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Discussion Starter · #1 ·
Anyone running on a road course with a Gear tronic using size 245 45 17 on their "R" using a 8.5 rim oppose to running the stock 18" rim and tire config.<br>
 

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Re: tire & wheel sizes vs road course (cloaked)

Funny you should post this. I was just reading how a 245 on an 8" rim can actually have a narrower contact patch than a 235 on an 8" rim, which is still less than a 225 on an 8" rim.<p>According to the post:<p>a 225 on a 8" rim will put 8.7"s of tread on the ground<br>a 235 on a 8" rim will put 8.6"s of tread on the ground<br>a 245 on a 8.5" rim will put 9"s of tread on the ground<p>Whether true or not I'm not sure, but it's a good argument. And wouldn't it be ironic if 225's were optimal for our cars and the sidewall bulge of a "pinched" 235 on an 8" rim is the culprit in rubbing issues on lowered cars or those running other than Rossos. <p><A HREF="http://forums.corner-carvers.com/archive/index.php/t-56.html" TARGET="_blank">http://forums.corner-carvers.c....html</A><p>
 

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Discussion Starter · #3 ·
would you or do you run size 17 " or size 18" on a road course the size that is available to me in the nitto 01 is 245 45 17, im thinking that would be better than running the same size in the 18" but I'm wondering if it will rub which what I cant have happen. both would be on a 8.5 rim
 

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Re: (cloaked)

A taller sidewall in the 17 is going to mean less bulge in the sidewall so it is less likely to rub. But what"s the offset of your 8.5" wheels?<p>For strictly track use the rule of thumb is to get as close as 1:1 for rim to tire width but that's not really practical anywhere but on a track. The crossover compromise for mostly street use that I can find seems to be 110% of rim width for tire width. This leaves some bulge as a rim protector but also nets a straighter sidewall for better cornering<p>8.5" x 25.4 mm/" x 1.1 = 237.49 (or about a 235 tire)<p>For comparison sake, using the same formula for the stock 8" rims would net 223.52 (or about a 225 tire). <p>Using 8.5"s and 17s with 245s I think would give you a larger contact patch and less pinching and bulging than an 18". Better for the street and track and less likely to rub - but the taller sidewalls are themselves a handling trade off. I have a headache now. If Oscar from TireRack still prowls the Wheel/Tire forum you might try asking there.<p>I'm seriously thinking about going 225s for my next set 18's if I can confirm some of these theories floating around on the interwebs.<p>
 

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Re: (StaggRLee)

If that's true, I would be interested to know.... Could be saving some rubbing and $ here...<p>Of course now that I think of it, I would probably end up buying wider wheels and more expensive tires.....Crap.... Nevermind, I don't want to know!!! <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/wink.gif" BORDER="0">
 

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Discussion Starter · #6 ·
Re: (StaggRLee)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>StaggRLee</b> »</i></TD></TR><TR><TD CLASS="quote"> If Oscar from TireRack still prowls the Wheel/Tire forum you might try asking there.</TD></TR></TABLE><br>Well lets just wait for Oscar, Oscar where are you bud..........what's his screen name? i'll IM him <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0">
 

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Re: tire & wheel sizes vs road course (StaggRLee)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>StaggRLee</b> »</i></TD></TR><TR><TD CLASS="quote">Funny you should post this. I was just reading how a 245 on an 8" rim can actually have a narrower contact patch than a 235 on an 8" rim, which is still less than a 225 on an 8" rim.<p>According to the post:<p>a 225 on a 8" rim will put 8.7"s of tread on the ground<br>a 235 on a 8" rim will put 8.6"s of tread on the ground<br>a 245 on a 8.5" rim will put 9"s of tread on the ground<p>Whether true or not I'm not sure, but it's a good argument. And wouldn't it be ironic if 225's were optimal for our cars and the sidewall bulge of a "pinched" 235 on an 8" rim is the culprit in rubbing issues on lowered cars or those running other than Rossos. <p><A HREF="http://forums.corner-carvers.com/archive/index.php/t-56.html" TARGET="_blank">http://forums.corner-carvers.c....html</A></TD></TR></TABLE><p>I have noticed that this is different from tire to tire..<br>Most cup tire specs come with optimal rim width recommendation.<p>
 

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Re: tire & wheel sizes vs road course (Johann)

Good point.<p>I am running Pilot Sport A/S right now. Michelin lists the acceptable rim width range for a 235/40/18 at 8-9.5" with a section width measured at 9.3 for an 8.5" rim.<p>For 225/40/18 they allow 7.5-9.0" rims with section width measured at 9.2 on an 8.0" rim.<p>That would seem to indicate to me that a 235 on a 8" rim would have a smaller section width than one on an 8.5" rim making a 225 a better choice for the PS A/S if I'm reading this correctly:<p><A HREF="http://www.michelinman.ca/assets/pdfs/doc_pilotsportas.pdf#search=%22michelin%20pilot%20sport%20recommended%20rim%20width%22" TARGET="_blank">http://www.michelinman.ca/asse...th%22</A>
 

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Discussion Starter · #10 ·
Re: tire & wheel sizes vs road course (StaggRLee)

The Nitto Tire sizes that I'm thinking of using either 225 45ZR 17 on a 7.5 rim or 245 45ZR 17 on a 8.0 rim. I'm not sure if that's the best setup for the track but I'm think that it maybe, I want to stay away from 18's do to the possibility of rubbing, and I think the car will accelerate quicker out of the corners.
 

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Discussion Starter · #11 ·
<IMG SRC="http://smileys.smileycentral.com/cat/4/4_12_12.gif" BORDER="0"> <p>waiting for Oscar of tire rack <br><BR><BR>
<i>Modified by cloaked at 11:28 AM 8-24-2006</i>
 

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Re: (cloaked)

Not sure if this will help, but I'm running 245 45 17 Kumho MX's on stock 17" pegs with 5 mm spacers. I still get a bit of rubbing at full lock...<p>However, the stick in the corners is well worth it! I can't reach the breakaway limit on the street, and have yet to find it on the track (still learning and taking it slow...).
 

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Re: (cloaked)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>cloaked</b> »</i></TD></TR><TR><TD CLASS="quote">Good info the pegs are 7.5 w right ? and where does the rubbing occur</TD></TR></TABLE><p>Bloops! I thought the 17s were 8" wide...if they're only 7.5" I really should not have put 245s on...I'll have to do some research.<p>I'm not lowered, and the tires rub on right turns at almost full lock--no real rubbing on left turns. Now this is only during parking lot manuevers, and I've never had any rubbing at any other time.<p>If only I could keep the wife from turning the wheel all the way to the lock and holding it there in either car...
 

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Discussion Starter · #15 ·
I'm not sure if the 17" pegs are 7.0, 7.5 or 8.0, I was hoping Ocar from tire rack would respond with some excellent info. Obviously he is a "NO ACK' so far, maybe someone who knows can jump in with that info. if they are 7.5 that helps alot. I'm thinking that they are not 8.0 wide just because factory rims are not usually that wide.
 

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Re: (cloaked)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>cloaked</b> »</i></TD></TR><TR><TD CLASS="quote">I'm not sure if the 17" pegs are 7.0, 7.5 or 8.0, I was hoping Ocar from tire rack would respond with some excellent info. Obviously he is a "NO ACK' so far, maybe someone who knows can jump in with that info. if they are 7.5 that helps alot. I'm thinking that they are not 8.0 wide just because factory rims are not usually that wide.</TD></TR></TABLE><p>8.0" on my Z!
 

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Re: (cloaked)

Oscar sells STREET tires. I would be very surprised if he's a RACE tire or track setup expert
 

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Discussion Starter · #18 ·
Re: (JRL)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Edogg218</b> »</i></TD></TR><TR><TD CLASS="quote"><p>8.0" on my Z!</TD></TR></TABLE><br>I was referring to Volvos <p><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>JRL</b> »</i></TD></TR><TR><TD CLASS="quote">Oscar sells STREET tires. I would be very surprised if he's a RACE tire or track setup expert</TD></TR></TABLE><br>You're probably right but I would think in his business he would know someone that could assist with info on the matter. Do you <B>JRL</B> have any suggestion or recommendation ?
 

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Discussion Starter · #19 ·
Re: (cloaked)

Ok I contacted Volvo and was told the following :The 18" rim that is an option on the 2005 "R" is 8" wide and have an offset of 49mm, that being said I can run a 225 X 45 X17 on an 8" rim with an offset of 43" without a problem. The idea with is 7.5 " which I may consider. This is the application for the Nitto 01's that I already possess. <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0"> <br><IMG SRC="http://smileys.smileycentral.com/cat/18_1_31.gif" BORDER="0"><p>
 

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Re: (cloaked)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>cloaked</b> »</i></TD></TR><TR><TD CLASS="quote">Ok I contacted Volvo and was told the following :The 18" rim that is an option on the 2005 "R" is 8" wide and have an offset of 49mm, that being said I can run a 225 X 45 X17 on an 8" rim with an offset of 43" without a problem. The idea with is 7.5 " which I may consider. This is the application for the Nitto 01's that I already possess. <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0"> <br><IMG SRC="http://smileys.smileycentral.com/cat/18_1_31.gif" BORDER="0"><p></TD></TR></TABLE><p>Your Volvo contact was a dumba$$!<p>Volvo Pegs 17s or 18s have an offset of 46mm and BOTH are 8" wide.<p><br>BTW, ask AaronSoto. I believe he tracked his car using the Evolve R5 wheels which are 8.5" wide.
 
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