you can hit around 170mph in 5th gear on the stock 16s if you had the power, when would you ever go faster than that? Make sure your speedometer is reading right when you get larger wheels and tires too, with 18s or 19s it will most likely show that you are going slower than what you actually are, you don't want to get a ticket because you thought you were going the speed limit.

 

[Slappster]

Yeah I know about the speedometer being off with larger wheels.

I'm wonderin how much the 19s are going to hurt with launchin/acceleration anybody with times or any experience with big big rims.

 

[cucumber]

I know my 60 ft with the 18's was about 2.4-2.6...

With 16's it was 2.1-2.2...

 

[Slappster]

Well I guess my dumbass is going to have to invest in some slicks when I get deep into performance mods.

 

[vertGST]

i know for a fact that larger wheels help in the top end, with each turn of the wheel you cover more ground and its like inertia once the car is moving you can keep it moving its the fact of getting it moving with 19s thats the problem once you have a nice rolling start you are good to go i like to think i know what i am talking about

 

[Slappster]

I hope u are right too. Seeing how most races on the street are from a roll I should be ok.