Savage XL spur/clutch gear meshing

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FirsthandSnow

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  1. Bashing
hi, so I've been hard at work repairing and giving some TLC to a second hand Sacage XL, I've kept the existing 52 tooth spur gear and got a 19 tooth clutch bell, however they mesh far, far too much, there is barely, if at all, any play in the gears, and I've wedged the engine as far over as possible. I don't know what to think, the HPI instructions say to use a 16 tooth clutch bell, but would that make any difference to the meshing?

Thanks for your time, good people! :]
 
A smaller bell would require you to move your engine closer to the spur. I think to go with that high of a clutchbell, you need to get a smaller spur for it to fit.

I run 18/47 on mine and I have room to go even larger on the bell before the engine won't slide over any further.
 
A smaller clutch bell would mean you needed to move the engine over more, have you changed the spur gear?
 
Hi, thanks for the help, I've not changed the spur gear, but could I not just get a clutch bell with less teeth and keep the 52 tooth spur? after all the clutch bells are cheaper to replace
 
I think 16 is as high as you can go that will fit with a 52T spur.

Here's a chart that shows what fits on most savage's:
SavGear.jpg
 
I think 16 is as high as you can go that will fit with a 52T spur.

Here's a chart that shows what fits on most savage's:
SavGear.jpg
Hi, I'll have to print that out, quite a handy thing But I have an F4.6 Big Block engine, will the 16 tooth be okay? Just because the K4.6 needs a 17 tooth or higher, according to the bottom table...
 
Hi, I'll have to print that out, quite a handy thing But I have an F4.6 Big Block engine, will the 16 tooth be okay? Just because the K4.6 needs a 17 tooth or higher, according to the bottom table...

It isn't necessarily what it "needs", it's more of a guide as to what you can use. The boxes with diagonal lines are the gears that won't fit regardless of your engine's capability, unless you have modified something.

What that's telling you for 16/52 is lower gearing than the more powerful engine can use, which means you will hit top speed quick and still have enough power to gear higher for more speed. Lower gearing on a powerful engine is also harder on the drive train.

I try to gear my rigs so they can hit top speed without laboring too bad or taking forever when in the grass, since that's where I drive 90% of the time. On pavement, they hit top speed faster due to less drag. The only time I'm on pavement is during break-in, warm up or in a skate park. I never hit top speed in the skate park or I go home with a truck that's in pieces from getting 20+ feet of air under it.

I'd maybe keep your 19T Cb and get a smaller spur. Pick up a 49T spur and it should fit and work ok with your engine. I run 47/18 on mine with an LRP28 in it and traxxas 3.8" tires on it. It could probably pull higher gearing, but I can barely control it once it's at speed as it is.
 
This might not apply here, but aren't there tooth patterns on certain gears that just don't mesh with others?
I don't remember where I ran into that, but I know it was RC gearing.
 
There are several different gear pitches and they won't mesh correctly. For example: the original 48p spur on my SCX-10 wouldn't work with 32p pinion (like the clutch bell on a nitro) that I had accidentally ordered for my new motor that had a 5mm shaft versus the older one's 3mm.
 
This might not apply here, but aren't there tooth patterns on certain gears that just don't mesh with others?
I don't remember where I ran into that, but I know it was RC gearing.
Thinking about this, do you have the brand/part# for the 19T bell you have?
 
How?! :p no matter how far over away from the spur I push the engine, I still have absolutely no play at all :thumbs-down:

I'm using the steel spur gears, my engine is pulled all the way over i kept checking as i was tightening the mount down to make sure its pulled all the way over,

i get no binding whatsoever and perfect mesh (virtually no play) I'm using a 19t clutch bell can't remember what brand it is i will try and take some pics later, after i have got a few hours sleep

if the mesh (play between spur and bell) it too tight or loose you risk stripping the spur gear or damaging the clutch bell or both

Edit: it was a cappu 19T clutch bell aso generic I'm probably going to pick up a heap 20t to test it
 
Thinking about this, do you have the brand/part# for the 19T bell you have?
The Spur gear is a HPI 77132 and the clutch bell, which comes under option parts for the Savage XL is HPI 77107, turns out I actually have a 17 tooth, I swore I bought a 19, either way the problem is still there.
However, I'm wondering if the problem lies with the flywheel. When I replaced it I couldn't for the life of my get the flywheel to completely cover the collet, so it sits about 1-1.5mm forward on the collet. Obviously that means the clutch bell sits further forwards and the spur gear sits awfully close to the edge of the clutch bell teeth.image.jpeg
That picture is the best I could get, I do apologise.
The spur gear turns okay, till a certain point and it feels a bit gritty and there is a little resistance, is it possible the clutch bell needs to bed in maybe?

Thanks everyone for your help!
 
Is your engine hitting the TVP or are you at the limit of the slots where the engine mount bolts go? In either case, your either going to have to grind something or buy a smaller bell or spur to get the mesh right.

The flywheel being too far forward doesn't matter much as long as your spur is getting full contact on the teeth. Actually, the closer you have it between to the center of the bearings of the CB, the better. Puts the load on both vs favoring the front or rear bearing.

Are you running any aftermarket bits? Chassis, engine plate, engine mount, trans case... engine?
 
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Is your engine hitting the TVP or are you at the limit of the slots where the engine mount bolts go? In either case, your either going to have to grind something or buy a smaller bell or spur to get the mesh right.

The flywheel being too far forward doesn't matter much as long as your spur is getting full contact on the teeth. Actually, the closer you have it between to the center of the bearings of the CB, the better. Puts the load on both vs favoring the front or rear bearing.

Are you running any aftermarket bits? Chassis, engine plate, engine mount, trans case... engine?
Hi, I'm running no aftermarket parts, chassis is the HPI TVP, engine plate is the HPI one, same for the transmission case and the engine is a HPI F4.6...
I might take a risk and start it up and give it a little throttle and see what happens, if it loosens up some, I doubt it will, but I can't think of anything myself, other than buying another spur or clutch bell as you guys have suggested ;)
 
i picked up and adjustable engine mount, its the same height as the stock mount but i can slide the engine forward or back if need be to accommodate different flywheels, although i'm using the stock one right now

i got quite a few flywheels and some are quite thick some are thin i also have lots of collets to mix and match for different fly wheels to get a nice fit

I'm using an Answer RC 34mm vented flywheel - part number = ANSCS4007-VE
the collet it came with was a too big on mine so i went through the ones that i had and found one that was perfect,

also if needed i have filed down the back side of a collet if they cause the flywheel to sit too far forward

i have attached a gearing chart i would say 17/52 combo is the highest clutch bell combo without needing mods but for me with no mods i can go 19/52 it kind of depends on how the engine sits in the mount and how much you can slide the engine over

I'm going to be changing the gearing on my truck to 47/14 so i gain some acceleration and bring back wheelies
 

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  • savage gearing chart.txt
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i picked up and adjustable engine mount, its the same height as the stock mount but i can slide the engine forward or back if need be to accommodate different flywheels, although i'm using the stock one right now

i got quite a few flywheels and some are quite thick some are thin i also have lots of collets to mix and match for different fly wheels to get a nice fit

I'm using an Answer RC 34mm vented flywheel - part number = ANSCS4007-VE
the collet it came with was a too big on mine so i went through the ones that i had and found one that was perfect,

also if needed i have filed down the back side of a collet if they cause the flywheel to sit too far forward

i have attached a gearing chart i would say 17/52 combo is the highest clutch bell combo without needing mods but for me with no mods i can go 19/52 it kind of depends on how the engine sits in the mount and how much you can slide the engine over

I'm going to be changing the gearing on my truck to 47/14 so i gain some acceleration and bring back wheelies
Okay then, I guess I'll have to take the hit and get a 16 tooth clutch bell, although what difference 1 tooth less will make I don't know, I hope some at least ;)
 
Odds are, it will give you good mesh if it's tight with a 17. Personally though, with that engine, your probably going to want to buy a smaller spur or it will be wheelie happy.
 
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