Aluminum Sprockets

Post by **AlisoBob** » January 23rd, 2011, 8:56 pm

I always run Ironman sprockets.... always.

But my XR650 has an aluminum Renthal.

So today I'm out riding my Hondapotums with Eric and Pecker, we stop... and I notice my chain is tight.... really tight.

It wasent like that when we left.

So I get home and its still tight. I go in and have dinner and come out to readjust it.... and now its fine.

Question? Could the heat of high speed riding cause the aluminum sprocket to expand enough to tighten the chain, which would cause even more heat, leading to even more expansion and increased tightness?

Weird, huh? Another reason to run steel sprockets......

fastkart · Post by **fastkart** » January 23rd, 2011, 9:54 pm

I run aluminum sprokets on the kart, which I know is different, but still the same. I've never had a chain go tight, except when I get a bend in the axle which causes only a tight spot. I would also think any expansion would have to be measured in the thousandths of an inch. Hard to believe a sprocket expanding enough to mess with the chain adjustment.

I'd be looking at the adjustment stuff to ensure everything is staying tight.

Post by **AlisoBob** » January 23rd, 2011, 10:02 pm

I hear ya Karty, but your sprockets are much smaller, correct?

The sprocket felt warm to the touch, but it cooled... the chain tension decreased...

Weird shit...

fastkart · Post by **fastkart** » January 23rd, 2011, 10:05 pm

Yeah, they're smaller, I run 26-29. They're also made of 'flavor of the day' aluminum, some if it's junk, some of it's decent. I've pulled them off immediately off the track and had to wear a glove to handle them and the chain has been good.

I agree though, weird.

seanmx57 · Post by **seanmx57** » January 24th, 2011, 7:19 am

Oring or standard? I think you have a chain issue.

Post by **AlisoBob** » January 24th, 2011, 8:19 am

DID O-rang.

Heat is not going to cause the chain to shrink.

I ordered a Ironman .... done.

Gmbond · Post by **Gmbond** » January 24th, 2011, 8:32 am

Could the sprocket be out of round? Tight in one spot possibly...?
Just a guess here really

seanmx57 · Post by **seanmx57** » January 24th, 2011, 8:34 am

Time will tell

lack of lube can tighten a chain up. Doubt that is the case with the oring though

Post by **AlisoBob** » January 24th, 2011, 9:03 am

Brit thinks I'm high....

I'm blaming Al Gava ... His koodies musta' rubbed off on me.

seanmx57 · Post by **seanmx57** » January 24th, 2011, 2:37 pm

AlisoBob wrote:Brit thinks I'm high....

X2

pstoffers · Post by **pstoffers** » January 24th, 2011, 3:24 pm

seanmx57 wrote:
AlisoBob wrote:Brit thinks I'm high....
X2

X491

Post by **MojoScojo** » January 24th, 2011, 3:32 pm

Kinda like "arm pump", your BRP musta had "chain pump".

2strokeforever · Post by **2strokeforever** » January 24th, 2011, 3:44 pm

i just run them real loose, and everything works out great, except everyone with a bone tight chain telling mine is too loose

lewisclan · Post by **lewisclan** » January 24th, 2011, 4:17 pm

Ive riped teeth off of the rear more that once on the BRP

seanmx57 · Post by **seanmx57** » January 24th, 2011, 4:19 pm

(10-6 m/m K)

Aluminum 22.2

so .00000222 is the Linear Temperature Expansion Coefficient

purdy small Id say unless you are running some super HOT sprocket..........

http://www.engineeringtoolbox.com/linea ... -d_95.html

Post by **AlisoBob** » January 24th, 2011, 4:32 pm

MojoScojo wrote:Kinda like "arm pump", your BRP musta had "chain pump".

BannedCR500Riders.com

Aluminum Sprockets

Aluminum Sprockets