Gearing, again...

[scoyle]

I have read through the threads in the group and I'm sorry if I have missed the answer...

I am running the kit 86 tooth spur and have noted the recommendations of starting with a ratio of 7.5 - 8. The manual does not give a pinion that goes above 7.04 on the 20 pulley.

I plan to run this weekend, indoors, on polished wood, with an MVP or Orion Core and was wondering if I need to swith to the 17 pulley or what my gearing should be with these motors?

Thanks,
Stephen

[dhamblin]

I have run 21 or 22 pinions with the 86 tooth and the 20 tooth layshaft pulley, indoors on polished wood for the MVP and the Orion Core (essentially they perform the same...)

Hope this helps ;)

[gatesy]

http://www.mkrctc.org.uk/Info/ratios.asp

[dhamblin]

22 tooth pinion ;)

[scoyle]

I have run 21 or 22 pinions with the 86 tooth and the 20 tooth layshaft pulley, indoors on polished wood for the MVP and the Orion Core (essentially they perform the same...)

Hope this helps ;)


I ran a 22 on Saturday and while the car did not seem to be rocket ship fast it was very smooth. I stuck with it but will try the 21 next time - have you tried the 17 tooth layshaft pulley - would that give a bit more acceleration?

Stephen

[MarkB]

If the overall ratio is the same, the 17-tooth pulley should make no difference in punch. A ratio of say 7.20 is the same however you get there - pulley, pinion, spur.

The reason I stick with the 20-pulley is the rear belt will be running on a bigger pulley. This should mean the belt runs a wee bit more efficiently - I know what I mean but cannot think how to explain it!

So far I've been able to get every ratio I want using the 20 pulley - easier for stock indoor, needs the use of a 92 tooth pulley sometimes for mod!

Cheers
MarkB

[marcoski]

The tooth stress on a larger pulley is less and the bend radius of the belt is less, all adding to greater efficiency. HTH

[dhamblin]

Stephen, great news!

Tried my MVP on Sunday newly skimmed and new brushes, 21 tooth pinion 86 spur gear, 20 tooth layshaft pulley. Plus I added Tribo comm drops to the commutator, WOW!!!!!!! :o

It went like a rocket!

I think the brushes are the recommended Reedy serrated ones.

[scoyle]

Stephen, great news!

Tried my MVP on Sunday newly skimmed and new brushes, 21 tooth pinion 86 spur gear, 20 tooth layshaft pulley. Plus I added Tribo comm drops to the commutator, WOW!!!!!!! :o

It went like a rocket!


I will give mine a go with a 21 pinion next time...

Were you running indoors, on a gym floor? Any chance of getting a look at your setup?

Stephen

[dhamblin]

Yes I am, will have to send it from my home machine though tonight!

You are also lucky that I now have the Hudy set up system which means I know exactly what settings are on my car! ;)

regards

[scoyle]

Yes I am, will have to send it from my home machine though tonight!

You are also lucky that I now have the Hudy set up system which means I know exactly what settings are on my car! ;)



:) Thanks got it...

It really does pay to have the Hudy system (especially for setting toe-in)

[gatesy]

Anyone fancy sharing the secret of how to get a 21t pinion on with 86 spur and 20t layshaft!?!?!? Ive been trying for an hour now and I cant get the thing to mesh!!

[al]

you tried all of the different holes on the motor,

if that doesnt fit then it aint ment to fit id say

al

[MattW]

21-86 won't go without modifications. It isn't possible to get the motor close enough as it hits the layshaft mounts. It is explained in the manuel that there most be at least 108 total teeth (spur+pinion) for the 20 tooth layshaft. 21+86 = 107.

However, with the aid of a file/knife/dremel you can remove some material from the layshaft mount to allow the motor to move close.

The alternative would be to try 22-92 which is slightly lower, or 22-89 which is slightly higher and need no modifications.

[scoyle]

21-86 won't go without modifications. It isn't possible to get the motor close enough as it hits the layshaft mounts. It is explained in the manuel that there most be at least 108 total teeth (spur+pinion) for the 20 tooth layshaft. 21+86 = 107.


I put a 21-86 on my car yesterday for stock - I am using the standard spur/pinion/layshaft - It seems to fit ok?

[MattW]

No Problem then is there ;)

I can't try it myself on my car as i modified the mounts when i built the car, so i checked the manual and it says it isn't possible to get it close enough......................

Beware, though, it is meshed, but is it meshed properly?? only you can be the judge of that. I would assume that they would have checked it before they wrote the manual.

Also bear in mind that one 86 spur isn't always the same size as another 86 spur gear ::). Usually if you keep to the same manufacture they will be the same, but they will vary between manufactures.

[al]

or they might not be round if you was talking about schumachers diff gears - lol the rw are miles better !

[MattW]

Al, please note phrase "Spur gears".

[scoyle]

Al, please note phrase "Spur gears".




On the subject of Spur gears can someone tell me (here or by PM) what I need to get to convert to RW gears (and where to get it) - do I need to use different pinions?

And a silly question... I am looking at converting because all the good drivers seem to use them... what are the advantages?

[Barry_Hughes]

To use any other gears than Schumachers you need part no U2252 Gear Adaptor. With this you can use RW, Kimbrogough gears etc.
You use standard pinions as the gears are 48p same as the it versions.

I use one with RW Spur gears, which are available from all good Model Shops.

I can run 21 - 86 with these and the alloy layshaft mounts, just !!!!!!!.

[MattW]

Schumacher sell a spur gear adaptor part number U2252. This has the holes on it to allow you to use nearly any spur gear you want.

Advantages - you can use other brands of spur gears if you wish. That is the only one really.

If you wish to use RW spur gears then this is the adaptor that you need. Keep an eye on it when you install it, as i believe it is very close to catching the top deck at certain points, if it is just file a little bit off.

Assuming you stick to 48dp gears then you would still use the same pinions.

Personally i run the adaptor with either Robinson or Kimbrough spur gears.

Quick off the mark, Barry!!!

[colin_jackson]

yow will need to purchase a spur gear adapter for the RW spur gears! this will set you back around a 10'er but not tottally sure. this is all you will need. it sits over the standered pin attachment and you simply screw the RW spur gear to it. you will also be able to use kimbrough, robinson racing and ride spur gears etc.

the advantages are that unfortunately not all schuy spur gears are completely round (not far off, good enough really). so using RW spurs solves this problem, and you can mesh up a bit better.

another advantage is that you can also get a larger gear ratio range as you can use far more different sized spurgears, as schuy only do 83,86,89,92 etc - you can fill the gaps.

colin

[colin_jackson]

you both beat me too it

aaaaarrrrrrrrrrrrrhhhhhhhhhh!!!!

colin

[KRob]

Personally I used the gear adapter because the Schumacher gears had a high wear rate.

At the nationals I would run the gear adapter with a Kimbrough spur on the Saturday practice (and when I ran at other meetings) but for the Sunday I would put an original Sch. spur on as they are lighter and there was less play where the drive is trasmitted through the little pin.

[scoyle]

I will give mine a go with a 21 pinion next time...



I ran my Mission again yesterday and I think it's safe to say that everyone was amazed - I am normally a bottom of the B, in the C kind of driver but yesterday I poled the B and was knocking on the door of the A final!!

I ran with a peak Hellfire and an Orion Core and tried the 21 but settled on the 22 pinion again - maybe the hall we race in is a bit bigger - it seemed to suit the length of the straight better.