Advice on replacing old MTB chainrings

[[email protected]]

I've worn out the middle ring on my old Bridgestone MB-3, and after
also just replacing my rear cassette, I'm thinking I'll just replace
all the rings at once. This is a 24-36-46 ring set, 110mm/74mm bolt
pattern, 7 speed. The original rings are Shimano SG "C".

It looks like I can get flat aluminum replacements (Salsa or Sugino)
for roughly $20+$20+$30 from various sources. I can substitute the
middle and outer rings with Shimano SG-X rings for an extra $20. I
think I'd prefer those for smoother shifting. Anything else I should
consider here? I think the SG-X rings are 7-speed compatible?

-- Dave

 

[Michael Dart]

[email protected] wrote:
> I've worn out the middle ring on my old Bridgestone MB-3, and after
> also just replacing my rear cassette, I'm thinking I'll just replace
> all the rings at once. This is a 24-36-46 ring set, 110mm/74mm bolt
> pattern, 7 speed. The original rings are Shimano SG "C".
>
> It looks like I can get flat aluminum replacements (Salsa or Sugino)
> for roughly $20+$20+$30 from various sources. I can substitute the
> middle and outer rings with Shimano SG-X rings for an extra $20. I
> think I'd prefer those for smoother shifting. Anything else I should
> consider here? I think the SG-X rings are 7-speed compatible?
>
> -- Dave

Pete is right. You want to look for "ramped and pinned" rings for the
middle and big to aid shifting.

Mike

 

[ellis]

"(PeteCresswell)" <[email protected]> wrote in message
news:[email protected]...
> Per [email protected]:
> > Anything else I should
> >consider here?
>
> Consider the intended use of the replacement ring.
>
> I suspect that some rings are designed for multi-ring applications and
others
> aren't.
>
> The Salsa I have on one of my bikes looks tb designed for a single-ring
setup.
> On my other rings there are various little sculpted areas that look to me
like
> they're designed to facilitate the chain moving from one ring to another.
>
> Maybe somebody who actually knows something can chime in here.
> --
> PeteCresswell


Get a "ramped" chainring for smooth shifting.

 

[Paul Kopit]

On Mon, 08 Aug 2005 19:50:15 GMT, [email protected] wrote:

>I've worn out the middle ring on my old Bridgestone MB-3, and after
>also just replacing my rear cassette, I'm thinking I'll just replace
>all the rings at once. This is a 24-36-46 ring set, 110mm/74mm bolt
>pattern, 7 speed. The original rings are Shimano SG "C".
>
>It looks like I can get flat aluminum replacements (Salsa or Sugino)
>for roughly $20+$20+$30 from various sources. I can substitute the
>middle and outer rings with Shimano SG-X rings for an extra $20. I
>think I'd prefer those for smoother shifting. Anything else I should
>consider here? I think the SG-X rings are 7-speed compatible?
>
>-- Dave

You can buy a crankset and throw away or sell the crankarms
<http://store.airbomb.com/ItemDesc.asp?IC=CR1033>

 

[The Quiet Man]

Check the auction site for NOS new old stock complete cranks.
I picked up an new old 7 speed Deore crank perfect match to my Trek
MB. Much cheaper than the rings and shifting is perfect. Here is one
but it ends soon.


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7173645292



On Mon, 08 Aug 2005 19:50:15 GMT, [email protected] wrote:

>I've worn out the middle ring on my old Bridgestone MB-3, and after
>also just replacing my rear cassette, I'm thinking I'll just replace
>all the rings at once. This is a 24-36-46 ring set, 110mm/74mm bolt
>pattern, 7 speed. The original rings are Shimano SG "C".
>
>It looks like I can get flat aluminum replacements (Salsa or Sugino)
>for roughly $20+$20+$30 from various sources. I can substitute the
>middle and outer rings with Shimano SG-X rings for an extra $20. I
>think I'd prefer those for smoother shifting. Anything else I should
>consider here? I think the SG-X rings are 7-speed compatible?
>
>-- Dave

 

[(PeteCresswell)]

Per [email protected]:
> Anything else I should
>consider here?

Consider the intended use of the replacement ring.

I suspect that some rings are designed for multi-ring applications and others
aren't.

The Salsa I have on one of my bikes looks tb designed for a single-ring setup.
On my other rings there are various little sculpted areas that look to me like
they're designed to facilitate the chain moving from one ring to another.

Maybe somebody who actually knows something can chime in here.
--
PeteCresswell

 

[[email protected]]

The Quiet Man <[email protected]> wrote:
> Check the auction site for NOS new old stock complete cranks.
> I picked up an new old 7 speed Deore crank perfect match to my Trek
> MB. Much cheaper than the rings and shifting is perfect. Here is one
> but it ends soon.


> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7173645292

I'd tried looking for chainrings on ebay but not whole crank sets.
I'm not sure about dealing with chainline issues if I replace the
whole crank set, and I didn't see any current listings that looked
like a close match to my existing crank.

- Dave

 

[[email protected]]

Paul Kopit <[email protected]> wrote:

> You can buy a crankset and throw away or sell the crankarms
> <http://store.airbomb.com/ItemDesc.asp?IC=CR1033>

That's not a bad idea. Though the inner ring is only a 26, and
swapping that would wipe out much of the savings. Any opinion on
steel vs aluminum alloy chainrings (i.e. XD300 @ $47 vs XD600 @ $71?)
Also these cranks have one bolt aligned with the crank arm rather than
offset as with my existing crank; is that any cause for concern
(i.e. does it mean the ramps/pins will be mispositioned if I swap
rings?)

I haven't seen any online catalogs with individual Sugino chainrings
with ramps/pins. The sold-separate rings seem to always be the "flat"
ones.

-- Dave

 

[Booker C. Bense]

-----BEGIN PGP SIGNED MESSAGE-----

In article <[email protected]>,
(PeteCresswell) <[email protected]> wrote:
>Per [email protected]:
>> Anything else I should
>>consider here?
>
>Consider the intended use of the replacement ring.
>
>I suspect that some rings are designed for multi-ring applications and others
>aren't.
>
>The Salsa I have on one of my bikes looks tb designed for a
> single-ring setup.

_ I would say any ring that is 3/32" is "designed" for a multi-ring
setup. The Salsa rings don't have pins and ramps, but they do
work with 3/32" chain. The key difference is indexed vs
non-indexed. Indexed front derailler shifters need the extra
help from the pins and ramps, since you can do the slight
overshift that you would with a friction shifter.

>On my other rings there are various little sculpted areas that look to me like
>they're designed to facilitate the chain moving from one ring to another.
>

_ If he has indexed front derailler shifting, then the various
ramps and pins are most like neccessary for proper shifting. If it's just a
thumbshifter then the ramps aren't needed. If you poke around
you can get a complete set of RaceFace 24-34-46 chainrings for
110/74 cranks for about $80 bucks[1]. They say 9-speed but will
work just fine with any speed and have all the ramps and pins.

_ Of course, you can get a Sugino XD crank and appropriate
shimano square taper BB for pretty close to $80. If the
original bike has a cartridge BB, then if the chainrings
are really worn out, it might be time to replace the BB
as well.

_ Booker C. Bense

[1]- Try Cambria Bike Outfitters or Performance.

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[[email protected]]

Booker C. Bense <[email protected]> wrote:

> _ If he has indexed front derailler shifting, then the various ramps
> and pins are most like neccessary for proper shifting. If it's just
> a thumbshifter then the ramps aren't needed. If you poke around you
> can get a complete set of RaceFace 24-34-46 chainrings for 110/74
> cranks for about $80 bucks[1]. They say 9-speed but will work just
> fine with any speed and have all the ramps and pins.

I do have a friction thumb shifter for the front, but still prefer the
ramped chainrings that came with the bike. I've already replaced the
middle ring once with a cheap flat ring and was never happy with the
shifting after doing so.

> _ Of course, you can get a Sugino XD crank and appropriate
> shimano square taper BB for pretty close to $80. If the
> original bike has a cartridge BB, then if the chainrings
> are really worn out, it might be time to replace the BB
> as well.

I swapped out the original non-cartridge BB for (I think) a UN72 a
couple years ago.

> [1]- Try Cambria Bike Outfitters or Performance.

Performance has a surprisingly lousy selection of chainrings in their
catalog. I had not looked at Cambria before but they seem to be much
better.

Cambria has SUN Ringle alloy chainrings for very low prices: $45 total
for a 24-36-46 set. The web page claims these are ramped but I can't
tell that from the photo and can find little information about them
online.

-- Dave

 

[Booker C. Bense]

-----BEGIN PGP SIGNED MESSAGE-----

In article <U28Ke.8266$p%[email protected]>, <[email protected]> wrote:
>Booker C. Bense <[email protected]> wrote:
>
>
>Cambria has SUN Ringle alloy chainrings for very low prices: $45 total
>for a 24-36-46 set. The web page claims these are ramped but I can't
>tell that from the photo and can find little information about them
>online.
>

_ CBO has lot's of closeout parts from various MTB
manufacturers. Some good and some I have no idea.
I've had good luck ordering from them and if they
say they have ramps I would expect them to have
ramps. SUN Ringle makes very good wheel rims.

_ If you can find them the older Shimano XT/XTR 110/74 rings
are really nice and very durable. CBO had sets of 3
available in 26-36-48 a while back. I see they still
have the 48 and 26. You can sometimes find them on
ebay as well.

_ Booker C. Bense



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