What is your front tire date code? I think you would be fine to replace rear only if your fronts are less than six years old.
Not sure where you got the old tire having more traction?

Welcome back ! Bridgestone Potenza RE-71R vs Bridgestone Potenza RE-71RS

In depth analysis of Bridgestone Potenza RE-71R vs Bridgestone Potenza RE-71RS with key results such as dry & wet obj/subj and wear evaluated.

toptirereview.com

 

see my add'l post...

 

The RE71RS is better than the RE71R in terms of total grip. It is very comparable to the Yokohama A052 but wears better. I've run through 1.5 sets on track/autocross/street use and they're my favorite of the current crop of 200TW tires. I would recommend replacing as a set - The driving characteristics are similar to the RE71R but not the same. I find the RE71RS immensely confidence inspiring.

 

tire rack review says the new re-71rs is better than the previous, at least in terms of performance, pretty much across the board.
it certainly looks different, reminds me of the firehawk indy 500 look.
if it's equal or better than the previous in the rear in terms of traction, i'd think that's a good thing at least until the fronts wear out and you can match them.

 

Thanks all, I bought the current tires in Dec 2015 from Tire Rack. They are
205/45R-16 BRIDGESTONE POTENZA RE-71R XL
245/40R-17 BRIDGESTONE POTENZA RE-71R SL

The additional factor is that I have a brand new set of the front tires sitting on a shelf at the shop. Tire Rack goofed and shipped them to me twice and didn't want to pay to ship them back.

Welcome your further thoughts and recommendations.

 

if you have brand new tires from 2015 that have been sitting on the shelf, those things are 8 years old I'd consider them dead. Would have been better to sell them off to someone else when you acquired them. 7-8 years is more than reasonable life for a performance tire on a performance car, if you're going to replace with RE71RS it would make more sense to replace the entire set.

also, that mechanic recommendation makes no sense to me. For a road driven car replace all four tires... what sort of conditions yield some other recommendation? For a tracked car you'd definitely replace all four tires. Maybe a car that doesn't see road use only two tires get replaced? Confusing.

 

I currently use Conti ECS on my 260 wheels at 195/50 and 225/45. It's enough grip for my driving as is (I'd have to be driving recklessly to need more grip, not used at the track at the moment) and been very cost effective the last few years. Unfortunately, 195/50 is not carrying to the new ECS2 tire, so once I exhaust all my rear sets or age sets in for the front set, I'll go the bridgestones next. I'll have this or the A052s to use.

I prefer to keep a mild stretch on my wheels, so I'll also be investing in 949 wheels as well to give myself more tire options in the future.

 

The fronts are the cheaper of the two, and tires do age out slowly so old stock do often have slightly less grip, and get more prone to cracking. Stored well though, and it's negligible.

I'd sell the front tires separately, because there's still decent demand.
And then run RE71RS's all around.
If you liked the RE71R, then the RE71RS's are a safe bet for next tire.

 

Thanks everyone for your thoughts and recommendations! I've ordered a new set of the RE71RS's all around since I haven't been burning through these rapidly. Now if I could only find somewhere to burn off the remainder of my now almost slick rears...perhaps on a rainy day...