Hello Guys,

I own a 2011 honda fit base MT and this past weekend I joined a local autocrossing group and took the fit out to an autocross event.

It was good fun and I want to go out and do it again.

The one thing several people commented on is the fact that the stock 175/65 dunlops on the base fit tend to roll over onto the sidewall and thought I should ditch them. Sounds a bit unsafe to me and I imagine people don't normally comment on such things. This also was a rainy weekend here so it would have slipped more and spent less time on the sidewalls then it would on a dry day.

So I am starting to think about what to do to amend this situation.

The tires on the car are getting worn out and I am going to replace them eventually with Michelin pilot sport A/S 3 tires anyway. The tires on the car would be fine through the fall of this year. So would it be worth it to replace the tires now and run with the A/S 3 tires now in autocrosses. They would still be 175/65, but would they tend to have stiffer sidewalls which would not roll over as bad?

Anyone run those tires and have opinions on whether they are good or bad?

Would they wear out quickly if I used them for 4 or 5 autocrosses.

At $450 for the set including installation,balancing, etc this would be the cheaper option.

The other option is what several people at the autocross event recommended

Several people at the event recommended getting a set of wheels and tires for autocrossing.

If I did that I would get a set of 15" steel wheels from tirerack and pair them with toyo r1r 195/50s. Without tpms this would cost $820 with shipping, balanced, mounted, etc.

Living in Maryland I can't pick them up sadly...

I would not be able to disable the traction control, but with the additional grip it would activate less often anyway and I reckon turning it off doesn't make much difference anyway.

This was my first event. So I'm not even sure its worth committing to any tires at this point. Thinking I might just help out the next event and just sit out competing.

What are your experiences autocrossing fits?
Is it worth the dedicated tires?

 

First question is which class are you running in? Stock? Stf? Street prepared? That's going to limit you. What are your mods?

 

If this is your first event I suggest go out and have fun. It's likely you will be put in a novice group so the playing field is even. I would run the all seasons because they will show you where you need to improve. A stickier tire can create bad habits early on.

Yes, dedicated wheels and tires are a must when you get to that point. Ebay believe it or not is a great source for buying tires cheap. Hankook and Kuhmo are a couple to look at. Any sport tire will have a stiffer side wall. Tire roll is usually due to too low of tire pressures. For auto xing you will run 40-45psi front to prevent roll. And 30-35 psi in the rear. Chalk on the side of the tires can tell you how to adjust the pressures.

Also there is what's called a PAX index that will level the field again, if another car is more modded. Best bet is to stay in the stock class for one season with all seasons. One wrong mod will put you in a class that you can't be competitive in, that's no fun. Mod responsibly.

DONT SIT OUT!!! There is nothing to be intimidated about.

 

STF is the class I run in. It's basically all underpowered fwd cars lol. The wheel and tire requirements are up to a 225 tires and up to 17x7.5 wheel. 16" Enkei RPF1 are the wheel of choice for autoxing imo.

 

bridgestone RE11A

 

Thanks for the responses.

My aim for the time being is to remain in stock class. The only mod is an added rear sway bar which is allowed in the stock rules.

And tires for stock class are a bit confusing. As in theory the Toyo R1Rs meet the stock class requirements at least to my understanding aside from the looking in the tire guide which you'd pay money for.

Good to know that sticky tires can create bad habits early on.

Ah ok did not know that. I ran my tires at 36 all around which was just a general suggestion to add a few psi. The bmwcca is the group I went with. I did read it somewhere once, but only once. The stock dunlops are rated at 44psi so I would probably put them at 40 front and 35 rear then next time and see if tire roll improves. If it doesn't then it sounds like I go for new all seasons.

I would buy the new tires from Costco which will only sell a few different tires which is why for all seasons I would get A/S 3s. Their service is very convenient if you get a hole in your tire.

I've heard of the PAX index and since its times against myself anyway being competitive in my class is not a huge deal to me at this point.

For the way your groups have set up courses you can make use of the extra speed. I would have thought for pure autoxing wheels and tires you'd want a slight buff to acceleration by going with 15". I found that on the course I used last week I wanted more revs not less. Although you probably have a fit sport so I could see 16" since that car has them stock.

Thanks for the tire suggestion for a more serious tire fitVtec.

If anyone else has any more suggestions feel free to comment.

 

I'd stick with '15's too, less rotating mass.

 

Discount Tire Direct has some good pricing, with free mount/balance and shipping to boot. I would check there as well.

For tires, when I first started, I was on Bridgestone RE760's. They were great tires (although no longer in production). Now I'm on S-Drives. I haven't been to an auto-x event with them, but they feel very similar to the RE760's. They're not as sticky as Azenis I ran, or R-comps, but I think a very good performance tire. I got the entire package with 15" wheels and 205/50/15 tires for $715 shipped. The wheels were Konig Feathers. I would skip on steelies, personally. With our weenie engines, we need all the help we can get on unsprung weight.

 

That brings up a good point...

From the sounds of it you may or may not know how to swap wheels and tires. I'm assuming, not trying to be insulting. This skill is going to be another requirement for Autoxing. You will have to get comfortable with jacking the car up and swapping wheels and tires.

Read into it, buy a torque wrench (I think the lug nut torque spec is 82 ftlbs) and a decent jack (not the one that comes with the car), learn how to jack up the car on its jack points, remove the wheel package and put it back on.

Of course you wont be able to mount and balance tire and wheels, but you should know how to remove them from the car and make sure the lugs are properly tighten. You will need to be comfortable doing this for Autoxing, and also you don't have to pay someone to install a wheel and tire package from Tire Rack.



The tires you are installing are they going to be on the car all year around? or are they just for autoxing?

 

I will have to check them out thanks for the suggestion.

The stock base wheels and tires are actually much lighter at 30lbs then the combination on the sport which are 40lbs each which makes up most of the weight difference between the cars on hondas website if you noticed.

Buying super light alloys like RPF1s are the only wheel that would save weight over what I have now and a new set of those are kind of pricey.
At this point investing tons of money into a hobby I'm not sure I will be doing in a few months is not very smart. Us young people can change our minds very quickly. From tirerack you'd be looking at paying 600bucks more over steelies.

I may spend time searching craigslist for used RPF1s while I use my current tires or the A/S 3 sports if I go with those. Then I would just need to get new tires mounted on them when I decide I want to get a second set of wheels/tires operating

No worries. I regularly rotate tires and change oil etc for mine and my parents cars in a home based garage with jacks and jack stands.
General maintanence.

I bought a small floor jack that I could bring in my car to events and I have torque wrenches and a good electric impact wrench and wood for wheel chocks. You are correct on the torque spec.

Now I am new to using a floor jack in a parking lot haha and more importantly new to the jack as it has never been used. I would do some practice runs with changing out wheels to get used to the jack and make sure it works properly.

If I bought a second set of wheels from tirerack I would buy them balanced and tires mounted, shipping is kind of a bear with them although I do not think it is unreasonable.

The A/S 3s would be for all year round use and would have the stock base fit tire size of 175/65.

If I got a second set of wheels/tires they would be for autoxing only.

Then there is the question if I bought a second set is it worth it to go 205 or stick with 195?

At this point I'm thinking I should try to inflate the stock base tires to 40/35 vs 36/36 and try again at least for another autox.

Or do you think the stock dunlops are 5 pounds lighter for a reason? and that reason is gumby sidewalls lol

Then consider buying the A/S 3 sports to replace my nearly worn out tires and use those for the rest of the season. Slowly buying RFP1s if I notice a good deal on some.

Then next season if I'm still serious mounting the RFP1s and using them as pure autoxing wheels.

 

I don't know anything about the A/S3, I run the Conti Extreme DWS. I've loved them since I put them on my WRX. But if you read good reviews and youre confidant in them, go with them.

For auto-crossing, yes, 205 is what you will want. It's a wider tire (the contact patch stays the same though, another topic) In AXing you are in a turn 99.9% of the time, so wider is better.

I would suggest with a 16"x7.5 wheel so you have the option to upgrade brakes. Also a bit stiffer side wall, and you have a wider variety of tire selection. The weight difference from a 15" to 16" is negligible concerning acceleration.

Definitely play with the pressures. Ask others at the race about the chalk trick (on the sidewall) to figure out the correct PSI.

I'm not sure why the Dunlops are lighter, maybe because they are a fuel economy tire!?! Just guessing.

Good plan!

 

The A/S 3 is rated well on tire rack, much better then my stock tires are.

Ah so wider= more stability=less stress

slightly more drag from tire friction but its minimal relative for autoxing.

Ah I looked up the chalk trick. I'll have to try it out this weekend. I imagine that might give me my answer. If I find that inflating the tires further would not make sense then going with new tires sounds worthwhile.

Now begs the question will 205/55s fit in the well of a stock base fit when the wheel is turned etc? I would then have to buy the tires somewhere else besides Costco as they will only do oem tire sire.

I believe the suspension between the sport and the fit is the same as the base aside from the wheel offset because the tires on the sport are wider.

I will have to measure the well again. The only thing you get close to is the bottom of the spring in the front macpherson struts as far as I can tell and those would move up and down with the tire. I would also have to check it with the wheels turned would they hit anything.

The ratio between 175*.65=113.75 is fairly close to 205*.55=112.75. The 205s would have a slightly smaller diameter but only by 2mm.
The actual difference if added to the 15" rim size would be .2%. No effect on speedometer basically.
Just a thought.

Not sure I'm at this point ready to make a call to get that serious with my car that I plan to change brakes etc.

 

No Drag. Not to get all engineering on you, but the friction force is in the direction you want to go (forward). The tire pushes on the ground rearward, friction always opposes force. Therefor the friction force points forward. Its hard not to explain without science. There is whats called a friction coefficient (0-100%), basically 0-100% traction. the only way "drag" could be introduced is if the coefficient was over 100%, so the tire would have to melt/stick to the ground to create what you are calling "drag".

I hope I didn't confuse you more. lol.

Yes 205s will fit, my DD tires are 205s, my track tires are 225s.

x

 

Lol I'm a mechanical engineer you aren't confusing me to badly. Rolling resistance is a thing along with wind resistance, but more area of tire means more drag, but more tire means less normal force so it cancels out the net gain in rolling resistance possibly. Can't say without running numbers. I actually have a calculator for rolling resistance/wind resistance.

And no need for any extra spacers or anything?

Turns out they don't make that size in the A/S 3 so its a moot point anyway lol.

The only thing that seems reasonable is Kumho Ecsta 4X and they are rated no where near as good as the A/S 3 sports are. Still much better then my current ones are though haha

Kumhos(205/55) gets 7.2 A/S(175/65) gets 7.8 DunlopSP31(175/65) gets 4.7 lol on tirerack surveys.

Now its a matter of finding a place that sells them and would make that option to go with the Kumhos.

 

We use Dunlop Direzza Star Spec's, year round.
https://mail.google.com/mail/?ui=2&i...=emb&zw&atsh=1

 

Today I made a paper strip to simulate the tread width on the kumos and when I taped it on it seemed like to me that at full lock the tire gets a bit close to the inside of the wheel wells. If the suspension traveled too far I get the impression the outside edge would rub?!?! with the stock suspension.

As long as you stay from lock one way at speed it should be fine. I'm gonna go for a drive to see how far I turn the wheel related to turning radius going around a corner at speed.

Edit: It would appear that the most you ever would turn the wheel would be half a revolution in either direction at speed so it doesn't look like it would be an issue.

 

As far as Bridgestone tires go:

RE760 are a good tire but will not grip even close to RE-11. Plus this tire only comes in 16" and up. Great bang for the buck tire for cruising around or DD.

RE-11 is now the RE-11 A. This is a great gripping tire. Comes in both 15 and 16" options. Plus the new "A" is now a 200 tread wear so your set for next year when they switch to rules to 200 tread wear. Also the "A" has a new sticker compound claiming faster track times.

The AS3 is an all season UHP tire. Thats all I will say for legal purposes haha. I actually work for Bridgestone.

I use Re-11's currently for AutoX. They are awesome. Grip excellent for the power the car has. I just ordered the RE-11 A which will be going on my Volk's 15x7 43et. I'm looking forward to running these next week.

 

You have your info mixed up. First normal force stays the same. Normal force= weight of car.

2nd the contract patch stays the same when going to a wider tire. This confuses most people. The only way to increase contact patch is to add weight, less psi or taller tires.

 

In terms of autoxing tires they are all amazing. ZII, XS, RE11A, Rivals, RS3... its splitting hairs really. I'm trying out the Kuhmo XS next weekend in a 225 at the event.Should be fun.

 

The current standard for a/x winners is either Dunlop Direzza Dll or BFG Rivals unless your rules do not require UTOG ratings in excess of 100. If they do allow lower UTOG the Hoosiers are the choice.
While you're at, if serious, add some lightweight wheels such as Kosei K4R's or used Honda hybrid wheels typically 9 -11 lb. The wheels are a 99thh percentile but the tires are required. Steel wheels are pretty heavy.
In the future use Tirerack's lap times as final rule and back up with Grassroots Motorsports tire trials. If you want a tie-breaker use tire weight; the lightest tire wins on equal lap times.
Fits do pretty well except when opposed by good Minis, and even then can outdrive the binis (bmw minis). Oh, and the lower your tire profile without compromising tire diameter too much the better off you are. Allow up to 0.5" less diameter, no more. Thats especially true with wider, heavier, tires.
The tire sizes of choice herebouts is 195/55x15 or 195/50x16 or 205/50x16's on 6 or 7 inch idths
If allowed add a 6mm thick spacer on each wheel, no more.