Carisma F14 Blog - Part 5
While the kit rubber tyres are perfectly usable, and very pretty mounted on realistic spoked chrome race rims, if you want race performance you are going to need foam tyres. But which ones? Dez Chand investigates.
Getting a Grip
After much experimentation with various grades, I settled for 'Pink' Medium rear, and V54J '52' front, Mardave tyres mounted onto the optional Carisma foam rims for the F14. The tyres are fairly big as they come out of the packet so I needed to remove a lot of foam off the diameter in order to maintain ride height and chassis geometry, so I?ll need to make up a tyre truer adaptor.
For the F14 you need a 7mm diameter spindle to do the fronts and 8/32" inch hex mounts for the rears. You are aiming for diameters around 47mm front and 49mm rear so there is quite a bit of foam rubber to remove!
Once glued you need to get the diameters correct on a tyre truer, aim for 49mm rear, 47mm fronts.
As I said in Part 2 of this blog series, the front suspension is mounted on spacers and the rear axle sits in eccentrics so you can adjust the chassis as the tyres wear in order to maintain the required ground clearance, which is great! The kit sits clear of the floor by 4mm at the front and 5mm at the rear so that?s what I?ll aim for on the foams too!
The option foam wheels are a plain white dish design, but there are optional wheel decals available to bring back the detailed realism we so enjoy, but more of that in a later blog! At least the bright white wheels make the F14 easier to see on larger circuits, and they match the white front and rear wings, so my usual red/white paint scheme works even better than ever!
Indoors at the larger Ardent Raceway the Carisma F14 was simply stunning on foam tyres.
Whether racing at small local clubs like indoors at Bedworth on a Wednesday night with friends, or at larger meetings like Ardent Raceway near Derby, I found the grip on carpet tracks typically starts low then increases as the tyre additive affects the carpet, so always start with full width applications on the rears, with just the inside 5mm on the fronts for the first round, then just apply to just the rears for the second run and then usually nothing more for the rest of the day as the grip becomes a problem and no one likes grip roll!
Before and after, with nicely rounded shoulders, and a perfectly concentric diameter for smooth high speed running . With a hard wall of CA adhesive applied to the outside edge of the front tyres, grip roll was reduced.
Always thoroughly dry your tyres at least one race before you go on track to make sure they are ready to go without leaving parallel streaks across the track as you set off! With your tyres properly dry from lap one, your F14 will handle far more consistent than if you have to wait for your tyres to settle down and dry off lap by lap, so you settle straight into your race pace.
Ardent Raceway, Derby. Enormous, smooth, flowing and very fast, 15 second lap times..
Bedworth Indoor Winter series. Tight and technical, 7 second lap times.
Once glued you need to get the diameters correct on a tyre truer, aim for 49mm rear, 47mm fronts.
As I said in Part 2 of this blog series, the front suspension is mounted on spacers and the rear axle sits in eccentrics so you can adjust the chassis as the tyres wear in order to maintain the required ground clearance, which is great! The kit sits clear of the floor by 4mm at the front and 5mm at the rear so that?s what I?ll aim for on the foams too!
The option foam wheels are a plain white dish design, but there are optional wheel decals available to bring back the detailed realism we so enjoy, but more of that in a later blog! At least the bright white wheels make the F14 easier to see on larger circuits, and they match the white front and rear wings, so my usual red/white paint scheme works even better than ever!
Indoors at the larger Ardent Raceway the Carisma F14 was simply stunning on foam tyres.
Whether racing at small local clubs like indoors at Bedworth on a Wednesday night with friends, or at larger meetings like Ardent Raceway near Derby, I found the grip on carpet tracks typically starts low then increases as the tyre additive affects the carpet, so always start with full width applications on the rears, with just the inside 5mm on the fronts for the first round, then just apply to just the rears for the second run and then usually nothing more for the rest of the day as the grip becomes a problem and no one likes grip roll!
Before and after, with nicely rounded shoulders, and a perfectly concentric diameter for smooth high speed running . With a hard wall of CA adhesive applied to the outside edge of the front tyres, grip roll was reduced.
Always thoroughly dry your tyres at least one race before you go on track to make sure they are ready to go without leaving parallel streaks across the track as you set off! With your tyres properly dry from lap one, your F14 will handle far more consistent than if you have to wait for your tyres to settle down and dry off lap by lap, so you settle straight into your race pace.
Top Tip - To cure grip roll in high bite conditions add a smooth even layer of CA adhesive to the outside walls of the front tyres and allow to dry completely before you spin them! I adjusted the front camber turnbuckles to zero, yes the front wheels were dead upright, with the front toe set to parallel or very slightly toe-in, and the grip roll vanished allowing me to maintain high cornering speeds while still having plenty of bite in hairpins and medium speed corners. I have yet to adjust the king pin inclination (or rake, castor, whatever you prefer to call it) so I?m still using the kit setting but you could angle it further back to reduce bite on corner entry still further if need be.
So do they work? Well, compared to the kit rubber tyres, if 3 second per lap around Ardent Raceway is worth having, then the answer is Yes Indeed! My little 1/14th scale F14 was lapping within a second of my times with the 1/10th scale Formula 1 car, and that?s no slouch! But Foams Wear Out Fast, don?t they? After several meetings I am still using the same set of tyres, swapping side to side occasionally to share the wear, but as yet, after 8 rounds of the Bedworth winter series, and three visits to Ardent Raceway I am still running the same ride height. With such a light car (600g RTR), and a sensitive 2WD throttle finger, you?ll find foam tyres wear very little compared to power hungry 4WD tourers you might be more used to. I have even completed a race meeting outdoors at Bedworth on the tarmac track and the same tyres worked just fine!
Top Tip - Ideally you should have two sets of foam tyres in your pit box, to share the wear, to avoid getting your tyres over soaked with additive on any given day, and just in case you get a chunk torn out of a tyre in a crash.
Ardent Raceway, Derby. Enormous, smooth, flowing and very fast, 15 second lap times..
Bedworth Indoor Winter series. Tight and technical, 7 second lap times.
Dez Chand
Click the images below to view the other parts of the blog.
