Ken - thanks for your thoughts, When you say "quite wide rims" what size are you thinking of? I am currently running the widest rims I am allowed to run - 7"
Compound is not an issue - we have to run a control tyre - Yokohama A032 As for brakes - I am lucky that I have a four spot Calliper that will fit in a 13" rim. Trust me when I say I hammer the brakes, due to lack of horsepower (at the moment) I try to make up for it under brakes and through the turns - suspension is well setup. I recently pulled the rotors off, and they actually have a blue tinge to them - so I guess they are getting pretty warm. Perhaps the fact that I have a decent size vented rotor, run good pads, and change my brake fluid regularly (Castrol SRF) all helps? Thanks again for your feed back. Mark. ----- Original Message ----- From: "Ken Abraham" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, April 04, 2002 8:24 PM Subject: Re: What size wheels are best? > Mark, > > The following statements are unproven, untenable, and indefensible:) > > </crap on> > > You'd need very wide rims to stretch the sidewall of your 205/60-13's enough > to get the best performance out of them. > If you don't stretch them them flex in the sidewalls will give bad driver > feedback and will heat up the tyres faster. > Because the 14's are slightly narrower, but still have the same aspect ratio > (60%) the sidewalls will be shorter. So you could use quite sensible rims > and still stretch the sidewall. > > You also have a benefit of being able to use a softer compound since they > are easier to set up better. ie the 14's won't heat up as quickly as the > 13's > > The wide, but short, contact patch of the 205/60-13's would be more > sensitive to camber change (bumps, dynamic or steady state cornering etc). > The Semi-trailing arm rear-end and MacPherson strut front-end are not very > precise suspension methods and suffer from lots of camber, castor, scrub and > toe change > > The 195/60-14 tyres are narrower (obviously). This doesn't mean that there > is less rubber on the road as the increased rolling diameter means the > contact patch, whilst narrower, is also longer than for the 13's. This long > and thin contact patch is less sensitive to camber changes. > > The other, and main, benefit of 14's is the increased room for brakes and > brake cooling. > If you are not getting brake fade you probably aren't going hard enough :) > Seriously, it really depends on the car, track, budget and driver so I can't > really say anything useful here. > > 14's will increase the ride height of your car, you would have to lower it > again to get back the CofG and this would cause the suspension geometry > front and rear to get worse.ie going to 14" requires suspension geometry > changes. > > You can't really compare your car to an F1 car as F1 cars have effectively > zero suspension movement and the tyres are the only actual deflecting > element. > > All high performance and competition saloon cars go for the biggest wheel > and lowest profile tyre that is allowable. This gives more room for brakes > and reduces sidewall flexing (which generates heat) so that they can run a > softer compund and the driver can get better quality feedback. > </crap off> > > PS When the flag drops and the bullshit stops, how do you go when you race > together? Is he faster down the straights, say, and you are better under > brakes and quicker through certain turns ? etc... > If he is particularly faster through a bumpy corner, or if your performance > drops off, relative to his, as the race progresses, I'd suspect the tyres. > > Regards, > Nick > ----- Original Message ----- > From: "Mark Alford" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Thursday, April 04, 2002 5:16 PM > Subject: Re: What size wheels are best? > > > > Andrew, > > > > Needless to say, he runs 14" wheels and we are usually pretty close when > it > > comes down to lap times etc. Also, I think nearly everyone else runs 14" > > wheels, but that doesn't mean they are all right! > > > > He has a number of points - some of them I find difficult to swallow, > others > > have some credence. > > > > 1) Run 14" wheels and let the torque (I run an FJ - which is very torquey) > > pull the car out of the corner with the 14" wheels. - my argument is that > I > > could change diff ratios if that is what I wanted to achieve. > > > > 2) 14" rim will have a larger outer diameter, therefore more rubber - > which > > in turn means the tyres will not get as hot because you are using more > > rubber to do the same task. (I think he's clutching at straws here!) > > > > 3) 195/60 will have a smaller side wall than a 205/60 - which is true. > > But.....the 205 is only a 13" when the 195 is a 14" therefore won't they > > pretty much cancel each other out or at least the contact patch of the 205 > > must be worth something here? > > > > 4) The whole bigger brakes argument - my opinion there is that I am > already > > out braking other people so why would I need bigger brakes? I am running > > four spots with a 260mm vented disk up front, with disks in the rear > also - > > stops pretty good! > > > > He had some others also, but they were a bit left of field and/or he > didn't > > have a good explanation as to why. I'm all for taking advise, hence I > posted > > this message, but I don't like to change things simply on someone's word - > I > > like to know why, and so far, no one has managed to show me why 14" wheels > > will give me a better package than what I already have, or will bring my > lap > > times down any further. > > > > Cheers, > > > > Mark. > > > > ----- Original Message ----- > > From: "Andrew Greenbury" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Thursday, April 04, 2002 4:49 PM > > Subject: Re: What size wheels are best? > > > > > > > Hey Mark, > > > > > > No worries - what is the view of the guy you have been having a > > > long running discussion with?? > > > > > > > > > > Cheers Andrew, I appreciate the feedback. > > > > > > > > So far nothing has been said to make me think that 14's are the way to > > go. > > > > This justifies what I have been telling myself for ages, just needed > > some > > > > other opinions to confirm it. > > > > > > > > Thanks to all who have replied. > > > > > > > > Mark. > > > > > > > > P.S. If any one thinks that 14's would be the way to go, I would still > > like > > > > to hear why. > > > > ----- Original Message ----- > > > > From: "Andrew Greenbury" <[EMAIL PROTECTED]> > > > > To: <[EMAIL PROTECTED]> > > > > Sent: Thursday, April 04, 2002 4:20 PM > > > > Subject: Re: What size wheels are best? > > > > > > > > > > > > > Hi Mark, > > > > > > > > > > yeah I agree with Errol for the same kind of reasons esp in your > > > > > racing context. Your rubber choice is greater, and you already have > > > > > the 13s. > > > > > > > > > > Rotational inertia is proportional to mass*radius^2, so the > > > > > distribution of mass around the wheel has a greater effect than the > > > > > overall weight itself. The lower the inertia the less torque/force > > > > > required to accelerate (and brake) the wheel. Also the wheel will > > > > > accelerate/brake faster. > > > > > > > > > > Because of this as Errol said, bigger rims also require bigger > > > > > brakes, but bigger brakes add more rotating mass etc etc. > > > > > Generally, larger diameter tyres weight more too, and this mass > > > > > has the largest radius. > > > > > > > > > > >From a handling point of view, the 13s give you a wider contact > > > > > patch and a larger grip envelope. Because you have to keep the 60 > > > > > profile, the difference in sidewall thickness should be similar as > > > > > Ben mentioned, so you would expect the cornering stiffness of both > > > > > sizes to be similar. The perception of the lower the profile the > > better > > > > > the performance isnt always the case - what size tyres do F1 use? > > > > > > > > > > Andrew > > > > > > > > > > > Ok Errol, > > > > > > > > > > > > I currently have the 13" wheels. Brake wise I am running a set of > > > > > > four piston sumitomo callipers. These callipers are apparently > > > > > > works Nissan Callipers from an older model Japanese 300ZX. The > > > > > > Callipers are not alloy, and are quite weighty. The disc is of > > > > > > unknown origin (came with the car) but is 260mm diameter and is > > > > > > vented. > > > > > > > > > > > > This setup works very well in it's current configuration. If > > > > > > however, I was to go to 14" wheels, what size rotor and which > > > > > > Callipers would you recommend? > > > > > > > > > > > > Also, from a handling point of view, would the 14" wheels provide > > > > > > better handling? Keeping in mind I still have to run the 60 series > > > > > > tyre, and would be forced to run a 195 as opposed to the 205/60/13 > > > > > > I am currently running? > > > > > > > > > > > > What do you think? > > > > > > > > > > > > Mark. > > > > > > ----- Original Message ----- > > > > > > From: E Smith > > > > > > To: [EMAIL PROTECTED] > > > > > > Sent: Thursday, April 04, 2002 11:43 AM > > > > > > Subject: RE: What size wheels are best? > > > > > > > > > > > > > > > > > > Its also a matter of moments and braking toque. Assuming the > > > > > > same caliper and applied pedal force in every condition: - > > > > > > > > > > > > The larger the rotational diameter of the wheel/tyre, the disc > > > > > > required must be proportionally larger diameter to maintain the > > > > > > same braking effort. > > > > > > > > > > > > > > > > > > > > > > > > The classic wheel size example is the "EVO mock up" lancer with > > > > > > the 9" discs inside 18" wheels and they wonder why they will not > > > > > > stop. I have a feeling that a lot of accidents recently have been > > > > > > caused by these mismatches of tyre - wheel / brake - caliper > > > > > > combinations. > > > > > > > > > > > > > > > > > > > > > > > > I personally like 13 X 7" rims as the range of rubber is better > > > > > > for this size wheel, from treaded competition tyres to slicks. > > > > > > They are also usually lighter. The next size up is 15" rims to > > > > > > get a good selection of rubber. As the diameter goes up though so > > > > > > does the price. > > > > > > > > > > > > > > > > > > > > > > > > Cheers > > > > > > > > > > > > Feral Errol > > > > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: [EMAIL PROTECTED] > > > > [mailto:[EMAIL PROTECTED]]On Behalf Of Mark Alford > > > > > > Sent: Thursday, 4 April 2002 9:26 AM > > > > > > To: Ozdat discussion list > > > > > > Subject: What size wheels are best? > > > > > > > > > > > > > > > > > > > > > > > > Hey listers, > > > > > > > > > > > > > > > > > > > > > > > > I have been having a long running discussion with a guy I race > > with > > > > regarding wheel sizes, and what size wheel is best to run. I thought I > > might > > > > throw the question open to the list and see what thoughts are out > there. > > > > > > > > > > > > > > > > > > > > > > > > What I would like to know is - What size (diameter) wheel is > > > > > > best to run? the choice is between two sizes 13" and 14" (both > > > > > > with 7" width). Something else that also needs consideration is > > > > > > the tyre that I must run. If I run the 13" I can use a 205/60. If > > > > > > I run the 14" I must run a 195/60. (Everyone must use a 60 series > > > > > > tyre) > > > > > > > > > > > > > > > > > > > > > > > > So who out there has some thoughts on which combination I should > > run? > > > > I would also like to know the reasons behind peoples thoughts. > > > > > > > > > > > > > > > > > > > > > > > > I look forward to the feedback. > > > > > > > > > > > > > > > > > > > > > > > > Mark. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat------------------------------------------------------- > > > > > > OZDAT Mailing List Please Note:- > > > > > > Send (un)subscribe requests to [EMAIL PROTECTED] > > > > > > Send submissions to [EMAIL PROTECTED] > > > > > > No unauthorised redistribution of this email > > > > > > http://www.ozdat.com/ozdatonline/index.htm > > > > > > http://www.ozdat.com/ozdatonline/listindex.html > > > > > > http://www.mail-archive.com/[email protected]/ > > > > > > > --------------------------------------------------------------------- > > > > > > > --membersozdat------------------------------------------------------- > > > > > > OZDAT Mailing List Please Note:- > > > > > > Send (un)subscribe requests to [EMAIL PROTECTED] > > > > > > Send submissions to [EMAIL PROTECTED] > > > > > > No unauthorised redistribution of this email > > > > > > http://www.ozdat.com/ozdatonline/index.htm > > > > > > http://www.ozdat.com/ozdatonline/listindex.html > > > > > > http://www.mail-archive.com/[email protected]/ > > > > > > > --------------------------------------------------------------------- > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
