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15x7 Rota RB wheels, anyone using these? What offset works?

Gumby

Donation Time
OK, so I am changing over from wire wheels to 4 lug wheels, and am looking at the multitude of of options. I'm sure this has been discussed to death before, but I was unable to find a "definitive" answer, to what fits, what rubs, what hits the suspension, etc. The rubbing of the valance only is not such a critical issue.

I see lots of people running 13x6. I once had ET mags 13x5.5 and I think zero offset way back in 1976, and they stuck out of the front fender with BFG Radial T/A BR-60x13 tires, and rubbed the valance.

So I am considering these Rota RB 15x7 with a 30mm offset and 73 mm bore. 7" is pretty wide, and figuring a 185 or 195 in a 60 series tire.

Do any of you have any experience with something close to this?

Looking forward to your wisdom...

Richardwheel.png
 

sunalp

Diamond Level Sponsor
I'm using 15x6 Rotas ( which are available) with 185/55 Toyo Proxes tires and they fit very nicely. To use 7" rims
I'm sure you'll need to trim the front valance and roll the rear fender lips .

I've had these on the car for just about 5 years and still really like them! Gives the car the right look.
Cheers!
Steve

IMG_1481.JPG
 

Bill Blue

Platinum Level Sponsor
I found that 15 X 6" steel wheels with 32mm offset barely cleared the upper arm of the suspension. By barely, I mean that lead wheel weights would work, zinc weights rubbed.

Bill
 

Barry

Diamond Level Sponsor
OK, so I am changing over from wire wheels to 4 lug wheels, and am looking at the multitude of of options. I'm sure this has been discussed to death before, but I was unable to find a "definitive" answer, to what fits, what rubs, what hits the suspension, etc. The rubbing of the valance only is not such a critical issue.

I see lots of people running 13x6. I once had ET mags 13x5.5 and I think zero offset way back in 1976, and they stuck out of the front fender with BFG Radial T/A BR-60x13 tires, and rubbed the valance.

So I am considering these Rota RB 15x7 with a 30mm offset and 73 mm bore. 7" is pretty wide, and figuring a 185 or 195 in a 60 series tire.

Do any of you have any experience with something close to this?

Looking forward to your wisdom...

RichardView attachment 23916




What is your reasoning for using 7" wide wheels with 185 or 195 section width tires? Tire manufacturers do a LOT of testing to determine the optimum and acceptable wheel widths for the tires they make and the information is readily available on websites such as tirerack.com.

For typical 185/60-15 tires, the recommended wheel width is about 5.5". For typical 195/60-15 tires, the recommended wheel width is about 6.0".
 

Gumby

Donation Time
I don't want to use 7" wheels. Current availability in 15" wheels with 4x108 patterns limits what's available. I prefer the black spokes and polished rim/lip. I can't find Rota's or Konig's in 15 x6 with a 20 to 30mm offset AND a 4x108 pattern...in black... Been at this for days... Anyone have a source for them? here in the US? I have no desire to drop a grand on just wheels...
 

Gumby

Donation Time
I found that 15 X 6" steel wheels with 32mm offset barely cleared the upper arm of the suspension. By barely, I mean that lead wheel weights would work, zinc weights rubbed.

Bill
So, in your case the 32mm offset was too much, there by pulling the inner edge of the wheel too close to the front suspension?
 

Gumby

Donation Time
OK found some. So I see them available with either 20mm offset, or 25mm offset. From above posts 32mm get too close.. So recommendations? 20 or 25? 5 mm isn't much, but.....
 

Gumby

Donation Time
It's done. Bought 4 Rota RB 15x6.0 with 4x108, 25mm off set, and 73mm hub. They weren't on the website because they were sold out, so the option never appeared. Called them, had just received 16 sets. they updated the website, and there they were... Now they have 12 left. $699 out the door. More than I was hoping for, but selection being what it is...
 

Toyanvil

Gold Level Sponsor
You are going to love them, I am running Rota 15x6 in front and 15x7 in back. My car is not stock or even close to it, I re-drilled mine to 4x114.3 to get more choices of off-sets to work with my car. I also built center caps for them.
RIMG0011-L%5B1%5D-L.jpg
 

Aladin Sane

Diamond Level Sponsor
So how much to make another set of center caps? The set that came with my project is missing one cap, so I need to source something different, and I have not seen anything better than yours.
 
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Barry

Diamond Level Sponsor
The critical dimension for front wheels on a Series Alpine (or Tiger) is backspace.

Too much backspace will result in the outer end of the upper A-arm interfering with the tire sidewall on 13" or 14" tires or with the outside surface of the tire mounting flange on 15" or 16" wheels.

Too little backspace will move the wheel / tire out which will result in the outside of the wheel / tire being outside of the top of the fender arch and will increase the possibility of tire rub on the corner of the lower valence.

With 13" wheels, the maximum backspace is about 4.25".

With 14" wheels, the maximum backspace is about 4.50".

With 15" or 16" wheels, the maximum backspace is about 4.75".

About because Series Alpines are notorious for being "dimensionally variable".​

Backspace is equal to 1/2 of the overall wheel width (typically about 1" greater than the measured wheel width) plus any positive offset or minus any negative offset.

For anyone who is not confident in calculating backspace, I can provide a simple spreadsheet which precisely calculates the backspace based on the overall wheel width and offset.

If you have access to the wheels, measuring the backspace is easy and possibly more accurate than depending on the listed offset.
 

Gumby

Donation Time
You are going to love them, I am running Rota 15x6 in front and 15x7 in back. My car is not stock or even close to it, I re-drilled mine to 4x114.3 to get more choices of off-sets to work with my car. I also built center caps for them.
RIMG0011-L%5B1%5D-L.jpg

I do like your center caps. Is that the Rootes badge from the front bonnet? What is the offset YOU are using on the front?
 

Toyanvil

Gold Level Sponsor
So how much to make another set of center caps? The set that came with my project is missing one cap, so I need to source something different, and I have not seen anything better than yours.
I wish I had the time to make more, I had about 14 hours to build 5. I will look around, I may have the ones that came with my wheels.
 

Gumby

Donation Time
I wish I had the time to make more, I had about 14 hours to build 5. I will look around, I may have the ones that came with my wheels.

That's OK. My wheels are coming with caps too, I just like the Rootes emblem you have in yours, and the unique octagonal shape...
 

Toyanvil

Gold Level Sponsor
I do like your center caps. Is that the Rootes badge from the front bonnet? What is the offset YOU are using on the front?
The Rootes badge is from SS, I think it is from the badge on the rear side of the later series. I am not sure my offset will work on a later series, my early series A arms have more room at the upper ball joint. My front is 15x6 rims with 25 offset and 15x7 rims with 20 offset in the rear, I cut down an Mazda RX7 rear axle to center the wheels in the wheel wells so I don't know if the rear offset will work on a stock Alpine. I also re-drilled my car to 4 x 114.3 which gave me more choices.
 

Hodee

Donation Time
I have 15X6 with 24mm offset at all 4 corners on my Ser V. I also added a 1/8 in spacer to the rear on each side. Fits well.
 

Gumby

Donation Time
Excellent news. Sounds like mine will fit fine then. NEXT.... Tires on that 15x6 inch format. I have these cheapo "Douglas" (made by Goodyear) from Walmart on my Hyundai Elantra Coupe, and I love them. cheap, and sticky. Will be going with those at less than $50 a tire... 185 60's, 195 60's, 205 60's, or possible 195 55's This will be a little harder since the car is not driveable yet, and I can't take the car to Walmart to install them, so it will just be the new wheels they mount them to. the 185 60's are the safe choice as far as clearance goes, but I do like meat on the road...

So What size 15" tires are people running on 6" wide wheels?
 

Hodee

Donation Time
I went with a very large diameter tire in the rear to make up for the gearing. 225/60/15 on the rear. Barely fits but it’s great for higher speeds and less rpm. The fronts are 215/60/15 with a bit of rubbing on bumpy corners. Front valence trimmed and rear has slightly rolled, trimmed inner wheel wells lips.
 

Bill Blue

Platinum Level Sponsor
Mostly 185's. Decided to tip the scales towards lower low speed steering effort and went to 175. Really could not tell much difference in cornering, braking, etc. Went back to 185 because my "tire guy" could not supply me with 175 X 15.
Bill
 
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