Hey V8,

Yes, in my experience, there is quite often a level of variation with these tyres.

If i buy 6 pairs of the same # tyre, then i would sort them into 3 pairs by eye, first.
If i was to just use the first and second tyre that came out the bag, i could end up with the 2 that are at different ends of the scale.

It can be frustrating when you buy just 1 pair, and they are mismatched. I had this with a pair of GT40 rears

A quick email to Colin, with a photo of the visable size discrepancy, saw a 3rd tyre arrive the next day.

As you have already noted, the process of truing, evens most pairs up.

I think you will agree though, once trued up, these tyres significantly improve the handling of any car!

apart from when they are wet!! The water splash at the SlotRally event found this out.

I would have got more traction using just the plastic rims

 

Don't all tyres need truing before they work properly?

 

I never true the ortmanns I have.

I find they wear down so quickly they true themselves in no time.

 

I suppose that depends on the surface you use, but they took

forever to sand down for me. And hopefully my Sport track is less abrasive than sandpaper

As for all tyres needing to be trued - I have never had to do so on my Slot.it tyres running on Slot.it rims - either OOB or as separate spares. But they don't seem to grip Sport track anything like the Ortmanns - and I could see that from just accelerating from zero on a powerbase

 

What kind of Ortmann's? A lot is dependent on type of Ortmann's. The ones for Slot.it wheels are pretty decent and will round down quickly at worst. The Trans-Am's are also decent.

Now, as for the Vintage F1 tires, they're awful and take a fair amount of sanding and grinding. The Fly Classic ones are also very inconsistent and are frustrating.

Bob

 

QUOTE Don't all tyres need truing before they work properly?
Michael Ortmann has been manufacturing the high-performance production tires for our TSRF cars and we never had to true a single one. We recommend the use of traction magnets to break them in (one hour of running or less), and after that they are absolutely perfect and smooth. Then they appear to last for at least 20-25 hours of driving if with magnet, and about 6-10 hours without magnet.
We had virtually no quality problems with any so far except for a batch that Michael took back graciously and exchanged to us as the mix had been done improperly.
Regards,

Philippe

 

I've mostly had problems with the Ortmanns fitting the large Slot.It rims (#51 I think). They have almost all been bad and needed serious sanding to get the round, but the #51a fitting the small Slot.It rims have all been really nice and round. The ones fitting Fly classics have been pretty bad too. They do grip better than anything though, so I guess we'll have to live with it...

Have a look at the ABslot Ultrathane tyres to see how it should be done qualitywise. They are as round as tyres get and are smooth and perfect allround unlike the Ortmanns with their one rough sidewall and messy inner surface. Sadly I haven't found them to have the same level of outright grip as the Ortmanns. The Ultrathanes are a lot smoother to drive somehow and on some surfaces they do beat the Ortmanns. They also make the cars whisper quiet compared to Ortmanns.

 

The ones that were really off-centre were the #47a 20x12 - supposedly for ProSlot, but they fit the 17x10mm Slot.it hubs.

Don't get me wrong, I'm very satisfied with the result - although I haven't managed to do a full test on a sizeable track yet. And if I know that there can be some variation, then I know not to buy just two at once.

But if it does seem to be predominantly one size that has issues, then maybe that's something to watch for.

One thing I'm very pleased about is that the ones I got for the rear of my Revell March - which have some of the deepest sidewalls seen on a slot car - appear to be nicely round and centred - when there's potentially the most scope for getting these horribly wrong.

Perhaps it's just that authentic ProSlot hubs don't have the axle dead centre, so when the tyre's fitted you get a nicely true running surface

 

I have brought Ortmans from several sources and not been happy with any of them as regards the roundness. We run on routed tracks and then tyres need to be glued on to the rims. The six sets of 20 x12 that I had were all out or true only managed to salvage one pair,they work great on the routed track and I would like some more but I am reluctant to order more.

Phil

 

My experiences with the roundness is the same as Phil's and Zipp's and like Zipp I order a bunch of them at a time and sort them in pairs with the odd one out. What I have experienced then is that trueing shows, by the dust coming off the tyres, that the compound of the tyres might differ between batches. One tyre might give off whitish dust while the other gives grey to dark grey dust. Now I am wondering if this could result in different adherance to the track? I haven't tested this yet.

Regards,

Don Quislot

 

The tyre below is one of my most recent purchases.
I think this may be the result of an inconsistent mix, as Philippe mentioned earlier.
It certainly is the only one, of a bunch of 8 to go that way. All the others are fine.

I have had some good fitting batches, but mostly, they are not so perfect.
It is difficult to weigh up, because the grip achieved and the level of control with the Ortmanns is superb.......even if it does take 10 minutes fettling and truing.

If only a little quality control, was put in place

Philippe,
Running with mags to true up the tyres, sounds like a good idea.
I think i may give that a whirl with my next batch.

Do you think this will work on Scaley Sport track??

 

I guess I've been lucky, as I have Ortman's fitted to over 100 cars and never really had a problem.

How are you guy's trueing the tyres?.......I have come to the conclusion that Ortman's don't really like to be trued too much.....the more you true them, the less grip you have. All you need to do is remove any highspots.

1.Glue the tyre to the rim, (Andy Brown sells the stuff you need to do this).

2. Remove high spots (by hand and eye) with these :-

They are diamond tyre truers as sold by AB Slotsport at £8.50 a set.

When your finished your tyre should have an almost patchwork like apperance

Proper tyre truers tend to remove too much material and sandpaper tends to put a chamfer across the tyre.

Then as Phillipe says...run the cars

Regards

Alan

 

Ooooh! More bits to buy !!!

Actually, to answer Beejay's question, I used sandpaper on a hard flat surface to get the majority off, with the wheel on an axle being driven by a hand-held Dremel-a-like. I didn't want all the dust clogging up a nice motor and chassis.

To start off with (because the wheels were so off-centre and therefore hideously unbalanced) I had to stick the axle through the rear bearings of a spare chassis, so I could control the vibration and apply the wheel to the sandpaper more steadily and with more control.

I finished off by using a cast-off nail-board from my wife to get the final flatness of the tyre that I wanted.

I had to do the tyres one-by-one because they were just so out of true.

 

They last for only 6/7 hours and are not always round? I'll forget buying any of these in the future.

 

QUOTE (Screwneck @ 16 Nov 2006, 09:50) <{POST_SNAPBACK}>They last for only 6/7 hours and are not always round? I'll forget buying any of these in the future.

They are a benefit for Club racers ( for those clubs that allow them ! ), and this is the price we have to pay for performance

I can understand your point of view.

 

Cheap & easy tire trueing:

get 1" x 30" or 1' x 42" sanding belts - metal or woodworking supply; 100 or 120 grit & 150 or 180 grit

rubber cement, contact cement, Goop

I cut pieces of thin masonite or MDF about 3-1/2"W x 5"L

cut the sanding belts whatever width the boards are cut

glue the back of the paper, put one coarse and one fine @ the ends of the boards. if you are making multiples, put plastic wrap between each one clamp 4 - 6 hours

you get a hard flat (true) surface with a cutting end (new tires) & a dressing end (before heats, after swapping).

I usually set it on the track backwards, put the car down backwards, with the controller hand hold the board down, then slide the car across the board side to side. Viola! true tires that are hot & ready, matched and on the car. you generate great clag (marbles) to put off-line for real track conditions!

some tires may need alcohol lube to "break" the skin - Ninco GT slicks, once broken they will "scrub up" each & every time easily.

I do it backwards because the directional action of the car pulls towards your other hand, very easy to control.

***WARNING*** cars with light kits, esp. capacitors, may burn out if current goes backwards, do these with the car pulling forwards.

th-th-th-that's all folks!