janaka Posted January 8, 2009 Share Posted January 8, 2009 Ok so I'm looking for people who know more about tires than I do on this topic. I'm looking at tires for the Z as its the only car that I have that this would apply to. My setup currently is 16x8" rims all around. I'm running 225/50/16 up front and 245/45/16's out back currently. I have BFG G-Force TA KDW (300 A AA rating) up front and Sumitomo HTR Z's out back (160 AA rating). I'm looking at the Hankook z211 R-COMP tires that a local guy has for sale, new and cheap. The only downside that i see is that I would be running a narrower rear tire as they are only 225/50/16's. That said the overall diameter is basically the same and I can reprogram my speedo to account for that. My question is this: Does the upgraded tire compound from the 160 rating to the R compound make up for the loss of 20mm of tread width? I can't find any technical data that tells me the exact width of the tread as we all know that it varies from manufacturer to manufacturer. I know for example that Nitto 555's are wider than nitto 555r's so I'm interested to know how wide the Hankook actually is in comparison to the sumitomo's A 20mm difference should be a .78" difference. The sectional width difference for my two tires is only .6" by the tech data so there definately are descrepancies between manufacturers. The car is not a Daily driver, more of a 2 day a week fun car and weekend car during the summer only. 3000miles would be a lot for a year so I'm not overly worried about the faster wear aspect. Thoughts? Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 8, 2009 Share Posted January 8, 2009 I would say you would be better off with the 225's. 8" is really not wide enough for 245's and perfect for 225's. The wider the wheel in relation to the section width the less squirm you get in cornering, therefore more consistency. I read an article in Turbo Magazine in the early 90's when they hopped up and Eclipse. Went to 7" rims and tried the same brand/model tire in two different sizes - 205/55/16 and 225/50/16. The 205/55's cornered better in both slalom and skidpad. Immediately after each test the would take tread temperatures across the tire treads and the narrower tires were more consistent, the wider having cold spots, showing uneven contact. Quote Link to comment Share on other sites More sharing options...
zguitar71 Posted January 8, 2009 Share Posted January 8, 2009 A narrower but stickier tire is better. The 20mm difference is not that much and R compound tires are usually much stickier than a street tire. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 8, 2009 Share Posted January 8, 2009 My question is this: Does the upgraded tire compound from the 160 rating to the R compound make up for the loss of 20mm of tread width? You'll see a big difference in lateral grip once the tire gets warm. Quote Link to comment Share on other sites More sharing options...
janaka Posted January 10, 2009 Author Share Posted January 10, 2009 Well I did the unthinkable today. Look out anyone going to a track that has turns in it. Gunna be a fun fast summer Quote Link to comment Share on other sites More sharing options...
Mike Rowe Posted March 22, 2009 Share Posted March 22, 2009 You'll see a big difference in lateral grip once the tire gets warm. John I value your experience and opinion. With R compound tyres they require warming up. On a mainly road car do the R compound tyres not properly warm up in mostly normal driving therefore making them potentially not as grippy and therefore in some ways a bit hazardouus? Whats your thoughts regards Quote Link to comment Share on other sites More sharing options...
zguitar71 Posted March 22, 2009 Share Posted March 22, 2009 If the air temp is warm and the pavement is warm the tires will get warm enough to rip around corners at a speed that cops would not like. If it is cooler, say 45 or 50 and you try to corner at the same speed as the warm day you could easily end up facing the wrong direction before you know it or under steer like crazy straight into a curb or worse traffic. Here in Montana the mornings are in the 40's to 50's in the summer so at the beginning of an autocross I have to be very careful but by the time noon comes around it in the 80's or higher and I can let it rip! Quote Link to comment Share on other sites More sharing options...
Mike Rowe Posted March 22, 2009 Share Posted March 22, 2009 thats what I was thinking. I may have to put street tyres on the new 16 x 8 inch rims and use my 15 x 7inch race tyres (205) off my 240Z when on the circuit Quote Link to comment Share on other sites More sharing options...
zguitar71 Posted March 23, 2009 Share Posted March 23, 2009 The other thing about R compound tires is the soft tread (when warm) will pick up all types of road debris like bits of glass or any other sharp item that could eventually work its way into the tire carcass running your tire. R compounds are really built for the track even though they are DOT approved. Quote Link to comment Share on other sites More sharing options...
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