chainring on Truvativ GXP hangerset

[Walt Shekrota]

I recently purchased a new Scattante R-560
with powerglide 130BCD 50/39/30 AL-7075-T6

The 50 ring on closer inspection after some 70-100mi appeared to have non
symmetric teeth. I don't recall seeing it new but it may have been that
way. In one spot like every 3rd tooth looks half height for 2 or 3 groups
then there is a tooth that appears bevelled on both edges while the
majority are bevelled on one side. Then some have flat edges both sides.
The bike has a wonderfully smooth and fast ride and gear change.
I talked to SRAM/Truvativ tech support and they verified that these can have
almost a custom look due to shifting technology. Thing that bothers me is
the few that seem shorter or almost half high like they were damaged.

I thought to look at another new one in the shop when I get a chance to put
my curiosity to rest.

Any one else notice this or have explanations?
Thanks!!

-Walt

 

[Hank]

On Apr 11, 5:03 pm, Walt Shekrota <[email protected]> wrote:
> I recently purchased a new Scattante R-560
> with powerglide 130BCD 50/39/30 AL-7075-T6
>
> The 50 ring on closer inspection after some 70-100mi appeared to have non
> symmetric teeth. I don't recall seeing it new but it may have been that
> way. In one spot like every 3rd tooth looks half height for 2 or 3 groups
> then there is a tooth that appears bevelled on both edges while the
> majority are bevelled on one side. Then some have flat edges both sides.
> The bike has a wonderfully smooth and fast ride and gear change.
> I talked to SRAM/Truvativ tech support and they verified that these can have
> almost a custom look due to shifting technology. Thing that bothers me is
> the few that seem shorter or almost half high like they were damaged.
>
> I thought to look at another new one in the shop when I get a chance to put
> my curiosity to rest.
>
> Any one else notice this or have explanations?
> Thanks!!
>
> -Walt

That's "ramp" half of the decade-old idea of ramped & pinned
chainrings. Everybody's done it for ages, after chains got too narrow
to upshift reliably up front.

As far as looking damaged, check out SRAM 10-speed cassettes. Each cog
has fewer actual teeth than its nominal size. The space where the
missing tooth was is a kind of a gate for the chain to more easily
derail through.

 

[Walt Shekrota]

> That's "ramp" half of the decade-old idea of ramped & pinned
> chainrings. Everybody's done it for ages, after chains got too narrow
> to upshift reliably up front.
>
> As far as looking damaged, check out SRAM 10-speed cassettes. Each cog
> has fewer actual teeth than its nominal size. The space where the
> missing tooth was is a kind of a gate for the chain to more easily
> derail through.

yup .... haven't bought a new bike in that long
I did notice this on every good outer chain ring I saw though.
Hey its hard to visualize what it does but by virtue of the utter silence
and smooth responsive shifting I love it!
Just a scary sight to old eyes.

Kind of like looking at straight laced spokes, another thing I can't cozy up
to.

Hey thanks for the info....

-Walt