Steven:
My thoughts are a little simpler:
33 inches scales to .38 inches 36 inches converts to .41 inches.
As they roll past or sit in a siding can YOU tell the difference. 33 inch will always work, the only problem might be coupler heights, the shims fix that.
36 inch wheels on trucks\cars not designed for them may rub.
Do as you feel best
Dave
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The only wheel size I have ever had problems with is 28 inch wheels. When these are installed in some truck frames they allow the trucks to contact the track, and if it is a metal truck, you will have an intermittent short.
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-Kevin
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So 33" it is!
The main applications for the 28-inch wheels seems to be certain intermodal cars including the Impack spine cars, and the Tri-level auto racks which need them to fit within low clearance specs.
The 33" wheels will work for most of the Accurail cars except maybe the 4600 cu ft covered hoppers.
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I was trying 28 inch wheels to get two flat cars to sit as low as possible. That was when I found out about the intermittent shorts.
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I don’t use 28 inch wheels anymore.
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-Kevin
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The only thing I bought IMRC 28" wheels for are the Impack spine cars used to haul piggy pack trailers. There isn’t any clearance issues with them.
The main thing is to use the right wheels for the right car. IIRC, flat cars would be 33" wheels.
Was it the flat cars needing to be lower or the couplers. The old Athearn blue box 85’ flush deck flat cars did sit too high, so A-line made a metal bolster kit which would make them more correct in height and also add weight.
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This was a straight side 36 foot flat car from Funario & Camerlengo. The instructions said the cars had very low deck height. I used offset shank Kadee couplers and the 28 inch wheels to get the deck as low as I possibly could and still get the correct coupler height.
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It was low when all was said and done. Too bad about the short circuits!
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-Kevin
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I’m sure you’ve already figured out what you want to do. Here’s the straight answer you probably wanted in the begining.
If you haven’t already purchased one, get a coupler height gauge from Kadee. Check the coupler height while the cars still have their plastic wheels on them. If the coupler is lower when measured with the gauge, you’ll need to add a shim at the bolster to raise the coupler height. Get the shims from Kadee the red ones or gray ones (get both). If the coupler height is higher then you’ll have to figure out how to deal with that.
Most cars with plastic wheels are the 33" flavor. There are some that come with plastic 36" wheels but I think it’s only the Athearn 5-unit well cars and some passenger cars. If your coupler’s height was good, then swapping out the 33" metal wheels will not affect the height. Don’t worry about capy or prototype wheel stuff (unless that’s what you want).
Now one thing to keep in mind is that there could be an issue with axle length. When you swap out the wheels you may find that the new wheels might have too much play or feel tight in the truck. In a situation like that you’ll have to measure the original axle lenght (the one with plastic wheels). I know Reebox makes wheels with different size axles to fit a lot of stuff out there.
Another great tool to get is a truck tuner from Micro Mark. Good luck.
As a general rule of thumb, near-and-over 200 ton capacity cars ride on 36 inch wheels while 100 - 200 ton capacity cars ride on 33 inch wheels. se
(Edit: Of course the break point I’m talking about is 100 tons, or 200,000 pounds, not 200 tons)
Also as a general rule for the modern era, everything except boxcars ride on 36 inch wheels.
^ Standard procedures for building and getting kits ready for the layout. If coupler is too high, which is pretty rare, you can go with an over-set shank Kadee. You might also be able to file the bolster down.
For beginners that may be ok. The size is more noticable for cars like tank cars or hi-hip covered hoppers where you can see the wheels are alot more exposed visually. YMMV
REBOXX makes an axle sample kit which has a range of axle lengths which are color coded. I bought one in case I need to check for axles sizes and order something specific from them.
So far I haven’t felt it necessary to buy one of the truck tuning tools but may eventually buy one. They do seem like they would come in handy.
Truth be told, I do try to use correct wheel sizes and put 36" where they belong (tanks, hoppers, intermodal, etc.). I just tried to keep it simple for the OP since it appeared to me that he wasn’t splitting hairs about wheel size and was just wanting to use 33" for all his stuff.
Right now I’m just trying to get my cars rolling at the club, with time proto correct wheels, couplers, trucks, and NMRA proper weighting will be added, (not saying my cars aren’t weighted but they’re just stock weighted.) perhaps I’ll even equip my cars with RFID chips to aid tracking on my own railroad.
I’m just trying to take a step in the right direction.
I made the mistake of buying a whole box of 36" metal wheels to replace 33" plastic wheels on my NYC passenger fleet. Major problem: the increased diameter made the new wheels rub against the false brake shoes on each car. Nuts! Size matters.
Is mixing wheel set size a problem? Given the 40-year AAR rule on freight cars, I’d think that there are a mx of different wheel sizes on layouts. Do you check the coupler height whenever the cars are together of different wheel sizes?
A ton is 2000 pounds. So cars of 200 000 LB CAPY are 100 TON cars. Cars of around 100000 LB CAPY are usually on trucks with 5’ 6" wheelbase and 33" wheels. Cars of around 140000 LB CAPY are usually on trucks with 5’ 8" wheelbase and 33" wheels. Cars of around 200000 LB CAPY are usually on trucks with 5’ 10" wheelbase and 36" wheels. The newest cars are now often 125 TONS Cars of around 250000 LB CAPY are usually on trucks with 6’ wheelbase and 38" wheels.
Wheels, what size to use???
When replacing wheel sets, axle length can be important.
Intermountain is 1.002" long (all lengths are +/-)
Bachmann is 1.012"
Kadee is 1.017"
Bowser is 1.025"
Excessive endplay (length too short) will cause the car to sit lower and tilt from side to side. Too long, and the wheels bind.
The old Athearn blue box trucks used 1.040". The Kadee 1.017" seem to work OK, perhaps because of the rounded axle ends.
You will find significant variations in a single manufacture’s trucks, probably based on the China source. I test the supplied wheel set for end play, and then test different replacements for best fit.
This is a very good point to make.
I recently bought a whole bunch of code 88 Intermountain Wheelsets (they were on sale) to replace the code 110s on some cars. Ive discovered that they dont fit on Atlas cars, so I will need to find another source (NWSL has different axle lengths I belive).
From my memory, I did not have any trouble installing Intermountain wheelsets in Accurail cars.
Anywho, for resistor wheelsets, you will need to discuss that with your club. They likely have an exact standard stating the resistor value and part number required to achieve occupancy detection.
Generally speaking you will want in the ball park of 5k-10k ohms of per car to acheive single car detection (depending on the type of block detector and wiring configuration). Again this is a question for the club. If they specify two resistors per car, then put two resistors per car.
I can tell you that I know a guy who did two 20kohm resistors per car and a single car did not trip the circuit (not sure what detectors he was using). It took him 1.5 cars (or three tru
Checked with the club, according to the rolling stock master he says use 0805 resistors with (I am not completely sure of this) 15kohms of resistance, another thing are 33" wheels suitable for streamlined passenger cars?
Searching the 1956 and 1961 Car Builders Cyclopedias, all streamlined passenger cars rode on 36 inch wheels. This holds true for passenger cars from the heavyweight era as well. Remember, these heavyweight cars wore this title because vehicles in the 80-90 ton range were the norm, especially sleepers and diners. The heavy cars often rode on six wheel trucks, to give a smoother ride on the stick rail of the era. Also, consider the fact that the three inch difference in wheel diameter only raises the axle center 1.5 inches. If the scale three inch difference in wheel diameter is considered insignificant, why should a scale 1.5 inches be such an issue in coupler height? Experience with equipment of many HO manufacturers, past and present, prove that over half of the couplers don’t meet the “recommended standard” height. I’ve sanded down or replaced a lot of body bolsters to lower cars that were too high, and mounted shims IN the draft gear box to raise the shanks of couplers that sagged too low. If necessary, removal and replacement of the draft gear box was preferrable to offset shank couplers or red or gray shim washers. Not knowing your views on prototypical accurracy,I offer this. When you come to a decision such as this, think long term vs. “right now”. Spend your money and time once, on a decision you can live with ten or twenty years from now instead of a temporary fix for right now that will be revisited in the future with your time and money.
The passenger cars are old IHC cars, I doubt they have scale wheels stock, also they’ll only be running as a consist so if the couplers are a little “low” as long as they arent getting caught on stuff it should be fine, I mean 1.5 inches in HO is 0.017241379 inches, I highly doubt .017 inches will seriously impact anything, let alone anyone noticing.
my bigger issue is converting to Kadee body mount couplers instead of Talgo. And the hardest is going to be getting the observation car to have an operating coupler on the tail end, why? Because there’s a dummy coupler there that’s glued on and is surrounded by skirting. I figure I’ll have to carefully carve out a slot for a coupler.