Brian Bosley

iTrader: (13)

47g front kyosho, titanium pins

27g front capricorn, plastic gears, alum pins (stock)

14g ybslow aluminum spool

25g kyosho oneway

as you can see, vs kyosho, the capricorn is at least 36g lighter in overall drivetrain mass. one time back in the day i took everything that spun besides belts, clutch and bearings (cvds, hexes, shafts, diffs, gears, everything) and compared xray vs kyosho. the kyosho evo wc at the time with titanium pins, titanium screws on the gears, basically all i could do.. was about 230g. Xray with all of their available lightweight parts (in dec 2008) was around 190g.

So I played with the #'s again since the 41t thing bothered me some and it's still raining.

lets say you are running the rrr stock, 23/55 and 16/60 gears 23t front pulley and 60/58mm tires.

0.87% more front drive

In contrast, lets say you run the 24t front pulley
3.33% more rear drive, you need 60/60 tires to be equal.

Lets say you run the 41t diff, same setup
1.53% more front drive with the 41t diff
0.85% more drive if you run less split, 60mm rears and 58.4mm fronts.

So really, true your fronts slightly bigger than the usual 2mm split and you are perfect. on my track we get massive rear tire wear so I will still cut 2mm and the car will just get better, and then worse later that it usually would in a 10 minute qualifier if I can go as small as 60 in the rear, might have to start at 61 or 62.

LiL_JaSoN

iTrader: (6)

true front smaller or bigger? since there is more rotation in the rear now.

brian, are you coverting the front aswell?

or only rear?

LiL_JaSoN

iTrader: (6)

brian, are you coverting the front aswell?

or only rear?

i wonder how much my drive chain weighs now.

speed6

What Brain was explaining if i understood him well and i believe he was really smart about it, is that in order to run the rear diff with one less tooth which obviosly it will shorten the rear drive ratio you will have to find another way to high up the front drive ratio by swapping the 23 spool with the 24th side belt gear which is normally used for rubber tires or equal sized tyres.

As i was reading the post our track also really give the rear tyres a beating would you consider try using the 24 teeth. I almost run 1.5 sets of rear with a trued fronts so by the end of the race the car ends up like a speed boat.

LiL_JaSoN

iTrader: (6)

yes, i have discussed this earlier before starting the conversion.

1t wouldnt of mattered so much, and that we could use the stock 2mm split ratio rather then the 0mm ratio..

Brian Bosley

iTrader: (13)

the 24 would make it worse, I like a car that is slightly forward driving but mostly neutral which is what the 24 does with no split (say 60mm tires front/rear). the 23 with a 2mm split is equal. using this 41t rear diff with 23 side pulley, you need to run larger fronts (1.1mm split) to allow the fronts to be bigger. like you said with the 1.5:1 rear/front wear ratio, you probably want to still cut at 2mm and the car will come in through practice and 2-3 minutes into the qualifier and be neutral at some point and then wear past where your car will go into more front drive.

I tried changing the 21t brake pulley, the 18t side/front pulleys and I couldn't come up with any ratios that make the car right except changing the rear side to a 19, and the front to a 24 which would make your tires 58.23mm and 60.00mm for equal ratios. Not really worth it to me.

I am using both front and rear capricorn diffs at the moment, gaining only 11g to go from a spool to a diff is well worth it in my book because of two corners on the worlds track. the real reason I've always run a spool was because it was 47g vs 14g and then I just got used to it and never gave the diff a second chance until IFMAR came up with that non-spool rule that got thrown out.

I'm going to clean my bearings if I can get some practice in next weekend, I can weigh everything then but I run the hollow steel shafts and evolva 2nd holder (heavy steel) so its not as light as it could be. I am guessing I should be in the 200g area though, maybe with the use of aluminum rear dogbones or something. I have aluminum axles for my cvds that I will probably qualify with as well since I will be running the lightweight version of the new Contact tire anyway. tire selection is probably one of the most important here, the pro-light version of twisters were good for up to 20g per pair depending what you used before.

LiL_JaSoN

iTrader: (6)

leave it as stock .

as said earlier
1.95:1 (41t)
2.0 (42t)

0.05 is not going to make a massive difference with the rear tyre wear.

kyosho_ken

iTrader: (3)

just buy an xray or lab co1. the cap is a great car except tossollini shattering the rear diffs.

LiL_JaSoN

iTrader: (6)

maybe when im done with the kyosho.

LiL_JaSoN

iTrader: (6)

ok front and rear diff is in and car is back together..

crap the rear diff was a effort to fit.. did'nt know it required so much work.. but in the end, i got it in.. hopefully take it to the track soon

speed6

Can't wait to hear some reviews about this drive train mod

LiL_JaSoN

iTrader: (6)

wasnt happy with how the rear was spinning..

so i took everything apart and did some more dremeling..

now its smooth cant feel no friction and it will roll down anything.... all you can hear is just the bearings.

smoothest iv ever had my car actually.

also, 100k at the front, felt lighter than 50k which i had in the stock diff..

60k rear, felt around the same as the 20k i had.

LiL_JaSoN

iTrader: (6)

front diff


rear diff


side view.

speed6

I saw that your upper rear link is on the outside how come?

Also it seems you are running an xray tank with a modified upper tray, is it KM's?

Thanks

LiL_JaSoN

iTrader: (6)

huh? upper rear link on outside? im confused.

the xray top-deck is capricorn, which they sent to me for free.. the xray tank is more longer and flat. i also lowered it by a extra 5mm.