To Enkei RPF1 or not to??

[evo165]

Hi guys,

I am having a hard time if i should go for 16"x7 Enkei RPF1 or not to?

Currently my set up is SSR Type-F 15"x6.5.

My reason for changing is to increase the 6.5" to 7" width and use wider 205 tires.

Anyone??:biggrin:

[1.5]

what is your ultimate goal? Do you race? Are you hoping to get better handling with a 205? they make a 15x7 i believe and you can run the 205 on that as well.

[WeeYari]

While the RPF1 is an excellent wheel, I personally feel that it is played out.

[1.5]

It still is one of the lightest wheels out there so for racing, few things beat it and I can understand the allure

[ilikerice]

agreed with the played out.. but like phil says, you can't beat the weight of that wheel for performance reasons.. but if this is his daily and no plans to do any form of racing. there are better unique rims out there for half the price.

[evo165]

Tried 15x7 Rpf1, cannot clear my 285mm rotor. Therefore I opt for the 16". I have tried 17" wheel with 205. It handle great but I loss the acceleration speed. :(

Now on 15x6.5, love the acceleration speed now and lighter wheel give much better braking performance. Not sure is the 16 rpf1 rim at 13.5lbs light enough for my acceleration craving.

Currently my type-F is at 9.5lbs. I love current set up and I just want a little better road handling.

Btw I am not tracking/auto crossing. Just love some street sprinting. ;)

[1.5]

how does the ssr fit in 15" if the rpf1 does not?

[WeeYari]

^ It's the spoke design with the rpf1. They will not clear BBKs without the use of spacers.

[evo165]

how does the ssr fit in 15" if the rpf1 does not?

As you can see the pics, the clearance is very fitting for my SSR 15". Due to the RPF1 15" rim design, the center section is very thick compare to semi-forge SSR.

The pics of the 16" RPF1 fit perfectly with 3 to 4mm of clearance. Where the 15" hit the caliper.:redface:

In fact, the 15" RPF1 rim can fit over the 4 screws stud, the spoke can clear no problem. It is the round O rims that hit outside edge of the caliper. With some grinder, it might clear the 15" rim. Not sure should i take this option...

[cali yaris]

You can put 205's on your SSR's but they'd look a little better with 7". I wouldn't grind wheel spokes to make them fit, unless I were shaving the hub or re-drilling.

The SSR is SO much nicer of a wheel. Just my opinion.

[ilikerice]

Not sure is the 16 rpf1 rim at 13.5lbs light enough for my acceleration craving

13 lbs. is about what my 15" rota GT3 weigh. I autocross and do track events often and pretty competitive also. I am sure if I can get some RPF1's it would benifit quite a bit, but need to pull myself out of debt first.

[1.5]

ahhhh got it.

[Jason@SportsCar]

Tried 15x7 Rpf1, cannot clear my 285mm rotor. Therefore I opt for the 16". I have tried 17" wheel with 205. It handle great but I loss the acceleration speed. :(

Now on 15x6.5, love the acceleration speed now and lighter wheel give much better braking performance. Not sure is the 16 rpf1 rim at 13.5lbs light enough for my acceleration craving.

Currently my type-F is at 9.5lbs. I love current set up and I just want a little better road handling.

Btw I am not tracking/auto crossing. Just love some street sprinting. ;)

I don't know what brand/model of tire you plan to use but in almost every case the 15x7-205 setup is going to beat 16x7-205. The 15" package will be lighter (both the wheel and tire in most cases), and the diameter (effective gear ratio) will be better - most 205-50-15"s are 23", while a 205-50-16 is around 24" and a 205-45-16 is around 23.2". Its all little stuff, but it adds up.

I would go with the RPF1 and add a spacer/stud kit in the front. Its not much work and should solve your problem. You don't even have to remove the front hubs to swap out the studs, there is an indent in the knuckle that lets you slip them by. http://shop.microimageonline.com/Ichiba-Wheel-Spacers-SC-58805.htm

The easy button to better performance would just be a tire change with your current wheels. The top 15" street tire in autox for about the last five years has been the 195-50-15 Toyo R1R. It seems small, but it works like a champ on light FWD cars, no other 15" tire has won a ST class Solo championship in years.

[cali yaris]

^ Definitive answer.

[evo165]

Thanks guys for all the advices sir. Seem like 16inch is a big no no to me...

I'll start looking around for 15x7" rims. Maybe get the same SSR with 7" width or RPF1 to mod.it to fit... one thing I know for sure, nothing beat the lightness n acceleration of 15" setup. :)

[CrankyOldMan]

The easy button to better performance would just be a tire change with your current wheels. The top 15" street tire in autox for about the last five years has been the 195-50-15 Toyo R1R. It seems small, but it works like a champ on light FWD cars, no other 15" tire has won a ST class Solo championship in years.

This. It's is on my dream list for the coming season. After the helical diff, of course. If you just want stupids amounts of acceleration, smaller diameter is almost as good as lighter. There's some physics involved in it, but I'll skip it since most people start throwing things at me when I start in on it.

I ended up with the Tire Rack house brand 15x7 this past summer, about 13 lbs per wheel. I ran the new BFG Rival in 205/50R15 but had serious acceleration loss compared to my street setup (15x5.5 11 lb Mini Cooper wheels w/205/50R15 DZ101's).

[Lars]

There's some physics involved in it, but I'll skip it since most people start throwing things at me when I start in on it.
The physics are simple actually!

Two objects of the same weight and "shape/size", the rotational inertia will be lower in the one where the weight is most concentrated close to the rotation center.

So, even if you have two wheels of the same total diameter, same weight, acceleration/braking will be better with the wheels that have a smaller rim, as the weight is closer to the rotation axis (or the biggest part of the weight).

The trade off, I would say, is tire deformation on hard cornering, but in light cars like ours I would say that trade off is not as critical as on big heavy porsches/bmws...