mok

iTrader: (9)

The 105T spur gear from Tamiya is more than likely the .04 module spur gear. This is very close to 64 pitch but not quite the same. The Tamiya AV pinions will work without issue with the 105 spur gear, as will any other brand .04 module pinion.

FDR = (spur / pinion ) * IDR
IDR = diff pulley / centre pulley

If you want an FDR of 4.5 then you'll need a pinion of size 52 or 53 to be either 4.45 or 4.54 FDR with the 105T spur gear.

I'd be looking for a smaller spur gear...

-Mark

Limey

iTrader: (3)

Can anybody tell me Is there a reason why Tamiya put 18 tooth diff pulleys
into the "R" instead of 36-37 tooth pulleys.?
I run a stock brushed motor on rubber tires, could you also tell me what would be a good starting point for my FDR, the track I run on is carpet 80ft by 48ft.
With a 75ft straight.

I have a TOA 5R and i am just getting back into the hobby.

Thanks Limey

mok

iTrader: (9)

The 18 tooth diff pulley you're referring to is the wide pitch diff pulley. Essentially this means that compared to the 36 tooth diff pulley, it has half as many teeth contacting the belt. This means less friction and a more efficient drivetrain. For calculation purposes though, you need to use 36.

The gear ratio for your stock motor is dependant on the motor itself and the track you run on. I would suggest that try something in the realms of 9:1 as a starting ratio and see if it reaches top speed down the straight. If it does then decrease your FDR until the motor hits max rpm at roughly 3/4 of the straight. If it doesnt, increase the FDR until you can tell that its hit max RPM down the straight. From here you can tune to your preference and lap times.

-Mark

AreCee

iTrader: (1)

Let's answer your first question. Are you referring to the diff pulleys or the layshaft pulleys. The diff pulleys are 36T but may be the wide spaced version so it has 18T but the same circumference. That is supposed to reduce friction. The layshaft pulleys are attached to the spur gear and can be 18T.

As for your second question the answer is "It depends". See what your mates are using at your track. The FDR for a stock motor could be anywhere between 8 to 6. The non R version comes out of the box with a 6.8 FDR.

Limey

iTrader: (3)

Thanks, Mark and AreCee for your quick answers to my questions,
I am sure I will have lots more. LOL

Limey

94eg!

iTrader: (17)

Just wanted to point out that Tamiya AV & HP pinions are 0.6module. I believe all of Tamiya's 0.4module pinions are just labled 0.4module. This may save someone a headache on down the line...

macnkitty2002

iTrader: (7)

ahh how many times has this come up lol. just slap on a 64 pitch spur and be done with it.

mok

iTrader: (9)

Yes, good point. Should have clarified that bit about the AV gears!

jubilee

iTrader: (37)

Hi guys...

I'm building a ta05 ifs-r, and decided to go with a 115t 64p spur. The spur spins free, but pokes out from the bottom of the chassis just a little.

I'm guessing this isn't desireable...or is it rare to scuff the chassis? FYI...racing indoor asphalt.

Thanks for any info/opinions...

macnkitty2002

iTrader: (7)

Why did you decide to go with a 115t spur? Just get something around the stock 105 and you wont have any problems. Most gear setups revolve around a spur that is about 105.

mok

iTrader: (9)

IMHO I think its undesirable to have the spur poke up from the chassis like you describe. Some interpretations of ISTC rules would have it that the spur gear cant be any closer than 5mm to the ground (along with any other part of the chassis except the wheels). Others would suggest that this is the chassis plate only. Its possible that you might need to consider this, depending on the rules your club races with.

-Mark

PutAwayWet

iTrader: (1)

I'd start with a smaller spur. I currently run the Tamiya 102t, but I've also run the Robinson 96t. Both are good choices and you can use any 64p or 04 module pinion with either. You don't want that spur poking through the bottom.

stocker

iTrader: (2)

I am running the TB EVO's 90T, it comes in a pack of 90 and 96T. You can get the FDR you want easily with a pinion in the 40+ range with these.

http://www.tamiyausa.com/product/ite...oduct-id=50978

jubilee

iTrader: (37)

Thanks for the info guys. The 115t gets me closest to the FDR specified by the local track. Could be I'm getting a bit OCD about FDR...

I'll pick up a smaller spur.

TwoTone

iTrader: (12)

Any of you have a good set up for carpet?

Will be running USVTA so one car is 21.5/lipo and the other 27t/4 cell