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I have 2 sets of 15x6.5 rims for my NB track car.

One set of rims came on the car from Japan and are shod with "Maxgrande" 195/50/15 tyres,
the other set of rims I bough recently and are fitted with completely stuffed tyres.

The plan is to put new S-spec tyres on one set of rims for track use,
and have the "Maxgrande" tyres on the other set for motorkhanas.

The question is, how to decide which set of rims to use for track days, and which for motorkhanas.

Weight?
I believe lightness is better for handling

Strength?
Not sure if they would cop more of a hiding at the track or at a motorkhana

Looks? :-)
Have to look good at track days, ... kidding!

Neither set of rims is anything special, so I don't imagine there will be much difference,
but still want to consider the options.

Advice please?

949 racing 6ULs are very popular as a track wheel. 15x8" wheels weigh 5.7kg (lighter than stock 15x6 NB8A wheels) and cost $225 a corner from mx5centre.

My opinion:

Just pick any, if you're just starting out doing trackwork you aren't going to be consistant enough, or fast enough, to notice any difference in times from a wheel that weighs 6kg versus 5kg
(assuming of course, both rims are similar..... ie: one set isn't steel or something silly)

I went from the stock 15x6 NB8A wheels to a set of 15x7 Mazdaspeed wheels.

I think the Mazdaspeeds are about 1kg more per wheel? (not 100%, i never weighed them)


I felt no difference.

lee wrote:949 racing 6ULs are very popular as a track wheel. 15x8" wheels weigh 5.7kg (lighter than stock 15x6 NB8A wheels) and cost $225 a corner from mx5centre.

Buying another set of rims wouldn't be popular with the domestic financial controller,
so I'll just have to be content with choosing between the 2 sets of rims I already have.

hks_kansei wrote:My opinion:
Just pick any, if you're just starting out doing trackwork you aren't going to be consistant enough, or fast enough, to notice any difference in times from a wheel that weighs 6kg versus 5kg
(assuming of course, both rims are similar..... ie: one set isn't steel or something silly)

I went from the stock 15x6 NB8A wheels to a set of 15x7 Mazdaspeed wheels.

I think the Mazdaspeeds are about 1kg more per wheel? (not 100%, i never weighed them)

I felt no difference.

Both sets are alloy. I have no idea of any weight difference.

So it sounds like rim weight can be significant, but is much less important than a lot of other factors, such as driver skill & experience.

So just pick the pretty ones then :-)

Thanks

david_syd_au wrote:So it sounds like rim weight can be significant, but is much less important than a lot of other factors, such as driver skill & experience.

So just pick the pretty ones then :-)

Thanks

That's my way of looking at it anyway.

A badly dríven Ferrari will most likely be slower than a very well dríven Corolla around a track.

Use the widest ones on the circuit.

/thread

Dann

Suggestion:

Leave the dodgy tyres where they are and use those wheels for the motorkhana. At this early stage, it's not worth worrying about it that much, and certainly not worth the cost of having them taken off and swapped onto the other wheels.

Fit the new S-specs on your other wheels and use those for trackdays. But make sure you weigh these wheels before fitting the tyres. Even better, get a set of R888s in 195/50R15 from Taleb Tyres ($189 each), which will be better on the track and cost about the same as decent S-specs.

Then when you've worn out the dodgy Maxgrandes, get the tyres stripped off and weigh the wheels. Then you'll have the info you need and can pick the lightest wheels for trackdays where you'll appreciate them the most.

NitroDann wrote:Use the widest ones on the circuit.

Both sets are the same width.

Then its hardly going to make any difference whatsoever.

The weight helps acceleration and braking, and ride/grip over bumps, so Use the lightest ones in the situation where you use full throttle most.

Dann

Via pm, another contributor suggested using the rims with the most negative offset, to get the widest stance.
That sounds sensible.

As a few people have said, differences in weight/offset etc will probably not have any significance for now,
but as the car is going to SW on Saturday for new tyres, and they said they will switch all the tyres around for no extra cost, I though it best to make an informed decision now to avoid potential hassles later.

Guran, I will make sure to weight the rims when the opportunity arises.

Decision made. The rims that came on the car are white and pretty, and have the most negative offset of the 2 sets.

That person who said that....

Did they elaborate, or was that it?

Cos if thats all they said they are an idiot.

Dann

Differences in weight can have a huge impact if the track is bumpy. Light wheels move more easily and maintain traction over bumps, especially in braking zones. Offset makes stuff-all difference on the track, it's mainly an appearance thing.

My ranking for a relatively stock car is:
1. Weight
2. Rim width
3. Strength

I recommend running grippy tyres on the front for khanas,
No rear grip is fun, but as you found last time, understeer isn't much fun. In a tight event like that you want to take advantage of the chuck-ability of the 5!
Utilizing your set of crap tyres as two pairs of rears will be great fun!
You won't wear your good tyres on the front, but avoid lengthy lockups in the finish garage and keep them round and flat spot free.

Smokinscotty wrote:I recommend running grippy tyres on the front for khanas,
No rear grip is fun, but as you found last time, understeer isn't much fun. In a tight event like that you want to take advantage of the chuck-ability of the 5!
Utilizing your set of crap tyres as two pairs of rears will be great fun!
You won't wear your good tyres on the front, but avoid lengthy lockups in the finish garage and keep them round and flat spot free.

Thanks Scott, good points. I'll try that combination.
Lockups shouldn't be a problem as the car has ABS.

BTW, hope to see you in action again at Nirimba in July. I want to be there, but it will be difficult as there is a track day at Wakefield the next day, and we usually head down to Goulburn the arfternoon before track days. Good organisation will be required.

NitroDann wrote:That person who said that....

Did they elaborate, or was that it?

Cos if thats all they said they are an idiot.

Dann

Come on Dann, play the ball not the man.

What they said is:
"... just go by the offset, use the lower number offset IE: 35 for your track rims as the lower offset will handle much better ."

Hopefully I reported the advice correctly.
If not, I am the idiot.