Using a different size rim for practice days?

[gran racing]

I have a feeling I already know the answer this but keep trying to convince myself otherwise.

Last year I damaged a couple of my 13" rims and for a few reasons have decided to buy 14" rims for the upcoming season. My delima is what to do with all of the 13" Hoosier tires I have. (There all are R3S04s. Three of the 9 Hoosiers have never been used.) My original thought was to put these on another set of 13" rims I have which are 5.5" wide and use that at HPDEs where I instruct thinking that these will last me quite a while. At the same point, I my goal this year is to use the HPDE days a bit better this year especially since I'm planning on getting a data DL1 acq system. How much would I be hurt by using a different size rim which will effect gearing, ride height, and have a different contact patch?

My wallet says use the 13" tires but a big part of the racing side of my brain says sell them and use the money to buy some 14" tires. What do you recommend?

[Andy Bettencourt]

Dave,

You know the answer. If you want something to bomb around as an instructor, go with the 13's. If you are trying to test - in ANY way, you need to be using the stuff you will be using. Otherwise, it's useless.

If it was me, I would sell what I had and buy what I need - and then be productive.

[Greg Amy]

People say "practice makes perfect." That's wrong. What it should actually say is

Perfect practice makes perfect.

[gran racing]

I knew selling the tires was what I should do. It's tough since I've got 11 of them in my basement. Darn it. :(

[Knestis]

Yeah, but...

While, if you are developing the CAR, then all of that is true. If you are using the DL1 to find time in the DRIVER, then relative improvements can be identified and will translate to whatever set-up you end up with regardless. Now, whether you can effectively do either an HPDE kind of setting is a different question.

K

EDIT - remember that this comes from a guy who believes in looking to the driver first, as the source of any slowness. Based only on experience. :)

[gran racing]

I agree with you Kirk - look at the driver first. I'm thinking that because this will impact areas such as my shifting points, I should use 14" tires. (I just had a different final drive installed, so it will be nice to practice a bit on what I'll be racing.)

I got the extra nudge and listed them for sale.

[racer_tim]

Dave, just remember, that the outside diameter of the 13" rims and tires might be different than the 14" rims and tires, so your shift points might be off, and your R&P ratio might also change.

[tom_sprecher]

You did not mention the make of the 14" tires but even still measure the roll out of both rim/tire combos and if it not to dissimilar run what ya brung especially for HDPE.

On Edit: Sorry, I meant HPDE. Mixing work with pleasure.

[JeffYoung]

Same boat here. Switching to 15"s from 13"s as allowed by the rules now. My thought was the same as Andy and Greg's. It doesn't make sense to keep the 13"s around to "practice" on. Just going from 225/50 to 225/45 changes the shift points in my car, so I suspect the change will be much larger with the bigger rims.

BUT -- I do plan on keeping the 13"s for this reason -- cheap gearing. For CMP, a twight twisy track, the 13"s are perfect. At VIR and Lowe's, I run out of gear, so I need the 15s.

Since you now can run 13s and 14s, if you have any gearing issues you can "solve" them cheaply via this route.

[RSTPerformance]

Dave-

You know what I would do... Track time is track time and anything to get some laps with the car/track is a plus, and fun!!!

Raymond