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Exact wheelset dimensions?


rapidotrains

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Hi guys,

 

The factory is asking us for exact wheelset dimensions for OO, EM and 4mm.

 

I suspect this is like them telling us: "Here is can of worms. Please open!"

 

The wheelset back-to-back dimension for HO scale is 14.55mm. This should be the same for OO gauge, if we are using "NMRA Code 110" (2.8mm thick) wheelsets.  (That is our plan, unless there is a general chorus of disapproval.)

 

Are EM wheelsets generally also Code 110?

 

I think the factory wants to include EM and 4mm wheelsets in the box, but I suspect that many of the 4mm guys will want P4, which is more worms in the can.  I am leaning towards including EM but leaving the P4 guys to turn their own wheelsets using a 1:76 lathe or whatever it is those guys do.

 

One more thing: Are there accepted standard axle lengths as well?

 

Any thoughts/suggestions would be appreciated.

 

Thanks,

 

Jason

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Hi Jason

 

For P4, the wheel standards are available from the Scalefour Society web-site

 

 http://www.scalefour.org/resources/downloads#

 

It might be worth posting on the forum guestbook to elicit further opinions, particularly regarding the target values for the dimensions.

 

http://www.scalefour.org/forum/viewforum.php?f=37

 

Best Wishes

 

Martin

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I've checked with our engineers and it doesn't look like 26mm is going to work for axle length.  I suspect third-party wheelset providers will need to make custom axle lengths.

 

 

All that being said, if we include OO and EM in the box, I can't imagine there being more than about three guys out there who would want to run the track on proper 4mm scale track.

 

-Jason

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I see Rapidos own HO wheel sets use a 25.78mm axle

http://www.rapidotrains.com/wheels_ho.html

 

Could the 26mm dimension be a rounding up of this figure?

 

Just measured Hornby OO gauge wheel axle and those are about 25.2mm although I won,t claim my calipers were the most accurate in the world!

 

I also suspect these days there are more people doing P4 than EM as the conversion process is probably just as difficult for both.

The last and probably only time an RTR manufacturer included an EM conversion pack wheel set was Dapol in the late 1980s, early 1990s for their J94 steam loco (still made by Hornby but not with the extra wheel set anymore).

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JSpencer, on 24 Sept 2014 - 22:55, said:JSpencer, on 24 Sept 2014 - 22:55, said:

I see Rapidos own HO wheel sets use a 25.78mm axle

http://www.rapidotrains.com/wheels_ho.html

 

Could the 26mm dimension be a rounding up of this figure?

 

Just measured Hornby OO gauge wheel axle and those are about 25.2mm although I won,t claim my calipers were the most accurate in the world!

 

I also suspect these days there are more people doing P4 than EM as the conversion process is probably just as difficult for both.

The last and probably only time an RTR manufacturer included an EM conversion pack wheel set was Dapol in the late 1980s, early 1990s for their J94 steam loco (still made by Hornby but not with the extra wheel set anymore).

Interestingly, Exact Rails 'scale' wheel sets axles are a little shorter at 25.45 mm according to the conversion chart I used. https://www.exactrail.com/33-natural-nickel-silver-wheel-sets

I'm quite surprised that a manufacturer is offering an "in the box" conversion with a model. Surely this would add to the cost of the model and leave a 00 modeller with a set of wheels he doesn't need?

Would it not be better for Rapido to offer a set of EM or P4 wheels as a separate item for the model?

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Interestingly, Exact Rails 'scale' wheel sets axles are a little shorter at 25.45 mm according to the conversion chart I used. https://www.exactrail.com/33-natural-nickel-silver-wheel-sets

I'm quite surprised that a manufacturer is offering an "in the box" conversion with a model. Surely this would add to the cost of the model and leave a 00 modeller with a set of wheels he doesn't need?

Would it not be better for Rapido to offer a set of EM or P4 wheels as a separate item for the model?

I don,t think it would be worth Rapido selling EM and P4 sets per se as they are not really specialist players in these wheel sets. I think for them it will be an all or nothing scenario, either all sets come with these conversion packs or none at all. Remember Rapidos main market is HO and there aren't many people converting HO CN trains to run on 18mm + track!

 

This explains a lot of discussion for a OO gauge model to readily convertible but left to after market specialists at the start of the project. Note such a decision can influence the design of the open ended bogies making the sides shallower in depth which would reduce their rigidity (we only have to look at Bachmann recent porthole coaches to problems that makes).

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JSpencer, on 14 Oct 2014 - 22:13, said:

 Rapidos main market is HO and there aren't many people converting HO CN trains to run on 18mm + track!

 

 

Really!!! You do surprise me! :laugh:  :laugh:

STBO.

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With all the EM and P4 talk, lets not forget us OO guys.

 

So long as the train is to 4mm scale 16.5mm gauge and runs on code 75 track without the flanges hitting the chairs, most people here will probably be happy.

 

Hornby, Bachmann and Heljan wheel dimensions run happly on Tillig code 83, Peco code 100 and Peco code 75 so I would expect that Rapido can manage this too.

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