16x8 245/50/16

[Mike1992]

I currently run RX7 16x8's with 8mm wheels spacers and 225/50/16's, wheel clearence is fine. In the next month I plan to lower the car with K-Sports and want to buy 245/50/16's. I'm thinking I'm gonna need a bolt on spacer such as http://cgi.ebay.com/ebaymotors/5x11...5QQihZ015QQcategoryZ42614QQrdZ1QQcmdZViewItem

15mm seems more than adequate and should bring the rims to a +35 offset. The rims are 50mm stock. Think it'll work? Think I only need the extra offset in the back and can keep the 8mm spacers up front?

 

[jtmcinder]

Why such tall tires? Why not 245/45/16?

- Jtoby

 

[mavisky]

also You'll want a seriously stiff sidwalled tires as 245's on an 8" will bulge out pretty good. Not so bad you can't run them, but they'll feel really mushy as they roll around. My buddy had some crap ass Khumo's on his 8" wheels in 245 and the steering response sucked.

 

[Mike1992]

Why such tall tires? Why not 245/45/16?

- Jtoby

I bought the wheels off ebay and they came with 225/50's and I'm looking at buying a set of BFGoodrich G-Force Sports. The 245's only seem to come in a 50 series. If I could locate a place that sell a 40/45 series I'd go with that. Know anywhere that might sell the lower profile series?

 

[mavisky]

Tirerack sells both the Yokohama AVS ES100, Bridgestone RE750, and Continental Contisportcontact in 245/45-16.

They also sell the BFGoodrich G-force Sport in a 245/40-16 along with the Yokohama Parada Spec-2, Dunlop Direzza DZ101, and stickier Dunlop SP Sport FM901.

 

[Mike1992]

Tireracks search system is bajanxed, sometimes it shows the results other times it won't.

What seres would you go with for more of a drag car a 40 or a 45 series? I'm worried about clearence when I go to lower the car. and feel a 40 series would be better, although a taller tire would have more flex off the line and wouldn't spin as hard.

 

[jtmcinder]

If drag-racing is your thing, then isn't one of the key issues (at your current time and speed) whether you have to go to fourth? When I dropped back down to 245/40/17s (which are the same diameter as 245/45/16), I picked up a tenth in my 60', but lost mph and only broke even in ET because I had to go to fourth. On my stock-sized tires, I could stay in third. If you're already over 106, then you're in fourth either way, right? So why not go a bit smaller and have better gearing all the way down the track.

Ergo: 245/45/16s.

- Jtoby

 

[Mike1992]

If drag-racing is your thing, then isn't one of the key issues (at your current time and speed) whether you have to go to fourth? When I dropped back down to 245/40/17s (which are the same diameter as 245/45/16), I picked up a tenth in my 60', but lost mph and only broke even in ET because I had to go to fourth. On my stock-sized tires, I could stay in third. If you're already over 106, then you're in fourth either way, right? So why not go a bit smaller and have better gearing all the way down the track.

Ergo: 245/45/16s.

- Jtoby

Interesting advice, but I must be an idiot because it doesn't make much sense to me. I have a bolt on Holset HX-35 ready to go on within the week so I'm pretty sure I'll be trapping well over 110 and be in 4th gear for sure. Only reason I wanna go with a wide tire is to hook off the line and better my 1.7 60's. How will a shorter tire give me better gearing?

 

[jtmcinder]

Oh, my, how to explain this?

The smaller the tire diameter, the more then engine must accelerate to produce the same amount of ground-speed acceleration. So, it's the same thing as having a higher gear ratio; as in: it effectively makes the ratios of every gear higher. Now, if you're having traction issues, then this won't help you at all, but in the gears where you aren't slipping, it will help.

Maybe my local track has more VHT or maybe I just don't have the power, but I don't have traction issues at all. So, I accelerate much better on my smaller tires, finally getting into the 1.7s on 245/40/17s, where 1.85 was my best on stock-diameter tires. But I can't go 104 on 245/40/17s without shifting to fourth, so I dropped back into the 102s, because my car is a dog (with only three legs) in fourth.

But, again, all of this is moot if you lack traction. But I'd still consider some good 245/45/16s if you can find some that allow you to launch.

- Jtoby

 

[Mike1992]

Very informative JToby, thanks alot

On to the offset, I'm sure I'm gonna need the 15mm spacers out back. I had to shave the lip off the rear control arms just to tuck these wheels in with a +42mm offset (8mm Spacer). Only thing that would limit me up front would be the spring seat on the shock itself. I figure with full on coilovers whether is be K-Sports/D2's I should have room with 245's and 8mm spacers. But, I guess I should get the coilovers installed before I buy new tires to be sure

 

[jtmcinder]

When it gets tight, the specific brand of tire makes a difference. If these will see double-duty as street tires, consider Kumho MXs or Kumho SPTs (if it rains a lot where you live).

- Jtoby