Scrub radius

[Rhys1983]

Technical question. How far can you go with wheel offset before it affects the scrub radius?
I currently have 42et wheels with a 10mm spacer to accommodate the big brake kit giving an offset of 32et.
Does anyone know how far you can go whilst maintaining a negative scrub radius?

 

[Dpro]

88

Technical question. How far can you go with wheel offset before it affects the scrub radius?
I currently have 42et wheels with a 10mm spacer to accommodate the big brake kit giving an offset of 32et.
Does anyone know how far you can go whilst maintaining a negative scrub radius?

well having a 32 offset is going to be felt in your steering and turn in. i.e. negative scrub radius . I have been to 37 and some people have run 35 . 32 is definitely getting down there.

 

[Rhys1983]

88

well having a 32 offset is going to be felt in your steering and turn in. i.e. negative scrub radius . I have been to 37 and some people have run 35 . 32 is definitely getting down there.

From what I understand, most performance front wheel drive cars benefit from having a negative scrub radius and as you move the wheels out and lower the ET the scrub radius gets closer to zero and will eventually end up being positive scrub radius.
I’m just wandering if anyone’s measured this on their cars or know how low offset you can go before this happens.

 

[Dpro]

From what I understand, most performance front wheel drive cars benefit from having a negative scrub radius and as you move the wheels out and lower the ET the scrub radius gets closer to zero and will eventually end up being positive scrub radius.
I’m just wandering if anyone’s measured this on their cars or know how low offset you can go before this happens.

ah excuse me i meant positive scrub radius when you lower the offer on our car it put the setup in positive scrub radius that will effect turn and create a heavier wheel. Now it not really felt till you get round 35 and below . In fact our scrub radius is pretty much zero. stock and 32 offset will be about 13mm positive

 

[Rhys1983]

The other option would be fitting a big brake kit that’s not too big to fit under my OZ Superturismo wheels which are 42et.
Does anyone know of a lower profile big brake kit? I know that the mountune one isn’t that big.
The other option would be going to standard Ford ST brakes with an upgraded pad.

 

[Dpro]

The other option would be fitting a big brake kit that’s not too big to fit under my OZ Superturismo wheels which are 42et.
Does anyone know of a lower profile big brake kit? I know that the mountune one isn’t that big.
The other option would be going to standard Ford ST brakes with an upgraded pad.

I just put Wilwoods on my car with a 12.3 inch rotor . They clear my 40 offset 16 inch Dekagrams.

 

[Rhys1983]

I just put Wilwoods on my car with a 12.3 inch rotor . They clear my 40 offset 16 inch Dekagrams.

Perfect! The Wilwoods should work with my OZ superturismo 42 offset 17 inch wheels then. Funnily enough I was just looking at the Wilowoods now! They look like a good option and are very light. How much clearance do you have from the brake calipers to the wheel?

 

[Dpro]

Perfect! The Wilwoods should work with my OZ superturismo 42 offset 17 inch wheels then. Funnily enough I was just looking at the Wilowoods now! They look like a good option and are very light. How much clearance do you have from the brake calipers to the wheel?

about an inch or so just glancing . from the rim and about a inch and a half from the spokes . Word on the street is they also clear Team Dynamics 15’s.

 

[Rhys1983]

about an inch or so just glancing . from the rim and about an inch and a half from the spokes . Word on the street is they also clear Team Dynamics 15’s.

Thanks. That should give plenty of space for my wheels.

 

[M-Sport fan]

What does M-Sport Poland currently use for their TARMAC setup on the Rally 4/R2T cars??
I do not think that they use the same 18x8 wheels as the Rally1/Rally2/R5 tarmac setups, and therefore neither do they spec those huge (335mm?) brakes behind them.

In any case, the Wilwoods are most likely lighter, and much MUCH less coin.

 

[Rhys1983]

I think the M-Sport R2T tarmac came with 310mm Alcon kit.
I wander what offset wheel they used and if the brake kit was low profile as I wouldn’t have thought that they’d run spacers?
I’m just wandering if I could further improve the handling of my car by removing the 10mm spacer and having a 42et offset as a 32et is quite a bit further out than the original 47.5et that our cars came with. And my Oz
I’m now thinking of getting the front and rear wilwoods (more cost!!! ) which are a lot lighter than stock and look very nice, or go for standard front set up with upgraded brake pads?

 

[M-Sport fan]

I just looked it up, and for the Mk8 Rally 4s at least, yes, they are using the Alcons.

But, they ARE using pretty big 330s in the front, with solid disc 280s in the back, with a17x7 OZ wheel for tarmac (they do not give an offset, but they use the Focus (I believe) 5 bolt pattern hubs, so who knows what the ET actually is?

 

[Dpro]

I think the M-Sport R2T tarmac came with 310mm Alcon kit.
I wander what offset wheel they used and if the brake kit was low profile as I wouldn’t have thought that they’d run spacers?
I’m just wandering if I could further improve the handling of my car by removing the 10mm spacer and having a 42et offset as a 32et is quite a bit further out than the original 47.5et that our cars came with. And my Oz
I’m now thinking of getting the front and rear wilwoods (more cost!!! ) which are a lot lighter than stock and look very nice, or go for standard front set up with upgraded brake pads?

It depends on what kind of driving you are doing and if one is hybrid or big turbo or not.

If you have done a turbo upgrade you’re pushing more power and moving quicker and possibly going faster. Stock braking with good pads is actually pretty good on a stock engine setup. Though with more power and higher speed you start reaching the limits. In our experience on roads like the Crest with high speeds and bigger turbo you notice brake fade 3 or four corners in. Hence going larger brakes.

Same goes for tracking with more power. Honestly as cool as 32 offset could look with flares and whatnot these are front wheel drive cars designed with a much higher offset to start with and like I said earlier lowering that offset as much as going down to 32 does will effect turn in and steering wheel effort.

Whether or not that bothers someone could be up to the person though I feel it detracts from the greatness of how the car drives.15 inch wheel guys accept the 35 offset trade off for the sake of putting larger width tires on for greater grip .
Lose some turn in gain a lot of grip. It’s up to the person. I like sharp turn in. I also like lots of grip I try to strike a compromise which I fee falls between 37 offset and 40 for our cars.

 

[Rhys1983]

I wouldn’t have thought that they would change the offset much from original on the mk7.5 fiesta R2T.
Again, fitting spacers and lower offset wheels are more for looks than performance. A bit like lowering springs and suspension!!
I think that the Wilwoods are looking like the best bet as I believe you save over 20lbs in total just on the front from standard st brakes plus I could then run the car without any spacers.

 

[Dpro]

I wouldn’t have thought that they would change the offset much from original on the mk7.5 fiesta R2T.
Again, fitting spacers and lower offset wheels are more for looks than performance. A bit like lowering springs and suspension!!
I think that the Wilwoods are looking like the best bet as I believe you save over 20lbs in total just on the front from standard st brakes plus I could then run the car without any spacers.

Except there is something to be said by being able to run more tire as its one of this cars biggest issues stock is being limited to minimal tire due to the wheel wells never being designed for a 17 inch wheel. They were designed for 15’s and 16’s . Tires on our car is one of if not the biggest limiting factor.
I get two benefits from running 16’s more sidewall height for ride comfort lol and the ability to run a bit more tire overall yes you can get 225/45/16’s from some tire companies. oh and yes people have been able to run them.

 

[Rhys1983]

It depends on what kind of driving you are doing and if one is hybrid or big turbo or not.

If you have done a turbo upgrade you’re pushing more power and moving quicker and possibly going faster. Stock braking with good pads is actually pretty good on a stock engine setup. Though with more power and higher speed you start reaching the limits. In our experience on roads like the Crest with high speeds and bigger turbo you notice brake fade 3 or four corners in. Hence going larger brakes.

Same goes for tracking with more power. Honestly as cool as 32 offset could look with flares and whatnot these are front wheel drive cars designed with a much higher offset to start with and like I said earlier lowering that offset as much as going down to 32 does will effect turn in and steering wheel effort.

Whether or not that bothers someone could be up to the person though I feel it detracts from the greatness of how the car drives.15 inch wheel guys accept the 35 offset trade off for the sake of putting larger width tires on for greater grip .
Lose some turn in gain a lot of grip. It’s up to the person. I like sharp turn in. I also like lots of grip I try to strike a compromise which I fee falls between 37 offset and 40 for our cars.

My car is running a mountune mp215 map and I don’t get up to big speeds on the roads I drive on as they’re very twisty undulating roads, although I do need to brake hard and often.
I feel like the standard set up with upgraded pads and discs would cope fine, but there’s a big weight saving which is mostly unsprung weight to be had by fitting the Wilwood set up. And they do look really nice!
Yes, I feel like losing the spacers and going back to a 42 offset could further improve the turn in and cause less torque steer and tram lining which going too low an offset on a fwd car can cause.

 

[Dpro]

My car is running a mountune mp215 map and I don’t get up to big speeds on the roads I drive on as they’re very twisty undulating roads, although I do need to brake hard and often.
I feel like the standard set up with upgraded pads and discs would cope fine, but there’s a big weight saving which is mostly unsprung weight to be had by fitting the Wilwood set up. And they do look really nice!
Yes, I feel like losing the spacers and going back to a 42 offset could further improve the turn in and cause less torque steer and tram lining which going too low an offset on a fwd car can cause.

oh it will definitely help on the TQ steer. People often forgot these are FWD cars not RWD cars lower offset has more effect. 😂I noticed TQ steer increase even adding 3mm spacers when I had the Whoosh brakes that lowered my offset to 37.
Oh and yes the unsprung weight advantage is noticeable and really one of the great features. Stock brakes are not exactly light🤣

 

[Rhys1983]

oh it will definitely help on the TQ steer. People often forgot these are FWD cars not RWD cars lower offset has more effect. 😂I noticed TQ steer increase even adding 3mm spacers when I had the Whoosh brakes that lowered my offset to 37.

Yes, most people are only concerned whether the wheels rub on the arches when going too wide, but from what I understand there’s a lot more negative effects going too wide on a front wheel drive car without many benefits.
I know that the Honda Civic type r was designed around a certain offset to stop the car from torque steering which would be a lot more noticeable when you’re running 300+bhp through a front wheel drive system like they are.

 

[M-Sport fan]

Yes, I am running the very same 16x8 Dekagrams that Dpro is, and I (even on pure factory stock tune/power levels) wish that they were closer to a 45ET than the 40ET they are.

 

[Intuit]

Technical question. How far can you go with wheel offset before it affects the scrub radius?

Input the parameters.
https://www.wheel-size.com/calc/?wh...45-17X7ET48&fcl=50mm&scl=50mm&wcl=50mm&sr=0mm

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