Do I have an LSD? and diff gear question?

sailaholic · Postby **sailaholic** » Fri Mar 14, 2014 9:25 am

well a 205/50/15 is going to be better on the track in terms of grip (assuming comparable tire types). Plenty also run 225/50/15 race rubber.
195's are cheaper though and will give you the gearing change.

hks_kansei · Postby **hks_kansei** » Fri Mar 14, 2014 10:01 am

emily_mx5 wrote:OP be aware that 99% of this forum is happy with nothing but 15" NB8A/6UL/RPF1 wheels regardless of what MX5 you have lol.

I only use 15s because they're cheaper. Cheaper to buy, and cheaper to get tyres.

OP, standard sizing for a 99 MX5 is 195/50/15, which is a total rolling diameter of 576mm

If you've got something larger than that (rolling) it will have the effect of slightly taller gearing. (and I mean slightly)

Alos bear in mind that some states have rules about rolling diameter, in Vic it was (I think still is, but I haven't checked lately) that you could increase rolling diameter by up to 15mm I think.

Guran · Postby **Guran** » Fri Mar 14, 2014 1:35 pm

sailaholic wrote:A Torsen will not do the opposite spin thing. They are based on a torque bias not a speed bias. So when both wheel are in the air they act like an open diff.

You're correct! I recently bought a 10AE (standard Torsen LSD) and just tried this test. With both rear wheels raised, turning one wheel causes the other to slowly rotate in the opposite direction (at reduced speed).

Dweezle · Postby **Dweezle** » Fri Mar 14, 2014 1:37 pm

Bryan are you buying one of each ???

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93_Clubman · Postby **93_Clubman** » Fri Mar 14, 2014 1:48 pm

Guran wrote:
hks_kansei wrote:NB8A 10th Anniversary - 3.? - Torsen T2

In Australia, the 10AE had 3.636:1 final drive ratio (Torsen) in place of the 4.10:1 (open) used with five-speeds. The 10AE had 3.909:1 diff ratio (Torsen) in other markets.

Reference

Here's the Mazda Australia Specification Sheet (along with Equipment Sheet) that also confirms 3.6 FD:
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