choosing new sprockets, need help

[DvDRip]

I've got a 140xr & wanna get some new sprockets to enhance performance and a HD chain to go with it. (not sure about 420# or #428 yet, that all depends on price/availability.)
I don't do much track riding, mostly in the bush with lots of rough hill climbs, rough windy trails and some wide open smooth tails where max speed is used. I want 1st gear to be more usable hopefully.
So what size sprockets would you recommend for this type of riding? pros/cons of different setups?

cheers for any and all info

ps, I did a search and couldn't find a good enough answer

 

[I_THUMP]

What sprocket setup are you currently running? How many teeth?

 

[DvDRip]

What sprocket setup are you currently running? How many teeth?

stock 140xr, I'll count them now

 

[DvDRip]

16/41 420#

 

[I_THUMP]

For the type of riding you describe I would try a 37 tooth rear or you could try a 15 tooth front instead but id go with at least a 37t or maybe 36t.

 

[Dabomb]

yes exactly what i was thinking, wont loose to much pickup

 

[DvDRip]

So if I get a 37tooth rear I don't have to change the front? and vice versa if I get a 15 tooth front?
what would be the advantages of a 37tooth rear vs. 15tooth front? or did you mean a 15 front in combination with a 37 rear?

 

[Dabomb]

Smaller Rear = More speed
Smaller Front = More Acceleration

Bigger Rear = More Acceleration
Bigger Front = More Speed

only have to change the front if you want more speed than the 16/37

when you buy one, make sure its the same pitch as the chain and the rear sprocket.

 

[DvDRip]

thank for the help guys I think I'll look into getting a 37 rear, any tips on where to buy one from at a good price?
and I'm gonna look into getting a 428 pitch setup, If I do this should get a 16/37 or 15/37 ??

 

[DvDRip]

See the price difference from the same shop:
NEW BILLET CNC ALLOY 37T SPROCKET #420 PITCH SPROCKET - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 11-Feb-09 19:54:24 AEDST)
NEW HD 37T REAR SPROCKET #428 CHAIN PITCH DHZ PITPRO - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 06-Mar-09 12:59:47 AEDST)

does this mean the 428 pitch one is crap?

 

[Dabomb]

428 is a stronger pitch so i dunno, maybe they got too many 420 pitch sprockets instock.

 

[DvDRip]

well with a price difference like that it looks like either: the 420 pitch is way over priced or the 428 pitch is made of inferior metal and won't last long.
the 420 pitch one does say "BILLET CNC ALLOY"
I don't know what to do now, I don't wanna end up with a really crappy 428 pitch sprocket when the whole idea of 428 pitch is meant to make it stronger.
I'd happily pay more for the 420 pitch sprocket if I knew it was worth the extra $$ (much MUCH stronger)

maybe the "bling" factor of the CNC billet is what boosts the price up? it does look a whole heap better

 

[BananaMan]

dvd rip, i can help you with this...
the 428 one he is selling is a mass produced steel sprocket that is punched out of a plate rather than being cut, gets the job done but they are ruff as guts.
the 420 is cnc machined from billet alloy (starts as a solid piece - not cast) therefore it should be very accurate, however cnc machining is what i do for a living and i have found on more than one occasion stat cnc work from china (if that is where his sprockets are from) can be quite crappy and the material can be soft, there is a large range of alloy's available now so who knows what they are using.

When i make sprockets i either use a 5083 grade or a 6061 depending on the application, both are hard wearing, machine grade alloys.

hope this helps

 

[DvDRip]

cnc work from china (if that is where his sprockets are from) can be quite crappy and the material can be soft, there is a large range of alloy's available now so who knows what they are using.

good point, I'm sure it's from china like most other cnc billet stuff for pit bikes is, a bit of a gamble. I'd rather get the cheaper one and if it craps out after a month it's no great loss

ok, so now I need to decide if I wanna get a 15tooth front 428pitch with 37tooth rear from dhz, or get a 37tooth rear 420pitch and leave my front sprocket as stock.

so my final question before I put this plan into action, is a 428pitch setup really that much better/stronger? and should I get a 15tooth sprocket to go with the 37 or just leave the 16 on?

 

[BananaMan]

in my opinion the 428 is a far superior chain size, the rollers increase in diameter from 7.9 up to 8.5mm and the width increases from 6.35mm to 7.9mm, this allows for a much larger surface area for the chain to run on providing less wear all round.

tooth sizes..... its up to you my friend....

 

[DvDRip]

is any bottom of the range $30 RK chain gonna be fine or do I need to get a race chain which are about $50? I jjust want it to not stretch like crazy like my KMC chain does atm and be reliable.

 

[01nutracing]

Dvdrip, a bigger sprocket on the front gives you more top end so the 15tooth will take away top speed.If you want more top end just get either a smaller back or a bigger front. Its simple. If you get a smaller front to go with the smaller back it defeats the porpoise

 

[DvDRip]

Dvdrip, a bigger sprocket on the front gives you more top end so the 15tooth will take away top speed.If you want more top end just get either a smaller back or a bigger front. Its simple. If you get a smaller front to go with the smaller back it defeats the porpoise

yea I thought that might be the case so bought a 16 front today, now just waiting for my 37 rear to come in the mail

I went and looked at chains today and there's a HUGE difference between 420 & 428 pitch so I'm going with 428

 

[Dabomb]

just bought a 428 gold heavy duty RK chain today...bloody hell its a step up from the 420 stocko!

 

[DvDRip]

just bought a 428 gold heavy duty RK chain today...bloody hell its a step up from the 420 stocko!

how much was that?

I'm thinking I might just get the basic RK for $30 unless someone can give me a good reason to get the race one which is about $50. I'm waiting till I get my rear sprocket from ebay so I've got plenty of time to figure out which chain I want. plz share your thoughts on this people