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SNeed help with new car

Andy P.

1681 posts


Community Moderator

What I meant was leaving the magnet in its current position but flipping the "top" to the bottom. Sometimes magnets have a "better" side.

You can also get a stronger magnet online that fits in the same slot.

Twigman

91 posts

It is very apparent that the grip of recent Scalextric tyres is far poorer than it was.

Has the compound been compromised?

Is this a cost saving exercise?

I have 3 recent BMW Z4s which all have appalling grip and tend to slide far too easily on R2 often getting so sideways they no longer have any forward drive. This is definitely due to tyres.

If it is a cost saving exercise making tyres cheaper and thus less grippy then in my opinion it's a false economy: it makes the customer less inclined to buy the cars.

I certainly have no intention of buying any further Scalextric cars until I hear that the tyre grip is back to expected levels.

Andy P.

1681 posts


Community Moderator

Twigman

91 posts

@Andy P.

Have you seen this?

https://www.scalextric.com/uk-en/forum/tire-quality-on-recent-models-has-changed-no-longer-race-worthy/?p=1

I have  - I'm not sure that i belive the claim that nothing's changed.

Where are the tyres moulded? Do Scalextric have absolute control over the chemical mix of the rubber used in those moulds?

I read on another forum that another manufacturer had recently had problems with their chinese moulded tyre rubber compounds - the supplier had used cheaper ingredients without clearing it with the manufacturer. Perhaps the same is happening with Scalextric?

woodcote

783 posts

@Twigman - This is what the Admin said in the thread Andy linked to:

I've brought this thread to the attention of our Development team and they've let me know that nothing has changed with our tyres - no changes have been made with their production on our end.

However, given your feedback, it is something we'll look into and keep in mind as we work on future models.

My reading of what that means is: 1) Scalextric themselves have not changed the tyre manufacturing process, 2) Scalextric are looking into why a change in grip levels has been reported and 3) Scalextric will take note of what they find in relation to future production.

 

I suspect what you say is correct - this is likely to be a change at the factory level and something that has happened with other manufacturers too. I've certainly noticed it with the latest reliveries of the sidewinder GT cars. Of course, the new inline cars take the Slot.it tyres, which is a handy interim solution. And I really like using Paul Gage urethane tyres when I take the traction magnets out of my Scalextric cars. These tyres are available for a huge range of Scalextric models.

 

Returning to the BTCC grip issue, all I can say is that we race these cars (BMW 125, Civic R, MG6 and VW Passat) without the magnets, plus a little lead weight and with either Slot.it PT1207P6 rear tyres or Paul Gage urethanes. They are a blast to drive, certainly as quick and nimble as similarly prepared GT cars.

 

With the magnets, the grip will be determined by how strong the magnetic attraction is on the track rails - and that depends on the raw strength of the magnet and the distance of magnet to rail. To increase the strength, a stronger magnet or extra magnets can be used (Pendle Slot Racing have these) or the rear tyre diameter can be reduced by sanding them down and getting the magnet closer to the rails. Increasing the magnetic attraction will increase the drag on the car and means the motor will heat up quicker - not great for longer races and worth keeping an eye on.

 

However, my rule of thumb for similar performance is to race similar cars - BMW 125 vs BMW 125. The performance may never be identical, but it will be close and the racing is more enjoyable.

alan_west

26 posts

Interesting debate on the BMW 125. I have a couple and see same issue where the time difference per lap is up to 20% slower than the Honda or VW especially. I think that some difference is good - it makes the Beemer behave more like a RWD car and the difference can be used to level the playing field for racers too. However, I do feel the difference is too great. Has anyone switched a magnet over as Andy suggests? What was the effect? Maybe, I'll just change the tyres to compensate....

woodcote

783 posts

I used my magnetic downforce gauge (see here to make your own) to measure the downforce on the rear of the BMW 125 and the Civic R from my Touring Car Battle set.

 

BMW 125 - 25.3g of downforce

Civic R - 39.4g

 

I didn't touch the existing magnet - the chassis on these BTCC cars is pretty fragile. I added a small Slot.it neodymium (ie shiny silver) bar magnet on top (it fits under the motor shaft) and took a measurement of 47.3g. Too much...

 

I then took two small round neodymium button magnets (from an Auto World HO car, but similar to the Micro Scalextric traction magnets) and placed one to the side of the motor shaft. I took a reading of 31.1g. Adding another button magnet to the other side of the motor shaft, the reading went up to 35.9g. The two cars then had a similar 'pull' when I picked up the rear of them on a piece of Scalextric track.

 

If you, like me, have magnets lying around from other projects, this is easy to experiment with. If not, I'd try 5mm diameter x 1mm thick N52 neodymium button magnets. Or 3mm x 1.5mm. Anything bigger (more volume) may be too strong. I see a pack of 5 of the 3 x 1.5 buttons for £0.99 on eBay. Two of those should be perfect to boost the BMWs to compete with the other BTCC cars.

 

Certainly without the magnets, the BTCC cars are nicely matched. We did this 20 minute test session with five different cars/drivers on a big digital track:

 

1. BMW125 Priaulx - Tyres: Paul Gage - Fast Time: 10.186 secs

2. MG6 Goff - Slot.it P6 - 10.506 secs

3. Honda Civic R Shedden - Slot.it P6 - 11.015 secs

4. BMW125 Tordoff - Paul Gage - 11.312 secs

5. VW Passat Plato - Scalextric tyres - 11.917 secs

6. BMW125 Collard - Scalextric tyres - 11.968 secs

 

In race conditions and on a slower, more technical track, we got these fast times:

 

1. BMW125 Priaulx (Paul Gage) 11.44 secs

2. Civic R Shedden (Slot.it P6) 11.755 secs

3. BMW125 Tordoff (Paul Gage) 11.78 secs

4. VW Passat Smith (Paul Gage) 11.921 secs

5. MG6 Goff (Slot.it P6) 12.15 secs

6. MG6 Cook (Slot.it P6) 12.852 secs

7. VW Passat Plato (Slot.it P6) 12.932 secs

8. Civic R Smith (Paul Gage) 14.551 secs

woodcote

783 posts

Here's a pic of where I put the magnets. A little blurry, but the orange dots help...

 

 

The magnets are, of course, held in place by magnetism! They should stay there okay, but a little glue (being careful to avoid the motor shaft and gears) might be an idea to keep them securely in the car. These little magnets are pretty hazardous if ingested, so definitely use the glue if you have inquisitive children and/or pets around.

alan_west

26 posts

Great detail -really helpful thanks Woodcote! Will get some of those button magnets.

barryhi33

93 posts

Well the magnets arrived today - so installed and what a difference ..... lap times are reduced by 4 to 5 seconds on a 816cm track.

I originally tried to fit a stonger magnet but could not easily remove the existing one without fear of damage so then added a second magnet the same size as the original but it fouled on the main cog.

Ordered the small magnets as per Woodcote suggestion (thank you) and they did the trick - originally fitted 2 but not so succesful. Added a total of 4 in the end and that did it. The resistance when lifting the car from the track is now very much the same as other cars I have.

Far happier with the car now ...................

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