Sense check on wheel and tyre combo

[m1tch]

Hi all,

I will be looking to swap out my stock FL wheels and tyres next year, still planning to run staggered wheels and tyres but slightly wider than stock owing to the extra power being planned (but not too wide).

My plan is to run 15s all round:

Front

15x7
205/50/15 = +0.4% larger than stock

Rear

15x8
225/50/15 = +1.3% larger than stock

Looking at the car with the stock 16x7 rears I can see that there is still a fair bit of space before the arch, I will also be running coilovers so can drop the ET slightly as well so an 8" rear should fit ok.

I have come to the sizing above as I have looked at tyre choice, it seems that on a 15" rim its quite hard to find anything wider than a 225, I don't want to be running a 17" wheel due to weight coupled with the fact that equivalent tyre sizes in a 17" aren't much wider.

I guess I could look to get a speedo correcter if needed but I think the tyre sizes above should hopefully give me a fair range of tyres - although not the Yokohama AD08R in anything wider than a 205 for a 15 that will work with a stock speedo.

[J03]

Another thing to consider is whether or not you'll be fitting a bigger brake setup at some point. Most BBK's require 16" minimum wheel size 

[1979scotte]

Don't those tyre sizes fit on stock FL wheels?
With a 16" rear you can make AD08R work.
I think.

[james_ly]

You could fit 195/50/15 and 225/45/16 on FL wheels I think. Which is the same tyre size as a Lotus Elise S1 so plenty of tyre choice, I plan for AD08Rs in these sizes.

[m1tch]

I am looking to run the same size wheel all round and run an aftermarket lighter set, I don't really need extra brake clearance as I am planning on running the stock brakes but upgraded discs and pads etc.

I seem to be pretty stuck for choice for wider sized wheels, ideally I would want to run 15" all round for, tyre choice is going to be easier for 15s or 17s, I notice that Toyo R888 tyres seem to come in a lot of odd tyre sizes so I guess there is that option for track day tyres.

Current rears are already 215/45/16 with the fronts being 185/55/15, I know the usual upgrade is going to a 195/50/15 front and a 225/40/16 rear which I could get Toyo T1Rs in that size etc.

Really wanting to go with a 15" wheel, not too keen on a 17" wheel - could always look at options for speedo correction though if there is a common tyre that would work, I know I was looking at something like a 255 rear which would need a 6% correction to the speedo but don't need to go that wide.

[Topdownman]

If you are running a staggered tyre set up then I dont see any benefit to having the same wheel radius.

I have aftermarket wheels (team dynamics pro race 1.2) which were no problem to get as two 15" and two 16". They are all 7" wide so 0.5" wider at the front over standard.

I run 195 front and 225 rear AD08rs and love the handling.

The only thing I would do different would be the ET, I went for ET35 all round but its too much, no more than ET38 as they do rub on the arch a bit on the rear!

[J03]

If you are running a staggered tyre set up then I dont see any benefit to having the same wheel radius.

I have aftermarket wheels (team dynamics pro race 1.2) which were no problem to get as two 15" and two 16". They are all 7" wide so 0.5" wider at the front over standard.

I run 195 front and 225 rear AD08rs and love the handling.

The only thing I would do different would be the ET, I went for ET35 all round but its too much, no more than ET38 as they do rub on the arch a bit on the rear!

Added bonus is that it looks awesome as well    I'd run the same if it wasn't for the bbk.

Don't want to detract from the OP, but are your 225 rears a 45 profile?

[m1tch]

I want to run the same sized diameter wheels front and back, might look to run 17s if needed and get a speedo adjuster for the couple of % difference as there aren't really any tyre options in 15 wider than a 225.

I do not want to run OEM alloys, was hoping that there were some performance 15" tyres around but it seems not so will perhaps look to run a 17x8 on the rear, stock rear is 7".

[Topdownman]

"Don't want to detract from the OP, but are your 225 rears a 45 profile? "

Yep, 45 rear and 50 front profiles.

[m1tch]

Having a look at 16" wheels now, looks like I could run this combo:

205/50/16 F (narrower than rear but close size to stock rear)
215/45/16 R (stock rear)

Looks like I can simply run a 16x7 rim to fit both tyres on, I am still looking around though, I have had a look at the Boba racing VW Golf which is running over 1000bhp and is lighter than our cars and they are running a 225 width tyre on the street so I am happy to nudge down the width slightly so looking at 215 or 225 rears rather than going bigger. I can always adjust the contact patch with the tyre pressures etc.

[m1tch]

Also just had a look at the 17" wheel selection in terms of tyres available, looks like the closest options are:

205/45/17 front - would need to be a 7" rim

215/40/17 rear - probably go to an 8" rear for this

I have noticed that the front and rear tyres are different by 2.6% with the fronts being smaller, with the setup above the rear would be around 2% smaller than the front, I believe that 205/45/17 is an OEM Lotus, BMW and Alfa size so there will be a good choice out there. 215/40/17 is an OEM Audi size which is why there is also choice out there for tyres.

For the 16" tyres I have also found the following that might work:

205/50/16 front (+1.3% vs stock front) - Yokohamas are in this size
225/45/16 rear (+1.7% vs stock rear) - Yokohamas are in this size

Ideally I want to be running a set of Yoko AD08R tyres so I might be ok to run with 15s all round, tyres chosen would probably be:

185/55/15 or 205/50/15 on the front with a 225/50/15 on the back.

[J03]

On 16's 205 50 F + 225 45 R will look uneven & the 205 50 F + 215 45 R just plain daft.

Best combo for 16's is 205 45 F + 225 45 R. NS-2R are available in this flavour (I've just ordered some & have 16 x 7 wheels)

If rear traction is your main concern, I'd ultimately go 16 / 17 stagger, there's wider options for the 17's.

[m1tch]

On 16's 205 50 F + 225 45 R will look uneven & the 205 50 F + 215 45 R just plain daft.

Best combo for 16's is 205 45 F + 225 45 R. NS-2R are available in this flavour (I've just ordered some & have 16 x 7 wheels)

If rear traction is your main concern, I'd ultimately go 16 / 17 stagger, there's wider options for the 17's.

I am wanting to run the same size rim but different tyre widths, looks like I might need to go to a different aspect ratio and get a speedo correcter or something - really having a tough time keeping within 3% of the stock sizes, especially as the stock sizes are different front to back!

Does anyone know which wheel the speed sensor comes from? I am guessing one of the rears?

Have you run the NS-2Rs before? They seem to be getting good reviews, not as good as the AD08Rs but for the price they seem good - where do you get your tyres from btw?

[J03]

On 16's 205 50 F + 225 45 R will look uneven & the 205 50 F + 215 45 R just plain daft.

Best combo for 16's is 205 45 F + 225 45 R. NS-2R are available in this flavour (I've just ordered some & have 16 x 7 wheels)

If rear traction is your main concern, I'd ultimately go 16 / 17 stagger, there's wider options for the 17's.

I am wanting to run the same size rim but different tyre widths, looks like I might need to go to a different aspect ratio and get a speedo correcter or something - really having a tough time keeping within 3% of the stock sizes, especially as the stock sizes are different front to back!

Does anyone know which wheel the speed sensor comes from? I am guessing one of the rears?

Have you run the NS-2Rs before? They seem to be getting good reviews, not as good as the AD08Rs but for the price they seem good - where do you get your tyres from btw?

I had the same problem & have deliberated over the issue for a while. I needed 16" min to clear my bbk, wanted as much rear traction as possible without losing front end feel or ridiculously upping the unsprung weight (although the progressive nature of the Rotrex setup means less unpredictable torque wallop)

Originally I was looking at 16/17 stagger but the 17 just looks way too big with a track based tyre imo. I know a guy who has run them on the road with a high power Rotrex setup & he loved them. The general feeling is that the Yokohama is the go to tyre if you're chasing lap times. Personally I'm not & the NS2R's are cheaper, have a good rep & come in the sizes I want.

I think for such a modified beast, you're worrying about the speedo issue way too much. I'd much rather get the handling right over a small discrepancy with mph. Just visualise it purely as a chassis for improvement, not an actual model if that makes sense.

Tyres have just arrived actually, bought them from RoundTripTyres & they came to £288 delivered 205 45 / 225 45 street compound.

[m1tch]

On 16's 205 50 F + 225 45 R will look uneven & the 205 50 F + 215 45 R just plain daft.

Best combo for 16's is 205 45 F + 225 45 R. NS-2R are available in this flavour (I've just ordered some & have 16 x 7 wheels)

If rear traction is your main concern, I'd ultimately go 16 / 17 stagger, there's wider options for the 17's.

I am wanting to run the same size rim but different tyre widths, looks like I might need to go to a different aspect ratio and get a speedo correcter or something - really having a tough time keeping within 3% of the stock sizes, especially as the stock sizes are different front to back!

Does anyone know which wheel the speed sensor comes from? I am guessing one of the rears?

Have you run the NS-2Rs before? They seem to be getting good reviews, not as good as the AD08Rs but for the price they seem good - where do you get your tyres from btw?

I had the same problem & have deliberated over the issue for a while. I needed 16" min to clear my bbk, wanted as much rear traction as possible without losing front end feel or ridiculously upping the unsprung weight (although the progressive nature of the Rotrex setup means less unpredictable torque wallop)

Originally I was looking at 16/17 stagger but the 17 just looks way too big with a track based tyre imo. I know a guy who has run them on the road with a high power Rotrex setup & he loved them. The general feeling is that the Yokohama is the go to tyre if you're chasing lap times. Personally I'm not & the NS2R's are cheaper, have a good rep & come in the sizes I want.

I think for such a modified beast, you're worrying about the speedo issue way too much. I'd much rather get the handling right over a small discrepancy with mph. Just visualise it purely as a chassis for improvement, not an actual model if that makes sense.

Tyres have just arrived actually, bought them from RoundTripTyres & they came to £288 delivered 205 45 / 225 45 street compound.

I agree with me worrying about the speedo issue, I can get a corrector if needed anyway, its mainly for me to find a good setup that will work with the power level and not limit me with tyre choice. I see that there are also a lot of tyre options for the Toyo R888 - the car will be 95% a road car, will only be on track every now and then so leaning more torwards a high performance road tyre like the AD08R rather than some of the track only tyres.

Might look at the 17s still as I can get a wider rear, but issue getting a narrower front tyre - might look at 15s though as they will be light weight and should have a good choice of tyres - I can see I can get 225/50/15 and 195/50/15s for the AD08R.