Is it okay to run RE71Rs in the front and Sport Cup2's in the rear?

[ABenLauda]

My rear RE71Rs need to be replaced and I cannot find any in stock. Will it be okay to run Cup2's in the rear instead (especially on track) ?

TIA.

[jfritz27]

Originally Posted by ABenChod

My rear RE71Rs need to be replaced and I cannot find any in stock. Will it be okay to run Cup2's in the rear instead?

TIA.

Maybe try out the AR-1? They make a 305/30/20 -- and I believe these tires tend to run narrow, so would probably be a nice fit

https://philstireservice.com/shop/nankang-ar-1/

If these are for daily duty as well, then AR-1 may not be best choice. For street purposes I'd imagine rear Cup2's would be fine. I've never run these, but not sure your rear grip would be as good as with the 71R on track

[FormulaMMM]

Mismatched front and rear axle isn't recommended, meets no safety standards, creates handling imbalance, etc. etc. etc. but I've seen it a handful of times.

+1 on alternatives to Cup 2, if you can find the right sizing. Would run A052, R-S4, Dunlop ZIII, other similar options before most Cup 2.

Additional consideration is that this sets you up for tire mismatches moving forward. If your front RE-71R have good life left, I'd probably shelf those, get a new alternative set of 4, then pick up the rear RE-71R when they're available.

[SYT_Shadow]

I try not to mismatch tires, but I think you'll be ok.

Both are sticky track tires. Their handling characteristics differ (so one axle may get greasy while the other is still happy) but at the same time even when you run matched tires both axles see very different forces and stresses... you should be ok


Edit: what tire size do you have in the rear? I have a pair of surplus RE71R that are at 70% life sitting in my basement, 295 20" CS fitment for stock wheels. Depending on your timeline this may be an option

[4play]

Would just buy 4 new tires and save the 71R fronts for when rears are available.

If you are going to run a mismatched set, I would recommend a "grippier" tire on the rears than the fronts (which is likely the case here). Front axle of the F82 is very good but rear axle need help (in my experience).

[hC1001]

Depending on the event organizer, some tech inspections require you to have same brand and model tires on all 4 wheels.

[sc_tr0jan_m3]

i wouldn't recommend it. it's just gonna make you work more than you should.

[Gomeler]

Originally Posted by SYT_Shadow

I try not to mismatch tires, but I think you'll be ok.

Both are sticky track tires. Their handling characteristics differ (so one axle may get greasy while the other is still happy) but at the same time even when you run matched tires both axles see very different forces and stresses... you should be ok


Edit: what tire size do you have in the rear? I have a pair of surplus RE71R that are at 70% life sitting in my basement, 295 20" CS fitment for stock wheels. Depending on your timeline this may be an option

2020 ///M4 CS | Goodridge stainless steel brake lines | Bridgestone Potenza RE71R 265/35/19, 295/30/20 | Ground Control camber plates | PFC11 brake pads.

^ his signature. Based on that, I'd take Shadow up on that offer pending price. It's probably the sanest approach unless you're okay with shelving the fronts and buying 4x of another compound.

[SYT_Shadow]

Originally Posted by Gomeler

2020 ///M4 CS | Goodridge stainless steel brake lines | Bridgestone Potenza RE71R 265/35/19, 295/30/20 | Ground Control camber plates | PFC11 brake pads.

^ his signature. Based on that, I'd take Shadow up on that offer pending price. It's probably the sanest approach unless you're okay with shelving the fronts and buying 4x of another compound.

You're right, thank you for pointing it out. Ben was able to solve his tire issue already so I think he's good to go.
I need to post up the 295 rears for sale, I want to take the CS wheels back to the PSS tires which are brand new and just sitting around. I have 5 sets for TA5R wheels already for track related stuff

[USSEnterprise]

In a pinch, I would run that combo. I was in the same situation a little while ago and ran RE-71Rs in front and stock MPSS in rear for two track days. Car did fine, though obviously you will be leaving some time on the table.