I was running 9.5” 245s on my STU Evo X... I need to go back and figure out what to do now if we can run 265s. You shouldn’t have to touch the fenders if you have the right offset wheels; my problem was clearing out the front plastic inner fenders.


I was thinking about running a different class next year… maybe I should give STU another try.


When are they going to make it official?

 

^Its in the latest Fastrack, page 24 - http://cdn.growassets.net/user_files...pdf?1450468301

 

Finally got un-lazy after the holidays and sent a PM on RoadRaceAutoX about RE-71R tread width measurements. I sent it late in the day yesterday, got immediate response, and as of this morning at 6:30AM, I heard Tire Rack re-measured three sizes of the RE-71R.

Corrected measurements are below and will be updated on the site shortly. It was explained the measurements are +/- 0.1" but these measurements make much more sense since they're exactly in line with Rival S measurements (except BFG doesn't make a 265/18 so we can't compare that).

Corrected Data:
Section Tread Width Measured Rim Width
245/40r17 9.8" 8.6" 8.5"
255/40r17 10.2" 8.9" 9"
265/35r18 10.7" 9.7" 9.5"

So, based on this, it does look like 265's are the route to go (not a huge surprise), even if we use the 9.5" tread width measurement that Tire Rack initially indicated for the size.

Since I only go through one set of tires per season, I'll probably go for the 265's so then it's just a matter of wheels since I only have 17's right now. I've identified a couple target wheels but now I'm debating between 9.5" or 10" wide. I know the conventional wisdom is to go for the wider wheel to minimize sidewall deflection but I'm wondering if and how the shorter, stiffer sidewall of the 265/35 impacts that. And since tires act as a spring as a function of sidewall and tire pressure, I'm also wondering how spring rate and tire pressures impact the decision, or how they SHOULD be impacted after the decision-- I know just enough to be dangerous, not enough to do chassis and suspension mathz.

 

[QUOTE=BriK;11558829]

Since I only go through one set of tires per season, I'll probably go for the 265's so then it's just a matter of wheels since I only have 17's right now. /QUOTE]

I won't get a season out of a set of the new tires. We're seeing 3-4x times the wear on an Evo, compared to last year's tires. I think 285s would've helped wear also (beating a dead horse).

They do grip well, was .8 behind the Nat champ on an Evo friendly course. 12th in PAX was good for me, even with it being the last event with folks not running in their normal class/cars, etc.

 

Are Rear Lower Camber Arm & Rear Toe Control Arms legal for STU?

From 2016 SCCA Solo rule book
“On double/unequal arm (e.g., wishbone, multi-link) suspensions, only the upper arms OR lower arms may be modified or replaced, but not both. Non-integral longitudinal arms that primarily control fore/aft wheel movement (e.g., trailing arm(s) or link(s) of a multi-link suspension) may not be replaced, changed, or modified.”

So it is either the camber arm (rear control arm) or the Toe arm but not both? But toe arms are not the same as the upper arms so it is legal? Or is it just the camber arm legal?
Also I am planning to get rid of the eccentric bolts if I can replace these arms…

 

Hey'ya Rick, are you saying you're running the 265s RE71Rs now?

 

I'm trying the "wide" 255 for now. I have some 265s on my vette, but no wheels to try them on the Evo.

Here's front tire wear from 2 events, with 24 runs on asphalt. Prob no use as a wet tire now. Rears are only a little worn.

 

That wear is absurd. I know you know what you are doing but what are your camber and toe settings at for a reference point?

 

thats from 24 runs??? what are other people getting on these tires?? i was gonna go with these but given that i want them to last a season maybe z2ss' are the way to go for me...

 

imo, the bridges will not last a 'season' ..regardless of how 'you' might define one

 

heard a lot of guys getting a hundred runs out of them.. maybe not for the evo

are you also daily driving them? i plan on treating these like race rubber - no/very few street miles

 

Neg 1.5 deg with .25" toe- in. I kid, I have more than 3deg neg camber, zero toe. Probably 200 street miles.

My 15 year old son with 7 years autocross experience, did take 8 of the runs and he's harder on the front tires than I am. I've seen this much wear on other cars, my friend's CS FRS wore the fronts quickly. The Evo is puts power down through a heavy front end, it needs more front tire.

Kyoo, this is the first time I've seen people not using their good street tires for practices. You may be able get 100 runs, by remounting/flipping and rotating the tires. Street miles shouldn't cause too much wear, the rears show normal wear.

 

Interestingly, in our region we've noticed a pretty steep drop off in test n tune participation, and I honestly think this is one of the reasons. we've got plenty of events in our area, and people don't want to waste their fast wearing tires on test n tunes. with the proliferation of street tires (in general, plus cam class, plus people with undriveable ST cars), I've been seeing it more and more, and I did last year as well anyway.

One of my friends who autoxes literally every weekend during the season went through FOUR sets of RE71Rs last summer (STF Mazda3, ~2700lbs). He drove pretty long distances for events at times (you have to if you want to autox every weekend) and refused to swap on highway tires lol

 

Our local surfaces probably aren't as grippy as what the rest of you are driving on, but I still got 14 events and about 5000-6000 street miles out of my RE-71Rs last year.

Maybe I just need to drive harder.

 

If you are not getting good amount of heat into rears, might point that you are not using them enough. On a front heavy AWD cars like these, you can not afford not to use everything you have from the rear in order to help fronts to survive the torture they get.

I would make sure that you figure out how to get rears to do more work by any means possible...otherwise, I think you are leaving too much out there...