[Nonfractal]

Normally I pick up ortmanns in person from Steve Carter at London Slot Car club.

However, in 1st lockdown, i used these guys 

http://www.rsslotracing.com/tyres_modernRacing.htm

Alan W

[autoavia]

Tracks get a layer of dust whenever they are not used for a while so it is possible that it is not Ortmanns causing lack of grip. If I forget to vacuum my track then all tyres pick up some dust and need cleaning after a few laps. Soon sorted with some sticky tape.

 The track is covered between club nights and it is only after we have run vintage with ortmanns that we get the grip problem. Maybe because vintage cars, particularly 1/24 scale tend to be much heavier than modern cars they wear the tyres faster and produce more dust. Most vintage cars also run much wider tyres than modern cars so more tyre area to produce dust. 
 I have tested modern cars with other urethanes during club nights and no one has complained of loss of grip when they followed me onto a lane which led us to conclude that Ortmanns on vintage cars are causing the problem.

[BAracer]

Just thinking about the comparative performance difference between G25 (shore 25?) and the magical NSR tyres in the original posting, is it simply the case that softer rubber grips better than harder rubber? So SI G25 is harder than SI F22, which in turn is harder than NSR Ultra15...or are NSR tyres made out of different stuff?

[CMOTD]

The track is covered between club nights and it is only after we have run vintage with ortmanns that we get the grip problem. Maybe because vintage cars, particularly 1/24 scale tend to be much heavier than modern cars they wear the tyres faster and produce more dust. Most vintage cars also run much wider tyres than modern cars so more tyre area to produce dust. 
 I have tested modern cars with other urethanes during club nights and no one has complained of loss of grip when they followed me onto a lane which led us to conclude that Ortmanns on vintage cars are causing the problem.

Thinking about it, there have been at least three different formulations of Ortmann tyres over the years so it is possible that one of them could have caused some problems. The original version was the best but the EU banned certain components of it. The second version was not very good and produced blue dust when trued. I am unsure about the latest version. Any idea how old the ones you are using are?

[slotloco]

I hadn't heard of the urethanes vs. rubber supposed incompatibility debate before.
Personally, I cannot see how one would affect the grip of the other, unless one was pulling "rubber" off the track, or the urethanes were leaving dust marbles behind
-  so again, thanks for being so thorough.

Not an uncommon debate over here. Complete nonsense in my opinion but some UK clubs ban urethanes over this alleged problem. Running both types together has never given me cause for concern on either my home track or the club one. Our local club runs an IROC class with handout Scalextric Ferrari F430s fitted with urethanes and virtually every other class has free choice of tyres (apart from silicone which does cause problems). The outright lap record was once broken by an NSR ultra clad GT immediately after a full race session with the urethane fitted club cars!

P.S. You have people using wintergreen on tyres? Really? Are they mad? It has been banned at UK clubs since God was a lad. The active ingredient is toxic and can be fatal.

No, no-one is using the old Methyl, I DID consider it, as my brother in law has a 20 gallon drum he uses for softening new/old stock tyres for vintage cars (the 1:1 scale), but couldn't bear the pong. - It's okay so long as you don't get too much on the skin, and of course drinking it will give you about the same effect as a good dose of warfarin.
But I never REALLY considered lacing my competitors coffees with it....... except the fast ones..... 
But we do use a bit of WD40 or the CRC brand equivalent on occasion, but NSR tyre oil is all most of us use. A rolling rub treatment to prep them before first use.

[slotloco]

Just thinking about the comparative performance difference between G25 (shore 25?) and the magical NSR tyres in the original posting, is it simply the case that softer rubber grips better than harder rubber? So SI G25 is harder than SI F22, which in turn is harder than NSR Ultra15...or are NSR tyres made out of different stuff?

I think that is a big part of it. You only have to feel the difference between Hi-Grip medium and Hi-grip soft, or N18 vs N22 when you need more grip.

[autoavia]

BAR Racer wrote
Thinking about it, there have been at least three different formulations of Ortmann tyres over the years so it is possible that one of them could have caused some problems. The original version was the best but the EU banned certain components of it. The second version was not very good and produced blue dust when trued. I am unsure about the latest version. Any idea how old the ones you are using are?

 You are right in saying that the original formula was the best but old Ortmanns are hard to find now.
We are all using the latest mix which produces a grey dust when trued. The same grey dust is picked up by modern rubber tyres on the Tuesday club night following a vintage meeting but it cleans off with tape and eventually we get a grippy track again.

[autoavia]

I am curious as to why Slotit and NSR have decided to tinker with tyre compounds.

 Is it simply an attempt to improve the brand or are there other reasons such as a new EU rule which bans some of the components in the mix or is it an attempt to make tyres which don't respond to traditional tyre treatments to help prevent cheating in championships which require tyres to be untreated? 

 Don't get me wrong this isn't a compliant. It does seem that many people are put off club racing and open events because they don't understand the black art of tyre treatments (who does?) so anything which might help attract more racers to clubs and open meetings has to be a good thing.

[BAracer]

I read that Slot.it lost their N22/F22 supplier, so they had to refresh the product.

[CMOTD]

Interestingly, Pendle have just introduced their own brand of F22 tyres. LINK