Cheapo Chainring Replacement



S

Stephen Harding

Guest
I've got an entry level Mongoose threshold from about
7 years ago that is starting to jump teeth when standup
pedaling from a stop. The chain wants to jump off to the
middle ring.

Although the chain and cogs have been replaced several
times, the rings have never been replaced. They're those
cheapo stamped steel rings on a crank that is attached by
rivets rather than bolts.

Can I drill out the rivets and replace the large ring
as one would a higher end crank/ring component? I'm certain
I can wander around the local hardware store to find some
sort of attachment nut/bolt combo to *make it fit*, but I
was wondering if I could just go to a bike shop and they
would have the correct bolts.

Although I've replaced chains and cogs many times on several
bikes, surprisingly, I've always had the shop do over my
chainrings, so I'm not up on the details of how they're
attached beyond various size bolt patterns.


SMH
 
B

Brian Huntley

Guest
Stephen Harding wrote:
> Can I drill out the rivets and replace the large ring
> as one would a higher end crank/ring component? I'm certain
> I can wander around the local hardware store to find some
> sort of attachment nut/bolt combo to *make it fit*, but I
> was wondering if I could just go to a bike shop and they
> would have the correct bolts.


Considering the cost of individual rings, you'd probaby be better off
getting a whole crankset. I'm not even sure the riveted ones use the
same "bolt" pattern as the standard ones.
 
B

Brian

Guest
well...IIRC.

The one-piece crank isn't actually physically attached to the chainrings.
The chainrings are held against the crank with a notched lockring and a peg
on the RH crankarm turns the rings.

I have a "like new" set of rings (triple) from an *mart bike...maybe I could
mail them to ya?

B.
 
R

Ron Hardin

Guest
With Huffy, I just order new ones from Huffy parts, and they are
super cheap. Try Mongoose.

--
Ron Hardin
[email protected]

On the internet, nobody knows you're a jerk.
 
T

Tom Keats

Guest
In article <btvng.9107$U%[email protected]>,
Stephen Harding <[email protected]> writes:
> I've got an entry level Mongoose threshold from about
> 7 years ago that is starting to jump teeth when standup
> pedaling from a stop. The chain wants to jump off to the
> middle ring.
>
> Although the chain and cogs have been replaced several
> times, the rings have never been replaced. They're those
> cheapo stamped steel rings on a crank that is attached by
> rivets rather than bolts.
>
> Can I drill out the rivets and replace the large ring
> as one would a higher end crank/ring component? I'm certain
> I can wander around the local hardware store to find some
> sort of attachment nut/bolt combo to *make it fit*, but I
> was wondering if I could just go to a bike shop and they
> would have the correct bolts.
>
> Although I've replaced chains and cogs many times on several
> bikes, surprisingly, I've always had the shop do over my
> chainrings, so I'm not up on the details of how they're
> attached beyond various size bolt patterns.


Rather than going through a bunch of jerry-riggery, I'd be
inclined to just obtain a Sugino XD-300 crankset, described at:
http://www.sheldonbrown.com/harris/cranks.html

providing the bottom bracket is compatible. 60 bux and totally
servicable as long as you can still get 5-bolt 110/74 bcd rings.

If it outlives the rest of the bike, you can always retain it
for use on another bike.


cheers,
Tom

--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca
 
R

R Brickston

Guest
On Sun, 25 Jun 2006 14:53:03 -0700, [email protected] (Tom Keats)
wrote:

>In article <btvng.9107$U%[email protected]>,
> Stephen Harding <[email protected]> writes:
>> I've got an entry level Mongoose threshold from about
>> 7 years ago that is starting to jump teeth when standup
>> pedaling from a stop. The chain wants to jump off to the
>> middle ring.
>>
>> Although the chain and cogs have been replaced several
>> times, the rings have never been replaced. They're those
>> cheapo stamped steel rings on a crank that is attached by
>> rivets rather than bolts.
>>
>> Can I drill out the rivets and replace the large ring
>> as one would a higher end crank/ring component? I'm certain
>> I can wander around the local hardware store to find some
>> sort of attachment nut/bolt combo to *make it fit*, but I
>> was wondering if I could just go to a bike shop and they
>> would have the correct bolts.
>>
>> Although I've replaced chains and cogs many times on several
>> bikes, surprisingly, I've always had the shop do over my
>> chainrings, so I'm not up on the details of how they're
>> attached beyond various size bolt patterns.

>
>Rather than going through a bunch of jerry-riggery, I'd be
>inclined to just obtain a Sugino XD-300 crankset, described at:
> http://www.sheldonbrown.com/harris/cranks.html
>
>providing the bottom bracket is compatible. 60 bux and totally
>servicable as long as you can still get 5-bolt 110/74 bcd rings.
>
>If it outlives the rest of the bike, you can always retain it
>for use on another bike.
>
>
>cheers,
> Tom



The Sugino Impel series is even cheaper and commensurate with the what
he bike deserves.
 
T

Tom Keats

Guest
In article <[email protected]>,
R Brickston <[email protected]> writes:

>>Rather than going through a bunch of jerry-riggery, I'd be
>>inclined to just obtain a Sugino XD-300 crankset, described at:
>> http://www.sheldonbrown.com/harris/cranks.html
>>
>>providing the bottom bracket is compatible. 60 bux and totally
>>servicable as long as you can still get 5-bolt 110/74 bcd rings.
>>
>>If it outlives the rest of the bike, you can always retain it
>>for use on another bike.


> The Sugino Impel series is even cheaper and commensurate with the what
> he bike deserves.


I expect you're right; I think that's a good suggestion.

As far as "deserving" goes, sometimes I wonder if any bike
worth riding at all deserves contemporary steel middle and
outer rings.

But if they're replaceable I suppose they're also likely
upgradeable, so perhaps that opens options up.

Or one could get something better in the first place,
and salvage it when eventually consigning the rest of
the bike to the deep (figuratively speaking, of course.
Although I wouldn't be surprised if old bike frames
make good artificial reef material.)


cheers,
Tom

--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca
 
C

Chris Z The Wheelman

Guest
If I were you I'd get a new crankset. MacGyvering things are great when
you have no other choice, but in this case you probably hae many. Low
cost cranksets are, as you stated, "cheap", costwise ane will help avoid
similar headaches in the future.

Talk with your LBS and see what they can set your bike up with.

- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"

My web Site:
http://geocities.com/czcorner

To E-mail me:
ChrisZCorner "at" webtv "dot" net
 
P

peter

Guest
Stephen Harding wrote:
> I've got an entry level Mongoose threshold from about
> 7 years ago that is starting to jump teeth when standup
> pedaling from a stop.


I had this same problem last year with my road bike that has Shimano
600 (now called Ultegra) components. It has around 70 k miles on it
and has been through a number of chain & cassette replacements but not
of the rings.

> Can I drill out the rivets and replace the large ring
> as one would a higher end crank/ring component?


Probably, but it may not be necessary to replace the ring. I just
turned mine over and it's been working fine for a few thousand miles
already. The teeth wear assymetrically so flipping the ring over puts
the pressure point on the opposite (i.e. relatively unworn) side of
each tooth. It should be good for a few more years of use before I
need to replace the ring.

Since your rings aren't meant to be replaced you might be on your own
for finding the right bolts and spacer washers to make it fit right -
but your LBS may be willing to let you scrounge through their old junk
parts for appropriate pieces.
 
S

Stephen Harding

Guest
R Brickston wrote:
> On Sun, 25 Jun 2006 14:53:03 -0700, [email protected] (Tom Keats)
> wrote:
>>
>>Rather than going through a bunch of jerry-riggery, I'd be
>>inclined to just obtain a Sugino XD-300 crankset, described at:
>> http://www.sheldonbrown.com/harris/cranks.html
>>
>>providing the bottom bracket is compatible. 60 bux and totally
>>servicable as long as you can still get 5-bolt 110/74 bcd rings.
>>
>>If it outlives the rest of the bike, you can always retain it
>>for use on another bike.

>
> The Sugino Impel series is even cheaper and commensurate with the what
> he bike deserves.


That seems a very likely possibility.

Also, RH's suggestion to just replace the old one from
Mongoose supply.

I'm not certain today's Mongoose would still have parts
from a Mongoose of 7 years ago, as they are now more of
a *Mart type supplier. I'll definitely check them out
though. I have no idea what type of BB the bike has.
It seems in excellent shape though.

I looked over the crank and rings more closely yesterday
and it looks like the rivets are under a lip of the
crank arm. Strange setup.

Doesn't seem a trip to the hardware supply is going to
easily remedy any rebuild I may have intended.


SMH
 
S

Stephen Harding

Guest
Ron Hardin wrote:
> With Huffy, I just order new ones from Huffy parts, and they are
> super cheap. Try Mongoose.


Indeed.

New parts may be the route I must take.


SMH
 
S

Stephen Harding

Guest
Brian wrote:
> well...IIRC.
>
> The one-piece crank isn't actually physically attached to the chainrings.
> The chainrings are held against the crank with a notched lockring and a peg
> on the RH crankarm turns the rings.
>
> I have a "like new" set of rings (triple) from an *mart bike...maybe I could
> mail them to ya?


The bike doesn't have a one piece crank. It's very
conventional looking with two crank arms and a BB.

I never actually looked too closely at those one piece
cranks to see how the heck the rings were attached.

I think I'll just do a replacement from somewhere.

Thanks for the offer though!


SMH
 
S

Stephen Harding

Guest
Tom Keats wrote:

> Or one could get something better in the first place,
> and salvage it when eventually consigning the rest of
> the bike to the deep (figuratively speaking, of course.
> Although I wouldn't be surprised if old bike frames
> make good artificial reef material.)


The Sugino Impel cranks I came across all say 7-8 speed
compatible.

My old Mongoose is 6 speed!

I don't quite understand how a crank would necessarily
care how many cogs it was pulling. I suppose you'd
want the crank roughly centered against the cog set,
but wouldn't that be more a function of the BB? Is it
just chain thickness? Six and 7 speed chains are the
same AFAIK. I've replaced several chains on this Mongoose
without problems (SRAM PC48).

Do I dare put a 7-8 speed compatible crank on a 6 cog
bike?

Dang bike compatibility and obsolescence issues! Worse
than cars!


SMH
 
R

R Brickston

Guest
On Mon, 26 Jun 2006 11:46:14 GMT, Stephen Harding
<[email protected]> wrote:

>Tom Keats wrote:
>
>> Or one could get something better in the first place,
>> and salvage it when eventually consigning the rest of
>> the bike to the deep (figuratively speaking, of course.
>> Although I wouldn't be surprised if old bike frames
>> make good artificial reef material.)

>
>The Sugino Impel cranks I came across all say 7-8 speed
>compatible.
>
>My old Mongoose is 6 speed!
>
>I don't quite understand how a crank would necessarily
>care how many cogs it was pulling. I suppose you'd
>want the crank roughly centered against the cog set,
>but wouldn't that be more a function of the BB? Is it
>just chain thickness? Six and 7 speed chains are the
>same AFAIK. I've replaced several chains on this Mongoose
>without problems (SRAM PC48).
>
>Do I dare put a 7-8 speed compatible crank on a 6 cog
>bike?
>
>Dang bike compatibility and obsolescence issues! Worse
>than cars!
>
>
>SMH


The issue is the thickness of the chain, for example, a seven speed
fits the seven cogs in the same space as the six and therefore
requires a thinner chain. I think your sram chain will work, but I'll
defer to the experts.
 
B

Booker C. Bense

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

In article <[email protected]>,
Stephen Harding <[email protected]> wrote:
>Tom Keats wrote:
>
>
>The Sugino Impel cranks I came across all say 7-8 speed
>compatible.
>
>My old Mongoose is 6 speed!
>


_ Doesn't matter. The inside dimension is 3/32 on 5-6-7-8-9-10
speeds. Only the outside dimension of the chain gets skinnier.

>I don't quite understand how a crank would necessarily
>care how many cogs it was pulling. I suppose you'd
>want the crank roughly centered against the cog set,
>but wouldn't that be more a function of the BB? Is it
>just chain thickness? Six and 7 speed chains are the
>same AFAIK. I've replaced several chains on this Mongoose
>without problems (SRAM PC48).
>
>Do I dare put a 7-8 speed compatible crank on a 6 cog
>bike?


_ It will work just fine. I'm pretty sure the outside thickness
on 5-6-7-8 is pretty much the same, it's only
when you get to 9 and 10sp that the chains get skinnier.

You can learn this and a lot more at

www.sheldonbrown.com

Very useful site.

_ Booekr C. Bense



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S

Stephen Harding

Guest
Booker C. Bense wrote:

> In article <[email protected]>,
> Stephen Harding <[email protected]> wrote:
>
>>Do I dare put a 7-8 speed compatible crank on a 6 cog
>>bike?

>
> _ It will work just fine. I'm pretty sure the outside thickness
> on 5-6-7-8 is pretty much the same, it's only
> when you get to 9 and 10sp that the chains get skinnier.


Thanks for the info.

> You can learn this and a lot more at
>
> www.sheldonbrown.com
>
> Very useful site.


Yes indeed.

Sheldon be da man!


SMH
 
B

Bill

Guest
Stephen Harding wrote:
> Booker C. Bense wrote:
>
>> In article <[email protected]>,
>> Stephen Harding <[email protected]> wrote:
> >
>>> Do I dare put a 7-8 speed compatible crank on a 6 cog
>>> bike?

>>
>> _ It will work just fine. I'm pretty sure the outside thickness
>> on 5-6-7-8 is pretty much the same, it's only when you get to 9 and
>> 10sp that the chains get skinnier.

>
> Thanks for the info.
>
>> You can learn this and a lot more at
>> www.sheldonbrown.com
>> Very useful site.

>
> Yes indeed.
>
> Sheldon be da man!
>
>
> SMH


I have a final comment. A few years back I went nuts on Ebay and bought
about a dozen cranks sets, all with the square bracket mount. The first
thing you learn is that you HAVE to buy a real puller from your LBS
because those cranks are not just going to fall off after you take out
the bolts. The next thing I learned is that there are at least 3
different offsets to the bracket / crank interface. Third, to add insult
to injury, some of the square holes are parallel to the crank arm and
some are 45 degrees off so you have to make sure of both sides. Lastly,
about half of the cranksets I got from sellers on Ebay were the riveted
3 ring assemblies that you can't change. I was going to sell these on
Ebay but I won't screw anybody that way. I have 3 cranks, right side
only, that I will GIVE to anyone who wants to pay shipping.

1. Shimano Acera 175mm 42/34/24, new.
2. Shimano FC-M330, 170mm 42/32/22, used but has 4 bolt Allen screw to
remove the cast rings.
3. ShimanoFC-MC16, 175mm 42/32/24, used.

Free, really. They are just in my way. All have essentially a zero
offset between the edge of the mounting hole and the small ring, so
maybe that is the standard setup.

Bill Baka

Real mail is [email protected]

I have to use someone else's newsgroup access or Comcast cuts me off in
the middle of the month. $45 a month for high speed and they are
chickenshit about it.
 
S

Stephen Harding

Guest
Bill wrote:
> Stephen Harding wrote:
>
>> Booker C. Bense wrote:
>>
>>> In article <[email protected]>,
>>> Stephen Harding <[email protected]> wrote:

>>
>> >

>>
>>>> Do I dare put a 7-8 speed compatible crank on a 6 cog
>>>> bike?
>>>
>>>
>>> _ It will work just fine. I'm pretty sure the outside thickness
>>> on 5-6-7-8 is pretty much the same, it's only when you get to 9 and
>>> 10sp that the chains get skinnier.

>>
>>
>> Thanks for the info.
>>
>>> You can learn this and a lot more at
>>> www.sheldonbrown.com
>>> Very useful site.

>>
>>
>> Yes indeed.
>>
>> Sheldon be da man!
>>
>>
>> SMH

>
>
> I have a final comment. A few years back I went nuts on Ebay and bought
> about a dozen cranks sets, all with the square bracket mount. The first
> thing you learn is that you HAVE to buy a real puller from your LBS
> because those cranks are not just going to fall off after you take out
> the bolts. The next thing I learned is that there are at least 3
> different offsets to the bracket / crank interface. Third, to add insult
> to injury, some of the square holes are parallel to the crank arm and
> some are 45 degrees off so you have to make sure of both sides. Lastly,
> about half of the cranksets I got from sellers on Ebay were the riveted
> 3 ring assemblies that you can't change. I was going to sell these on
> Ebay but I won't screw anybody that way. I have 3 cranks, right side
> only, that I will GIVE to anyone who wants to pay shipping.
>
> 1. Shimano Acera 175mm 42/34/24, new.
> 2. Shimano FC-M330, 170mm 42/32/22, used but has 4 bolt Allen screw to
> remove the cast rings.
> 3. ShimanoFC-MC16, 175mm 42/32/24, used.
>
> Free, really. They are just in my way. All have essentially a zero
> offset between the edge of the mounting hole and the small ring, so
> maybe that is the standard setup.


Well I ordered the Sugino Impel 150s along with a new chain
yesterday. Crankset was $26 which is just about right for
that Mongoose!

At least now I know where there's a guy with a box filled
with cranksets for the next replacement exercise.


SMH
 
B

Bill

Guest
Stephen Harding wrote:
> Bill wrote:
>>
>> I have a final comment. A few years back I went nuts on Ebay and
>> bought about a dozen cranks sets, all with the square bracket mount.
>> The first thing you learn is that you HAVE to buy a real puller from
>> your LBS because those cranks are not just going to fall off after you
>> take out the bolts. The next thing I learned is that there are at
>> least 3 different offsets to the bracket / crank interface. Third, to
>> add insult to injury, some of the square holes are parallel to the
>> crank arm and some are 45 degrees off so you have to make sure of both
>> sides. Lastly, about half of the cranksets I got from sellers on Ebay
>> were the riveted 3 ring assemblies that you can't change. I was going
>> to sell these on Ebay but I won't screw anybody that way. I have 3
>> cranks, right side only, that I will GIVE to anyone who wants to pay
>> shipping.
>>
>> 1. Shimano Acera 175mm 42/34/24, new.
>> 2. Shimano FC-M330, 170mm 42/32/22, used but has 4 bolt Allen screw to
>> remove the cast rings.
>> 3. ShimanoFC-MC16, 175mm 42/32/24, used.
>>
>> Free, really. They are just in my way. All have essentially a zero
>> offset between the edge of the mounting hole and the small ring, so
>> maybe that is the standard setup.

>
> Well I ordered the Sugino Impel 150s along with a new chain
> yesterday. Crankset was $26 which is just about right for
> that Mongoose!
>
> At least now I know where there's a guy with a box filled
> with cranksets for the next replacement exercise.
>
>
> SMH


Yup,
Anybody wants them can have them all for just the shipping cost and a
slight fee to cover my gas (bad word) costs. I am actually kind of
amazed that Shimano put out those cheap crank sets in the first place.
Bill Baka