X/C double chainring cranks?

[Brian Nystrom]

Is anyone out there making a X/C double rather than a triple? The only
doubles I've seen are heavy downhill triple cranks with a "bash guard"
instead of an outer ring.

I'm thinking of setting up a 24/36 front with an 11-34 9 speed cassette
to replace my current 22/32/42 front w/11-30 8 speed rear. For the
riding I do, the 42 tooth ring is nearly useless and is basically just
excess weight. With the new setup, all I lose is the topmost 99" gear,
which I never use anyway.

I realize that I can just buy new rings for my existing crank, but that
doesn't result in the optimum chainline. Thoughts?

 

[G.T.]

Brian Nystrom wrote:
> Is anyone out there making a X/C double rather than a triple? The only
> doubles I've seen are heavy downhill triple cranks with a "bash guard"
> instead of an outer ring.
>
> I'm thinking of setting up a 24/36 front with an 11-34 9 speed cassette
> to replace my current 22/32/42 front w/11-30 8 speed rear. For the
> riding I do, the 42 tooth ring is nearly useless and is basically just
> excess weight. With the new setup, all I lose is the topmost 99" gear,
> which I never use anyway.
>
> I realize that I can just buy new rings for my existing crank, but that
> doesn't result in the optimum chainline. Thoughts?

Ritchey used to make an XC double. Don't feel like looking right now.
But there are plenty of 'cross doubles out there, usually setup for
46/38, though, don't know what other chainrings would fit.

Greg

 

[[email protected]]

Brian Nystrom wrote:
> Is anyone out there making a X/C double rather than a triple? The only
> doubles I've seen are heavy downhill triple cranks with a "bash guard"
> instead of an outer ring.

Talk to the guys from FRM Components. They make a double, but IIRC it
is a 44-29. Aaahhh those silly cross-country racers ... getting rid of
the inner ring ...


> I'm thinking of setting up a 24/36 front with an 11-34 9 speed cassette
> to replace my current 22/32/42 front w/11-30 8 speed rear. For the
> riding I do, the 42 tooth ring is nearly useless and is basically just
> excess weight. With the new setup, all I lose is the topmost 99" gear,
> which I never use anyway.

Sounds like it is time to break out the mill. Most double are made to
get rid of the small ring not the large. I have yet to see a (hmmm
perhaps) 110/74 crank with a single outside position for cross-country
use (same goes for 94/58).

The FRM is a 94 mm bolt circle double, I believe. WIth a with a "hole
center to hole center measurement of 55.3 mm, the smallest ring you can
set up is 29 th on a 94 mm ring. That 24 th inner you are looking for
is the real limiting factor.

> I realize that I can just buy new rings for my existing crank, but that
> doesn't result in the optimum chainline. Thoughts?

Older "high end" 110/74 crank using the middle and inner positions with
a Phil Wood BB (or other adjustable chainline BB), but you are still
going to end up with a "vacant" outside position.

R

 

[[email protected]]

A few years back I demo Cannondales that way.

 

[Brian Nystrom]

You're right about FRM making X/C doubles. In fact, they make two, the
"CU2-M 110 Integral" which is 110/74 and the "CU2-M 2x9 Integral" which
is the 94 BCD, 29/44T crank you referred to.

I couldn't find any pics of the the CU2-M 110 Integral and they don't
list the ring sizes, but I know that 24T rings are available in 74 BCD
and 36T 110 BCD rings are possible, if not common.

Thanks for the info! Now I just have to find a source for FRM components...


[email protected] wrote:
> Brian Nystrom wrote:
>
>>Is anyone out there making a X/C double rather than a triple? The only
>>doubles I've seen are heavy downhill triple cranks with a "bash guard"
>>instead of an outer ring.
>
> Talk to the guys from FRM Components. They make a double, but IIRC it
> is a 44-29. Aaahhh those silly cross-country racers ... getting rid of
> the inner ring ...
>
>>I'm thinking of setting up a 24/36 front with an 11-34 9 speed cassette
>>to replace my current 22/32/42 front w/11-30 8 speed rear. For the
>>riding I do, the 42 tooth ring is nearly useless and is basically just
>>excess weight. With the new setup, all I lose is the topmost 99" gear,
>>which I never use anyway.
>
> Sounds like it is time to break out the mill. Most double are made to
> get rid of the small ring not the large. I have yet to see a (hmmm
> perhaps) 110/74 crank with a single outside position for cross-country
> use (same goes for 94/58).
>
> The FRM is a 94 mm bolt circle double, I believe. WIth a with a "hole
> center to hole center measurement of 55.3 mm, the smallest ring you can
> set up is 29 th on a 94 mm ring. That 24 th inner you are looking for
> is the real limiting factor.
>
>>I realize that I can just buy new rings for my existing crank, but that
>>doesn't result in the optimum chainline. Thoughts?
>
> Older "high end" 110/74 crank using the middle and inner positions with
> a Phil Wood BB (or other adjustable chainline BB), but you are still
> going to end up with a "vacant" outside position.
>
> R

 

[JD]

Brian Nystrom wrote:
> I realize that I can just buy new rings for my existing crank, but that
> doesn't result in the optimum chainline. Thoughts?


Shorty chainring bolts (singlespeed) so you don't need the bashguard
and an adjustable type bottom bracket to help with the chainline (ie.
Race Face Taperlock).

JD

 

[[email protected]]

Brian Nystrom wrote:
> You're right about FRM making X/C doubles. In fact, they make two, the
> "CU2-M 110 Integral" which is 110/74 and the "CU2-M 2x9 Integral" which
> is the 94 BCD, 29/44T crank you referred to.
>
> I couldn't find any pics of the the CU2-M 110 Integral and they don't
> list the ring sizes, but I know that 24T rings are available in 74 BCD
> and 36T 110 BCD rings are possible, if not common.
>
> Thanks for the info! Now I just have to find a source for FRM components...
>

<snip>

http://www.notubes.com/home.php

Although I don't believe they import that model ....

And not to be confused with:

http://www.yestubes.com/product.htm

R

 

[Carla A-G]

"Brian Nystrom" <[email protected]> wrote in message
news:MQIef.3774$Rb.2044@trndny01...
> Is anyone out there making a X/C double rather than a triple? The only
> doubles I've seen are heavy downhill triple cranks with a "bash guard"
> instead of an outer ring.
>
> I'm thinking of setting up a 24/36 front with an 11-34 9 speed cassette
> to replace my current 22/32/42 front w/11-30 8 speed rear. For the
> riding I do, the 42 tooth ring is nearly useless and is basically just
> excess weight. With the new setup, all I lose is the topmost 99" gear,
> which I never use anyway.
>
> I realize that I can just buy new rings for my existing crank, but that
> doesn't result in the optimum chainline. Thoughts?

I use an XC double on my geared full sus. bike. It just uses a granny ring,
middle ring and the bash guard. There is no necessity for the use of a big
ring where I ride. I have 9 speed in the rear, and yeah, it can be a pain in
the ass the set up the chainline correctly, but you also need to know which
gear combos are so bad that they leave your chainline extreme.

- CA-G

Can-Am Girls Kick Ass!

 

[Brian Nystrom]

[email protected] wrote:
> Brian Nystrom wrote:
>
>>You're right about FRM making X/C doubles. In fact, they make two, the
>>"CU2-M 110 Integral" which is 110/74 and the "CU2-M 2x9 Integral" which
>>is the 94 BCD, 29/44T crank you referred to.
>>
>>I couldn't find any pics of the the CU2-M 110 Integral and they don't
>>list the ring sizes, but I know that 24T rings are available in 74 BCD
>>and 36T 110 BCD rings are possible, if not common.
>>
>>Thanks for the info! Now I just have to find a source for FRM components...
>
> <snip>
>
> http://www.notubes.com/home.php
>
> Although I don't believe they import that model ....

Yeah, I found them a few hours after I posted. I imagine they could
order any FRM crank, if I decide to go that route.
>
> And not to be confused with:
>
> http://www.yestubes.com/product.htm

That site's a hoot!

I spent a lot of time watching Stan's videos. While I like the concept
and performance demonstrated in the videos, They're awfully pricey and
obviously a pain in the ass to install. I've thought about installing
them in my girlfriend's bike, as she tends to get a lot of thorn
punctures, but the the funky Mr. Tuffy liners do a pretty good job of
keeping her pedaling for a lot less money and hassle and she doesn't
notice the extra weight.