My son and I are currently running my 03 Shinsen in ES. We've got the stock "twisted five" 16 inch wheels on it. RE-71's were out of the budget, but we were able to get a pretty decent deal on some Dunlop Star Specs (or whatever they call the current version). So far, I like them a lot EXCEPT we seem to have picked up a scrape in the front end during hard (i.e. pretty much on the bumpstop) right turns. As far as I can tell, it's scraping on the driver's front tire. The Dunlops don't come in the "stock size" so I jumped from 205/45r16 all seasons to 205/50r16 Dunlops. The Dunlops actually seem narrower than the all seasons we had before (Conti DWS's) and GPS indicated speed matches the speedometer EXACTLY all the way past 70mph, so I suspect we haven't really picked up an substantial diameter increase. (It's always seemed to me that Dunlops run smaller than their advertised size) In short, any gains in the diameter of the wheel/tire combo appear to be minimal, and there is NO gain in width from the old Conti's, which never rubbed. Before purchasing, I spoke with Tire Rack who assured me there shouldn't be any rubbing issues.
I've done a visual inspection and found no indication either on the tire or the bodywork/splash guards that anything is making contact. No apparent contact points on the suspension either. I had a shop put it on the hoist and they came to the same conclusion. In fact, there appears to be SUBSTANTIAL clearance all around. Given the steamroller tires some people run on lowered Miatas, I can't believe these are rubbing at stock ride height. They also checked the brakes and wheel bearings and they indicated no apparent issues.
So I'm at a loss. The only thing I can think of is the tires were actually scrubbing sideways and I'm so used to the all seasons just sliding that I'm misinterpreting it as a rub. Any thoughts?
Put grease marker marks on the tires especially on the inside side walls and see if you can see any thing missing after you get the rub.
Is it possible that the brake disc is rubbing the splash guard tin or the caliper? Given the flexy nature of Miata spindles and the much increased grip of the new tires I would look there next
Duke
MegaDork
6/14/19 7:39 p.m.
Also, more grip can be generating more roll / compression than previously, causing rub where ther was not before.
Did you look at the front anti-sway bar? Had something similar once, tire rubbed the anti-sway bar. Wasn't centered. Shifted it slightly away from the rubbing wheel and haven't had an issue since.
Thanks for the suggestions so far. I'll check the splash guards, calipers and sway bar tomorrow. Marking the tires will probably have to wait until the next autox. I've never had the rubbing issues with ordinary street driving.
Ride height doesn’t matter when you’re on the bumpstops.
You increased in diameter by about an inch based on the tire specs for the ZIII on Tire Rack. So rubbing is not a surprise. I don’t care what Tire Rack said, a 24.2” OD tire is likely to rub. Heck, Mazda limited the steering lock on the MSM to prevent rubbing on a tire that smaller than your new ones. Miata speedos are usually optimistic, so you’ve probably just corrected that :)
Look for where the periphery of the right front tire will make contact at full lock. There will be marks somewhere.
In reply to Keith Tanner :
Well . . . that sucks. Proposed solutions other than a 2nd new set of tires in as many months?
kazoospec said:
In reply to Keith Tanner :
Well . . . that sucks. Proposed solutions other than a the 2nd new set of tires in as many months?
clearly there is only one answer for your Answer
irish44j said:
kazoospec said:
In reply to Keith Tanner :
Well . . . that sucks. Proposed solutions other than a the 2nd new set of tires in as many months?
clearly there is only one answer for your Answer
you are a terrible influence. I am trying to payoff my ND RF before i get a rally miata.
irish44j said:
kazoospec said:
In reply to Keith Tanner :
Well . . . that sucks. Proposed solutions other than a the 2nd new set of tires in as many months?
clearly there is only one answer for your Answer
Hahahaha. Nope. It's finally fast, I'm not slowing it back down! (Although, if I ever had a 10 car garage, at least one slot will have a lifted Miata in it)
Vigo
MegaDork
6/14/19 10:43 p.m.
Proposed solutions other than a 2nd new set of tires in as many months?
Sure, space down your bumpstops?
You either move the tire or the thing it’s rubbing on. I’d start with identifying the point of contact and hope it’ll respond to a hammer :) Bumpstop spacers are an option but I hate to give up travel if I have an alternative.
Belated update on this: As it turns out, the tires didn't like the AP2 front lip. Not sure why the "marks" weren't showing up on the tires or the lip itself, but I finally got a chance to jack it up and look at it myself. I put the front of the car on jack stands, then lifted each front tire with a floor jack to compress the suspension. At about 2/3 suspension compression and a little short of full turn in, the outside edge of the tire was making contact with the inside corner of the lip. Both the suspension compression and turn in were more than you'd typically see in regular street driving, which is probably why I only noticed it autocrossing. I did a bit of Dremel surgery and the problem appears to be fixed. Fortunately, the "fix" is only visible from under the car, or with the wheels turned all the way in one direction, so it isn't very noticeable. I took it to my first autocross since the fix today and neither I nor my codriver noticed any rubbing/scraping, so I think we're good.
