X4F’25 - Set-Up from XRS Cotswold Model Car Club

Ok so please see my set up for the X4F’25 from this weekends racing at Cotswolds. This meeting was run to BRCA rules (notably ESC, Motor, RPM limit and Control Tires)!! First of all I’m going to give a massive shout out to Alfie Hart (9 years old) - he was pushing me and out-qualifying me all weekend, really making me work hard to match his speed…. We had great fun all weekend and although I eventually won, I suspect it might be one of the last times I beat this future superstar (my driver of the weekend at XRS for sure)👍

Anyway back to my set up for our latest spec X4F….

One of the key struggles was to get a stable balance in the car while searching for steering (from a class of car that will generally understeer)!

The ‘eureka’ moment was getting the rear end to stick in the chicane/sweeper corners, I achieved this by firming up the rear shock oil (500cst) springs (2.8 ) and adjusting the roll centres.

There is no doubt some more performance to find but this set up definitely put me in the ballpark of speed and stability👍

I was struggling with forward drive and this rear end adjustment improved drive from corners too, I guess less weight transfer to the rear and loading the front tires gave a small but noticeable improvement… another win😎

Up the front end I dropped the diff from the super thick 500,000 weight to 200,000 to try improve turn-in…. It was a tiny improvement but I may try 500k again or even a Spool to try further find forward drive (potentially outweighing the turn-in understeer this creates)!?!? More testing required I think…. (I note since I posted this I’ve been made aware a spool is not allowed, so scrap this comment)😆

I opted to run the -1mm Upper Clamps on the front. This again smoothed out the steering in the faster parts of the track and although possibly lost a tiny bit of turn in, it allowed me to turn in harder and generally drive the car harder without upsetting the front-rear balance - and gave more apex-to-exit tire bite (so faster exit/could push harder exiting the corners)!! Note my comment above about stiffening the rear gave more forward drive, I thought this really worked👍

There are a number of other small tweaks, one being thinner front oil (300cst) and 2.6 spring… I will try the 2.5 spring and also the 1.2 front roll bar to try find that last bit of steering still needed…. But these are really small gains I’m talking about, like a 1/10th or 2/10ths a lap maximum!!

Gearing - I think in this bigger type of track I could go 1 or 2 teeth bigger on the pinion (2 teeth absolutely maximum) - first up I didn’t have a bigger pinion or smaller spur to try so I had to settle for what I ran. Fitment is an issue hence why 1 tooth bigger pinion might just squeeze in there as things are, 2 teeth bigger you might need to cut the lugs off the top of your servo!! I think changing this would have found another 1-2ths per lap as it’s a long straight (and Alfie was fractionally, fractionally faster than me here) - but what I’m getting at is with these Frontie cars you end up looking for those absolute last minuscule fractions of seconds!!! It’s great fun pushing for such fine margins, I thoroughly enjoyed this part of the challenge👌

Overall though I thought I ended up the XRS weekend with a really good car so I hope if you race the X4F’25 (I think almost everything I’m explaining here will work on the 24 car too btw) you find this info and set-up useful. If you have any questions please don’t hesitate to ask.

Obviously if you like what you’ve read and like the sound of the Frontie class then feel free to give me a shout as we have a few kits left in stock and we’d very much welcome you to join us with the rest of the XRAY Frontie gang especially as we head towards the indoor winter season where I’ll be doing the MICC and maybe the EWS International (along with the XRAY Factory Team)!!

Ohh and did I mention value for money…. The Frontie tires last FOREVER, literally getting better and better until you actually wear them through to the canvas (I got about 20x runs from mine and that folks is awesome in my opinion👍)!!!

Frontie Class is ace…. Greg Hill

X4F’25 - Chassis Focus😎

A couple people have asked to see pictures of my car after the weekend. As you can see it is largely the standard car/kit - apart from the 2.6 front springs and the 2.8 rear springs and the -1mm Upper Clamps up front👍

I borrowed the alloy T-Brace from Martin Hudy so gave that back at the end of the XRS (it was tempting to keep it😆)!! Hence why it is not on my car, but was used and is on my set up sheet I posted the other day...

Something I don’t think I mentioned the other day was the servo horn position. As you can see I mounted (moved it) to the lower mounting hole on the Hudy servo Horn. This smoothened out the initial servo response which helps you ‘position’ the car around the lap (eg if you need to adjust the direction while travelling down the straight this means you fear less about twitching the car left or right so aggressively which in turn gives you confidence to position the car when needed everywhere on track)!! This is something Alexander Hagberg did on his X4’24 in Mod class to (he was using a new near-production ready adjustable Hudy servo horn which looked super neat too).

I did notice from the BRCA Nationals that the Gorilla Frontie shell seems popular which I had but didn’t paint in time for the XRS weekend, I have finished this shell now and will add it to the finer list of things to try next👍.

All in all though, I hope you like seeing the car and how I ran it (and things I’m planning trying next too).